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Thermodynamic modeling of NH_3-CO_2-SO_2-K_2SO_4-H_2O system for combined CO_2 and SO_2 capture using aqueous NH_3

International Nuclear Information System (INIS)

Qi, Guojie; Wang, Shujuan

2017-01-01

Highlights: • A new application of aqueous NH_3 based combined CO_2 and SO_2 process was proposed. • A thermodynamic model simulated the heat of absorption and the K_2SO_4 precipitation. • The CO_2 content can be regenerated in a stripper with lower heat of desorption. • The SO_2 content can be removed by K_2SO_4 precipitation from the lean NH_3 solvent. - Abstract: A new application of aqueous NH_3 based post-combustion CO_2 and SO_2 combined capture process was proposed to simultaneously capture CO_2 and SO_2, and remove sulfite by solid (K_2SO_4) precipitation method. The thermodynamic model of the NH_3-CO_2-SO_2-K_2SO_4-H_2O system for the combined CO_2 and SO_2 capture process was developed and validated in this work to analyze the heat of CO_2 and SO_2 absorption in the NH_3-CO_2-SO_2-H_2O system, and the K_2SO_4 precipitation characteristics in the NH_3-CO_2-SO_2-K_2SO_4-H_2O system. The average heat of CO_2 absorption in the NH_3-CO_2-H_2O system at 40 °C is around −73 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N. The average heat of SO_2 absorption in the NH_3-SO_2-H_2O system at 40 °C is around −120 kJ/mol SO_2 in 2.5 wt% NH_3 with SO_2 loading between 0 and 0.5 S/N. The average heat of CO_2 absorption in the NH_3-CO_2-SO_2-H_2O system at 40 °C is 77, 68, and 58 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N, when SO_2 loading is 0, 0.1, 0.2 S/N, respectively. The solubility of K_2SO_4 increases with temperature, CO_2 and SO_2 loadings, but decreases with NH_3 concentration in the CO_2 and SO_2 loaded aqueous NH_3. The thermodynamic evaluation indicates that the combined CO_2 and SO_2 capture process could employ the typical absorption/regeneration process to simultaneously capture CO_2 and SO_2 in an absorber, thermally desorb CO_2 in a stripper, and feasibly remove sulfite (oxidized to sulfate) content by precipitating K_2SO_4 from the lean NH_3 solvent after the lean/rich heat exchanger.
CO2, SO2, and H2S Degassing Related to the 2009 Redoubt Eruption, Alaska

Science.gov (United States)

Werner, C. A.; Kelly, P. J.; Evans, W.; Doukas, M. P.; McGimsey, R. G.; Neal, C. A.

2012-12-01

The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions with 35 airborne measurements of CO2, SO2, and H2S that span from October 2008 to August 2010. Increases in CO2 degassing were detected up to 5 months prior to the eruption and varied between 3630 and 9020 tonnes per day (t/d) in the 6 weeks prior to the eruption. Increased pre-eruptive CO2 degassing was accompanied by comparatively low S emission, resulting in molar C/S ratios that ranged between 30-60. However, the C/S ratio dropped to 2.4 coincident with the first phreatic explosion on March 15, 2009, and remained steady during the explosive (March 22 - April 4, 2009), effusive dome-building (April 5 - July 1, 2009), and waning phases (August 2009 onward) of the eruption. Observations of ice-melt rates, melt water discharge, and water chemistry in the months leading up to the eruption suggested that surface waters represented drainage from surficial, perched reservoirs of condensed magmatic steam and glacial meltwater. While the surface waters were capable of scrubbing many thousands of t/d of SO2, sampling of these fluids revealed that only a few hundred tonnes of SO2 was reacting to a dissolved component each day. This is also much less than the ~ 2100 t/d SO2 expected from degassing of magma in the upper crust (3-6.5 km), where petrologic analysis shows the final magma equilibration occurred. Thus, the high pre-eruptive C/S ratios observed could reflect bulk degassing of upper-crustal magma followed by nearly complete loss of SO2 in a magmatic-hydrothermal system. Alternatively, high C/S ratios could be attributed to degassing of low silica andesitic magma that intruded into the mid-crust in the 5 months prior to eruption; modeling suggests that mixing of this magma with pre-existing high silica andesite magma or mush would have caused a reduction of the C/S ratio to a value consistent with that measured during the eruption. Monitoring emissions regularly
Numerical modeling of injection and mineral trapping of CO2 withH2S and SO2 in a Sandstone Formation

Energy Technology Data Exchange (ETDEWEB)

Xu, Tianfu; Apps, John A.; Pruess, Karsten; Yamamoto, Hajime

2004-09-07

Carbon dioxide (CO{sub 2}) injection into deep geologic formations could decrease the atmospheric accumulation of this gas from anthropogenic sources. Furthermore, by co-injecting H{sub 2}S or SO{sub 2}, the products respectively of coal gasification or combustion, with captured CO{sub 2}, problems associated with surface disposal would be mitigated. We developed models that simulate the co-injection of H{sub 2}S or SO{sub 2} with CO{sub 2} into an arkose formation at a depth of about 2 km and 75 C. The hydrogeology and mineralogy of the injected formation are typical of those encountered in Gulf Coast aquifers of the United States. Six numerical simulations of a simplified 1-D radial region surrounding the injection well were performed. The injection of CO{sub 2} alone or co-injection with SO{sub 2} or H{sub 2}S results in a concentrically zoned distribution of secondary minerals surrounding a leached and acidified region adjacent to the injection well. Co-injection of SO{sub 2} with CO{sub 2} results in a larger and more strongly acidified zone, and alteration differs substantially from that caused by the co-injection of H{sub 2}S or injection of CO{sub 2} alone. Precipitation of carbonates occurs within a higher pH (pH > 5) peripheral zone. Significant quantities of CO{sub 2} are sequestered by ankerite, dawsonite, and lesser siderite. The CO{sub 2} mineral-trapping capacity of the formation can attain 40-50 kg/m{sup 3} medium for the selected arkose. In contrast, secondary sulfates precipitate at lower pH (pH < 5) within the acidified zone. Most of the injected SO{sub 2} is transformed and immobilized through alunite precipitation with lesser amounts of anhydrite and minor quantities of pyrite. The dissolved CO{sub 2} increases with time (enhanced solubility trapping). The mineral alteration induced by injection of CO{sub 2} with either SO{sub 2} or H{sub 2}S leads to corresponding changes in porosity. Significant increases in porosity occur in the acidified
Degassing of CO2, SO2, and H2S associated with the 2009 eruption of Redoubt Volcano, Alaska

Science.gov (United States)

Werner, Cynthia; Kelly, Peter J.; Doukas, Michael; Lopez, Taryn; Pfeffer, Melissa; McGimsey, Robert; Neal, Christina

2013-06-01

The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions. We report 35 airborne measurements of CO2, SO2, and H2S emission rates that span from October 2008 to August 2010. The magmatic system degassed primarily as a closed system although minor amounts of open system degassing were observed in the 6 months prior to eruption on March 15, 2009 and over 1 year following cessation of dome extrusion. Only 14% of the total CO2 was emitted prior to eruption even though high emissions rates (between 3630 and 9020 t/d) were observed in the final 6 weeks preceding the eruption. A minor amount of the total SO2 was observed prior to eruption (4%), which was consistent with the low emission rates at that time (up to 180 t/d). The amount of the gas emitted during the explosive and dome growth period (March 15-July 1, 2009) was 59 and 66% of the total CO2 and SO2, respectively. Maximum emission rates were 33,110 t/d CO2, 16,650 t/d SO2, and 1230 t/d H2S. Post-eruptive passive degassing was responsible for 27 and 30% of the total CO2 and SO2, respectively. SO2 made up on average 92% of the total sulfur degassing throughout the eruption. Magmas were vapor saturated with a C- and S-rich volatile phase, and regardless of composition, the magmas appear to be buffered by a volatile composition with a molar CO2/SO2 ratio of ~ 2.4. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9 to 2.1 wt.% CO2 and 0.27-0.56 wt.% S; whole-rock normalized values are slightly lower (0.8-1.7 wt.% CO2 and 0.22-0.47 wt.% S) and are similar to what was calculated for the 1989-90 eruption of Redoubt. Such contents argue that primary arc magmas are rich in CO2 and S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25 wt.% CO2 and 0.35 wt.% S. Assuming these values, up to 30% additional unerupted magma degassed in the
Degassing of CO2, SO2, and H2S associated with the 2009 eruption of Redoubt Volcano, Alaska

Science.gov (United States)

Werner, Cynthia A.; Kelly, Peter; Doukas, Michael P.; Lopez, Taryn; Pfeffer, Melissa; McGimsey, Robert G.; Neal, Christina

2013-01-01

The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions. We report 35 airborne measurements of CO2, SO2, and H2S emission rates that span from October 2008 to August 2010. The magmatic system degassed primarily as a closed system although minor amounts of open system degassing were observed in the 6 months prior to eruption on March 15, 2009 and over 1 year following cessation of dome extrusion. Only 14% of the total CO2 was emitted prior to eruption even though high emissions rates (between 3630 and 9020 t/d) were observed in the final 6 weeks preceding the eruption. A minor amount of the total SO2 was observed prior to eruption (4%), which was consistent with the low emission rates at that time (up to 180 t/d). The amount of the gas emitted during the explosive and dome growth period (March 15–July 1, 2009) was 59 and 66% of the total CO2and SO2, respectively. Maximum emission rates were 33,110 t/d CO2, 16,650 t/d SO2, and 1230 t/d H2S. Post-eruptive passive degassing was responsible for 27 and 30% of the total CO2 and SO2, respectively. SO2 made up on average 92% of the total sulfur degassing throughout the eruption. Magmas were vapor saturated with a C- and S-rich volatile phase, and regardless of composition, the magmas appear to be buffered by a volatile composition with a molar CO2/SO2 ratio of ~ 2.4. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9 to 2.1 wt.% CO2 and 0.27–0.56 wt.% S; whole-rock normalized values are slightly lower (0.8–1.7 wt.% CO2 and 0.22–0.47 wt.% S) and are similar to what was calculated for the 1989–90 eruption of Redoubt. Such contents argue that primary arc magmas are rich in CO2 and S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25 wt.% CO2 and 0.35 wt.% S. Assuming these values, up to 30% additional
Emission of SO2, CO2, and H2S from Augustine Volcano, 2002-2008: Chapter 26 in The 2006 eruption of Augustine Volcano, Alaska

Science.gov (United States)

McGee, Kenneth A.; Doukas, Michael P.; McGimsey, Robert G.; Neal, Christina A.; Wessels, Rick L.; Power, John A.; Coombs, Michelle L.; Freymueller, Jeffrey T.

2010-01-01

Airborne surveillance of gas emissions from Augustine Volcano and other Cook Inlet volcanoes began in 1990 to identify baseline emission levels during noneruptive conditions. Gas measurements at Augustine for SO2, CO2, and H2S showed essentially no evidence of anomalous degassing through spring 2005. Neither did a measurement on May 10, 2005, right after the onset of low level seismicity and inflation. The following measurement, on December 20, 2005, showed Augustine to be degassing about 600 metric tons per day (t/d) of SO2, and by January 4, 2006, only 7 days before the first explosive event, SO2 emissions had climbed to ten times that amount. Maximum emission rates measured during the subsequent eruption were: 8,930 t/d SO2 (February 24, 2006), 1,800 t/d CO2 (March 9, 2006), and 4.3 t/d H2S (January 19, 2006). In total, 45 measurements for SO2 were made from December 2005 through the end of 2008, with 19 each for CO2 and H2S during the same period. Molar CO2/SO2 ratios averaged about 1.6. In general, SO2 emissions appeared to increase during inflation of the volcanic edifice, whereas CO2 emissions were at their highest during the period of deflation associated with the vigorous effusive phase of the eruption in March. High SO2 was probably associated with degassing of shallow magma, whereas high CO2 likely reflected deep (>4 km) magma recharge of the sub-volcanic plumbing system, For the 2005–6 period, the volcano released a total of about 1.5×106 tons of CO2 to the atmosphere, a level similar to the annual output of a medium-sized natural-gas-fired powerplant. Augustine also emitted about 8×105 tons of SO2, similar to that produced by the 1976 and 1986 eruptions of the volcano.
Broadening of spectral lines of CO2, N2O , H2CO, HCN, and H2S by pressure of gases dominant in planetary atmospheres (H2, He and CO2)

Science.gov (United States)

Samuels, Shanelle; Gordon, Iouli; Tan, Yan

2018-01-01

HITRAN1,2 is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in planetary atmospheres. The goal of this project is to add to the potential of the HITRAN database towards the exploration of the planetary atmospheres by including parameters describing broadening of spectral lines by H2, CO2, and He. These spectroscopic data are very important for the study of the hydrogen and helium-rich atmospheres of gas giants as well as rocky planets with volcanic activities, including Venus and Mars, since their atmospheres are dominated by CO2. First step in this direction was accomplished by Wilzewski et al.3 where this was done for SO2, NH3, HF, HCl, OCS and C2H2. The molecules investigated in this work were CO2, N2O, H2CO, HCN and H2S. Line-broadening coefficients, line shifts and temperature-dependence exponents for transitions of these molecules perturbed by H2, CO2 and He have been assembled from available peer-reviewed experimental and theoretical sources. The data was evaluated and the database was populated with these data and their extrapolations/interpolations using semi-empirical models that were developed to this end.Acknowledgements: Financial support from NASA PDART grant NNX16AG51G and the Smithsonian Astrophysical Observatory Latino Initiative Program from the Latino Initiatives Pool, administered by the Smithsonian Latino Center is gratefully acknowledged.References: 1. HITRAN online http://hitran.org/2. Gordon, I.E., Rothman, L.S., Hill, C., Kochanov, R.V., Tan, Y., et al., 2017. The HITRAN2016 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transf. doi:10.1016/j.jqsrt.2017.06.0383. Wilzewski, J.S., Gordon, I.E., Kochanov, R. V., Hill, C., Rothman, L.S., 2016. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2. J. Quant. Spectrosc. Radiat
Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

Energy Technology Data Exchange (ETDEWEB)

Zhang, W.; Xu, T.; Li, Y.

2010-12-15

The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} mineral trapping, the presence of Fe-bearing siliciclastic and/or carbonate is more favorable to the H{sub 2}S mineral trapping.
Effects of CO, O2, NO, H2O, and irradiation temperature on the radiation-induced oxidation of SO2

International Nuclear Information System (INIS)

Tokunaga, Okihiro; Nishimura, Koichi; Suzuki, Nobutake; Washino, Masamitsu

1977-01-01

When a SO 2 -H 2 O-O 2 -N 2 gaseous mixture was irradiated by electron beams of 1.5 MeV, SO 2 was easily oxidized to H 2 SO 4 . Effects of CO, O 2 , NO, H 2 O, and irradiation temperature on the radiation-induced oxidation of SO 2 were studied by measuring the SO 2 concentration gas chromatographically. The G(-SO 2 ) increased greatly at the addition of a small amount of O 2 , and then decreased gradually with an increase in the O 2 concentration, i.e., the G(-SO 2 ) values were 0.9, 8.0, and 5.3 for the 0, 0.1, and 20% O 2 concentrations at 100 0 C, respectively (Fig.4). The G(-SO 2 ) was independent of the H 2 O concentration in the range of 0.84 to 8.4% (Fig.5). The G(-SO 2 ) decreased with a rise in the irradiation temperature (Fig.6) and an apparent activation energy of the oxidation reaction of SO 2 obtained was -4.2 kcal.mol -1 . The effects of CO, NO, and O 2 on the G(-SO 2 ) showed that SO 2 was mainly oxidized by OH and O and that the contribution of OH to the oxidation of SO 2 increased with an increase in the O 2 concentration (Table 1). The rate constants for the reactions of SO 2 with OH and O, obtained from competitive reactions of SO 2 with CO and O 2 , were 5.4 x 10 11 cm 3 .mol -1 .sec -1 and 5.0 x 10 11 cm 3 .mol -1 .sec -1 , respectively. (auth.)
A Method for the Simultaneous Cleansing of H2S and SO2

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Dzhamal R. Uzun

2016-01-01

Full Text Available A method for the simultaneous electrochemical purification of hydrogen sulfide and sulfur dioxide from sea water or industrial wastes is proposed. Fundamentally the method is based on the electrochemical affinity of the pair H2S and SO2. The reactions (oxidation of H2S and reduction of SO2 proceed on а proper catalyst in a flow reactor, without an external power by electrochemical means. The partial curves of oxidation of H2S and reduction of SO2 have been studied electrochemically on different catalysts. Following the additive principle the rate of the process has been found by intersection of the curves. The overall process rate has been studied in a flow type reactor. Similar values of the process rate have been found and these prove the electrochemical mechanism of the reactions. As a result the electrochemical method at adequate conditions is developed. The process is able to completely convert the initial reagents (concentrations CH2S, SO2=0, which is difficult given the chemical kinetics.
Evaluation of the impact of H2O, O2, and SO2 on postcombustion CO2 capture in metal-organic frameworks.

Science.gov (United States)

Yu, Jiamei; Ma, Yuguang; Balbuena, Perla B

2012-05-29

Molecular modeling methods are used to estimate the influence of impurity species: water, O(2), and SO(2) in flue gas mixtures present in postcombustion CO(2) capture using a metal organic framework, HKUST-1, as a model sorbent material. Coordinated and uncoordinated water effects on CO(2) capture are analyzed. Increase of CO(2) adsorption is observed for both cases, which can be attributed to the enhanced binding energy between CO(2) and HKUST-1 due to the introduction of a small amount of water. Density functional theory calculations indicate that the binding energy between CO(2) and HKUST-1 with coordinated water is ~1 kcal/mol higher than that without coordinated water. It is found that the improvement of CO(2)/N(2) selectivity induced by coordinated water may mainly be attributed to the increased CO(2) adsorption on the hydrated HKUST-1. On the other hand, the enhanced selectivity induced by uncoordinated water in the flue gas mixture can be explained on the basis of the competition of adsorption sites between water and CO(2) (N(2)). At low pressures, a significant CO(2)/N(2) selectivity increase is due to the increase of CO(2) adsorption and decrease of N(2) adsorption as a consequence of competition of adsorption sites between water and N(2). However, with more water molecules adsorbed at higher pressures, the competition between water and CO(2) leads to the decrease of CO(2) adsorption capacity. Therefore, high pressure operation should be avoided in HKUST-1 sorbents for CO(2) capture. In addition, the effects of O(2) and SO(2) on CO(2) capture in HKUST-1 are investigated: The CO(2)/N(2) selectivity does not change much even with relatively high concentrations of O(2) in the flue gas (up to 8%). A slightly lower CO(2)/N(2) selectivity of a CO(2)/N(2)/H(2)O/SO(2) mixture is observed compared with that in a CO(2)/N(2)/H(2)O mixture, especially at high pressures, due to the strong SO(2) binding with HKUST-1.
Degradation kinetics of monoethanolamine during CO2 and H2 S absorption from biogas

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Preecha Kasikamphaiboon

2015-02-01

Full Text Available The rate of degradation of MEA during CO2 and H2 S absorption in the biogas upgrading process was examined in four degradation systems, i.e., MEA-CO2 , MEA-CO2 -O2 , MEA-CO2 -H2 S and MEA-CO2 -O2 -H2 S. Degradation experiments were performed in a 800-ml stainless steel autoclave reactor, using MEA concentrations of 3 and 5 mol/L, CO2 loadings of 0.4 and 0.5 mol CO2 /mol MEA, O2 pressure of 200 kPa, and H2 S concentrations of 84 and 87 mg/L at temperatures of 120 and 140C. The results showed that, for the MEA-CO2 system, an increase in temperature or MEA concentration resulted in a higher rate of MEA degradation. In contrast, an increase in CO2 loading in the MEA-CO2 -O2 system led to a reduction of MEA degradation. The degradation rate of the system with O2 was with 8.3 times as high as that of the system without O2 . The presence of H2 S did not appear to affect the rate of degradation in the MEA-CO2 -H2 S system. However, for the system in which both H2 S and O2 were present, the MEA degradation was additionally induced by H2 S, thus, resulting in higher degradation rates than those of the system with O2 only. The extent of degradation under the same period of time increased in the order MEA-CO2 , MEA-CO2 -H2 S < MEA-CO2 -O2 < MEA-CO2 -O2 -H2 S.
Production of 34S-labeled gypsum (Ca34SO4.2H2O Produção de gesso (Ca34SO4.2H2O, marcado com 34S

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Alexssandra Luiza Rodrigues Molina Rossete

2006-08-01

Full Text Available Agricultural gypsum (CaSO4.2H2O stands out as an effective source of calcium and sulfur, and to control aluminum saturation in the soil. Labeled as 34S it can elucidate important aspects of the sulfur cycle. Ca34SO4.2H2O was obtained by chemical reaction between Ca(OH2 and H2(34SO4, performed under slow agitation. The acid was produced by ion exchange chromatography using the Dowex 50WX8 cation exchange resin and a Na2(34SO4 eluting solution. After precipitation, the precipitate was separated and dried in a ventilated oven at 60ºC. From 2.2 L H2SO4 0.2 mol L-1 and 33.6 g Ca(OH2, 73.7 ± 0.6 g Ca34SO4.2H2O were produced on average in the tests, representing a mean yield of 94.6 ± 0.8%, with 98% purity. The 34SO2 gas was obtained from Ca34SO4.2H2O in the presence of NaPO3 in a high vacuum line and was used for the isotopic determination of S in an ATLAS-MAT model CH-4 mass spectrometer.O gesso agrícola (CaSO4.2H2O destaca-se como fonte eficiente de cálcio e enxofre e na redução da saturação de alumínio no solo. O 34S como traçador isotópico pode elucidar aspectos importantes no ciclo do enxofre. Para tanto o Ca34SO4.2H2O foi obtido por reação química entre o Ca(OH2 e solução de H2(34SO4, realizada sob agitação lenta. O ácido foi produzido por cromatografia de troca iônica, utilizando resina catiônica Dowex 50WX8 e solução eluente de Na2(34SO4. Após a precipitação foi separado o precipitado e realizada a secagem em estufa ventilada à temperatura de 60ºC. Nos testes, a partir de 2,2 L de H2SO4 0,2 mol L-1 e 33,6 g de Ca(OH2, foram produzidos em média 73,7 ± 0,6 g de Ca34SO4.2H2O representando um rendimento médio de 94,6 ± 0,8%, com pureza de 98%. A partir do Ca34SO4.2H2O na presença de NaPO3, em linha de alto vácuo, obteve-se o gás 34SO2 utilizado para a determinação isotópica do S no espectrômetro de massas ATLAS-MAT modelo CH-4.
PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. II. H{sub 2}S AND SO{sub 2} PHOTOCHEMISTRY IN ANOXIC ATMOSPHERES

Energy Technology Data Exchange (ETDEWEB)

Hu Renyu; Seager, Sara; Bains, William, E-mail: hury@mit.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2013-05-20

Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H{sub 2}S and SO{sub 2}) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing. The most important finding is that both H{sub 2}S and SO{sub 2} are chemically short-lived in virtually all types of atmospheres on terrestrial exoplanets, based on models of H{sub 2}, N{sub 2}, and CO{sub 2} atmospheres. This implies that direct detection of surface sulfur emission is unlikely, as their surface emission rates need to be extremely high (>1000 times Earth's volcanic sulfur emission) for these gases to build up to a detectable level. We also find that sulfur compounds emitted from the surface lead to photochemical formation of elemental sulfur and sulfuric acid in the atmosphere, which would condense to form aerosols if saturated. For terrestrial exoplanets in the habitable zone of Sun-like stars or M stars, Earth-like sulfur emission rates result in optically thick haze composed of elemental sulfur in reducing H{sub 2}-dominated atmospheres for a wide range of particle diameters (0.1-1 {mu}m), which is assumed as a free parameter in our simulations. In oxidized atmospheres composed of N{sub 2} and CO{sub 2}, optically thick haze, composed of elemental sulfur aerosols (S{sub 8}) or sulfuric acid aerosols (H{sub 2}SO{sub 4}), will form if the surface sulfur emission is two orders of magnitude more than the volcanic sulfur emission of Earth. Although direct detection of H{sub 2}S and SO{sub 2} by their spectral features is unlikely, their emission might be inferred by observing aerosol-related features in reflected light with future generation
High resolution spectroscopy of the Martian atmosphere - Study of seasonal variations of CO, O3, H2O, and T on the north polar cap and a search for SO2, H2O2, and H2CO

Science.gov (United States)

Krasnopolsky, V. A.; Chakrabarti, S.; Larson, H.; Sandel, B. R.

1992-01-01

An overview is presented of an observational campaign which will measure (1) the seasonal variations of the CO mixing ratio on the Martian polar cap due to accumulation and depletion of CO during the condensation and evaporation of CO2, as well as (2) the early spring ozone and water vapor of the Martian north polar cap, and (3) the presence of H2CO, H2O2, and SO2. The lines of these compounds will be measured by a combined 4-m telescope and Fourier-transform spectrometer 27097.
Compound effect of CaCO3 and CaSO4·2H2O on the strength of steel slag: cement binding materials

International Nuclear Information System (INIS)

Qi, Liqian; Liu, Jiaxiang; Liu, Qian

2016-01-01

In this study, we replaced 30% of the cement with steel slag to prepare binding material; additionally, small amounts of CaCO 3 and CaSO 4 ·2H 2 O were added. This was done to study the compound effect of CaCO 3 and CaSO 4 ·2H 2 O on the strength of steel slag-cement binding materials. The hydration degree of the steel slag cementitious material was analyzed by XRD, TG and SEM. The results showed that the optimum proportions of CaCO 3 and CaSO 4 ·2H 2 O were 3% and 2%, respectively. Compared with the steel slag-cement binders without adding CaCO 3 and CaSO 4 ·2H 2 O, the compressive strength increased by 59.9% at 3 days and by 17.8% at 28 days. Acting as the nucleation matrix, CaCO 3 could accelerate the hydration of C 3 S. In addition, CaCO 3 was involved in the hydration reaction, generating a new hydration product, which could stably exist in a slurry. Meanwhile, CaSO 4 ·2H 2 O could increase the number of AFt. The compound effect of CaCO 3 and CaSO 4 ·2H 2 O enhanced the intensity of steel slag-cement binding materials and improved the whole hydration behavior. (author)
Responses of plants to sulfur containing air pollutants (H2S and SO2)

NARCIS (Netherlands)

Maas, Franciscus Marie

1987-01-01

Effects of air pollution by hydrogen sulfide (H2S) and sulfur dioxide (SO2) were already reported more than half a century ago. The wider range of pollution by SO2 is reflected in the number of publications concerning effects of SO2 on plants. The major part of the reported studies effects of SO2
Obtention of agricultural gypsum traced on 34 S (Ca34 SO4.2H2O), by chemical reaction between H234 SO4 and Ca(OH)2

International Nuclear Information System (INIS)

Rossete, Alessandra L.R.M.; Bendassolli, Jose A.; Ignoto, Raquel de Fatima; Batagello, Hugo Henrique

2002-01-01

The gypsum (CaSO 4 .2H 2 O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer 34 S can elucidate important aspects in the sulfur cycle. The Ca 34 SO 4 .2H 2 O was obtained by chemical reaction between Ca(OH) 2 and H 2 34 SO 4 solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na 2 34 SO 4 solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca 34 SO 4 .2H 2 O produced was determined by method gravimetric. This way, a system contends resin 426 cm 3 , considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H 2 34 SO 4 , theoretically could be produced 78.0 g of Ca 34 SO 4 .2H 2 O approximately. With results of the tests were verified that there was not total precipitation of the Ca 34 SO 4 .2H 2 O. Were produced 73.7± 0.6 g of Ca 34 SO 4 .2H 2 O representing average income 94.6±0.8 %. The purity of the produced CaSO 4 .2H 2 O was 98%. (author)
The Cs2SO4-Ce2(SO4)3-H2SO4-H2O system at 150 and 200 deg C

International Nuclear Information System (INIS)

Bondar', S.A.; Belokoskov, V.I.; Trofimov, G.V.

1982-01-01

Solubility in the system Cs 2 SO 4 -Ce 2 (SO 4 ) 3 -H 2 SO 4 -H 2 O using the isothermal method at 150 and 200 deg C at molar ratios Cs 2 SO 4 :Ce 2 (SO 4 ) 3 =1:5 and conditions of sulfate crystallization Cs 2 SO 4 xCe 2 (SO 4 ) 3 , Ce 2 (SO 4 ) 3 x0.5H 2 SO 4 xnH 2 O (n=2-3) and Ce 2 (SO 4 ) 3 x3H 2 SO 4 are determined. Double sulfate Cs 2 SO 4 xCe 2 (SO 4 ) 3 is studied using the methods of crystallooptical, thermal, X-ray phase analyses and IR spectroscopy
Reactivity of micas and cap-rock in wet supercritical CO_2 with SO_2 and O_2 at CO_2 storage conditions

International Nuclear Information System (INIS)

Pearce, Julie K.; Dawson, Grant K.W.; Law, Alison C.K.; Biddle, Dean; Golding, Suzanne D.

2016-01-01

Seal or cap-rock integrity is a safety issue during geological carbon dioxide capture and storage (CCS). Industrial impurities such as SO_2, O_2, and NOx, may be present in CO_2 streams from coal combustion sources. SO_2 and O_2 have been shown recently to influence rock reactivity when dissolved in formation water. Buoyant water-saturated supercritical CO_2 fluid may also come into contact with the base of cap-rock after CO_2 injection. Supercritical fluid-rock reactions have the potential to result in corrosion of reactive minerals in rock, with impurity gases additionally present there is the potential for enhanced reactivity but also favourable mineral precipitation. The first observation of mineral dissolution and precipitation on phyllosilicates and CO_2 storage cap-rock (siliciclastic reservoir) core during water-saturated supercritical CO_2 reactions with industrial impurities SO_2 and O_2 at simulated reservoir conditions is presented. Phyllosilicates (biotite, phlogopite and muscovite) were reacted in contact with a water-saturated supercritical CO_2 containing SO_2, or SO_2 and O_2, and were also immersed in the gas-saturated bulk water. Secondary precipitated sulfate minerals were formed on mineral surfaces concentrated at sheet edges. SO_2 dissolution and oxidation resulted in solution pH decreasing to 0.74 through sulfuric acid formation. Phyllosilicate dissolution released elements to solution with ∼50% Fe mobilized. Geochemical modelling was in good agreement with experimental water chemistry. New minerals nontronite (smectite), hematite, jarosite and goethite were saturated in models. A cap-rock core siltstone sample from the Surat Basin, Australia, was also reacted in water-saturated supercritical CO_2 containing SO_2 or in pure supercritical CO_2. In the presence of SO_2, siderite and ankerite were corroded, and Fe-chlorite altered by the leaching of mainly Fe and Al. Corrosion of micas in the cap-rock was however not observed as the pH was

CO2-, He- and H2-broadening coefficients of SO2 for ν1 band and ground state transitions for astrophysical applications

Science.gov (United States)

Ceselin, Giorgia; Tasinato, Nicola; Puzzarini, Cristina; Pietropolli Charmet, Andrea; Stoppa, Paolo; Giorgianni, Santi

2017-12-01

The discovery of the Universe and of the interstellar medium (ISM) is based on the knowledge of the molecules that are present in those places. Most of our understanding about the composition of the ISM and planetary atmospheres has been made possible almost entirely thanks to spectroscopic observations. Sulfur dioxide, SO2, is one of the about 200 molecules that have been detected in the ISM or circumstellar shells. In addition to its astrophysical relevance, SO2 has a proved role in the Earth's atmosphere. It origins from biomass burning and volcanic eruptions and directly enters in the sulfur cycle. In this work high-resolution tunable diode laser (TDL) infrared (IR) spectroscopy and mm-/sub-mm wave spectroscopy are exploited to retrieve the broadening parameters of sulfur dioxide perturbed by H2, He and CO2. IR measurements are carried out for ν1 band transitions around 9 μm by using He and CO2 as damping gases. As far as the vibrational ground state is concerned, about 20 rotational transitions are analyzed by means of the speed dependent Voigt profile to retrieve H2- and He-broadening coefficients. From the experimental results some conclusions about the quantum number dependence of the H2-, CO2- and He-collisional cross sections are drawn. Both IR and MW experiments highlight a very weak dependence of He broadening parameters on the Ka and J rotational quantum numbers. In a similar way, also SO2-H2 broadening coefficients show a negligible dependence on the rotational quantum numbers. Conversely, when CO2 is employed as perturbing species, the observed collisional cross sections tend to decrease with increasing Ka values and to increase against J, at least over the range of quantum numbers considered. The present results provide the first systematic determination of line-by-line SO2-CO2 broadening coefficients and they are of relevance to increase the potential use of spectroscopic databases for astronomical applications.
Biochars as Potential Adsorbers of CH4, CO2 and H2S

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Sumathi Sethupathi

2017-01-01

Full Text Available Methane gas, as one of the major biogases, is a potential source of renewable energy for power production. Biochar can be readily used to purify biogas contaminants such as H2S and CO2. This study assessed the adsorption of CH4, H2S, and CO2 onto four different types of biochars. The adsorption dynamics of biochars were investigated in a fixed-bed column, by determining the breakthrough curves and adsorption capacities of biochars. The physicochemical properties of biochars were considered to justify the adsorption performance. The results showed that CH4 was not adsorbed well by the subjected biochars whereas CO2 and H2S were successfully captured. The H2S and CO2 breakthrough capacity were related to both the surface adsorption and chemical reaction. The adsorption capacity was in the following order: perilla > soybean stover > Korean oak > Japanese oak biochars. The simultaneous adsorption also leads to a competition of sorption sites. Biochars are a promising material for the biogas purification industry.
Mineral storage of CO2/H2S gas mixture injection in basaltic rocks

Science.gov (United States)

Clark, D. E.; Gunnarsson, I.; Aradottir, E. S.; Oelkers, E. H.; Sigfússon, B.; Snæbjörnsdottír, S. Ó.; Matter, J. M.; Stute, M.; Júlíusson, B. M.; Gíslason, S. R.

2017-12-01

carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions. Science 352 (6291), 1312-1314. [3] Snæbjörnsdottír, S.O., et al. (2017). The chemistry and saturation states of subsurface fluids during the in-situ mineralisation of CO2 and H2S at the CarbFix site in SW-Iceland. International Journal of Greenhouse Gas Control 58, 87-102.
Imaging volcanic CO2 and SO2

Science.gov (United States)

Gabrieli, A.; Wright, R.; Lucey, P. G.; Porter, J. N.

2017-12-01

Detecting and quantifying volcanic carbon dioxide (CO2) and sulfur dioxide (SO2) emissions is of relevance to volcanologists. Changes in the amount and composition of gases that volcanoes emit are related to subsurface magma movements and the probability of eruptions. Volcanic gases and related acidic aerosols are also an important atmospheric pollution source that create environmental health hazards for people, animals, plants, and infrastructures. For these reasons, it is important to measure emissions from volcanic plumes during both day and night. We present image measurements of the volcanic plume at Kīlauea volcano, HI, and flux derivation, using a newly developed 8-14 um hyperspectral imaging spectrometer, the Thermal Hyperspectral Imager (THI). THI is capable of acquiring images of the scene it views from which spectra can be derived from each pixel. Each spectrum contains 50 wavelength samples between 8 and 14 um where CO2 and SO2 volcanic gases have diagnostic absorption/emission features respectively at 8.6 and 14 um. Plume radiance measurements were carried out both during the day and the night by using both the lava lake in the Halema'uma'u crater as a hot source and the sky as a cold background to detect respectively the spectral signatures of volcanic CO2 and SO2 gases. CO2 and SO2 path-concentrations were then obtained from the spectral radiance measurements using a new Partial Least Squares Regression (PLSR)-based inversion algorithm, which was developed as part of this project. Volcanic emission fluxes were determined by combining the path measurements with wind observations, derived directly from the images. Several hours long time-series of volcanic emission fluxes will be presented and the SO2 conversion rates into aerosols will be discussed. The new imaging and inversion technique, discussed here, are novel allowing for continuous CO2 and SO2 plume mapping during both day and night.
The effect of CO2, H2O and SO2 on the kinetics of NO reduction by CH4 over La2O3

International Nuclear Information System (INIS)

Toops, Todd J.; Walters, Arden B.; Vannice, M.A.

2002-01-01

The effect of CO 2 , H 2 O and SO 2 on the kinetics of NO reduction by CH 4 over unsupported La 2 O 3 has been examined between 773 and 973K in the presence of O 2 in the feed. La 2 O 3 can maintain a stable, high specific activity (mol/(sm 2 )) for NO reduction with high concentrations of CO 2 and H 2 O in the feed; however, either of these two products reversibly inhibits the activity by about one-half in the presence of excess O 2 . The catalyst is poisoned by SO 2 at these temperatures and an oxysulfate phase is formed, but partial regeneration can be achieved at 1023K. CO 2 in the feed causes the formation of lanthanum oxycarbonate, which reverts to La 2 O 3 when CO 2 is removed, but no bulk La oxyhydroxide is detected after quenching with H 2 O in the feed. The influence of CO 2 and H 2 O on kinetic behavior can be described by assuming they compete with reactants for adsorption on surface sites, including them in the site balance equation, and using the rate expression proposed previously for NO reduction by CH 4 in excess O 2 . With O 2 in the feed, integral conversions of CH 4 and O 2 frequently occurred due to the direct combustion of CH 4 by O 2 , although NO conversions remained differential; thus, an integral reactor model was chosen to analyze the data which utilized a recently determined rate equation for CH 4 combustion on La 2 O 3 in conjunction with a previously proposed model for NO reduction by CH 4 . The following rate expression described the rate of N 2 formation: N 2 T = ' NO P NO P CH 4 P O 2 0.5 / 1 + K NO P NO + K CH 4 P CH 4 + K O 2 0.5 P O 2 0.5 + K CO 2 P CO 2 + K H 2 O P H 2 O 2 . It gave a good fit to the experimental rate data for NO reduction, as well as providing enthalpies and entropies of adsorption obtained from the fitting parameters that demonstrated thermodynamic consistency and were similar to previous values. The heats of adsorption were altered somewhat when either CO 2 or H 2 O was added to the feed, and the following
Phase formation in the systems ZrO2-H2SO4-Na2SO4 (NaCl)-H2O

International Nuclear Information System (INIS)

Sozinova, Yu.P.; Motov, D.L.; Rys'kina, M.P.

1988-01-01

Formation of solid phases in the systems ZrO 2 - H 2 SO 4 - Na 2 SO 4 (NaCl) - H 2 O at 25 and 75 deg C is studied. Three basic Na 2 Zr(OH) 2 (SO 4 ) 2 x (0.2 - 0.4)H 2 O, NaZrOH(SO 4 ) 2 x H 2 O, NaZrO 0.5 (OH) 2 SO 4 x 2H 2 O and three normal sodium sulfatozirconates Na 2 Zr(SO 4 ) 3 x 3H 2 O, Na 4 Zr(SO 4 ) 4 x 3H 2 O, Na 6 Zr(SO 4 ) 5 x 4H 2 O have been isolated, their solubility and crystal optical properties are determined
Obtention of agricultural gypsum traced on {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), by chemical reaction between H{sub 2}{sup 34} SO{sub 4} and Ca(OH){sub 2}; Obtencao do gesso agricola marcado no {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), por reacao quimica entre o H{sub 2}{sup 34} SO{sub 4} e Ca(OH){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Rossete, Alessandra L.R.M.; Bendassolli, Jose A.; Ignoto, Raquel de Fatima; Batagello, Hugo Henrique [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis

2002-07-01

The gypsum (CaSO{sub 4}.2H{sub 2}O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer {sup 34} S can elucidate important aspects in the sulfur cycle. The Ca{sup 34} SO{sub 4}.2H{sub 2}O was obtained by chemical reaction between Ca(OH){sub 2} and H{sub 2}{sup 34} SO{sub 4} solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na{sub 2}{sup 34} SO{sub 4} solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca{sup 34} SO{sub 4}.2H{sub 2}O produced was determined by method gravimetric. This way, a system contends resin 426 cm{sup 3}, considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H{sub 2}{sup 34} SO{sub 4}, theoretically could be produced 78.0 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O approximately. With results of the tests were verified that there was not total precipitation of the Ca{sup 34}SO{sub 4}.2H{sub 2}O. Were produced 73.7{+-} 0.6 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O representing average income 94.6{+-}0.8 %. The purity of the produced CaSO{sub 4}.2H{sub 2}O was 98%. (author)
Study of ZrO2-H2SO4-(NH4)2SO4(NH4Cl)-H2O systems

International Nuclear Information System (INIS)

Motov, D.L.; Sozinova, Yu.P.; Rys'kina, M.P.

1988-01-01

Regions of formation, composition and solubility of ammonium sulfatozirconates (ASZ) in ZrO 2 -H 2 SO 4 -(NH 4 ) 2 SO 4 (NH 4 Cl)-H 2 O systems at 25 and 75 deg C are studied by the isothermal method. Five ASZ: (NH 4 ) 2 Zr(OH) 2 (SO 4 ) 2 , NH 4 ZrOH(SO 4 ) 2 xH 2 O, NH 4 ZrO 0.5 (OH) 2 SO 4 x1.5H 2 O, (NH 4 ) 2 Zr(SO 4 ) 3 x2H 2 O, (NH 4 ) 4 Zr(SO 4 ) 4 x4H 2 O are detected, their properties are investigated. Main sulfates are new compounds never described ealier
Online analysis of H2S and SO2 via advanced mid-infrared gas sensors.

Science.gov (United States)

Petruci, João Flavio da Silveira; Wilk, Andreas; Cardoso, Arnaldo Alves; Mizaikoff, Boris

2015-10-06

Volatile sulfur compounds (VSCs) are among the most prevalent emitted pollutants in urban and rural atmospheres. Mainly because of the versatility of sulfur regarding its oxidation state (2- to 6+), VSCs are present in a wide variety of redox-environments, concentration levels, and molar ratios. Among the VSCs, hydrogen sulfide and sulfur dioxide are considered most relevant and have simultaneously been detected within naturally and anthropogenically caused emission events (e.g., volcano emissions, food production and industries, coal pyrolysis, and various biological activities). Next to their presence as pollutants, changes within their molar ratio may also indicate natural anomalies. Prior to analysis, H2S- and SO2-containing samples are usually preconcentrated via solid sorbents and are then detected by gas chromatographic techniques. However, such analytical strategies may be of limited selectivity, and the dimensions and operation modalities of the involved instruments prevent routine field usage. In this contribution, we therefore describe an innovative portable mid-infrared chemical sensor for simultaneously determining and quantifying gaseous H2S and SO2 via coupling a substrate-integrated hollow waveguides (iHWG) serving as a highly miniaturized mid-infrared photon conduit and gas cell with a custom-made preconcentration tube and an in-line UV-converter device. Both species were collected onto a solid sorbent within the preconcentrator and then released by thermal desorption into the UV-device. Hydrogen sulfide is detected by UV-assisted quantitative conversion of the rather weak IR-absorber H2S into SO2, which provides a significantly more pronounced and distinctively detectable rovibrational signature. Modulation of the UV-device system (i.e., UV-lamp on/off) enables discriminating between SO2 generated from H2S conversion and abundant SO2 signals. After optimization of the operational parameters, calibrations in the range of 0.75-10 ppmv with a limit
Compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O on the strength of steel slag: cement binding materials

Energy Technology Data Exchange (ETDEWEB)

Qi, Liqian; Liu, Jiaxiang; Liu, Qian, E-mail: ljxpost@263.net [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, The State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing (China)

2016-03-15

In this study, we replaced 30% of the cement with steel slag to prepare binding material; additionally, small amounts of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were added. This was done to study the compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O on the strength of steel slag-cement binding materials. The hydration degree of the steel slag cementitious material was analyzed by XRD, TG and SEM. The results showed that the optimum proportions of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were 3% and 2%, respectively. Compared with the steel slag-cement binders without adding CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O, the compressive strength increased by 59.9% at 3 days and by 17.8% at 28 days. Acting as the nucleation matrix, CaCO{sub 3} could accelerate the hydration of C{sub 3}S. In addition, CaCO{sub 3} was involved in the hydration reaction, generating a new hydration product, which could stably exist in a slurry. Meanwhile, CaSO{sub 4}·2H{sub 2}O could increase the number of AFt. The compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O enhanced the intensity of steel slag-cement binding materials and improved the whole hydration behavior. (author)
Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants

Science.gov (United States)

Sun, Shichen; Awadallah, Osama; Cheng, Zhe

2018-02-01

It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.
Corrosion of Pipeline and Wellbore Steel by Liquid CO2 Containing Trace Amounts of Water and SO2

Science.gov (United States)

McGrail, P.; Schaef, H. T.; Owen, A. T.

2009-12-01

Carbon dioxide capture and storage in deep saline formations is currently considered the most attractive option to reduce greenhouse gas emissions with continued use of fossil fuels for energy production. Transporting captured CO2 and injection into suitable formations for storage will necessarily involve pipeline systems and wellbores constructed of carbon steels. Industry standards currently require nearly complete dehydration of liquid CO2 to reduce corrosion in the pipeline transport system. However, it may be possible to establish a corrosion threshold based on H2O content in the CO2 that could allow for minor amounts of H2O to remain in the liquid CO2 and thereby eliminate a costly dehydration step. Similarly, trace amounts of sulfur and nitrogen compounds common in flue gas streams are currently removed through expensive desulfurization and catalytic reduction processes. Provided these contaminants could be safely and permanently transported and stored in the geologic reservoir, retrofits of existing fossil-fuel plants could address comprehensive emissions reductions, including CO2 at perhaps nearly the same capital and operating cost. Because CO2-SO2 mixtures have never been commercially transported or injected, both experimental and theoretical work is needed to understand corrosion mechanisms of various steels in these gas mixtures containing varying amounts of water. Experiments were conducted with common tool steel (AISI-01) and pipeline steel (X65) immersed in liquid CO2 at room temperature containing ~1% SO2 and varying amounts of H2O (0 to 2500 ppmw). A threshold concentration of H2O in the liquid CO2-SO2 mixture was established based on the absence of visible surface corrosion. For example, experiments exposing steel to liquid CO2-SO2 containing ~300 ppmw H2O showed a delay in onset of visible corrosion products and minimal surface corrosion was visible after five days of testing. However increasing the water content to 760 ppmw produced extensive
Catalytic conversion of CO, NO and SO2 on supported sulfide catalysts. Part 2. Catalytic reduction of NO and SO2 by CO

International Nuclear Information System (INIS)

Zhuang, S.-X.; Yamazaki, M.; Omata, K.; Takahashi, Y.; Yamada, M.

2001-01-01

To investigate the possibility of simultaneous catalytic reduction of NO and SO 2 by CO, reactions of NO, NO-CO, and NO-SO 2 -CO were performed on γ-alumina-supported sulfides of transition metals including Co, Mo, CoMo and FeMo. NO was decomposed into N 2 O and N 2 accompanied with the formation of SO 2 ; this serious oxidation of lattice sulfur resulted in the deactivation of the catalysts. The addition of CO to the NO stream suppressed SO 2 formation and yielded COS instead. A stoichiometric conversion of NO and CO to N 2 and CO 2 was observed above 350C on the CoMo and the FeMo catalysts. Although the CO addition lengthened catalyst life, it was not enough to maintain activity. After the NO-CO reaction, an XPS analysis showed the growth of Mo 6+ and SO 4 2- peaks, especially for the sulfided FeMo/Al 2 O 3 ; the FeMo catalyst underwent strong oxidation in the NO-CO reaction. The NO and the NO-CO reactions proceeded non-catalytically, consuming catalyst lattice sulfur to yield SO 2 or COS. The addition of SO 2 in the NO-CO system enabled in situ regeneration of the catalysts; the catalysts oxidized through abstraction of lattice sulfur experienced anew reduction and sulfurization through the SO 2 -CO reaction at higher temperature. NO and SO 2 were completely and catalytically converted at 400C on the sulfided CoMo/Al 2 O 3 . By contrast, the sulfided FeMo/Al 2 O 3 was easily oxidized by NO and hardly re-sulfided under the test conditions. Oxidation states of the metals before and after the reactions were determined. Silica and titania-supported CoMo catalysts were also evaluated to study support effects
Cs2SO4-Pr2(SO4)3-H2O and NiSO4-Pr2(SO4)3-H2O systems at 75 deg C

International Nuclear Information System (INIS)

Onishchenko, M.K.; Skorikov, V.M.; Shevchuk, V.G.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1979-01-01

To investigate physico-chemical properties of equilibrium saturated solutions and to elucidate the chemical changes under way, the aqueous systems of cesium, nickel and praseodymium (3) sulfates are studied. The method of isothermal saturation of salts at 75 deg C is used. It has been found that in the system Cs 2 SO 4 -Pr 2 (SO 4 ) 3 -H 2 O in a wide concentration range the soluble binary salt Cs 2 SO 4 xPr 2 (SO 4 ) 3 csytallizes in a congruent way. For the system NiSO 4 -Pr 2 (SO 4 ) 3 -H 2 O a solubility curve of the eutonic type is obtained, there being no chemical interaction between the components. The solubility isotherms for the system are given
Re-Examining Embodied SO2 and CO2 Emissions in China

Directory of Open Access Journals (Sweden)

Rui Huang

2018-05-01

Full Text Available CO2 and SO2, while having different environmental impacts, are both linked to the burning of fossil fuels. Research on joint patterns of CO2 emissions and SO2 emissions may provide useful information for decision-makers to reduce these emissions effectively. This study analyzes both CO2 emissions and SO2 emissions embodied in interprovincial trade in 2007 and 2010 using multi-regional input–output analysis. Backward and forward linkage analysis shows that Production and Supply of Electric Power and Steam, Non-metal Mineral Products, and Metal Smelting and Pressing are key sectors for mitigating SO2 and CO2 emissions along the national supply chain. The total SO2 emissions and CO2 emissions of these sectors accounted for 81% and 76% of the total national SO2 emissions and CO2 emissions, respectively.
Synthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2 }2 {μ-η2 :η2 -B2 H4 }] and [{Cp*M(CO)2 }2 B2 H2 M(CO)4 ], M=Mo,W.

Science.gov (United States)

Mondal, Bijan; Bag, Ranjit; Ghorai, Sagar; Bakthavachalam, K; Jemmis, Eluvathingal D; Ghosh, Sundargopal

2018-04-26

The reaction of [(Cp*Mo) 2 (μ-Cl) 2 B 2 H 6 ] (1) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO) 2 } 2 {μ-η 2 :η 2 -B 2 H 4 }] (2). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum-alkyne complex [{CpMo(CO) 2 } 2 C 2 H 2 ]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO) 4 ] fragment, [{Cp*Mo(CO) 2 } 2 B 2 H 2 W(CO) 4 ] (3) was isolated upon treatment with [W(CO) 5 ⋅thf]. Compound 3 shows the intriguing presence of [B 2 H 2 ] with a short B-B length of 1.624(4) Å. We isolated the tungsten analogues of 3, [{Cp*W(CO) 2 } 2 B 2 H 2 W(CO) 4 ] (4) and [{Cp*W(CO) 2 } 2 B 2 H 2 Mo(CO) 4 ] (5), which provided direct proof of the existence of the tungsten analogue of 2. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
A DFT study of SO2 and H2S gas adsorption on Au-doped single-walled carbon nanotubes

International Nuclear Information System (INIS)

Zhang, Xiaoxing; Dai, Ziqiang; Chen, Qinchuan; Tang, Ju

2014-01-01

Intrinsic carbon nanotubes (CNTs) show limited toxic gas detection, thus, we need to develop a method to fabricate a novel CNT sensor that has good sensitivity. In this study, density functional theory (DFT) was applied to determine the adsorption behavior of Au-doped single-walled carbon nanotubes (Au-SWCNTs) to SO 2 and H 2 S. The calculated results show that Au-SWCNTs have a high sensitivity to SO 2 and H 2 S. When SO 2 adsorbs on the surface of the nanotube, a large number of electrons transfer from the Au-SWCNT to SO 2 , which results in a decrease in the frontier orbital energy gap and an increase in electrical conductivity. On the other hand, when H 2 S adsorbs on the surface of the nanotube, the electrons transfer from H 2 S to the Au-SWCNT, the frontier orbital energy gap increases, and the electrical conductivity decreases. Thus, SO 2 and H 2 S could be detected by Au-SWCNTs. This conclusion is useful for the development of CNT-based gas sensors and provides a theoretical basis to fabricate Au-SWCNT-based gas sensors. (papers)
Study of Paramagnetic Monohydrates MeSO4.1H2O (Me = Mn2+, Co2+, Fe2+, Ni2+, Cu2+

Directory of Open Access Journals (Sweden)

Jelšovská Kamila

2000-09-01

Full Text Available Nuclear magnetic resonance (NMR of protons of crystrallization water in isomorphous paramagnetic monohydrates MeSO4.1H2O with Me = Mn2+ , Co2+ , Fe2+ , Ni2+ , Cu2+ is studied in the present paper. Several physically important parameters characterizing the studied substances were derived from the NMR spectra. In this paper we analysed the dependences of the NMR second moment M2 on the magnitude of the external magnetic field induction Br and the temperature. The proton NMR spectra in paramagnetic hydrates have an asymmetric form caused by the anisotropy of the local magnetic field acting on resonating nuclei and their second moments, M2, depend linearly on the square of the external magnetic field Br. The parameters M20 (the part of the second moment M2 which corresponds to the nuclear dipole-dipole interactions and á which characterize nuclear dipole-dipole interactions of protons and paramagnetic ions, respectively, are derived from experimentally obtained dependences of M2 vs Br2. The measurements were performed at the room temperature. Calculations were realized using the approximation where two nearest neighbour ions Me2+ to each water molecule are considered. The temperature dependence of the second moment, which was realised in the temperature range 123-313 K, was more informative than the field one. Besides the individual dependences M2(T measured at fr1 and fr2 we analysed the temperature dependence of the difference ∆M2(T. Beside the second moment M20 the Curie-Weiss constant è and the magnetic moment µi of paramagnetic ions were determined from the temperature dependences. The parameters è and M20 were determined directly from the experimental data. Some knowledge on the crystalline structure for the studied substance was required for the calculation of the magnetic moment µi. By means of the classification of substances according to the Curie-Weiss parameter, the negative value of the temperature parameter è for all studied
Numerical simulation of H2S and CO2 generation during SAGD

Energy Technology Data Exchange (ETDEWEB)

Perez-Perez, A.; Kamp, A.M. [CHLOE, UFR Science, University of Pau, 64000, Pau (France); Soleimani, H. (IFP School (France)); Darche, G. (TOTAL, Pau (France))

2011-07-01

In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but the production of undesirable gases occurs during this process. These gases are mainly hydrogen sulphide and carbon dioxide, generated through chemical reactions triggered by high temperatures and water presence. The aim of this paper is to create a kinetic model for H2S and CO2 generation and to insert it in a reservoir simulation. This model was then tested under steam injection conditions in an SAGD system using experimental data available in the literature. The model developed successfully reproduced gas plateaus at different temperatures and results from the test showed that the model's predicted gas emissions are of the same order of magnitude as the field results. This paper presented a new kinetic model which can predict H2S and CO2 emissions of a SAGD system and could thus be used in the design of treatment facilities.
Impact of SO2 and NO on CO Oxidation under Post-Flame Conditions

DEFF Research Database (Denmark)

Glarborg, Peter; Kubel, Dorte; Dam-Johansen, Kim

1996-01-01

An experimental and theoretical study of the effect of SO2 on moist CO oxidation with and without NO present was carried out under plug-flow conditions. The H/S/O thermochemistry and reaction subset was revised and a chemical kinetic model established that provide a good description of the effect...... of SO2 and NO on CO oxidation as well as the SO2/SO3 ratio in the products....

[H2en]2{La2M(SO4)6(H2O)2} (M=Co, Ni): First organically templated 3d-4f mixed metal sulfates

International Nuclear Information System (INIS)

Yuan Yanping; Wang Ruiyao; Kong Deyuan; Mao Jianggao; Clearfield, Abraham

2005-01-01

The first organically templated 3d-4f mixed metal sulfates, [H 2 en] 2 {La 2 M(SO 4 ) 6 (H 2 O) 2 } (M=Co 1, Ni 2) have been synthesized and structurally determined from non-merohedrally twinned crystals. The two compounds are isostructural and their structures feature a three-dimensional anionic network formed by the lanthanum(III) and nickel(II) ions bridged by sulfate anions. The La(III) ions in both compounds are 10-coordinated by four sulfate anions in bidentate chelating fashion, and two sulfate anions in a unidentate fashion. The transition metal(II) ion is octahedrally coordinated by six oxygens from four sulfate anions and two aqua ligands. The doubly protonated enthylenediamine cations are located at the tunnels formed by 8-membered rings (four La and four sulfate anions)
Metal organic framework absorbent platforms for removal of co2 and h2s from natural gas

KAUST Repository

Belmabkhout, Youssef; Eddaoudi, Mohamed; Adil, Karim; Cadiau, Amandine; Bhatt, Prashant M.

2016-01-01

Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Methods include capturing one or more of H2S, H2O, and CO2 from fluid compositions, such as natural gas.
Metal organic framework absorbent platforms for removal of co2 and h2s from natural gas

KAUST Repository

Belmabkhout, Youssef

2016-10-13

Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Methods include capturing one or more of H2S, H2O, and CO2 from fluid compositions, such as natural gas.
Dissociative phototionization cross sections of H2, SO2 and H2O

International Nuclear Information System (INIS)

Chung, Y.

1989-01-01

The partial photoionization cross sections of H 2 , SO 2 , and H 2 O were calculated from the measured photoionization branching ratios and the known total photoionization cross sections. The branching ratios were measured with a time-of-flight mass spectrometer and synchrotron radiation. The branching ratios Of H 2 , SO 2 , and H 2 O were measured for 100 ∼ 410, 150 ∼ 380 and 120 ∼ 720 angstrom. The author also measured the photoionization yield Of SO 2 from 520 to 665 angstrom using a double ion chamber and a glow discharge light source. The principle of a time-of-flight mass spectrometer is explained. New calculations were made to see how the design of the mass spectrometer, applied voltage, and kinetic energy of the ions affect the overall performance of the mass spectrometer. Several useful techniques that we used at the synchrotron for wavelength calibration and higher order suppression are also discussed
A breakthrough in flue gas cleanup, CO2 mitigation and H2S removal

Energy Technology Data Exchange (ETDEWEB)

Koch, Wolf; Wasas, James; Stenger, Raymond; Howell, Evan

2010-09-15

SWAPSOL Corp. is developing commercial processes around a newly discovered reaction that reduces H2S below detectable levels while reacting with CO2 to form water, sulfur and carsuls, a carbon-sulfur polymer. The Stenger-Wasas Process (SWAP) stands to simplify sulfur removal technology as it consumes CO2 in an exothermic reaction. The SWAP has applications in landfill, sour, flue and Claus tail gas cleanup and may replace Claus technology. Destruction of waste hydrocarbons provides a source of H2S. The primary reactions and variants have been independently verified and the chemical kinetics determined by a third party laboratory.
Investigation of H2S and CO2 Removal from Gas Streams Using Hollow Fiber Membrane Gas–liquid Contactors

Directory of Open Access Journals (Sweden)

S. M. Mirfendereski

2017-07-01

Full Text Available Chemical absorption of H2S and CO2 from CH4 was carried out in a polypropylene porous asymmetric hollow fiber membrane contactor (HFMC. A 0.5 mol L–1 aqueous solution of methyldiethanolamine (MDEA was used as chemical absorbent solution. Effects of gas flow rate, liquid flow rate, H2S concentration and CO2 concentration on the H2S outlet concentrations and CO2 removal percentage were investigated. The results showed that the removal of H2S with aqueous solution of MDEA was very high and indicated almost total removal of H2S. Experimental results also indicated that the membrane contactor was very efficient in the removal of trace H2S at high gas/ liquid flow ratio. The removal of H2S was almost complete with a recovery of more than 96 %. Using feed gas mixtures containing 5000 ppm H2S with CO2 concentrations in the range of 4–12 vol.%, the outlet H2S concentration of less than 1.0 ppm was attained with less than 4.0 vol.% of CO2 permeated and absorbed.
REMOVAL OF H(sub 2)S AND SO(sub 2) BY CaCO(sub 3)-BASED SORBENTS AT HIGH PRESSURES; SEMIANNUAL

International Nuclear Information System (INIS)

Prof. Stratis V. Sotirchos

1999-01-01

The effects of various operating and process parameters on the direct sulfidation of limestones, that is, their reaction with H(sub 2)S in the presence of CO(sub 2) at concentrations large enough to prevent the decomposition of CaCO(sub 3) to CaO. Two calcitic solids of high calcium carbonate content (over 97%) were employed in the experiments, and the reaction was studied in a thermogravimetric analysis system that can operate at pressures above atmospheric. Pressures in the 1-4 atm range were employed. The results showed that the pressure influenced the behavior of the process mainly through its effects on the concentration of H(sub 2)S, and the rate of the reaction was found to be of first order with respect to this variable. The behavior of the process could be described satisfactorily by a shrinking core model with a product layer diffusivity that depended only on the temperature and did not vary with the distance from the external surface of the particles. The results on the effects of particle size, temperature, limestone sample, and concentration of H(sub 2)S were in agreement with those in a past investigation of the direct sulfidation reaction of limestones in our laboratory at atmospheric pressure. For the next six-month period, we plan to conduct experiments on the effects of the effects of carbonation reaction on the sulfation of calcined limestones. As explained in the introductory section of this report, this situation may occur as calcined particles move into areas of the combustor where the concentration of CO(sub 2) is above the equilibrium value for the calcination reaction at the prevailing temperature
Coordination polymers of scandium sulfate. Crystal structures of (H2Bipy)[Sc(H2O)(SO4)2]2·2H2O and (H2Bipy)[HSO4]2

International Nuclear Information System (INIS)

Petrosyants, S.P.; Ilyukhin, A.B.

2005-01-01

Compounds with general formula Cat x [Sc(H 2 O) z (SO 4 ) y ]·nH 2 O (Cat=NH 4 , H 2 Bipy (Bipy - 4,4'-bipyridine), HEdp (Edp - ethylene dipyridine)) identified on element analysis data and IR spectra are synthesized. X-ray diffraction analysis of (H 2 Bipy)[Sc(H 2 O)(SO 4 ) 2 ] 2 ·2H 2 O shows that in structure of the compound chains of ScO 6 octahedron and SO 4 tetrahedrons are joined in bands by tridentate coordination of sulfate ions. Bands form skeleton in endless emptiness of which there are H 2 Bipy 2+ cations [ru
Carbonate mineral solubility at low temperatures in the Na-K-Mg-Ca-H-Cl-SO 4-OH-HCO 3-CO 3-CO 2-H 2O system

Science.gov (United States)

Marion, Giles M.

2001-06-01

Carbonate minerals have played an important role in the geochemical evolution of Earth, and may have also played an important role in the geochemical evolution of Mars and Europa. Several models have been published in recent years that describe chloride and sulfate mineral solubilities in concentrated brines using the Pitzer equations. Few of these models are parameterized for subzero temperatures, and those that are do not include carbonate chemistry. The objectives of this work are to estimate Pitzer-equation bicarbonate-carbonate parameters and carbonate mineral solubility products and to incorporate them into the FREZCHEM model to predict carbonate mineral solubilities in the Na-K-Mg-Ca-H-Cl-SO 4-OH-HCO 3-CO 3-CO 2-H 2O system at low temperatures (≤25°C) with a special focus on subzero temperatures. Most of the Pitzer-equation parameters and equilibrium constants are taken from the literature and extrapolated into the subzero temperature range. Solubility products for 14 sodium, potassium, magnesium, and calcium bicarbonate and carbonate minerals are included in the model. Most of the experimental data are at temperatures ≥ -8°C; only for the NaHCO 3-NaCl-H 2O and Na 2CO 3-NaCl-H 2O systems are there bicarbonate and carbonate data to temperatures as low as -21.6°C. In general, the fit of the model to the experimental data is good. For example, calculated eutectic temperatures and compositions for NaHCO 3, Na 2CO 3, and their mixtures with NaCl and Na 2SO 4 salts are in good agreement with experimental data to temperatures as low as -21.6°C. Application of the model to eight saline, alkaline carbonate waters give predicted pHs ranging from 9.2 to 10.2, in comparison with measured pHs that range from 8.7 to 10.2. The model suggests that the CaCO 3 mineral that precipitates during seawater freezing is probably calcite and not ikaite. The model demonstrates that a proposed salt assemblage for the icy surface of Europa consisting of highly hydrated MgSO 4
Enclathration of CO2 as a co-guest of structure H hydrates and its implications for CO2 capture and sequestration

International Nuclear Information System (INIS)

Lee, Yohan; Lee, Dongyoung; Lee, Jong-Won; Seo, Yongwon

2016-01-01

Highlights: • We examine sH hydrates with CO 2 + N 2 + neohexane for CO 2 capture and sequestration. • The structural transition occurs in the CO 2 (40%) + N 2 (60%) + neohexane system. • CO 2 molecules are enclathrated into sH hydrates in the N 2 -rich systems. • CO 2 selectivity in sH hydrates is slightly lower than that in sI hydrates. • ΔH d values provide information on the structural transition of sH to sI hydrates. - Abstract: In this study, the thermodynamic behaviors, cage-specific guest distributions, structural transition, and dissociation enthalpies of sH hydrates with CO 2 + N 2 gas mixtures were investigated for their potential applications to hydrate-based CO 2 capture and sequestration. The stability conditions of the CO 2 + N 2 + water systems and the CO 2 + N 2 + neohexane (2,2-dimethylbutane, NH) + water systems indicated that the gas mixtures in the range of flue gas compositions could form sH hydrates, thereby mitigating the pressure and temperature required for gas hydrate formation. Structure identification using powder X-ray diffraction (PXRD) revealed the coexistence of sI and sH hydrates in the CO 2 (40%) + N 2 (60%) + NH system and the hydrate structure transformed from sH into sI as the CO 2 concentration increased. In addition, the Raman analysis clearly demonstrated that CO 2 molecules were enclathrated into the cages of sH hydrates in the N 2 -rich systems. It was found from direct CO 2 composition measurements that CO 2 selectivity in the sH hydrate phase was slightly lower than that in the corresponding sI hydrate phase. Dissociation enthalpy (ΔH d ) measurements using a high-pressure micro-differential scanning calorimeter (HP μ-DSC) indicated that the ΔH d values could also provide valuable information on the structural transition of sH to sI hydrates with respect to the CO 2 concentration in the feed gas. This study provides a better understanding of the thermodynamic and physicochemical background for CO 2
Removal of SO42− from Li2CO3 by Recrystallization in Na2CO3 Solution

Directory of Open Access Journals (Sweden)

Wei Cai

2018-01-01

Full Text Available Li2CO3 with high purity is an important raw material for the fabrication of lithium rechargeable batteries. This paper reports a facile recrystallization way to produce Li2CO3 with high purity from commercial Li2CO3 containing 0.8 wt % of SO42− by the treatment of the commercial Li2CO3 in Na2CO3 solution. The increase of temperature from 30 °C to 90 °C favored the recrystallization of Li2CO3 in Na2CO3 solution and promoted the removal of SO42− adsorbed or doped on/in the commercial Li2CO3. The content of SO42− in Li2CO3 decreased to 0.08 wt % after the treatment of the commercial Li2CO3 in 1.0 mol·L−1 Na2CO3 solution at 90 °C for 10.0 h.
Isoreticular rare earth fcu-MOFs for the selective removal of H 2 S from CO 2 containing gases

KAUST Repository

Bhatt, Prashant

2017-05-04

In this work, we present the implementation of reticular chemistry and the molecular building block approach to unveil the appropriateness of Rare Earth (RE) based Metal-Organic Frameworks (MOFs) with fcu topology for H2S removal applications. Markedly, RE-fcu-MOFs, having different pore apertures sizes in the range of 4.7-6.0 Å and different functionalities, showed excellent properties for the removal of H2S from CO2 and CH4 containing gases such as natural gas, biogas and landfill gas. A series of cyclic mixed gas breakthrough experiments were carried out on three isoreticular fcu-MOFs, containing linkers of different lengths (between 8.4 and 5 Å), by using simulated natural gas mixture containing CO2/H2S/CH4 (5%/5%/90%) under different adsorption and regeneration conditions. The fcu-MOF platform has good H2S removal capacity with a high H2S/CO2 selectivity, outperforming benchmark materials like activated carbon and Zeolites in many aspects. The comparison of H2S removal performance with the related structures of the RE-fcu-MOFs provides insightful information to shed light on the relationship between the structural features of the MOF and its associated H2S separation properties. The excellent H2S/CO2 and H2S/CH4 selectivity of these materials offer great prospective for the production of pure H2S, with acceptable levels of CO2for Claus process to produce elemental sulfur.
Micropore Formation of [Zn2(Oxac) (Taz)2]·(H2O)2.5 via CO2 Adsorption.

Science.gov (United States)

Zubir, Moondra; Hamasaki, Atom; Iiyama, Taku; Ohta, Akira; Ohki, Hiroshi; Ozeki, Sumio

2017-01-24

As-synthesized [Zn 2 (Oxac) (Taz) 2 ]·(H 2 O) 2.5 , referred to as ZOTW 2.5 , was prepared from aqueous methanol solutions of Zn 5 (CO 3 ) 2 (OH) 6 and two kinds of ligands of 1,2,4-triazole (Taz) and oxalic acid (Oxac) at 453 K for 12 h. The crystal structure was determined by the Rietveld method. As-synthesized ZOTW 2.5 was pretreated at 383 K and 1 mPa for t pt h, ZOTW x (t pt h). ZOTW x (≥3h) showed a type I adsorption isotherm for N 2 at 77 K having a saturation amount (V s ) of 180 mg/g, but that pretreated shortly showed only 1/10 in V s . CO 2 was adsorbed at 303 K in sigmoid on nonporous ZOTW x (≤2h) and in Langmuir-type on ZOTW x (≥3h) to reach the adsorption amount of 120 mg/g at 700 Torr. N 2 adsorption on ZOTW x (≤2h)deCO 2 , degassed after CO 2 adsorption on ZOTW x (≤2h), was promoted 5-fold from 180 mg/g on ZOTW x (t pt h) and ZOTW x (≥3h)deCO 2 up to ca. 1000 mg/g. The interaction of CO 2 and H 2 O molecules in micropores may lead to a new route for micropore formation.
VUV photoionization cross sections of HO2, H2O2, and H2CO.

Science.gov (United States)

Dodson, Leah G; Shen, Linhan; Savee, John D; Eddingsaas, Nathan C; Welz, Oliver; Taatjes, Craig A; Osborn, David L; Sander, Stanley P; Okumura, Mitchio

2015-02-26

The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.
Methods for the analysis of SO/sub 2/, SO/sub 3/ and H/sub 2/S in flue gas and the calculation of the acid dew point

Energy Technology Data Exchange (ETDEWEB)

Albertyn, C.H.

1986-02-01

Methods are given for the analysis of SO/sub 2/, SO/sub 3/, and H/sub 2/S in flue gas. Two methods are described for the determination of SO/sub 2/. The method to be used depends on whether or not H/sub 2/S is present in the gas stream. An equation for the calculation of acid dew point is given as well.
Integrated assessment of CO2 and SO2 policies in North East Asia

International Nuclear Information System (INIS)

Chae, Yeora; Hope, Chris

2003-01-01

This study quantifies the costs and impacts of six scenarios for carbon dioxide (CO 2 ) and sulphur dioxide (SO 2 ) emissions in North East Asia (NEA) within an integrated probabilistic analysis. The inclusion of the cooling effect of sulphates means that CO 2 control in China would be likely to increase the regional temperature in NEA in the short-term. This is because CO 2 control measures would also automatically control SO 2 emissions, and so reduce their cooling effect. The scenario that involves no control for CO 2 and SO 2 emissions has the lowest mean total cumulative net present cost (NPC) as compared to scenarios with various SO 2 controls or with CO 2 reduced to 5% below year 1990 levels (in China and Japan), or any combination of SO 2 + CO 2 controls at these levels. The mean value of the total cumulative NPC of climate change damage, acid rain damage, CO 2 and SO 2 control cost in China for no CO 2 or SO 2 control is about US$ 0.1 trillion, compared, for instance, to about US$ 1.1 trillion for CO 2 emission stabilisation at 1990 levels and no SO 2 control. SO 2 control also brings more disadvantages than advantages in China and Japan. The higher mean climate change impacts and control costs outweigh the benefit of lower acid rain damage. However, strict SO 2 control brings more benefits than costs in South Korea where there is a large urban population and the sensitivity to acid rain is high. However, the impacts of emissions and valuation of these effects are very uncertain. Uncertainty analysis shows that the key determinants of the total NPC of costs and damages are exported climate change damages, followed by domestic climate change damages, and acid rain damages. The use of other valuation methods would make health damage bigger than this study's estimation and acid rain damage could be a major concern in the future
Plasmas pour la destruction de l'H2S et des mercaptans Plasmas for Destruction of H2s and Mercaptans

Directory of Open Access Journals (Sweden)

Czernichowski A.

2006-12-01

media for an oxidation of H2S or CH3SH diluted in air, CO2 or steam in order to convert them into less malodorous SO2. The product can be then used as a reagent in a Claus-like process in presence of water to convert twice as much of initial pollutants into elemental sulfur. A particular attention is devoted to the gliding electrical discharges (GlidArc. These powerful discharges produce non-thermal plasma, which activates oxidation reactions. Most of experiments were performed using one and four-stage GlidArc-I reactors. Air-diluted sulfides at initial concentrations up to 1% (H2S or 0. 1% (CH3SH were processed at up to 70 m3(n/h flow rate and 5 kW power scale. The tests were done at 1 atm. Up to 100% clean-up was obtained at a quite low energy cost depending on initial pollutant concentration: roughly 1000 kWh per 1 kg of removed sulfur at 100 ppm of H2S, but only 10 kWh/kg for 1% initial H2S in air. Almost the same energies were needed in the case of CH3SH-air mixtures. Using a very simple washing column in which water saturates with the produced SO2 and so captures unprocessed H2S we cut these process energy by three, avoiding the SO2 emission and obtaining non-toxic sulfur. New development based on GlidArc-ll brush-like electric discharges is also presented. Preliminary tests are very promising as the energy expense is already cut down by a factor of two with respect to the GlidArc-I devices. Up to industrial scale tests can be therefore performed.
Experimental Studies on the Interaction of scCO2 and scCO2-SO2 With Rock Forming Minerals at Conditions of Geologic Carbon Storages - First Results

Science.gov (United States)

Erzinger, J.; Wilke, F.; Wiersberg, T.; Vasquez Parra, M.

2010-12-01

Co-injection of SO2 (plus possibly NOx and O2) during CO2 storage in deep saline aquifers may cause stronger brine acidification than CO2 alone. Because of that, we investigate chemical corrosion of rocks and rock-forming minerals with impure supercritical CO2 (scCO2) at possible storage conditions of >73.7 bar and >31°C. Contaminates were chosen with respect to the composition of CO2 captured industrially from coal-fired power plants using the oxyfuel technology. The resulting data should build a base for the long-term prediction of the behavior of CO2 in geologic storage reservoirs. Experiments of up to 1000 hrs duration have been performed with 10 natural mineral concentrates (calcite, dolomite, siderite, anhydrite, hematite, albite, microcline, kaolinite, muscovite, biotite) in 3n NaCl solution and pure scCO2 or scCO2+SO2 (99.5+0.5 vol%). The NaCl reaction fluid resembles the average salinity of deep formation waters of the North German Basin and is not free of oxygen. To increase reaction rates all minerals were ground and the reagents agitated either by stirring or shaking in autoclaves of about one liter in volume. The autoclaves consist of Hastelloy™ or ferromagnetic stainless steel fully coated with PTFE. We used in average 15 g of solids, 700 ml liquid, and the vessels were pressurized up to 100 bars with CO2 or CO2-SO2 mixture. Experiments were run at temperatures up to 90°C. Before, during and after the experiments small amounts fluids were sampled and analyzed for dissolved constituents and pH. Solid phases were characterized by XRF, XRD, and EMPA before and after the experiments. Pure scCO2 corrodes all carbonates, reacts only slightly with anhydrite, albite, and microcline at a minimum pH of 4, and does not recognizably interact with the others. After the experiment, albite has gained in a, not yet fully identified, carbonate phase which might be dawsonite. Reaction fluids of the experiments with scCO2+SO2 have mostly lower pH than using scCO2
System for recovery of CO2 from flue gases containing SO2

International Nuclear Information System (INIS)

Sears, J. T.; Anada, H. R.

1985-01-01

An improved system for recovering CO 2 from flue gases containing SO 2 at low CO 2 partial pressure. The system includes the use of K 2 CO 3 as the solvent, regeneration of the solvent, and removal of SO 2 and SO 4
Charge transfer processes in collisions of H+ ions with H2, D2, CO, CO2 CH4, C2H2, C2H6 and C3H8 molecules below 10 keV

International Nuclear Information System (INIS)

Kusakabe, T.; Buenker, R.J.; Kimura, M.

2002-01-01

Charge transfer processes resulting from collisions of H + ions with H 2 , D 2 , CO, CO 2 CH 4 , C 2 H 2 , C 2 H 6 and C 3 H 8 molecules have been investigated in the energy range of 0.2 to 4.0 keV experimentally and theoretically. The initial growth rate method was employed in the experiment for studying the dynamics and cross sections. Theoretical analysis based on a molecular-orbital expansion method for H 2 , D 2 , CO, CH 4 and C 2 H 2 targets was also carried out. The present results for the H 2 , CO and CO 2 molecules by H + impact are found to be in excellent accord with most of previous measurements above 1 keV, but they show some differences below this energy where our result displays a stronger energy-dependence. For CH 4 , C 2 H 2 , C 2 H 6 and C 3 H 8 targets, both experimental and theoretical results indicate that if one assumes vibrationally excited molecular ions (CH 4 + , C 2 H 2 + , C 2 H 6 + and C 3 H 8 + ) formed in the exit channel, then charge transfer processes sometimes become more favorable since these vibrationally excited fragments meet an accidental resonant condition. This is a clear indication of the role of vibrational excited states for charge transfer, and is an important realization for general understanding. (author)

1H and 2H NMR relaxation study on the phase transitions of (NH4)3H(SO4)2 and (ND4)3D(SO4)2 single crystals

International Nuclear Information System (INIS)

Lim, Ae Ran; Jeong, Se-Young

2006-01-01

T 1 , T 1ρ and T 2 for the 1 H and 2 H nuclei in (NH 4 ) 3 H(SO 4 ) 2 and (ND 4 ) 3 D(SO 4 ) 2 single crystals grown using the slow evaporation method were measured for phases I, II, III, IV and V. The 1 H T 1 , T 1ρ , and T 2 values were found to exhibit different trends in phases II and III: T 1 , T 1ρ and T 2 for 1 H do not change significantly near the phase transition at 265 K, whereas near 413 K they change discontinuously. We conclude that the NH 4 + and H(SO 4 ) 2 - ions do not play an important role in the III-II phase transition, but do play important roles in the II-I phase transition. The liquid-like nature of the 1 H T 1ρ and T 2 above 413 K is indicative of the destruction and reconstruction of hydrogen bonds. Moreover, the phase transitions of the (NH 4 ) 3 H(SO 4 ) 2 crystal are accompanied by changes in the molecular motion of the (NH 4 ) + ions. The variations with temperature of the 2 H T 1 and T 2 of (ND 4 ) 3 D(SO 4 ) 2 crystals are not similar to those observed for the 1 H T 1 and T 2 . Our comparison of the results for (NH 4 ) 3 H(SO 4 ) 2 and (ND 4 ) 3 D(SO 4 ) 2 crystals indicates the following: the 1 H T 1ρ and T 2 of the (NH 4 ) + and H(SO 4 ) 2 - ions above T C1 are characteristic of fast, liquid-like motion, which is not the case for (ND 4 ) 3 D(SO 4 ) 2 ; and the 2 H T 1 of D(SO 4 ) 2 - in (ND 4 ) 3 D(SO 4 ) 2 is longer than the 2 H T 1 of (ND 4 ) + in contrast to the results for (NH 4 ) 3 H(SO 4 ) 2 crystals
Achieving Simultaneous CO2 and H2 S Conversion via a Coupled Solar-Driven Electrochemical Approach on Non-Precious-Metal Catalysts.

Science.gov (United States)

Ma, Weiguang; Wang, Hong; Yu, Wei; Wang, Xiaomei; Xu, Zhiqiang; Zong, Xu; Li, Can

2018-03-19

Carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) are generally concomitant with methane (CH 4 ) in natural gas and traditionally deemed useless or even harmful. Developing strategies that can simultaneously convert both CO 2 and H 2 S into value-added products is attractive; however it has not received enough attention. A solar-driven electrochemical process is demonstrated using graphene-encapsulated zinc oxide catalyst for CO 2 reduction and graphene catalyst for H 2 S oxidation mediated by EDTA-Fe 2+ /EDTA-Fe 3+ redox couples. The as-prepared solar-driven electrochemical system can realize the simultaneous conversion of CO 2 and H 2 S into carbon monoxide and elemental sulfur at near neutral conditions with high stability and selectivity. This conceptually provides an alternative avenue for the purification of natural gas with added economic and environmental benefits. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Reaction of H{sub 2}S with MoRu(CO){sub 6}(dppm){sub 2} to give H{sub 2} and a bridged-sulfide product via hydrido-sulfhydryl intermediates (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Khorasani-Motlagh, M. [Sistan and Baluchestan Univ., Zahedan (Iran, Islamic Republic of). Dept. of Chemistry; Safari, N. [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Pamplin, C.B.; Patrick, B.O.; James, B.R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemistry

2006-02-15

The reactivity of hydrogen sulphide toward transition metal complexes was studied with particular focus on the reactions of hydrogen sulphide (H{sub 2}S) with solutions of bimetallic-dppm complexes. The complex MoRu(CO){sub 6}({mu}-dppm){sub 2} (1) (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2}) reaction toward hydrogen sulphide was examined because of the fact that Ru is the second-row analogue of Fe and because of the key role of sulphur ligands in the Mo-Fe enzyme systems. This paper reported on the interaction of the Mo-Ru complex with hydrogen sulphide to form the bridged sulphide complex Mo(CO){sub 2}({mu}-CO)({mu}-S)(dppm){sub 2}Ru(CO) which can be synthesized with elemental sulphur. Oxidative addition of H{sub 2}S to MoRu(CO){sub 6}({mu}-dppm){sub 2} (1) at 20 degrees C in toluene yields an isolable complex formulated as Mo(CO){sub 3}({mu}-SH)({mu}-CO)({mu}-dppm){sub 2}RuH(CO) (2) via the possible intermediate Mo(CO){sub 3}({mu}-H)({mu}-CO)({mu}-dppm){sub 2}Ru(SH)(CO) (4) (dppm equals Ph{sub 2}PCH{sub 2}PPh{sub 2}) that is detectable at lower temperatures. Over 2 days, species 2 in toluene lost H{sub 2} (and CO) to yield the bridged-sulfide product, Mo(CO){sub 2}({mu}-CO)({mu}-S)({mu}-dppm){sub 2}Ru(CO) (5) that is also formed directly from the reaction of 1 with elemental sulfur. The solid-state molecular structure of 5 was determined by X-ray crystallography. A further hydrido-sulfhydryl species was found to be in equilibrium with 2 at ambient temperature. It was concluded that it is not impossible that hydrogen sulphide can react in a concerted manner with dimetallic precursors, without prior formation of an adduct. 24 refs., 2 tabs., 3 figs.
Precursory diffuse CO2 and H2S emission signatures of the 2011-2012 El Hierro submarine eruption, Canary Islands

Science.gov (United States)

Pérez, Nemesio M.; Padilla, Germán D.; Padrón, Eleazar; Hernández, Pedro A.; Melián, Gladys V.; Barrancos, José; Dionis, Samara; Nolasco, Dácil; Rodríguez, Fátima; Calvo, David; Hernández, Íñigo

2012-08-01

On October 12, 2011, a submarine eruption began 2 km off the coast of La Restinga, south of El Hierro Island. CO2 and H2S soil efflux were continuously measured during the period of volcanic unrest by using the accumulation chamber method at two different geochemical stations, HIE01 and HIE07. Recorded CO2 and H2S effluxes showed precursory signals that preceded the submarine eruption. Beginning in late August, the CO2 efflux time series started increasing at a relatively constant rate over one month, reaching a maximum of 19 gm-2d-1 one week before the onset of the submarine volcanic eruption. The H2S efflux time series at HIE07 showed a pulse in H2S emission just one day before the initiation of the submarine eruption, reaching peak values of 42 mg m-2 d-1, 10 times the average H2S efflux recorded during the observation period. Since CO2 and H2S effluxes are strongly influenced by external factors, we applied a multiple regression analysis to remove their contribution. A statistical analysis showed that the long-term trend of the filtered data is well correlated with the seismic energy. We find that these geochemical stations are important monitoring sites for evaluating the volcanic activity of El Hierro and that they demonstrate the potential of applying continuous monitoring of soil CO2 and H2S efflux to improve and optimize the detection of early warning signals of future volcanic unrest episodes at El Hierro. Continuous diffuse degassing studies would likely prove useful for monitoring other volcanoes during unrest episodes.
Laboratory studies of H2SO4/H2O binary homogeneous nucleation from the SO2+OH reaction: evaluation of the experimental setup and preliminary results

Directory of Open Access Journals (Sweden)

M. Kulmala

2008-08-01

Full Text Available Binary homogeneous nucleation (BHN of sulphuric acid and water (H2SO4/H2O is one of the most important atmospheric nucleation processes, but laboratory observations of this nucleation process are very limited and there are also large discrepancies between different laboratory studies. The difficulties associated with these experiments include wall loss of H2SO4 and uncertainties in estimation of H2SO4 concentration ([H2SO4] involved in nucleation. We have developed a new laboratory nucleation setup to study H2SO4/H2O BHN kinetics and provide relatively constrained [H2SO4] needed for nucleation. H2SO4 is produced from the SO2+OH→HSO3 reaction and OH radicals are produced from water vapor UV absorption. The residual [H2SO4] were measured at the end of the nucleation reactor with a chemical ionization mass spectrometer (CIMS. Wall loss factors (WLFs of H2SO4 were estimated by assuming that wall loss is diffusion limited and these calculated WLFs were in good agreement with simultaneous measurements of the initial and residual [H2SO4] with two CIMSs. The nucleation zone was estimated from numerical simulations based on the measured aerosol sizes (particle diameter, Dp and [H2SO4]. The measured BHN rates (J ranged from 0.01–220 cm−3 s−1 at the initial and residual [H2SO4] from 108−1010 cm−3, a temperature of 288 K and relative humidity (RH from 11–23%; J increased with increasing [H2SO4] and RH. J also showed a power dependence on [H2SO4] with the exponential power of 3–8. These power dependences are consistent with other laboratory studies under similar [H2SO4] and RH, but different from atmospheric field observations which showed that particle number concentrations are often linearly dependent on [H2SO4]. These results, together with a higher [H2SO4] threshold (108–109 cm−3 needed to produce the unit J measured from the laboratory studies compared to the atmospheric conditions (106–107 cm−3, imply that H2SO4/H2O BHN alone is
Physiological responses of Norway spruce trees to elevated CO2 and SO2

NARCIS (Netherlands)

Tausz, M.; De Kok, L.J.; Stulen, I.

Young Norway spruce (Picea abies (L.) Karst.) trees were exposed to elevated CO2 (0.8 mL L(-1)), SO2 (0.06 mu L L(-1)), and elevated CO2 and SO2 (0.8 mL L(-1) and 0.06 mu L L(-1), respectively) for three months. Exposure to elevated CO2 resulted in an increased biomass production of the needles,
Using HABIT to Estimate the Concentration of CO2 and H2SO4 for Kuosheng Nuclear Power Plant

OpenAIRE

Y. Chiang; W. Y. Li; J. R. Wang; S. W. Chen; W. S. Hsu; J. H. Yang; Y. S. Tseng; C. Shih

2017-01-01

In this research, the HABIT code was used to estimate the concentration under the CO2 and H2SO4 storage burst conditions for Kuosheng nuclear power plant (NPP). The Final Safety Analysis Report (FSAR) and reports were used in this research. In addition, to evaluate the control room habitability for these cases, the HABIT analysis results were compared with the R.G. 1.78 failure criteria. The comparison results show that the HABIT results are below the criteria. Additionally, some sensitivity ...
Far-UV, visible, and near-IR reflectance spectra of frosts of H2O, CO2, NH3 and SO2

Science.gov (United States)

Hapke, B.; Wells, E.; Wagner, J.; Partlow, W.

1981-01-01

Measurements in the 0.1-2.5 micron range are presented for the reflectance spectra of the frosts of several volatiles pertinent to the study of comet nuclei. The frost spectra have distinctive features permitting their identification by spectroscopic reflectance remote sensing, notably in the far UV. It is found that: (1) H2O has a minimum at 0.16 microns and a maximum at 0.13 microns; (2) CO2 has minima near 0.21, 0.18 and 0.125 microns, with maxima at 0.19, 0.135 and 0.120 microns; (3) NH3 is bright at wavelengths longer than 0.21 microns, where reflectance drops to a value of only a few per cent at shorter wavelengths; (4) SO2 has a sharp drop at 0.32 microns, with a minimum at 0.18 microns and a maximum at 0.13 microns. The features in the frost spectra largely correspond to absorption line bands in the gas phase.
Generation of H2 and CO by solar thermochemical splitting of H2O and CO2 by employing metal oxides

International Nuclear Information System (INIS)

Rao, C.N.R.; Dey, Sunita

2016-01-01

Generation of H 2 and CO by splitting H 2 O and CO 2 respectively constitutes an important aspect of the present-day concerns with energy and environment. The solar thermochemical route making use of metal oxides is a viable means of accomplishing these reduction reactions. The method essentially involves reducing a metal oxide by heating and passing H 2 O or CO 2 over the nonstoichiometric oxide to cause reverse oxidation by abstracting oxygen from H 2 O or CO 2 . While ceria, perovskites and other oxides have been investigated for this purpose, recent studies have demonstrated the superior performance of perovskites of the type Ln 1−x A x Mn 1−y M y O 3 (Ln=rare earth, A=alkaline earth, M=various +2 and +3 metal ions), in the thermochemical generation of H 2 and CO. We present the important results obtained hitherto to point out how the alkaine earth and the Ln ions, specially the radius of the latter, determine the performance of the perovskites. The encouraging results obtained are exemplefied by Y 0.5 Sr 0.5 MnO 3 which releases 483 µmol/g of O 2 at 1673 K and produces 757 µmol/g of CO from CO 2 at 1173 K. The production of H 2 from H 2 O is also quite appreciable. Modification of the B site ion of the perovskite also affects the performance. In addition to perovskites, we present the generation of H 2 based on the Mn 3 O 4 /NaMnO 2 cycle briefly. - Graphical abstract: Ln 0.5 A 0.5 Mn 1−x M x O 3 (Ln=lanthanide; A=Ca, Sr; M=Al, Ga, Sc, Mg, Cr, Fe, Co) perovskites are employed for the two step thermochemical splitting of CO 2 and H 2 O for the generation of CO and H 2 . - Highlights: • Perovskite oxides based on Mn are ideal for the two-step thermochemical splitting of CO 2 and H 2 O. • In Ln 1−x A x MnO 3 perovskite (Ln=rare earth, A=alkaline earth) both Ln and A ions play major roles in the thermochemical process. • H 2 O splitting is also achieved by the use of the Mn 3 O 4 -sodium carbonate system. • Thermochemical splitting of CO 2 and H
Rates of volcanic CO2 degassing from airborne determinations of SO2 Emission rates and plume CO2SO2: test study at Pu′u ′O′o Cone, Kilauea Volcano, Hawaii

Science.gov (United States)

Gerlach, Terrence M.; McGee, Kenneth A.; Sutton, A. Jefferson; Elias, Tamar

1998-01-01

We present an airborne method that eliminates or minimizes several disadvantages of the customary plume cross-section sampling method for determining volcanic CO2 emission rates. A LI-COR CO2analyzer system (LICOR), a Fourier transform infrared spectrometer system (FTIR), and a correlation spectrometer (COSPEC) were used to constrain the plume CO2/SO2 and the SO2 emission rate. The method yielded a CO2 emission rate of 300 td−1 (metric tons per day) for Pu′u ′O′o cone, Kilauea volcano, on 19 September 1995. The CO2/SO2 of 0.20 determined from airborne LICOR and FTIR plume measurements agreed with the CO2/SO2 of 204 ground-based samples collected from vents over a 14-year period since the Pu′u ′O′o eruption began in January 1983.
Geochemical alteration of wellbore cement by CO₂ or CO₂+H ₂ S reaction during long-term carbon storage: Original Research Article: Geochemical alteration of wellbore cement by CO₂

Energy Technology Data Exchange (ETDEWEB)

Um, Wooyong [Pacific Northwest National Laboratory, Richland WA USA; Rod, Kenton A. [Pacific Northwest National Laboratory, Richland WA USA; Jung, Hun Bok [New Jersey City University, Jersey City NJ USA; Brown, Christopher F. [Pacific Northwest National Laboratory, Richland WA USA

2016-03-22

Cement samples were reacted with CO₂-saturated groundwater, with or without added H2S (1 wt.%), at 50°C and 10 MPa for up to 13 months (CO₂ only) or for up to 3.5 months (CO₂ + H₂S) under static conditions. After the reaction, X-ray computed tomography images revealed that calcium carbonate precipitation (CaCO₃) occurred extensively within the fractures in the cement matrix, but only partially along fractures at the cement-basalt interface. Exposure of a fractured cement sample to CO2-saturated groundwater (50°C and 10 MPa) over a period of 13 months demonstrated progressive healing of cement fractures by CaCO₃(s) precipitation. After reaction with CO₂ + H₂S-saturated groundwater, CaCO₃ (s) precipitation also occurred more extensively within the cement fracture than along the cement-basalt caprock interfaces. X-ray diffraction analysis showed that major cement carbonation products of the CO₂ + H₂S-saturated groundwater were calcite, aragonite, and vaterite, all consistent with cement carbonation by CO₂-saturated groundwater. While pyrite is thermodynamically favored to form, due to the low H₂S concentration it was not identified by XRD in this study. The cement alteration rate into neat Portland cement columns by CO₂-saturated groundwater was similar at ~0.02 mm/d, regardless of the cement-curing pressure and temperature (P-T) conditions, or the presence of H₂S in the brine. The experimental results imply that the wellbore cement with fractures is likely to be healed during exposure to CO₂- or CO₂ + H₂S-saturated groundwater, whereas fractures along the cement-caprock interface are likely to remain open and vulnerable to the leakage of CO₂.
NO2-initiated multiphase oxidation of SO2 by O2 on CaCO3 particles

Science.gov (United States)

Yu, Ting; Zhao, Defeng; Song, Xiaojuan; Zhu, Tong

2018-05-01

The reaction of SO2 with NO2 on the surface of aerosol particles has been suggested to be important in sulfate formation during severe air pollution episodes in China. However, we found that the direct oxidation of SO2 by NO2 was slow and might not be the main reason for sulfate formation in ambient air. In this study, we investigated the multiphase reaction of SO2 with an O2 / NO2 mixture on single CaCO3 particles using Micro-Raman spectroscopy. The reaction converted the CaCO3 particle to a Ca(NO3)2 droplet, with CaSO4 ⚫ 2H2O solid particles embedded in it, which constituted a significant fraction of the droplet volume at the end of the reaction. The reactive uptake coefficient of SO2 for sulfate formation was on the order of 10-5, which was higher than that for the multiphase reaction of SO2 directly with NO2 by 2-3 orders of magnitude. According to our observations and the literature, we found that in the multiphase reaction of SO2 with the O2 / NO2 mixture, O2 was the main oxidant of SO2 and was necessary for radical chain propagation. NO2 acted as the initiator of radical formation, but not as the main oxidant. The synergy of NO2 and O2 resulted in much faster sulfate formation than the sum of the reaction rates with NO2 and with O2 alone. We estimated that the multiphase oxidation of SO2 by O2 initiated by NO2 could be an important source of sulfate and a sink of SO2, based on the calculated lifetime of SO2 regarding the loss through the multiphase reaction versus the loss through the gas-phase reaction with OH radicals. Parameterization of the reactive uptake coefficient of the reaction observed in our laboratory for further model simulation is needed, as well as an integrated assessment based on field observations, laboratory study results, and model simulations to evaluate the importance of the reaction in ambient air during severe air pollution episodes, especially in China.
H2SO4-HNO3-H2O ternary system in the stratosphere

Science.gov (United States)

Kiang, C. S.; Hamill, P.

1974-01-01

Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.
NO and H2O2 contribute to SO2 toxicity via Ca2+ signaling in Vicia faba guard cells.

Science.gov (United States)

Yi, Min; Bai, Heli; Xue, Meizhao; Yi, Huilan

2017-04-01

NO and H 2 O 2 have been implicated as important signals in biotic and abiotic stress responses of plants to the environment. Previously, we have shown that SO 2 exposure increased the levels of NO and H 2 O 2 in plant cells. We hypothesize that, as signaling molecules, NO and H 2 O 2 mediate SO 2 -caused toxicity. In this paper, we show that SO 2 hydrates caused guard cell death in a concentration-dependent manner in the concentration range of 0.25 to 6 mmol L -1 , which was associated with elevation of intracellular NO, H 2 O 2 , and Ca 2+ levels in Vicia faba guard cells. NO donor SNP enhanced SO 2 toxicity, while NO scavenger c-PTIO and NO synthesis inhibitors L-NAME and tungstate significantly prevented SO 2 toxicity. ROS scavenger ascorbic acid (AsA) and catalase (CAT), Ca 2+ chelating agent EGTA, and Ca 2+ channel inhibitor LaCl 3 also markedly blocked SO 2 toxicity. In addition, both c-PTIO and AsA could completely block SO 2 -induced elevation of intracellular Ca 2+ level. Moreover, c-PTIO efficiently blocked SO 2 -induced H 2 O 2 elevation, and AsA significantly blocked SO 2 -induced NO elevation. These results indicate that extra NO and H 2 O 2 are produced and accumulated in SO 2 -treated guard cells, which further activate Ca 2+ signaling to mediate SO 2 toxicity. Our findings suggest that both NO and H 2 O 2 contribute to SO 2 toxicity via Ca 2+ signaling.
Electron excitation cross sections for the 2s(2)2p(3)4S(O) -- 2s(2)2p(3)2D(O) (forbidden) and 4S(O) -- 2s2p(4) 4P (resonance) transitions in O II

Science.gov (United States)

Zuo, M.; Smith, Steven J.; Chutjian, A.; Williams, I. D.; Tayal, S. S.; Mclaughlin, Brendan M.

1995-01-01

Experimental and theoretical excitation cross sections are reported for the first forbidden transition 4S(O) -- 2S(2)2p(3) 2D(O) (lambda-lambda 3726, 3729) and the first allowed (resonance) transition 4S(O) -- 2s2p(4) 4P(lambda-833) in O II. Use is made of electron energy loss and merged-beams methods. The electron energy range covered is 3.33 (threshold) to 15 eV for the S -- D transition, and 14.9 (threshold) to 40 eV for the S -- P transition. Care was taken to assess and minimize the metastable fraction of the O II beam. An electron mirror was designed and tested to reflect inelastically backscattered electrons into the forward direction to account for the full range of polar scattering angles. Comparisons are made between present experiments and 11-state R-matrix calculations. Calculations are also presented for the 4S(O) -- 2s(2)2p(3)2P(O) (lambda-2470) transition.
Emissions of HC, CO, NOx, CO2, and SO2 from civil aviation in China in 2010

Science.gov (United States)

Fan, Weiyi; Sun, Yifei; Zhu, Tianle; Wen, Yi

2012-09-01

Civil aviation in China has developed rapidly in recent years, and the effects of civil aviation emissions on the atmospheric environment should not be neglected. The establishment of emission inventories of atmospheric pollutants from civil aviation contributes to related policy formation and pollution control. According to the 2010's China flight schedules, aircraft/engine combination information and revised emission indices from the International Civil Aviation Organization emission data bank based on meteorological data, the fuel consumption and HC, CO, NOx, CO2, SO2 emissions from domestic flights of civil aviation in China (excluding Taiwan Province) in 2010 are estimated in this paper. The results show that fuel consumption in 2010 on domestic flights in China is 12.12 million tons (metric tons), HC, CO, NOx, CO2 and SO2 emissions are 4600 tons, 39,700 tons, 154,100 tons, 38.21 million tons and 9700 tons, respectively. The fuel consumption and pollutant emissions of China Southern Airline are responsible for the largest national proportion of each, accounting for 27% and 25-28%, respectively.
Syngas production by gasification of aquatic biomass with CO2/O2 and simultaneous removal of H2S and COS using char obtained in the gasification

International Nuclear Information System (INIS)

Hanaoka, Toshiaki; Hiasa, Shou; Edashige, Yusuke

2013-01-01

Applicability of gulfweed as feedstock for a biomass-to-liquid (BTL) process was studied for both production of gas with high syngas (CO + H 2 ) content via gasification of gulfweed and removal of gaseous impurities using char obtained in the gasification. Gulfweed as aqueous biomass was gasified with He/CO 2 /O 2 using a downdraft fixed-bed gasifier at ambient pressure and 900 °C at equivalence ratios (ER) of 0.1–0.3. The syngas content increased while the conversion to gas on a carbon basis decreased with decreasing ER. At an ER of 0.1 and He/CO 2 /O 2 = 0/85/15%, the syngas content was maximized at 67.6% and conversion to gas on a carbon basis was 94.2%. The behavior of the desulfurization using char obtained during the gasification process at ER = 0.1 and He/CO 2 /O 2 = 0/85/15% was investigated using a downdraft fixed-bed reactor at 250–550 °C under 3 atmospheres (H 2 S/N 2 , COS/N 2 , and a mixture of gases composed of CO, CO 2 , H 2 , N 2 , CH 4 , H 2 S, COS, and steam). The char had a higher COS removal capacity at 350 °C than commercial activated carbon because (Ca,Mg)S crystals were formed during desulfurization. The char simultaneously removed H 2 S and COS from the mixture of gases at 450 °C more efficiently than did activated carbon. These results support this novel BTL process consisting of gasification of gulfweed with CO 2 /O 2 and dry gas cleaning using self-supplied bed material. -- Highlights: • A product gas with high syngas content was produced from the gasification of gulfweed with CO 2 /O 2 . • The syngas content increased with decreasing the equivalence ratio. • The syngas content was maximized at 67.6% at an ER of 0.1 and He/CO 2 /O 2 = 0/85/15%. • The char simultaneously removed H 2 S and COS from a mixture of gases at 450 °C efficiently
Solar kerosene from H2O and CO2

Science.gov (United States)

Furler, P.; Marxer, D.; Scheffe, J.; Reinalda, D.; Geerlings, H.; Falter, C.; Batteiger, V.; Sizmann, A.; Steinfeld, A.

2017-06-01

The entire production chain for renewable kerosene obtained directly from sunlight, H2O, and CO2 is experimentally demonstrated. The key component of the production process is a high-temperature solar reactor containing a reticulated porous ceramic (RPC) structure made of ceria, which enables the splitting of H2O and CO2 via a 2-step thermochemical redox cycle. In the 1st reduction step, ceria is endo-thermally reduced using concentrated solar radiation as the energy source of process heat. In the 2nd oxidation step, nonstoichiometric ceria reacts with H2O and CO2 to form H2 and CO - syngas - which is finally converted into kerosene by the Fischer-Tropsch process. The RPC featured dual-scale porosity for enhanced heat and mass transfer: mm-size pores for volumetric radiation absorption during the reduction step and μm-size pores within its struts for fast kinetics during the oxidation step. We report on the engineering design of the solar reactor and the experimental demonstration of over 290 consecutive redox cycles for producing high-quality syngas suitable for the processing of liquid hydrocarbon fuels.
Simultaneous mass transfer of H2S and CO2 with complex chemical reactions in an aqueous di-isopropanolamine solution = Gleichzeitige absorption von H2S und CO2 in Wässriger Di-isopropanolaminlösung

NARCIS (Netherlands)

Blauwhoff, P.M.M.; van Swaaij, Willibrordus Petrus Maria

1985-01-01

The absorption of H2S and CO2 into an aqueous di-isopropanolamine (DIPA) solution was studied experimentally and theoretically as an example of simultaneous mass transfer with complex reversible reactions. The absorption phenomena were classified into three regimes: (1) negligible mutual interaction
Achieving simultaneous CO{sub 2} and H{sub 2}S conversion via a coupled solar-driven electrochemical approach on non-precious-metal catalysts

Energy Technology Data Exchange (ETDEWEB)

Ma, Weiguang; Yu, Wei; Zong, Xu; Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, The Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian (China); Wang, Hong; Wang, Xiaomei; Xu, Zhiqiang [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, The Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian (China); University of Chinese Academy of Sciences, Beijing (China)

2018-03-19

Carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S) are generally concomitant with methane (CH{sub 4}) in natural gas and traditionally deemed useless or even harmful. Developing strategies that can simultaneously convert both CO{sub 2} and H{sub 2}S into value-added products is attractive; however it has not received enough attention. A solar-driven electrochemical process is demonstrated using graphene-encapsulated zinc oxide catalyst for CO{sub 2} reduction and graphene catalyst for H{sub 2}S oxidation mediated by EDTA-Fe{sup 2+}/EDTA-Fe{sup 3+} redox couples. The as-prepared solar-driven electrochemical system can realize the simultaneous conversion of CO{sub 2} and H{sub 2}S into carbon monoxide and elemental sulfur at near neutral conditions with high stability and selectivity. This conceptually provides an alternative avenue for the purification of natural gas with added economic and environmental benefits. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Simultaneous removal of CO2 and H2S using MEA solution in a packed column absorber for biogas upgrading

Directory of Open Access Journals (Sweden)

Preecha Kasikamphaiboon

2013-12-01

Full Text Available Biogas production and utilization is an emerging alternative energy technology that has gained importance since the price of oil and gas has increased steadily over the last two decades. Biogas primarily consists of methane (CH4 and carbon dioxide (CO2 with smaller amounts of hydrogen sulfide (H2S and ammonia (NH3. For many applications the quality of biogas has to be improved. The main parameters that may require removal in upgrading systems are CO2 and H2S. This work presents the study of simultaneous absorption of CO2 and H2S by Monoethanolamine (MEA solution in a packed column. Simulated biogas containing 40% CO2 and 60% N2 and biogas generated from an anaerobic digestion plant were used as feed gas streams. The effects of gas flow rate, L/G ratio and absorbent concentration were investigated. The performance of the system was found to vary with process parameters. Increasing L/G ratio and MEA concentration causes the system efficiency to increase whereas increasing gas flow rate results in lower efficiency. An operating condition of L/G ratio of 83.3 ml/L, gas flow rate of 3 L/min and MEA concentration of 3 mol/L was found to remove more than 99.5% of CO2 and H2S from biogas. The volumetric overall mass-transfer coefficient (KGav for CO2 removal initially increases with increasing gas flow rate up to a certain value beyond which the coefficient becomes essentially constant. The KGav also increases with increasing L/G ratio throughout the range tested in this study.
Availability of S from superphosphate and CaSO4.2H2O to alfafa (Medicago sativa L. Pers.) using tracer technique

International Nuclear Information System (INIS)

Aulakh, M.S.; Dev, G.

1977-01-01

The availability of S from superphosphate to alfalfa was evaluated and compared with CaSO 4 .2H 2 O (as the standard) in the greenhouse on a S deficient arid brown soil at 4 levels of applied S (0, 5, 10 and 20 ppm). A basal dose of N, P, K and Ca was made and the effect was studied for two growth stages (80 and 120 days). Sulphur application significantly increased the yield of dry matter, S content and total S removal in both the cuttings individually and for total harvest. In this effect, superphosphate was found to be more efficient. The radio-assay data confirmed that with graded levels of applied S, the fraction of fertilizer S in the plant increased without much off-setting S fraction from the native soil source, the effect being more with superphosphate treatment compared to CaSO 4 .2H 2 O. Phosphorus concentration in alfalfa decreased significantly with increasing level of applied S. The first cutting of alfalfa recorded higher P content in superphosphate series and in the second cutting, this difference between the two sources decreased. At optimum level of 20 ppm S, superphosphate was more effective than CaSO 4 .2H 2 O in narrowing N:S ratio to 11:1 and increasing S:P ratio to more than 1:1. (author)
Thermodynamic properties and crystal structure refinement of ferricopiapite, coquimbite, rhomboclase, and Fe2(SO4)3(H2O)5

Science.gov (United States)

Majzlan, J.; Navrotsky, A.; McCleskey, R. Blaine; Alpers, Charles N.

2006-01-01

Enthalpies of formation of ferricopiapite [nominally Fe4.67(SO4)6(OH)2 (H2O)20]. coquimbite [Fe2(SO4)3(H2O)9], rhomboclase [(H3O)Fe(SO4)2 (H2O)3], and Fe2(SO4)3(H2O)5 were measured by acid (5 N HCl) solution calorimetry. The samples were characterized by wet chemical analyses and synchrotron powder X-ray diffraction (XRD). The refinement of XRD patterns gave lattice parameters, atomic positions, thermal factors, and occupancies of the sites. The calculated formulae differ slightly from the nominal compositions: Fe4.78(SO4)6 (OH)2.34(H2O)20.71 (ferricopiapite), (Fe1.47Al0.53)(SO4)3 (H2O)9.65 (coquimbite), (H3O)1.34Fe(SO4)2.17 (H2O)3.06 (rhomboclase), and Fe2(SO4)3 (H2O)5.03. All thermodynamic data are given per mole of these formulae. The measured standard enthalpies (in kJ/mol) of formation from the elements (crystalline Fe, Al, S, and ideal gases O2 and H2) at T = 298.15 K are -4115.8??4.1 [Fe2(SO4)3 (H2O)5.03], -12045.1??9.2 (ferricopiapite), -5738.4??3.3 (coquimbite), and -3201.1??2.6 (rhomboclase). Standard entropy (S??) was estimated as a sum of entropies of oxide, hydroxide, and sulfate components. The estimated S?? (in J/mol.K) values for the iron sulfates are 488.2 [Fe2(SO4)3 (H2O)5.03], 1449.2 (ferricopiapite), 638.3 (coquimbite), and 380.1 (rhomboclase). The calculated Gibbs free energies of formation (in kJ/mol) are -3499.7??4.2 [Fe2(SO4)3 (H2O)5.03], -10089.8??9.3 (ferricopiapite), -4845.6??3.3 (coquimbite), and -2688.0??2.7 (rhomboclase). These results combined with other available thermodynamic data allow construction of mineral stability diagrams in the FeIII2(SO4)3-FeII SO4-H2O system. One such diagram is provided, indicating that the order of stability of ferric sulfate minerals with decreasing pH in the range of 1.5 to -0.5 is: hydronium jarosite, ferricopiapite, and rhomboclase. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.
Magnetoresistance in Co/2D MoS2/Co and Ni/2D MoS2/Ni junctions.

Science.gov (United States)

Zhang, Han; Ye, Meng; Wang, Yangyang; Quhe, Ruge; Pan, Yuanyuan; Guo, Ying; Song, Zhigang; Yang, Jinbo; Guo, Wanlin; Lu, Jing

2016-06-28

Semiconducting single-layer (SL) and few-layer MoS2 have a flat surface, free of dangling bonds. Using density functional theory coupled with non-equilibrium Green's function method, we investigate the spin-polarized transport properties of Co/2D MoS2/Co and Ni/2D MoS2/Ni junctions with MoS2 layer numbers of N = 1, 3, and 5. Well-defined interfaces are formed between MoS2 and metal electrodes. The junctions with a SL MoS2 spacer are almost metallic owing to the strong coupling between MoS2 and the ferromagnets, while those are tunneling with a few layer MoS2 spacer. Both large magnetoresistance and tunneling magnetoresistance are found when fcc or hcp Co is used as an electrode. Therefore, flat single- and few-layer MoS2 can serve as an effective nonmagnetic spacer in a magnetoresistance or tunneling magnetoresistance device with a well-defined interface.
The rate constant for the CO + H2O2 reaction

DEFF Research Database (Denmark)

Glarborg, Peter; Marshall, Paul

2009-01-01

The rate constant for the reaction CO + H2O2 -> HOCO + OH (R1) at 713 K is determined based on the batch reactor experiments of Baldwin et al. [ R. R. Baldwin, R. W. Walker, S. J. Webster, Combust. Flame 15 (1970) 167] on decomposition of H2O2 sensitized by CO. The value, k(1) (713 K) = 8.1 x 10...
The 2ν2 bands of H212CO and H213CO by high-resolution FTIR spectroscopy

Science.gov (United States)

Tan, T. L.; A'dawiah, Rabia'tul; Ng, L. L.

2017-10-01

The Fourier transform infrared (FTIR) absorption spectra of the 2ν2 overtone bands of formaldehyde H212CO and its isotopologue H213CO were recorded at an unapodized resolution of 0.0063 cm-1 in the 3300-3540 cm-1 region. Upper state (v2 = 2) rovibrational up to two sextic centrifugal distortion constants were accurately determined for both H212CO and H213CO. A total of 533 unperturbed infrared transitions of H212CO and 466 unperturbed infrared transitions of H212CO were assigned and fitted with rms deviations of 0.0012 cm-1 and 0.00084 cm-1 respectively using Watson's A-reduced Hamiltonian in the Ir representation. Analysis of new transitions for H212CO measured in this work yielded upper state constants with greater accuracy than previously reported. The infrared transitions of the 2ν2 band of H213CO were measured for the first time. The band center of the A-type 2ν2 band of H212CO was found to be 3471.71403 ± 0.00012 cm-1 and that of H213CO was 3396.628983 ± 0.000083 cm-1. Furthermore, the newly assigned high-resolution infrared lines of the 2ν2 bands in the 3300-3540 cm-1 region can be useful in detecting the H212CO and H213CO molecules in this IR region.
The reactions of SO3 with HO2 radical and H2O...HO2 radical complex. Theoretical study on the atmospheric formation of HSO5 and H2SO4.

Science.gov (United States)

Gonzalez, Javier; Torrent-Sucarrat, Miquel; Anglada, Josep M

2010-03-07

The influence of a single water molecule on the gas-phase reactivity of the HO(2) radical has been investigated by studying the reactions of SO(3) with the HO(2) radical and with the H(2)O...HO(2) radical complex. The naked reaction leads to the formation of the HSO(5) radical, with a computed binding energy of 13.81 kcal mol(-1). The reaction with the H(2)O...HO(2) radical complex can give two different products, namely (a) HSO(5) + H(2)O, which has a binding energy that is computed to be 4.76 kcal mol(-1) more stable than the SO(3) + H(2)O...HO(2) reactants (Delta(E + ZPE) at 0K) and an estimated branching ratio of about 34% at 298K and (b) sulfuric acid and the hydroperoxyl radical, which is computed to be 10.51 kcal mol(-1) below the energy of the reactants (Delta(E + ZPE) at 0K), with an estimated branching ratio of about 66% at 298K. The fact that one of the products is H(2)SO(4) may have relevance in the chemistry of the atmosphere. Interestingly, the water molecule acts as a catalyst, [as it occurs in (a)] or as a reactant [as it occurs in (b)]. For a sake of completeness we have also calculated the anharmonic vibrational frequencies for HO(2), HSO(5), the HSO(5)...H(2)O hydrogen bonded complex, H(2)SO(4), and two H(2)SO(4)...H(2)O complexes, in order to help with the possible experimental identification of some of these species.
Acidic gases (CO_2, NO_2 and SO_2) capture and dissociation on metal decorated phosphorene

International Nuclear Information System (INIS)

Kuang, Anlong; Kuang, Minquan; Yuan, Hongkuan; Wang, Guangzhao; Chen, Hong; Yang, Xiaolan

2017-01-01

Highlights: • The light metal decorated phosphorene sheets are very effective for capture of CO_2, NO_2 and SO_2 because of large adsorption energies. • The adsorption energy is obviously dependent on the amount of electrons transferred between acidic gases and metal decorated phosphorene. • Pt-decorated phosphorene can effectively catalyze the dissociation of acidic gas. - Abstract: Density functional theory is employed to investigate the adsorption and dissociation of several acidic gases (CO_2, NO_2 and SO_2) on metal (Li, Al, Ni and Pt) decorated phosphorene. The results show that light metal (Li, Al) decorated phosphorene exhibits a strong adsorption of acidic gases, i.e., the adsorption energy of CO_2 on Li decorated phosphorene is 0.376 eV which is the largest in all adsorption of CO_2 on metal decorated phosphorene and Al decorated phosphorene is most effective for capture of NO_2 and SO_2 due to large adsorption energies of 3.951 and 3.608 eV, respectively. Moreover, Li and Al light metals have stronger economic effectiveness and more friendly environment compared with the transition metals, the strong adsorption ability of acidic gases and low price suggest that Li, Al decorated phosphorene may be useful and promising for collection and filtration of exhaust gases. The reaction energy barriers of acidic gases dissociated process on Pt decorated phosphorene are relatively low and the reaction processes are significantly exothermic, indicating that the dissociation process is favorable.
A novel H2S/H2O2 fuel cell operating at the room temperature

Energy Technology Data Exchange (ETDEWEB)

Sanli, Ayse Elif [Gazi University (Turkey)], email: aecsanli@gmail.com; Aytac, Aylin [Department of Chemistry, Faculty of Science, Gazi University, Teknikokullar (Turkey)], email: aytaca@gazi.edu.tr

2011-07-01

This study concerns the oxidation mechanism of hydrogen sulfide and a fuel cell; acidic peroxide is used as the oxidant and basic hydrogen sulfide is the fuel. A solid state H2S/H2O2 stable fuel cell was produced at room temperature. A cell potential of 0.85 V was reached; this is quite remarkable in comparison to the H2S/O2 fuel cell potential of 0.85 V obtained at 850-1000 degree celsius. The hydrogen sulfide goes through an oxidation reaction in the alkaline fuel cell (H2S/H2O2 fuel cell) which opens up the possibility of using the cheaper nickel as a catalyst. As a result, the fuel cell becomes a potentially low cost technology. A further benefit from using H2S as the alkaline liquid H2S/H2O2 fuel cell, is that sulfide ions are oxidized at the anode, releasing electrons. Sulfur produced reacts with the other sulfide ions and forms disulfide and polysulfide ions in basic electrolytes (such as Black Sea water).
Highly luminescent S,N co-doped carbon quantum dots-sensitized chemiluminescence on luminol-H2 O2 system for the determination of ranitidine.

Science.gov (United States)

Chen, Jianqiu; Shu, Juan; Chen, Jiao; Cao, Zhiran; Xiao, An; Yan, Zhengyu

2017-05-01

S,N co-doped carbon quantum dots (N,S-CQDs) with super high quantum yield (79%) were prepared by the hydrothermal method and characterized by transmission electron microscopy, photoluminescence, UV-Vis spectroscopy and Fourier transformed infrared spectroscopy. N,S-CQDs can enhance the chemiluminescence intensity of a luminol-H 2 O 2 system. The possible mechanism of the luminol-H 2 O 2 -(N,S-CQDs) was illustrated by using chemiluminescence, photoluminescence and ultraviolet analysis. Ranitidine can quench the chemiluminescence intensity of a luminol-H 2 O 2 -N,S-CQDs system. So, a novel flow-injection chemiluminescence method was designed to determine ranitidine within a linear range of 0.5-50 μg ml -1 and a detection limit of 0.12 μg ml -1 . The method shows promising application prospects. Copyright © 2016 John Wiley & Sons, Ltd.
Adsorption of CO, CO2, H2, and H2O on titania surfaces with different oxidation states

International Nuclear Information System (INIS)

Raupp, G.B.; Dumesic, J.A.

1985-01-01

The adsorptive properties of titania surfaces with different oxidation states were proved by temperature-programmed desorption (TPD) of CO, H 2 , CO 2 , and H 2 O. Auger electron spectroscopy and X-ray photoelectron spectroscopy revealed that vacuum annealing an oxidized titanium foil at temperatures from 300 to 800 K was an effective means of systematically varying the average surface oxidation state from Ti 4+ to Ti 2+ . Carbon monoxide weakly adsorbed (desorption energy of 44-49 kJ x mol -1 ) in a carbonyl fashion on coordinatively unsaturated cation sites. Titania surfaces were inert with respect to H 2 adsorption and dissociation. Carbon dioxide adsorbed in a linear molecular fashion. Water adsorbed both molecularly and dissociatively. Results are discussed in terms of the role of titania oxidation state in CO hydrogenation over titania-supported metal catalysts. 74 references, 7 figures
Energy recovery of the H2S and CO2 elimination with technology by hybrid plasma

International Nuclear Information System (INIS)

Salazar T, J. A.

2014-01-01

This document is a research focused on energy recovery from acid gas removal contained in natural gas as hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ), by obtaining highly energetic gas such as syngas (mixture of hydrogen and carbon monoxide, in particular) using plasma technology in its hybrid form, namely, gliding arc plasma, that has the property to behave like a thermal plasma and cold plasma, besides possessing among other virtues the ability to treat large flows continuously at atmospheric pressure without the need of using noble gases, with a power consumption of no more than 1000 W. Furthermore, this type of plasma has demonstrated to be a clean and efficient not only by high conversion rates of H 2 S (86%) and CO 2 (56%) and high percentages of selectivity in the production of hydrogen (H 2 ) and carbon monoxide carbon (CO) obtained in this work, but because it can even be seriously considered to replace other technologies currently used in the process of sweetening natural gas as adsorption, absorption and sequestering membranes. The results shown are based on a series of analysis, simulations, experiments and calculations, from the design of the plasma generating source based on an impulse-phase circuit, to the electrical characterization results and simulation by acquiring electrical signals, without forgetting the characterization of the resulting chemical components using various analytical techniques such as mass spectrometry, gas chromatography (GC), optical emission spectroscopy (OES), optical spectroscopy Fourier inverse transformed (XRD) and scanning electron microscopy (Sem), X-ray diffraction (XRD) and multi-gas detectors (iBrid MX6). Additionally, performed chemical kinetics and reaction mechanism of the compounds involved in the degradation of H 2 S and CO 2 similar to those experienced as well as the study of energy efficiency (Ece), specific energy (Se), all this to meet a projects needs 127499, entitled -Development of alternative
Solubility of NaNd(CO3)2.6H2O(c) in concentrated Na2CO3 and NaHCO3 solutions

International Nuclear Information System (INIS)

Rao, L.; Rai, D.; Felmy, A.R.; Fulton, R.W.; Novak, C.F.

1996-01-01

NaNd(CO 3 ) 2 x 6 H 2 O(c) was identified to be the final equilibrium solid phase in suspensions containing concentrated sodium carbonate (0.1 to 2.0 M) and sodium bicarbonate (0.1 to 1.0 M), with either NaNd(CO 3 ) 2 x 6 H 2 O(c) or Nd 2 (CO 3 ) 3 x xH 2 O(s) as initial solids. A thermodynamic model, based on Pitzer's specific into-interaction approach, was developed to interpret the solubility of NaNd(CO 3 ) 2 x 6 H 2 O(c) as functions of sodium carbonate and sodium bicarbonate concentrations. In this model, the solubility data of NaNd(CO 3 ) 2 x 6 H 2 O(c) were explained by assuming the formation of NdCO 3 + , Nd(CO 3 ) 2 - and Nd(CO 3 ) 3 3- species and invoking the specific ion interactions between Na + and Nd(CO 3 ) 3 3- . Ion interaction parameters for Na + -Nd(CO 3 ) 3 3- were developed to fit the solubility data. Based on the model calculations, Nd(CO 3 ) 3 3- was the predominant aqueous neodymium species in 0.1 to 2 M sodium carbonate and 0.1 to 1 M sodium bicarbonate solutions. The logarithm of the NaNd(CO 3 ) 2 x 6 H 2 O solubility product (NaNd(CO 3 ) 2 x 6 H 2 O(c)=Na + +Nd 3+ +2 CO 3 2- +6 H 2 O) was calculated to be -21.39. This model also provided satisfactory interpretation of the solubility data of the analogous Am(III) system in less concentrated carbonate and bicarbonate solutions. (orig.)
High temperature H2/CO2 separation using cobalt oxide silica membranes

Energy Technology Data Exchange (ETDEWEB)

Smart, S.; Diniz da Costa, J.C. [The University of Queensland, FIMLab - Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, Qld 4072 (Australia); Vente, J.F. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands)

2012-09-15

In this work high quality cobalt oxide silica membranes were synthesized on alumina supports using a sol-gel, dip coating method. The membranes were subsequently connected into a steel module using a graphite based proprietary sealing method. The sealed membranes were tested for single gas permeance of He, H2, N2 and CO2 at temperatures up to 600C and feed pressures up to 600 kPa. Pressure tests confirmed that the sealing system was effective as no gas leaks were observed during testing. A H2 permeance of 1.9 x 10{sup -7} mol m{sup -2} s{sup -1} Pa-1 was measured in conjunction with a H2/CO2 permselectivity of more than 1500, suggesting that the membranes had a very narrow pore size distribution and an average pore diameter of approximately 3 Angstrom. The high temperature testing demonstrated that the incorporation of cobalt oxide into the silica matrix produced a structure with a higher thermal stability, able to resist thermally induced densification up to at least 600C. Furthermore, the membranes were tested for H2/CO2 binary feed mixtures between 400 and 600C. At these conditions, the reverse of the water gas shift reaction occurred, inadvertently generating CO and water which increased as a function of CO2 feed concentration. The purity of H2 in the permeate stream significantly decreased for CO2 feed concentrations in excess of 50 vol%. However, the gas mixtures (H2, CO2, CO and water) had a more profound effect on the H2 permeate flow rates which significantly decreased, almost exponentially as the CO2 feed concentration increased.
Acid Gas to Syngas (AG2S™) technology applied to solid fuel gasification: Cutting H_2S and CO_2 emissions by improving syngas production

International Nuclear Information System (INIS)

Bassani, Andrea; Pirola, Carlo; Maggio, Enrico; Pettinau, Alberto; Frau, Caterina; Bozzano, Giulia; Pierucci, Sauro; Ranzi, Eliseo; Manenti, Flavio

2016-01-01

Highlights: • Coal gasification with improved yield and reduced emissions. • AG2S™ process converts H_2S and CO_2 into syngas, elemental sulfur and water. • Techno-economic simulation of AG2S™ process is carried out. • Industrial case-study on the Sotacarbo S.p.A. gasification pilot plant is proposed. - Abstract: The paper deals with the application of the novel Acid Gas To Syngas (AG2S™) technology to the gasification of solid fuels. The AG2S technology is a completely new effective route of processing acid gases: H_2S and CO_2 are converted into syngas (CO and H_2) by means of a regenerative thermal reactor. To show the application of the AG2S technology, modeling and simulation advances for gasification systems are initially discussed. The multi-scale, multi-phase, and multi-component coal gasification system is described by means of detailed kinetic mechanisms for coal pyrolysis, char heterogeneous reactions and for successive gas-phase reactions. These kinetic mechanisms are then coupled with transport resistances resulting in first-principles dynamic modeling of non-ideal reactors of different types (e.g., downdraft, updraft, traveling grate), also including the catalytic effect of ashes. The generalized approach pursued in developing the model allows characterizing the main phenomena involved in the coal gasification process, including the formation of secondary species (e.g., COS, CS_2). This tool is here further validated on literature data and, then, adopted to demonstrate the AG2S effectiveness, where H_2S and CO_2 emissions are reduced with an increase of syngas production. The resulting process solution is more economically appealing with respect to the traditional Claus process and finds several application areas.
Et2NH2C6H3(CO23SnBr2.4H2O: SYNTHESIS AND INFRARED STUDY

Directory of Open Access Journals (Sweden)

DAOUDA NDOYE

2014-01-01

Full Text Available The title compound has been obtained on allowing [C6H3(CO23(Et2NH23] to react with SnBr4. The molecular structure of Et2NH2C6H3(CO23SnBr2.4H2O has been determined on the basis of the infrared data. The suggested structure is a dimer in which each tin atom is hexacoordinated by two chelating C6H3(CO233- anions and two Br atoms. Cy2NH2+cations are involved through hydrogen bonds with non-coordinating CO2 groups. The suggested structure is a cage.
Hydrogen constituents of the mesosphere inferred from positive ions - H2O, CH4, H2CO, H2O2, and HCN

Science.gov (United States)

Kopp, E.

1990-01-01

The concentrations in the mesosphere of H2O, CH4, H2CO, H2O2, and HCN were inferred from data on positive ion compositions, obtained from one mid-latitude and four high-latitude rocket flights. The inferred concentrations were found to agree only partially with the ground-based microwave measurements and/or model prediction by Garcia and Solomon (1985). The CH4 concentration was found to vary between 70 and 4 ppb in daytime and 900 and 100 ppbv at night, respectively. Unexpectedly high H2CO concentrations were obtained, with H2CO/H2O ratios between 0.0006 and 0.1, and a mean HCN volume mixing ratio of 6 x 10 to the -10th was inferred.
Methanesulfonates of high-valent metals. Syntheses and structural features of MoO_2(CH_3SO_3)_2, UO_2(CH_3SO_3)_2, ReO_3(CH_3SO_3), VO(CH_3SO_3)_2, and V_2O_3(CH_3SO_3)_4 and their thermal decomposition under N_2 and O_2 atmosphere

International Nuclear Information System (INIS)

Betke, Ulf; Neuschulz, Kai; Wickleder, Mathias S.

2011-01-01

Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO_3, UO_2(CH_3COO)_2.2 H_2O, Re_2O_7(H_2O)_2, and V_2O_5 with CH_3SO_3H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO_2(CH_3SO_3)_2 (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm"3, Z=8) contains [MoO_2] moieties connected by [CH_3SO_3] ions to form layers parallel to (100). UO_2(CH_3SO_3)_2 (P2_1/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1) "c"i"r"c"l"e, V=1.8937(3) nm"3, Z=8) consists of linear UO_2"2"+ ions coordinated by five [CH_3SO_3] ions, forming a layer structure. VO(CH_3SO_3)_2 (P2_1/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1) "c"i"r"c"l"e, V=0.8290(2) nm"3, Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO_3(CH_3SO_3) (P anti 1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2) "c"i"r"c"l"e, V=1.1523(4) nm"3, Z=8) a chain structure exhibiting infinite O-[ReO_2]-O-[ReO_2]-O chains is formed. Each [ReO_2]-O-[ReO_2] unit is coordinated by two bidentate [CH_3SO_3] ions. V_2O_3(CH_3SO_3)_4 (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm"3, Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH_3SO_3] ligands. Additional methanesulfonate ions connect the [V_2O_3] groups along [001]. Thermal decomposition of the compounds was monitored under N_2 and O_2 atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N_2 the decomposition proceeds with reduction of the metal leading to the oxides MoO_2, U_3O_7, V_4O_7, and VO_2; for MoO_2(CH_3SO_3)_2, a small amount of MoS_2 is formed. If the thermal decomposition is carried out in a atmosphere of O_2 the oxides MoO_3 and V_2O_5 are formed. (Copyright copyright 2011 WILEY-VCH Verlag
AOI [3] High-Temperature Nano-Derived Micro-H₂ and - H₂S Sensors

Energy Technology Data Exchange (ETDEWEB)

Sabolsky, Edward M. [West Virginia Univ., Morgantown, WV (United States)

2014-08-01

The emissions from coal-fired power plants remain a significant concern for air quality. This environmental challenge must be overcome by controlling the emission of sulfur dioxide (SO₂) and hydrogen sulfide (H₂S) throughout the entire coal combustion process. One of the processes which could specifically benefit from robust, low cost, and high temperature compatible gas sensors is the coal gasification process which converts coal and/or biomass into syngas. Hydrogen (H₂), carbon monoxide (CO) and sulfur compounds make up 33%, 43% and 2% of syngas, respectively. Therefore, development of a high temperature (>500°C) chemical sensor for in-situ monitoring of H₂, H₂S and SO2₂ levels during coal gasification is strongly desired. The selective detection of SO₂/H₂S in the presence of H₂, is a formidable task for a sensor designer. In order to ensure effective operation of these chemical sensors, the sensor system must inexpensively function within harsh temperature and chemical environment. Currently available sensing approaches, which are based on gas chromatography, electrochemistry, and IR-spectroscopy, do not satisfy the required cost and performance targets. This work focused on the development microsensors that can be applied to this application. In order to develop the high- temperature compatible microsensor, this work addressed various issues related to sensor stability, selectivity, and miniaturization. In the research project entitled “High-Temperature Nano-Derived Micro-H₂ and -H₂S Sensors”, the team worked to develop micro-scale, chemical sensors and sensor arrays composed of nano-derived, metal-oxide composite materials to detect gases like H₂, SO₂, and H₂S within high-temperature environments (>500°C). The research was completed in collaboration with NexTech Materials, Ltd. (Lewis Center, Ohio). Nex
Possible use of Fe/CO2 fuel cells for CO2 mitigation plus H2 and electricity production

International Nuclear Information System (INIS)

Rau, Greg H.

2004-01-01

The continuous oxidation of scrap iron in the presence of a constant CO 2 -rich waste gas stream and water is evaluated as a means of sequestering anthropogenic CO 2 as well as generating hydrogen gas and electricity. The stoichiometry of the net reaction, Fe 0 + CO 2 + H 2 O → FeCO 3 + H 2 , and assumptions about reaction rates, reactant and product prices/values and overhead costs suggest that CO 2 might be mitigated at a net profit in excess of $30/tonne CO 2 . The principle profit center of the process would be hydrogen production, alone providing a gross income of >$160/tonne CO 2 reacted. However, the realization of such fuel cell economics depends on a number of parameters including: (1) the rate at which the reaction can be sustained, (2) the areal and volumetric density with which H 2 and electricity can be produced, (3) the purity of the H 2 produced, (4) the transportation costs of the reactants (Fe, CO 2 and H 2 O) and products (FeCO 3 or Fe(HCO 3 ) 2 ) to/from the cells and (5) the cost/benefit trade-offs of optimizing the preceding variables in a given market and regulatory environment. Because of the carbon intensity of conventional iron metal production, a net carbon sequestration benefit for the process can be realized only when waste (rather than new) iron and steel are used as electrodes and/or when Fe(HCO 3 ) 2 is the end product. The used electrolyte could also provide a free source of Fe 2+ ions for enhancing iron-limited marine photosynthesis and, thus, greatly increasing the CO 2 sequestration potential of the process. Alternatively, the reaction of naturally occurring iron oxides (iron ore) with CO 2 can be considered for FeCO 3 formation and sequestration, but this foregoes the benefits of hydrogen and electricity production. Use of Fe/CO 2 fuel cells would appear to be particularly relevant for fossil fuel gasification/steam reforming systems given the highly concentrated CO 2 they generate and given the existing infrastructure they

Effect of SO 2 on CO 2 Capture Using Liquid-like Nanoparticle Organic Hybrid Materials

KAUST Repository

Lin, Kun-Yi Andrew

2013-08-15

Liquid-like nanoparticle organic hybrid materials (NOHMs), consisting of silica nanoparticles with a grafted polymeric canopy, were synthesized. Previous work on NOHMs has revealed that CO2 capture behaviors in these hybrid materials can be tuned by modifying the structure of the polymeric canopy. Because SO2, which is another acidic gas found in flue gas, would also interact with NOHMs, this study was designed to investigate its effect on CO2 capture in NOHMs. In particular, CO2 capture capacities as well as swelling and CO2 packing behaviors of NOHMs were analyzed using thermogravimetric analyses and Raman and attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopies before and after exposure of NOHMs to SO2. It was found that the SO2 absorption in NOHMs was only prominent at high SO2 levels (i.e., 3010 ppm; Ptot = 0.4 MPa) far exceeding the typical SO2 concentration in flue gas. As expected, the competitive absorption between SO2 and CO2 for the same absorption sites (i.e., ether and amine groups) resulted in a decreased CO2 capture capacity of NOHMs. The swelling of NOHMs was not notably affected by the presence of SO 2 within the given concentration range (Ptot = 0-0.68 MPa). On the other hand, SO2, owing to its Lewis acidic nature, interacted with the ether groups of the polymeric canopy and, thus, changed the CO2 packing behaviors in NOHMs. © 2013 American Chemical Society.
Effect of SO 2 on CO 2 Capture Using Liquid-like Nanoparticle Organic Hybrid Materials

KAUST Repository

Lin, Kun-Yi Andrew; Petit, Camille; Park, Ah-Hyung Alissa

2013-01-01

Liquid-like nanoparticle organic hybrid materials (NOHMs), consisting of silica nanoparticles with a grafted polymeric canopy, were synthesized. Previous work on NOHMs has revealed that CO2 capture behaviors in these hybrid materials can be tuned by modifying the structure of the polymeric canopy. Because SO2, which is another acidic gas found in flue gas, would also interact with NOHMs, this study was designed to investigate its effect on CO2 capture in NOHMs. In particular, CO2 capture capacities as well as swelling and CO2 packing behaviors of NOHMs were analyzed using thermogravimetric analyses and Raman and attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopies before and after exposure of NOHMs to SO2. It was found that the SO2 absorption in NOHMs was only prominent at high SO2 levels (i.e., 3010 ppm; Ptot = 0.4 MPa) far exceeding the typical SO2 concentration in flue gas. As expected, the competitive absorption between SO2 and CO2 for the same absorption sites (i.e., ether and amine groups) resulted in a decreased CO2 capture capacity of NOHMs. The swelling of NOHMs was not notably affected by the presence of SO 2 within the given concentration range (Ptot = 0-0.68 MPa). On the other hand, SO2, owing to its Lewis acidic nature, interacted with the ether groups of the polymeric canopy and, thus, changed the CO2 packing behaviors in NOHMs. © 2013 American Chemical Society.
Ternary CoS{sub 2}/MoS{sub 2}/RGO electrocatalyst with CoMoS phase for efficient hydrogen evolution

Energy Technology Data Exchange (ETDEWEB)

Liu, Yan-Ru; Shang, Xiao [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Gao, Wen-Kun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Dong, Bin, E-mail: dongbin@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Chi, Jing-Qi; Li, Xiao; Yan, Kai-Li; Chai, Yong-Ming [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Yun-Qi, E-mail: liuyq@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Chen-Guang [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China)

2017-08-01

Highlights: • Ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase as electrocatalyst for HER was prepared. • CoMoS phase have the metallic nature and highly intrinsic activity for HER. • RGO support ensures good distribution of CoMoS phase and enhances the conductivity. • The introduction of CoMoS and RGO may be a novel strategy for efficient HER of MoS{sub 2}. - Abstract: CoMoS phase with metallic character plays crucial role on enhancing the activity of MoS{sub 2} electrocatalysts for hydrogen evolution reaction (HER). However, only Co atoms located in the edges of MoS{sub 2} can create CoMoS phase, so it is a challenge to obtain CoMoS phase with homogeneous distribution limited by the layered MoS{sub 2} and doping method of Co. Herein, we reported a simple one-pot hydrothermal method to prepare novel ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase for HER using reduced graphene oxide (RGO) as support. XPS proves the formation of CoMoS phase, implying the enhanced activity for HER. RGO support ensures the well distribution of CoMoS phase and enhances the conductivity of CoS{sub 2}/MoS{sub 2}/RGO. Compared to CoS{sub 2}/RGO, MoS{sub 2}/RGO and CoS{sub 2}/MoS{sub 2}, the obtained CoS{sub 2}/MoS{sub 2}/RGO shows superior activity for HER with an onset overpotential of −80 mV (vs. RHE), small Tafel slope of 56 mV dec{sup −1}, high exchange current density of 11.4 μA cm{sup −2} and rigid electrochemical durability. The enhanced performances for HER may be ascribed to the formation of CoMoS phase with high activity and the existence of RGO support with good electrical conductivitys in ternary CoS{sub 2}/MoS{sub 2}/RGO. Therefore, the introduction of CoMoS phase and RGO into MoS{sub 2} could effectively enhance electrocatalytic properties for HER.
Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H2O)2SO4 and Cu(tn)Cl2

International Nuclear Information System (INIS)

Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander

2016-01-01

Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.
Energy recovery of the H{sub 2}S and CO{sub 2} elimination with technology by hybrid plasma; Recuperacion energetica de la eliminacion de H{sub 2}S y CO{sub 2} con tecnologia por plasma hibrido

Energy Technology Data Exchange (ETDEWEB)

Salazar T, J. A.

2014-07-01

This document is a research focused on energy recovery from acid gas removal contained in natural gas as hydrogen sulfide (H{sub 2}S) and carbon dioxide (CO{sub 2}), by obtaining highly energetic gas such as syngas (mixture of hydrogen and carbon monoxide, in particular) using plasma technology in its hybrid form, namely, gliding arc plasma, that has the property to behave like a thermal plasma and cold plasma, besides possessing among other virtues the ability to treat large flows continuously at atmospheric pressure without the need of using noble gases, with a power consumption of no more than 1000 W. Furthermore, this type of plasma has demonstrated to be a clean and efficient not only by high conversion rates of H{sub 2}S (86%) and CO{sub 2} (56%) and high percentages of selectivity in the production of hydrogen (H{sub 2}) and carbon monoxide carbon (CO) obtained in this work, but because it can even be seriously considered to replace other technologies currently used in the process of sweetening natural gas as adsorption, absorption and sequestering membranes. The results shown are based on a series of analysis, simulations, experiments and calculations, from the design of the plasma generating source based on an impulse-phase circuit, to the electrical characterization results and simulation by acquiring electrical signals, without forgetting the characterization of the resulting chemical components using various analytical techniques such as mass spectrometry, gas chromatography (GC), optical emission spectroscopy (OES), optical spectroscopy Fourier inverse transformed (XRD) and scanning electron microscopy (Sem), X-ray diffraction (XRD) and multi-gas detectors (iBrid MX6). Additionally, performed chemical kinetics and reaction mechanism of the compounds involved in the degradation of H{sub 2}S and CO{sub 2} similar to those experienced as well as the study of energy efficiency (Ece), specific energy (Se), all this to meet a projects needs 127499, entitled
Determination and modeling for the solubility of Na_2WO_4·2H_2O and Na_2MoO_4·2H_2O in the (Na"+ + MoO_4"2"− + WO_4"2"− + SO_4"2"− + H_2O) system

International Nuclear Information System (INIS)

Ning, Pengge; Xu, Weifeng; Cao, Hongbin; Xu, Hongbin

2016-01-01

Highlights: • The solubility of Na_2MoO_4·2H_2O and Na_2WO_4·2H_2O in Na_2MoO_4–Na_2WO_4–Na_2SO_4–H_2O were performed. • The solubility of sodium tungstate dihydrate in Na_2WO_4–Na_2SO_4–H_2O was determined. • The new model was established via regressing the published and the determined data. • The Pitzer parameter and the solubility product constant of the salt in solution were calculated. • The model was used to estimate the solubility of the sodium molybdate and sodium tungstate. - Abstract: The solubility of sodium tungstate dihydrate and sodium molybdate dihydrate in the (Na_2MoO_4 + Na_2WO_4 + Na_2SO_4 + H_2O) system was studied using experimental and calculated methods. The osmotic coefficient of sodium tungstate was fitted to calculate the thermodynamics parameters of (Na_2WO_4 + H_2O) system. The solubility of sodium tungstate dihydrate was determined using the dynamic method in Na_2WO_4–Na_2SO_4–H_2O to establish the new model which can provide an estimate the solubility of sodium tungstate dihydrate in various conditions, combined with the data published, the solubility of sodium tungstate dihydrate and the sodium molybdate dihydrate in quaternary system of (Na_2MoO_4 + Na_2WO_4 + Na_2SO_4 + H_2O) was estimated using the parameters of the two ternary systems of (Na_2WO_4 + Na_2SO_4 + H_2O) and (Na_2MoO_4 + Na_2SO_4 + H_2O). The results show that the AARD is always small and the calculated value is basically consistent with the experimental values for the system studied.
Rate-based modelling of combined SO2 removal and NH3 recycling integrated with an aqueous NH3-based CO2 capture process

International Nuclear Information System (INIS)

Li, Kangkang; Yu, Hai; Qi, Guojie; Feron, Paul; Tade, Moses; Yu, Jingwen; Wang, Shujuan

2015-01-01

Highlights: • A rigorous, rate-based model for an NH 3 –CO 2 –SO 2 –H 2 O system was developed. • Model predictions are in good agreement with pilot plant results. • >99.9% of SO 2 was captured and >99.9% of slipped ammonia was reused. • The process is highly adaptable to the variations of SO 2 /NH 3 level, temperatures. - Abstract: To reduce the costs of controlling emissions from coal-fired power stations, we propose an advanced and effective process of combined SO 2 removal and NH 3 recycling, which can be integrated with the aqueous NH 3 -based CO 2 capture process to simultaneously achieve SO 2 and CO 2 removal, NH 3 recycling and flue gas cooling in one process. A rigorous, rate-based model for an NH 3 –CO 2 –SO 2 –H 2 O system was developed and used to simulate the proposed process. The model was thermodynamically and kinetically validated by experimental results from the open literature and pilot-plant trials, respectively. Under typical flue gas conditions, the proposed process has SO 2 removal and NH 3 reuse efficiencies of >99.9%. The process is strongly adaptable to different scenarios such as high SO 2 levels in flue gas, high NH 3 levels from the CO 2 absorber and high flue gas temperatures, and has a low energy requirement. Because the process simplifies flue gas desulphurisation and resolves the problems of NH 3 loss and SO 2 removal, it could significantly reduce the cost of CO 2 and SO 2 capture by aqueous NH 3
H{sub 2}S and CO{sub 2} filtration of biogas used in internal combustion engines for power generation

Energy Technology Data Exchange (ETDEWEB)

Huertas, Jose Ignacio; Izquierdo, Sebastian [Instituto Tecnologico y de Estudios Superiores de Monterrey, (Mexico)]. E-mail: jhuertas@itesm.mx

2009-09-15

Currently, there is an increasing interest in connecting thousands of small electrical plants powered by renewable energy sources to national electrical grids. The use of biogas as fuel for internal combustion engines connected to an electric generator is emerging as one of the most attractive alternatives because of its very low cost benefit ratio and very high positive impact on the environment. However, the use of biogas to generate electricity has been limited by its high content of H{sub 2}S ({approx}3500 ppm) and CO{sub 2} ({approx}40%). CO{sub 2} presence reduces the energetic density of the fuel and therefore the power output of the system. The high content of H{sub 2}S corrodes important components of the engine like the combustion chamber, bronze gears and the exhaust system. This work aims to design and manufacture a low-cost industrial filter for this application. Among the different available methodologies, CaO, NaOH and amines where selected as the most appropriate for a typical farm application of 100 kW electric generations. Since there is not reported data for the H{sub 2}S absorbing capacity of these substances, it was proposed to measure it by means of a bubbler. It is an experimental set up where the gas stream passes through a fixed amount of the absorbing substance until it becomes saturated. The absorbing capacity is determined as the amount of substance being trapped divided by the mass of the absorbing substance being used. Results showed an absorbing capacity of 2.8, 41.4 and 124.8 g of H{sub 2}S per Kg of NaOH, CaO and monoethanolamine respectively. A gas absorbing system of amines was designed and manufactured for H{sub 2}S and CO{sub 2} biogas filtration. Three different types of amines were evaluated: Monoethanolamine, Diethanolamine, and methyldiethanolamine. Results show that all the amines require a ratio of amines to biogas flow of 0.7 to obtain a 95% of H{sub 2}S filtering efficiency. This data represent only a 30% of H{sub 2}S
Systems of Na/sup +/NO/sub 3/, Na/sub 2/SO/sub 4/, RbNO/sub 3/, Rb/sub 2/SO/sub 4/-H/sub 2/O and NaNO/sub 3/, Na/sub 2/SO/sub 4/, CsNO/sub 3/, Cs/sub 2/SO/sub 4/-H/sub 2/O at 25 and 75 deg C

Energy Technology Data Exchange (ETDEWEB)

Poletaev, I F; Krasnenkova, L V

1975-08-01

Quaternary Na/sup +/, Rb/sup +///NO/sub 3/-, SO/sub 4//sup 2 -/-H/sub 2/O and Nsub(+), Cs/sup +///NO/sub 3/-, SO/sub 4//sup 2 -/-H/sub 2/O mutual systems have been studied isothermally. The following six fields of crystallization have been revealed in these systems at 25 deg C: Cs/sub 2/SO/sub 4/, Na/sub 2/SO/sub 4/, Na/sub 2/SO/sub 4/x10H/sub 2/O, NaNO/sub 3/xNa/sub 2/SO/sub 4/x2H/sub 2/O, NaNO/sub 3/, and CsNO/sub 3/.
Generation of H{sub 2} and CO by solar thermochemical splitting of H{sub 2}O and CO{sub 2} by employing metal oxides

Energy Technology Data Exchange (ETDEWEB)

Rao, C.N.R., E-mail: cnrrao@jncasr.ac.in; Dey, Sunita

2016-10-15

Generation of H{sub 2} and CO by splitting H{sub 2}O and CO{sub 2} respectively constitutes an important aspect of the present-day concerns with energy and environment. The solar thermochemical route making use of metal oxides is a viable means of accomplishing these reduction reactions. The method essentially involves reducing a metal oxide by heating and passing H{sub 2}O or CO{sub 2} over the nonstoichiometric oxide to cause reverse oxidation by abstracting oxygen from H{sub 2}O or CO{sub 2}. While ceria, perovskites and other oxides have been investigated for this purpose, recent studies have demonstrated the superior performance of perovskites of the type Ln{sub 1−x}A{sub x}Mn{sub 1−y}M{sub y}O{sub 3} (Ln=rare earth, A=alkaline earth, M=various +2 and +3 metal ions), in the thermochemical generation of H{sub 2} and CO. We present the important results obtained hitherto to point out how the alkaine earth and the Ln ions, specially the radius of the latter, determine the performance of the perovskites. The encouraging results obtained are exemplefied by Y{sub 0.5}Sr{sub 0.5}MnO{sub 3} which releases 483 µmol/g of O{sub 2} at 1673 K and produces 757 µmol/g of CO from CO{sub 2} at 1173 K. The production of H{sub 2} from H{sub 2}O is also quite appreciable. Modification of the B site ion of the perovskite also affects the performance. In addition to perovskites, we present the generation of H{sub 2} based on the Mn{sub 3}O{sub 4}/NaMnO{sub 2} cycle briefly. - Graphical abstract: Ln{sub 0.5}A{sub 0.5}Mn{sub 1−x}M{sub x}O{sub 3} (Ln=lanthanide; A=Ca, Sr; M=Al, Ga, Sc, Mg, Cr, Fe, Co) perovskites are employed for the two step thermochemical splitting of CO{sub 2} and H{sub 2}O for the generation of CO and H{sub 2}. - Highlights: • Perovskite oxides based on Mn are ideal for the two-step thermochemical splitting of CO{sub 2} and H{sub 2}O. • In Ln{sub 1−x}A{sub x}MnO{sub 3} perovskite (Ln=rare earth, A=alkaline earth) both Ln and A ions play major roles
Photosynthesis under low-level SO/sub 2/ and CO/sub 2/ enhancement conditions in three duckweed species

Energy Technology Data Exchange (ETDEWEB)

Loats, K V [Denison Univ., Granville, OH; Noble, R; Takemoto, B

1981-09-01

Following exposure to 0.5 and 0.75 ppm SO/sub 2/ fumigation for up to 2 wk, apparent photosynthesis was determined in Lemna minor, L. valdiviana, and Spirodela oligorhiza by infrared gas analysis at 300, 500, and 1,000 ppm CO/sub 2/. Net photosynthesis was inhibited in L. valdiviana and S. oligorhiza but not in L. minor. The growth rate, as measured by frond count, was not affected in L. minor and L. valdiviana and only slightly in S. oligorhiza. Short-term CO/sub 2/ enhancement appreciably increased the photosynthetic rates.
Modeling Plasma-based CO2 and CH4 Conversion in Mixtures with N2, O2 and H2O: the Bigger Plasma Chemistry Picture

KAUST Repository

Wang, Weizong

2018-01-18

Due to the unique properties of plasma technology, its use in gas conversion applications is gaining significant interest around the globe. Plasma-based CO2 and CH4 conversion have become major research areas. Many investigations have already been performed regarding the single component gases, i.e. CO2 splitting and CH4 reforming, as well as for two component mixtures, i.e. dry reforming of methane (CO2/CH4), partial oxidation of methane (CH4/O2), artificial photosynthesis (CO2/H2O), CO2 hydrogenation (CO2/H2), and even first steps towards the influence of N2 impurities have been taken, i.e. CO2/N2 and CH4/N2. In this feature article we briefly discuss the advances made in literature for these different steps from a plasma chemistry modeling point of view. Subsequently, we present a comprehensive plasma chemistry set, combining the knowledge gathered in this field so far, and supported with extensive experimental data. This set can be used for chemical kinetics plasma modeling for all possible combinations of CO2, CH4, N2, O2 and H2O, to investigate the bigger picture of the underlying plasmachemical pathways for these mixtures in a dielectric barrier discharge plasma. This is extremely valuable for the optimization of existing plasma-based CO2 conversion and CH4 reforming processes, as well as for investigating the influence of N2, O2 and H2O on these processes, and even to support plasma-based multi-reforming processes.
Atmospheric H2S and SO2 as sulfur source for Brassica juncea and Brassica rapa: Impact on the glucosinolate composition

NARCIS (Netherlands)

Aghajanzadeh, T.; Kopriva, S; Hawkesford, M.J.; Koprivova, A.; De Kok, L.J.

2015-01-01

The impact of sulfate deprivation and atmospheric H2S and SO2 nutrition on the content and composition of glucosinolates was studied in Brassica juncea and Brasscia rapa. Both species contained a number of aliphatic and indolic glucosinolates. The total glucosinolate content was more than 5.5-fold
Laser photoelectron spectroscopy of MnH - 2, FeH - 2, CoH - 2, and NiH - 2: Determination of the electron affinities for the metal dihydrides

Science.gov (United States)

Miller, Amy E. S.; Feigerle, C. S.; Lineberger, W. C.

1986-04-01

The laser photoelectron spectra of MnH-2, FeH-2, CoH-2, and NiH-2 and the analogous deuterides are reported. Lack of vibrational structure in the spectra suggests that all of the dihydrides and their negative ions have linear geometries, and that the transitions observed in the spectra are due to the loss of nonbonding d electrons. The electron affinities for the metal dihydrides are determined to be 0.444±0.016 eV for MnH2, 1.049±0.014 eV for FeH2, 1.450±0.014 eV for CoH2, and 1.934±0.008 eV for NiH2. Electronic excitation energies are provided for excited states of FeH2, CoH2, and NiH2. Electron affinities and electronic excitation energies for the dideuterides are also reported. A limit on the electron affinity of CrH2 of ≥2.5 eV is determined. The electron affinities of the dihydrides directly correlate with the electron affinities of the high-spin states of the monohydrides, and with the electron affinities of the metal atoms. These results are in agreement with a qualitative model developed for bonding in the monohydrides.
Tail gas treatment of SEWGS technology. Literature review on CO2 and H2S separation

Energy Technology Data Exchange (ETDEWEB)

Fabbri, E.N.; Van Dijk, H.A.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2011-12-15

This literature review is the result of an investigation of the most important way to remove sulphur for the last decades. We will discuss Claus and Claus tail gas process options to solve the problem. Next to solutions which come from membranes, direct oxidation catalysis, from acid gas removal technology, sorbent technology, and liquid oxidation. Each field will be described and explained to understand in which way it could be suitable to separate CO2 and H2S and reach our goals with regard to CO2 transport and storage conditions. Finally, the target of this work will be to propose some interesting and promising solutions in view of future experiments.
submitter Thermodynamics of the formation of sulfuric acid dimers in the binary (H2SO4–H2O) and ternary (H2SO4–H2O–NH3) system

CERN Document Server

Kürten, A; Rondo, L; Bianchi, F; Duplissy, J; Jokinen, T; Junninen, H; Sarnela, N; Schobesberger, S; Simon, M; Sipilä, M; Almeida, J; Amorim, A; Dommen, J; Donahue, N M; Dunne, E M; Flagan, R C; Franchin, A; Kirkby, J; Kupc, A; Makhmutov, V; Petäjä, T; Praplan, A P; Riccobono, F; Steiner, G; Tomé, A; Tsagkogeorgas, G; Wagner, P E; Wimmer, D; Baltensperger, U; Kulmala, M; Worsnop, D R; Curtius, J

2015-01-01

Sulfuric acid is an important gas influencing atmospheric new particle formation (NPF). Both the binary $(H_2SO_4–H_2O)$ system and the ternary system involving ammonia $(H_2SO_4–H_2O–NH_3)$ may be important in the free troposphere. An essential step in the nucleation of aerosol particles from gas-phase precursors is the formation of a dimer, so an understanding of the thermodynamics of dimer formation over a wide range of atmospheric conditions is essential to describe NPF. We have used the CLOUD chamber to conduct nucleation experiments for these systems at temperatures from 208 to 248 K. Neutral monomer and dimer concentrations of sulfuric acid were measured using a chemical ionization mass spectrometer (CIMS). From these measurements, dimer evaporation rates in the binary system were derived for temperatures of 208 and 223 K. We compare these results to literature data from a previous study that was conducted at higher temperatures but is in good agreement with the present study. For the ternary sys...
Adsorption of H{sub 2}S or SO{sub 2} on an activated carbon cloth modified by ammonia treatment

Energy Technology Data Exchange (ETDEWEB)

Boudou, J.P.; Chehimi, M.; Broniek, E.; Siemieniewska, T.; Bimer, J. [University of Paris, Paris (France)

2003-07-01

The aim of this research is to investigate how ammonia treatment of the surface can influence the activity of a viscose-based activated carbon cloth (ACC) for the oxidative retention of H{sub 2}S and SO{sub 2} in humid air at 25{sup o}C. Surface basic nitrogen groups were introduced either by treatment with ammonia/air at 300{sup o}C or with ammonia/steam at 800{sup o}C. The pore structure of the samples so prepared was examined by adsorption measurements. Changes in the surface chemistry were assessed by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and temperature programmed desorption (TPD). The change of ACC activity could not be merely attributed to surface nitrogen groups but to other changes in the support. Ammonia/steam treatment improved ACC performance the most, not only by introducing nitrogen surface groups, but also by extending the microporosity and by modifying the distribution of surface oxygen groups. Successive adsorption-regeneration cycles showed important differences between oxidative retention of H{sub 2}S and SO{sub 2} and the subsequent catalyst/support regeneration process.
Exploring the atmospheric chemistry of O2SO3− and assessing the maximum turnover number of ion-catalysed H2SO4 formation

Directory of Open Access Journals (Sweden)

N. Bork

2013-04-01

Full Text Available It has recently been demonstrated that the O2SO3− ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density functional theory-based study of the reactions of O2SO3− with O3. The most important reactions are (a oxidation to O2SO3− and (b cluster decomposition into SO3, O2 and O3−. The former reaction is highly exothermic, and the nascent O2SO3− will rapidly decompose into SO4− and O2. If the origin of O2SO3− is SO2 oxidation by O3−, the latter reaction closes a catalytic cycle wherein SO2 is oxidized to SO3. The relative rate between the two major sinks for O2SO3− is assessed, thereby providing a measure of the maximum turnover number of ion-catalysed SO2 oxidation, i.e. how many SO2 can be oxidized per free electron. The rate ratio between reactions (a and (b is significantly altered by the presence or absence of a single water molecule, but reaction (b is in general much more probable. Although we are unable to assess the overall importance of this cycle in the real atmosphere due to the unknown influence of CO2 and NOx, we roughly estimate that ion-induced catalysis may contribute with several percent of H2SO4 levels in typical CO2-free and low NOx reaction chambers, e.g. the CLOUD chamber at CERN.
Interactive effects of high CO2 and SO2 on growth and antioxidant levels in wheat

NARCIS (Netherlands)

Rao, M.V.; De Kok, L.J.

1994-01-01

The impact of elevated CO2 and/or SO2 on the growth and antioxidant levels of wheat {Triticum aestivum L. cv. Urban) plants has been studied. High CO2 (0.7 ml I-1) significantly enhanced shoot biomass and photosynthetic capacity, while exposure to SO2 (0.14 ul I-1) resulted in a decreased shoot
Adsorption of CO2 and H2O on supported amine sorbents

NARCIS (Netherlands)

Veneman, Rens; Zhao, W.; Li, Z.; Cai, N.; Brilman, Derk Willem Frederik

2014-01-01

In this work we have evaluated the H2O and CO2 adsorption characteristics of Lewatit VP OC 1065 in view of the potential application of solid sorbents in post combustion CO2 capture. Here we present single component adsorption isotherms for H2O and CO2 as well as co-adsorption experiments. It was

Nd(NH2SO3)(SO4) . 1.5 H2O: a non-centrosymmetric amidosulfate-sulfate of neodymium

International Nuclear Information System (INIS)

Wickleder, M.S.

2005-01-01

The thermal decomposition of Nd(NH 2 SO 3 ) 3 . 2 H 2 O in a closed tube leads to violet single crystals of Nd(NH 2 SO 3 )(SO 4 ) . 1.5 H 2 O. The compound crystallizes with the space group P1 (Z = 2, a = 689.2, b = 691.4, c = 962.0 pm, α = 109.64, β = 97.00, γ = 109.62 ). The triclinic unit cell can be transformed into the respective bodycentered setting I1 (Z = 2, a = 977.9, b = 795.6, c = 1113.0 pm, α = 90.69, β = 115.06, γ = 88.98 ) leading to a nearly monoclinic unit cell for the compound. In the crystal structure of Nd(NH 2 SO 3 )(SO 4 ) . 1.5 H 2 O two Nd 3+ ions are present. Nd(1) 3+ is coordinated by four NH 2 SO 3 - and two SO 4 2- ions, and one H 2 O molecule. Owing to the chelating attack of the sulfate groups, the CN is nine. Nd(2) 3+ is surrounded by four monodentate SO 4 2- and two NH 2 SO 3 - groups. Two H 2 O ligands fill up the coordination sphere and lead to a CN of eight. The linkage of the polyhedra leads to a three-dimensional network. (orig.)
Preparation of {sup 35}SO{sub 4}H{sub 2} and of some other {sup 35}S labeled mineral compounds; Preparation de {sup 35}SO{sub 4}H{sub 2} et de quelques autres composes mineraux simples marques a {sup 35}S

Energy Technology Data Exchange (ETDEWEB)

De la Gueronniere, E; Henry, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

Methods of preparation, from pile irradiated KCI, of the following labeled molecules are described: - carrier free H{sub 2}SO{sub 4} - SCd (100 m curies/milli mole) - solution of SNa{sub 2} (100 m curies/milli mole) - solution of SK{sub 2} (100 m curies/milli mole) - S metalloid (100 m curies/milli mole) - SO{sub 3}Na{sub 2} (90 m curies/milli mole) - S{sub 2}C{sub 3}Na{sub 2} (50 m curies/mammalia). (author) [French] On decrit les methodes de preparation, a partir de KCl irradie dans les piles, des molecules suivantes marquees au {sup 35}S: - SO{sub 4}H{sub 2} (sans entraineur) - SCd (100 mcuries/millimole) - solution de SNa{sub 2} (100 mcuries/millimole) - solution de SK{sub 2} (100 mcuries/millimole) - S metalloide (100 mcuries/millimole) - Na{sub 2}SO{sub 3} (90 mcuries/millimole) - Na{sub 2}S{sub 2}C{sub 3} (50 mcuries/milIimole). (auteur)
Mixed-Matrix Membranes for CO2 and H2 Gas Separations Using Metal-Organic Framework and Mesoporus Hybrid Silicas

International Nuclear Information System (INIS)

Musselman, Inga; Balkus, Kenneth Jr.; Ferraris, John

2009-01-01

In this work, we have investigated the separation performance of polymer-based mixed-matrix membranes containing metal-organic frameworks and mesoporous hybrid silicas. The MOF/Matrimid(reg s ign) and MOP-18/Matrimid(reg s ign) membranes exhibited improved dispersion and mechanical strength that allowed high additive loadings with reduced aggregation, as is the case of the 80 wt% MOP-18/Matrimid(reg s ign) and the 80% (w/w) Cu-MOF/Matrimid(reg s ign) membranes. Membranes with up to 60% (w/w) ZIF-8 content exhibited similar mechanical strength and improved dispersion. The H 2 /CO 2 separation properties of MOF/Matrimid(reg s ign) mixed-matrix membranes was improved by either keeping the selectivity constant and increasing the permeability (MOF-5, Cu-MOF) or by improving both selectivity and permeability (ZIF-8). In the case of MOF-5/Matrimid(reg s ign) mixed-matrix membranes, the H 2 /CO 2 selectivity was kept at 2.6 and the H 2 permeability increased from 24.4 to 53.8 Barrers. For the Cu-MOF/Matrimid(reg s ign) mixed-matrix membranes, the H 2 /CO 2 selectivity was kept at 2.05 and the H 2 permeability increased from 17.1 to 158 Barrers. These two materials introduced porosity and uniform paths that enhanced the gas transport in the membranes. When ZIF-8/Matrimid(reg s ign) mixed-matrix membranes were studied, the H 2 /CO 2 selectivity increased from 2.9 to 4.4 and the permeability of H 2 increased from 26.5 to 35.8 Barrers. The increased H 2 /CO 2 selectivity in ZIF-8/Matrimid(reg s ign) membranes was explained by the sieving effect introduced by the ZIF-8 crystals (pore window 0.34 nm) that restricted the transport of molecules larger than H 2 . Materials with microporous and/or mesoporous cavities like carbon aerogel composites with zeolite A and zeolite Y, and membranes containing mesoporous ZSM-5 showed sieving effects for small molecules (e.g. H 2 and CO 2 ), however, the membranes were most selective for CO 2 due to the strong interaction of the zeolites with
A first principle Comparative study of electronic and optical properties of 1H –MoS2 and 2H –MoS2

International Nuclear Information System (INIS)

Kumar, Ashok; Ahluwalia, P.K.

2012-01-01

First principle calculations of electronic and optical properties of monolayer MoS 2 , so called 1H –MoS 2 , is performed which has emerged as a new direct band gap semiconductor. Before calculations of the properties of 1H –MoS 2 , we have calculated structural parameters, electronic properties (electronic band structure and electronic density of states) and frequency dependent optical response (real and imaginary part of dielectric function, energy loss function, absorption and reflectance spectra) of 2H –MoS 2 and compared with existing experimental results and found that our calculated results are in very good agreements with experimental results. To compare the dielectric functions of bulk (2H –MoS 2 ) and monolayer (1H –MoS 2 ) phases we have further extended these calculations to the single layer MoS 2 (1H –MoS 2 ) which is analogous to graphene. Structural parameters of 1H –MoS 2 are found very close to its bulk 2H –MoS 2 . We find direct electronic band gap at ‘K’ high symmetry point as compared to indirect band gap in its bulk 2H – MoS2. Our calculated dielectric function for 1H – MoS2 shows structure at nearly same energy positions as compared to 2H – MoS2 with additional structure at 3.8 eV. Also additional well defined energy loss peaks revealing the plasmonic resonances at 15.7 eV and 16.0 eV for E vector perpendicular and parallel to c axis respectively for 1H – MoS2 have been found, which are the signatures of surface plasmons at these energies. -- Highlights: ► Structural parameters of 2H-MoS2 and 1H-MoS2 are nearly identical. ► States around the Fermi energy are mainly due to the metal d states. ► Strong hybridization between Mo-d and S-p states below the Fermi energy has been found. ► Optical spectra of 2H-MoS2 finds very good agreements with experimental optical spectra. ► The band gap is found to be direct for 1H-MoS2 as compared to indirect for 2H-MoS2.
Testing the early Mars H2-CO2 greenhouse hypothesis with a 1-D photochemical model

Science.gov (United States)

Batalha, Natasha; Domagal-Goldman, Shawn D.; Ramirez, Ramses; Kasting, James F.

2015-09-01

A recent study by Ramirez et al. (Ramirez, R.M. et al. [2014]. Nat. Geosci. 7(1), 59-63. http://www.nature.com/doifinder/10.1038/ngeo2000 (accessed 16.09.14)) demonstrated that an atmosphere with 1.3-4 bar of CO2 and H2O, in addition to 5-20% H2, could have raised the mean annual and global surface temperature of early Mars above the freezing point of water. Such warm temperatures appear necessary to generate the rainfall (or snowfall) amounts required to carve the ancient martian valleys. Here, we use our best estimates for early martian outgassing rates, along with a 1-D photochemical model, to assess the conversion efficiency of CO, CH4, and H2S to CO2, SO2, and H2. Our outgassing estimates assume that Mars was actively recycling volatiles between its crust and interior, as Earth does today. H2 production from serpentinization and deposition of banded iron-formations is also considered. Under these assumptions, maintaining an H2 concentration of ˜1-2% by volume is achievable, but reaching 5% H2 requires additional H2 sources or a slowing of the hydrogen escape rate below the diffusion limit. If the early martian atmosphere was indeed H2-rich, we might be able to see evidence of this in the rock record. The hypothesis proposed here is consistent with new data from the Curiosity Rover, which show evidence for a long-lived lake in Gale Crater near Mt. Sharp. It is also consistent with measured oxygen fugacities of martian meteorites, which show evidence for progressive mantle oxidation over time.
Exploring the atmospheric chemistry of O2SO3- and assessing the maximum turnover number of ion-catalysed H2SO4 formation

DEFF Research Database (Denmark)

Bork, Nicolai Christian; Kurtén, T.; Vehkamäki, H.

2013-01-01

molecule, but reaction (b) is in general much more probable. Although we are unable to assess the overall importance of this cycle in the real atmosphere due to the unknown influence of CO2 and NOx, we roughly estimate that ion-induced catalysis may contribute with several percent of H2SO4 levels......It has recently been demonstrated that the O2SO3- ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density functional theory-based study of the reactions of O2SO3- with O-3. The most important reactions are (a) oxidation to O3SO3- and (b) cluster...... the two major sinks for O2SO3- is assessed, thereby providing a measure of the maximum turnover number of ion-catalysed SO2 oxidation, i.e. how many SO2 can be oxidized per free electron. The rate ratio between reactions (a) and (b) is significantly altered by the presence or absence of a single water...
FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H2S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

International Nuclear Information System (INIS)

Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S.; Nuevo, M.; Jiménez-Escobar, A.; Muñoz Caro, G. M.; Wu, C.-Y. R.; Fung, H.-S.; Ip, W.-H.

2015-01-01

Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H 2 S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H 2 S and CO 2 :H 2 S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS 2 , OCS, SO 2 , etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H 2 S ice mixtures is higher than that of CO 2 :H 2 S ice mixtures; (2) a lower concentration of H 2 S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS 2 differ significantly upon VUV and EUV irradiations. Furthermore, CS 2 was produced only after VUV photoprocessing of CO:H 2 S ices, while the VUV-induced production of SO 2 occurred only in CO 2 :H 2 S ice mixtures. More generally, the production yields of OCS, H 2 S 2 , and CS 2 were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H 2 S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments
GAS PHASE STRUCTURE AND STABILITY OF COMPLEX FORMED BY H2O, NH3, H2S AND THEIR METHYL DERIVATIVES WITH THE CATION CO2+

Directory of Open Access Journals (Sweden)

Cahyorini Kusumawardani

2010-06-01

Full Text Available Ab initio molecular orbital calculations at the Hartree-Fock-Self Consistent Field (HF-SCF have been performed in order to determine the structure and gas phase energies of complex formed by the Lewis bases of H2O, NH3, H2S and their methyl derivatives with the cation Co2+. The relative basicities of the base studied depend on both the substituent. The gas-phase interaction energies computed by the SCF method including electron correlation Møller-Plesset 2 (MP2 dan Configuration Iteration (CI were comparable in accuracy. The binding energies computed by these two methods reach the targeted chemical accuracy. Keywords: ab initio calculation, cobalt complex, structure stability
The nido-osmaboranes [2,2,2-(CO)(PPh(3))(2)-nido-2-OsB(5)H(9)] and [6,6,6-(CO)(PPh(3))(2)-nido-6-OsB(9)H(13)].

Science.gov (United States)

Bould, J; Kennedy, J D; Thomas, R L; Rath, N P; Barton, L

2001-11-01

The structural characterization of the osmahexaborane 2-carbonyl-2,2-bis(triphenylphosphine)-nido-2-osmahexaborane(9), [Os(B(5)H(9))(C(18)H(15)P)(2)(CO)], (I), a metallaborane analogue of B(6)H(10), confirms the structure proposed from NMR spectroscopy. The structure of the osmadecaborane 6-carbonyl-6,6-bis(triphenylphosphine)-nido-6-osmadecaborane(13), [Os(B(9)H(13))(C(18)H(15)P)(2)(CO)], (IV), is similarly confirmed. The short basal B-B distance of 1.652 (8) A in (I), not bridged by an H atom, mirrors that in the parent hexaborane(10) [1.626 (4) A].
Pumping characteristics for H2, CO and gas mixture of H2 and CO of distributed ion pump for the SPring-8 storage ring

International Nuclear Information System (INIS)

Hirano, Nobuo; Kobari, Toshiaki; Matsumoto, Manabu

1995-01-01

Evacuation in the vacuum chamber of the deflection magnet part of the SPring-8 storage ring is planned to be performed with a non evaporable getter pump (NEG) as well as a distributed ion pump (DIP). Pumping characteristics for H 2 , CO and a gas mixture of H 2 and CO of DIP was investigated. The structure of the DIP constructed on a trial basis and an experimental setup to measure the DIP pumping characteristics were described. Pumping speed above 100 L/s per 1 m at the 10 -6 Pa device and pumping speed of about 500 L/s per 1 m at the 10 -7 Pa device were achieved for a gas mixture of H 2 and CO (37% and 55% CO). On the DIP saturated with CO, pumping speed for H 2 is about twice that of pumping speed for CO at the 10 -7 Pa device. Pumping speed for CO is about 1.5 times of the speed for N 2 at the 10 -6 Pa device. Pressure of 1.2 x 10 -8 Pa (9.0 x 10 -11 Torr) is achieved at a room temperature by baking at 150degC for 40 hr. Thus, it was confirmed that the DIP has sufficient pumping characteristics as a pump for the SPring-8 storage ring. (T.H.)
Adsorption of H2O and CO2 on supported amine sorbents

NARCIS (Netherlands)

Veneman, Rens; Frigka, Natalia; Zhao, Wenying; Li, Zhenshan; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

2015-01-01

In this work the adsorption of H2O and CO2 on Lewatit VP OC 1065 was studied in view of the potential application of this sorbent in post combustion CO2 capture. Both CO2 and H2O were found to adsorb on the amine active sites present on the pore surface of the sorbent material. However, where the
Atmospheric H2S and SO2 as sulfur sources for Brassica juncea and Brassica rapa: Regulation of sulfur uptake and assimilation

NARCIS (Netherlands)

Aghajanzadeh, T.; Hawkesford, M.J.; De Kok, L.J.

2016-01-01

Brassica juncea and Brassica rapa were able to utilize foliarly absorbed H2S and SO2 as sulfur source for growth and resulted in a decreased sink capacity of the shoot for sulfur supplied by the root and subsequently in a partial decrease in sulfate uptake capacity of the roots. Sulfate-deprived
Measurement of CO{sub 2}, CO, SO{sub 2}, and NO emissions from coal-based thermal power plants in India

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, N.; Mukheriee, I.; Santra, A.K.; Chowdhury, S.; Chakraborty, S.; Bhattacharya, S.; Mitra, A.P.; Sharma, C. [Jadavpur University, Calcutta (India). Dept. of Power Engineering

2008-02-15

Measurements of CO{sub 2} (direct GHG) and CO, SO{sub 2}, NO (indirect GHGs) were conducted on-line at some of the coal-based thermal power plants in India. The objective of the study was three-fold: to quantify the measured emissions in terms of emission coefficient per kg of coal and per kWh of electricity, to calculate the total possible emission from Indian thermal power plants, and subsequently to compare them with some previous studies. Instrument IMR 2800P Flue Gas Analyzer was used on-line to measure the emission rates Of CO{sub 2}, CO, SO{sub 2}, and NO at 11 numbers of generating units of different ratings. Certain quality assurance (QA) and quality control (QC) techniques were also adopted to gather the data so as to avoid any ambiguity in subsequent data interpretation. For the betterment of data interpretation, the requisite statistical parameters (standard deviation and arithmetic mean) for the measured emissions have been also calculated. The emission coefficients determined for CO{sub 2}, CO, SO{sub 2}, and NO have been compared with their corresponding values as obtained in the studies conducted by other groups. The total emissions of CO{sub 2}, CO, SO{sub 2}, and NO calculated on the basis of the emission coefficients for the year 2003-2004 have been found to be 465.667, 1.583, 4.058, and 1.129 Tg, respectively.
Clinical Applications of CO2 and H2 Breath Test

Directory of Open Access Journals (Sweden)

ZHAO Si-qian;CHEN Bao-jun;LUO Zhi-fu

2016-08-01

Full Text Available Breath test is non-invasive, high sensitivity and high specificity. In this article, CO2 breath test, H2 breath test and their clinical applications were elaborated. The main applications of CO2 breath test include helicobacter pylori test, liver function detection, gastric emptying test, insulin resistance test, pancreatic exocrine secretion test, etc. H2 breath test can be applied in the diagnosis of lactose malabsorption and detecting small intestinal bacterial overgrowth. With further research, the breath test is expected to be applied in more diseases diagnosis.
Mineralogical controls on porosity and water chemistry during O_2-SO_2-CO_2 reaction of CO_2 storage reservoir and cap-rock core

International Nuclear Information System (INIS)

Pearce, Julie K.; Golab, Alexandra; Dawson, Grant K.W.; Knuefing, Lydia; Goodwin, Carley; Golding, Suzanne D.

2016-01-01

-rocks could be expected to act as baffles to fluids preventing vertical fluid migration. Concentrations of dissolved elements including Ca, Fe, Mn, and Ni increased during reactions of several core samples, with Mn, Mg, Co, and Zn correlated with Ca from cap-rock cores. Precipitation of gypsum, Fe-oxides and clays on seal core samples sequestered dissolved elements including Fe through co-precipitation or adsorption. A conceptual model of impure CO_2-water-rock interactions for a siliciclastic reservoir is discussed. - Highlights: • O_2-SO_2-CO_2 experiments on CO_2 sequestration site reservoir and cap-rock cores. • Coupled micro CT and geochemical characterization before and after reactions. • Strong acidification with reservoir core, no change in porosity. • Formation of open porosity in calcite cemented core, with buffered pH. • Dissolved Mn, Mg, Co, and Zn correlated with Ca from cap-rocks.
Functionalization of liquid-exfoliated two-dimensional 2H-MoS2.

Science.gov (United States)

Backes, Claudia; Berner, Nina C; Chen, Xin; Lafargue, Paul; LaPlace, Pierre; Freeley, Mark; Duesberg, Georg S; Coleman, Jonathan N; McDonald, Aidan R

2015-02-23

Layered two-dimensional (2D) inorganic transition-metal dichalchogenides (TMDs) have attracted great interest as a result of their potential application in optoelectronics, catalysis, and medicine. However, methods to functionalize and process such 2D TMDs remain scarce. We have established a facile route towards functionalized layered MoS2 . We found that the reaction of liquid-exfoliated 2D MoS2 , with M(OAc)2 salts (M=Ni, Cu, Zn; OAc=acetate) yielded functionalized MoS2 -M(OAc)2 materials. Importantly, this method furnished the 2H-polytype of MoS2 which is a semiconductor. X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT-IR), and thermogravimetric analysis (TGA) provide strong evidence for the coordination of MoS2 surface sulfur atoms to the M(OAc)2 salt. Interestingly, functionalization of 2H-MoS2 allows for its dispersion/processing in more conventional laboratory solvents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Supersaturation of dissolved H(2) and CO (2) during fermentative hydrogen production with N(2) sparging.

Science.gov (United States)

Kraemer, Jeremy T; Bagley, David M

2006-09-01

Dissolved H(2) and CO(2) were measured by an improved manual headspace-gas chromatographic method during fermentative H(2) production with N(2) sparging. Sparging increased the yield from 1.3 to 1.8 mol H(2)/mol glucose converted, although H(2) and CO(2) were still supersaturated regardless of sparging. The common assumption that sparging increases the H(2) yield because of lower dissolved H(2) concentrations may be incorrect, because H(2) was not lowered into the range necessary to affect the relevant enzymes. More likely, N(2) sparging decreased the rate of H(2) consumption via lower substrate concentrations.
40 CFR 1065.370 - CLD CO2 and H2O quench verification.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false CLD CO2 and H2O quench verification....370 CLD CO2 and H2O quench verification. (a) Scope and frequency. If you use a CLD analyzer to measure NOX, verify the amount of H2O and CO2 quench after installing the CLD analyzer and after major...
Calculation of phase equilibria in the Na2SO4-K2SO4-Cs2SO4-H2O system at 25 deg C

International Nuclear Information System (INIS)

Filippov, V.K.; Kalinkin, A.M.; Vasin, S.K.

1990-01-01

Calculation results of solubility diagram and water activity in saturated solutions of Na 2 SO 4 -K 2 SO 4 -Cs 2 SO 4 -H 2 O system at 25 deg C are presented. It is shown that for the calculation of quaternary systems one can use the Pitzer equations. Solubility diagram for the system studied is plotted and data on composition and water activity of solutions saturated by two or three solid phases are given. Classification of nonvariant equilibria from the viewpoint of isomorphism of solubility and fusibility diagrams permits to depict the direction of phase processes during isothermal evaporation of water
Low-Temperature Thermal Reactions Between SO2 and H2O2 and Their Relevance to the Jovian Icy Satellites

Science.gov (United States)

Loeffler, Mark J.; Hudson, Reggie L.

2013-01-01

Here we present first results on a non-radiolytic, thermally-driven reaction sequence in solid H2O +SO2 + H2O2 mixtures at 50-130 K, which produces sulfate (SO(-2)/(4)), and has an activation energy of 53 kJ/mole. We suspect that these results may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

Carbonate hydrates of the heavy alkali metals: preparation and structure of Rb{sub 2}CO{sub 3} . 1.5 H{sub 2}O und Cs{sub 2}CO{sub 3} . 3 H{sub 2}O; Carbonat-Hydrate der schweren Alkalimetalle: Darstellung und Struktur von Rb{sub 2}CO{sub 3} . 1,5 H{sub 2}O und Cs{sub 2}CO{sub 3} . 3 H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Cirpus, V.; Wittrock, J.; Adam, A. [Koeln Univ. (Germany). Inst. fuer Anorganische Chemie

2001-03-01

Rb{sub 2}CO{sub 3} . 1.5 H{sub 2}O and Cs{sub 2}CO{sub 3} . 3 H{sub 2}O were prepared from aqueous solution and by means of the reaction of dialkylcarbonates with RbOH and CsOH resp. in hydrous alcoholes. Based on four-circle diffractometer data, the crystal structures were determined (Rb{sub 2}CO{sub 3} . 1.5 H{sub 2}O: C2/c (no. 15), Z = 8, a = 1237.7(2) pm, b = 1385.94(7) pm, c = 747.7(4) pm, {beta} = 120.133(8) , V{sub EZ} = 1109.3(6) . 10{sup 6} pm{sup 3}; Cs{sub 2}CO{sub 3} . 3 H{sub 2}O: P2/c (no. 13), Z = 2, a = 654.5(2) pm, b = 679.06(6) pm, c = 886.4(2) pm, {beta} = 90.708(14) , V{sub EZ} = 393.9(2) . 10{sup 6} pm{sup 3}). Rb{sub 2}CO{sub 3} . 1.5 H{sub 2}O is isostructural with K{sub 2}CO{sub 3} . 1.5 H{sub 2}O. In case of Cs{sub 2}CO{sub 3} . 3 H{sub 2}O no comparable structure is known. Both structures show {sub {infinity}}{sup 1}[(CO{sub 3}{sup 2-})(H{sub 2}O)]-chains, being connected via additional H{sub 2}O forming columns (Rb{sub 2}CO{sub 3} . 1.5 H{sub 2}O) and layers (Cs{sub 2}CO{sub 3} . 3 H{sub 2}O), respectively. (orig.)
REMOVAL OF H(sub 2)S AND SO(sub 2) BY CaCO(sub 3)-BASED SORBENTS AT HIGH PRESSURES; SEMIANNUAL

International Nuclear Information System (INIS)

Prof. Stratis V. Sotirchos

1998-01-01

During the six months of this reporting period, we did more experiments on the study of the behavior of the sulfidation of precalcined limestones in the presence of small amounts of oxygen. Sulfidation experiments in the presence of oxygen were carried out because in past experiments we had observed that leaks of oxygen into the feed mixture led to completely different results from those obtained in the absence of oxygen. The new experiments reaffirmed the observations that we had made in our previous studies. The behavior of the sulfidation of limestone was found to depend strongly, in both a qualitative and a quantitative sense, on the level of the oxygen concentration in the feed. For small concentration of oxygen, the weight gained by the calcined sample during sulfidation in a N(sub 2)-H(sub 2)S atmosphere presented a maximum, whereas for concentrations above 0.5-0.8%, it increased continuously, reaching in some cases values that corresponded to complete conversion of CaO to CaSO(sub 4). The maximum in the variation of the weight gain with time tended to become more pronounced as the intraparticle diffusional limitations were decreased. The use of different sample sizes showed that the interparticle diffusional limitations had a similar effect, and this led us to the conclusion that the main cause for the presence of a maximum in the variation of the weight of the sample during sulfidation in the presence of oxygen is the formation of a volatile product (possibly Ca) in the CaS-CaSO(sub 4) solid-solid reaction
Noble metal (Pt or Au)-doped monolayer MoS2 as a promising adsorbent and gas-sensing material to SO2, SOF2 and SO2F2: a DFT study

Science.gov (United States)

Chen, Dachang; Zhang, Xiaoxing; Tang, Ju; Cui, Hao; Li, Yi

2018-02-01

We explored the adsorption of SO2, SOF2, and SO2F2 on Pt- or Au-doped MoS2 monolayer based on density functional theory. The adsorption energy, adsorption distance, charge transfer as well as density of states were discussed. SO2 and SOF2 exhibit strong chemical interactions with Pt-doped MoS2 based on large adsorption energy, charge transfer, and changes of electron orbitals in gas molecule. SO2 also shows obvious chemisorption on Au-doped MoS2 with apparent magnetism transfer from Au to gas molecules. The adsorption of SO2F2 on Pt-MoS2 and SOF2 on Au-MoS2 exhibits weaker chemical interactions and SO2F2 losses electrons when adsorbed on Pt-MoS2 which is different from other gas adsorption. The adsorption of SO2F2 on Au-MoS2 represents no obvious chemical interaction but physisorption. The gas-sensing properties are also evaluated based on DFT results. This work could provide prospects and application value for typical noble metal-doped MoS2 as gas-sensing materials.
Redução da emissão de CO2, CH4 e H2S através da compostagem de dejetos suínos Reduction emissions of CO2, CH4 and H2S through composting of swine manure

Directory of Open Access Journals (Sweden)

Luana G. Sardá

2010-09-01

Full Text Available Em conjunto com o crescente desenvolvimento da tecnologia para a produção de suínos ocorreu uma forte exploração e degradação do ambiente, razão pela qual a atividade se transformou em fonte poluidora das regiões produtoras. Buscam-se, então, alternativas que minimizem o potencial poluidor do atual sistema de produção. O trabalho proposto foi comparar o perfil de emissão de dióxido de carbono (CO2, metano (CH4 e gás sulfídrico (H2S do manejo de dejetos suínos nas formas sólida (compostagem e líquida (esterqueira, e avaliar a eficiência do processo de compostagem através dos parâmetros físico-químicos. O ensaio foi implantado no campo experimental da EMBRAPA Suínos e Aves, localizada no município de Concórdia, SC. Contatou-se, na compostagem, uma redução de 7 vezes na emissão de CH4, com relação à esterqueira; a emissão de CO2 representou 78,5% do carbono total mineralizado. Considerando-se que a emissão de H2S foi expressiva apenas no manejo dos dejetos na forma líquida, pode-se afirmar que o manejo dos resíduos na forma sólida é uma alternativa para a redução dos impactos ambientais pela mitigação do efeito estufa e pela redução de odores.In conjunction with the development of technologies for the production of swine meat, a strong exploration and degradation of the environment occurred and the activity became a source of pollution in the producing regions. Therefore, there is a need for alternative technologies that minimize the pollutant potential of the current system of production. The proposed work was to analyze and to compare the emission of carbon dioxide (CO2, methane (CH4 and hydrogen sulfide (H2S between the management of swine manure in solid form (composting and liquid manure (deep pit, and assess the efficiency of the process of composting through the physical and chemical parameters. The test was implemented in the experimental field of Embrapa Suínos e Aves, located in Concordia (SC
Oxidation and Condensation of Zinc Fume From Zn-CO2-CO-H2O Streams Relevant to Steelmaking Off-Gas Systems

International Nuclear Information System (INIS)

Bronson, Tyler Mark; Ma, Naiyang; Zhu, Liang Zhu; Sohn, Hong Yong

2017-01-01

Here the objective of this research was to study the condensation of zinc vapor to metallic zinc and zinc oxide solid under varying environments to investigate the feasibility of in-process separation of zinc from steelmaking off-gas dusts. Water vapor content, temperature, degree of cooling, gas composition, and initial zinc partial pressure were varied to simulate the possible conditions that can occur within steelmaking off-gas systems, limited to Zn-CO 2 -CO-H 2 O gas compositions. The temperature of deposition and the effect of rapidly quenching the gas were specifically studied. A homogeneous nucleation model for applicable experiments was applied to the analysis of the experimental data. It was determined that under the experimental conditions, oxidation of zinc vapor by H 2 O or CO 2 does not occur above 1108 K (835 °C) even for highly oxidizing streams (CO 2 /CO = 40/7). Rate expressions that correlate CO 2 and H 2 O oxidation rates to gas composition, partial pressure of water vapor, temperature, and zinc partial pressure were determined to be as follows: Rate ((mol)/(m 2 s)) = 406 exp ((−50.2kJ/mol)/(RT)) (pZnpCO 2 − PCO/K eq CO 2 ) ((mol)/(m 2 xs)) Rate (((mol)/(m 2 s))) = 32.9 exp (((−13.7kJ/mol)/(RT))) (pZnPH 2 O − PH 2 /K eq H 2 O) ((mol)/(m 2 xs)). It was proven that a rapid cooling rate (500 K/s) significantly increases the ratio of metallic zinc to zinc oxide as opposed to a slow cooling rate (250 K/s). SEM analysis found evidence of heterogeneous growth of ZnO as well as of homogeneous formation of metallic zinc. The homogeneous nucleation model fit well with experiments where only metallic zinc deposited. An expanded model with rates of oxidation by CO 2 and H 2 O as shown was combined with the homogenous nucleation model and then compared with experimental data. The calculated results based on the model gave a reasonable fit to the measured data. For the conditions used in this study, the rate equations for the oxidation of zinc by
Experimental and simulation studies of iron oxides for geochemical fixation of CO2-SO2 gas mixtures

Science.gov (United States)

Garcia, Susana; Rosenbauer, Robert J.; Palandri, James; Maroto-Valer, M. Mercedes

2011-01-01

Iron-bearing minerals are reactive phases of the subsurface environment and could potentially trap CO2–SO2gas mixtures derived from fossil fuel combustion processes by their conversion to siderite (FeCO3) and dissolved sulfate. Changes in fluid and mineral compositions resulting from reactions, involving the co-injection of SO2 with CO2 were observed both theoretically and experimentally. Experiments were conducted with a natural hematite (α-Fe2O3) sample. A high pressure-high temperature apparatus was used to simulate conditions in geologic formations deeper than 800 m, where CO2 is in the supercritical state. Solid samples were allowed to react with a NaCl–NaOH brine and SO2-bearing CO2-dominated gas mixtures. The predicted equilibrium mineral assemblage at 100 °C and 250 bar became hematite, dawsonite (NaAl(OH)2CO3), siderite (FeCO3) and quartz (SiO2). Experimentally, siderite and dawsonite, derived from the presence of kaolinite (Al2Si2O5(OH)4) in the parent material, were present in residual solids at longer reaction time intervals, which agreed well with results from the modelling work.
Ce2O3-SO3-H2O system at 150 and 200 deg C

International Nuclear Information System (INIS)

Belokoskov, V.I.; Trofimov, G.V.; Govorukhina, O.A.

1978-01-01

The solubility, solid phase composition and crystal characteristics in the Ce 2 O 3 -SO 3 -H 2 O system have been studied in a broad range of sulfuric acid concentrations (25 to 80% SO 3 ) at temperatures from 150 to 200 deg C. It has been established that in the system the equilibrium had been reached after 15 to 20 days. At 150 deg C, Ce 2 (SO 4 ) 3 x2H 2 O, Ce 2 (SO 4 ) 3 xH 2 O sulfates and Ce 2 (SO 4 ) 3 x3H 2 SO 4 acid salt crystallize in the system. At 200 deg C, the same sulfates crystallize in the system, except that the bisaturation points of the system are shifted, with respect to 150 deg C, into the region of higher SO 3 concentration and correspond to solutions with a SO 3 concentration of 57.8 and 65%. The solubility of cerium(3) at 150 deg C is about 0.5% Ce 2 O 3 . An increase in temperature up to 200 deg C leads to a slightly higher solubility of cerium sulfates
FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H{sub 2}S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

Energy Technology Data Exchange (ETDEWEB)

Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S. [Department of Physics, National Central University, Jhongli City, Taoyuan County 32054, Taiwan (China); Nuevo, M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Jiménez-Escobar, A.; Muñoz Caro, G. M. [Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, E-28850 Madrid (Spain); Wu, C.-Y. R. [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States); Fung, H.-S. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Ip, W.-H. [Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County 32049, Taiwan (China)

2015-01-10

Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H{sub 2}S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H{sub 2}S and CO{sub 2}:H{sub 2}S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS{sub 2}, OCS, SO{sub 2}, etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H{sub 2}S ice mixtures is higher than that of CO{sub 2}:H{sub 2}S ice mixtures; (2) a lower concentration of H{sub 2}S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS{sub 2} differ significantly upon VUV and EUV irradiations. Furthermore, CS{sub 2} was produced only after VUV photoprocessing of CO:H{sub 2}S ices, while the VUV-induced production of SO{sub 2} occurred only in CO{sub 2}:H{sub 2}S ice mixtures. More generally, the production yields of OCS, H{sub 2}S{sub 2}, and CS{sub 2} were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H{sub 2}S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments.
Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

Directory of Open Access Journals (Sweden)

Jianbo Sun

2016-03-01

Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.
Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

Science.gov (United States)

Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng

2016-01-01

The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328
Isostructural and cage-specific replacement occurring in sII hydrate with external CO2/N2 gas and its implications for natural gas production and CO2 storage

International Nuclear Information System (INIS)

Seo, Young-ju; Park, Seongmin; Kang, Hyery; Ahn, Yun-Ho; Lim, Dongwook; Kim, Se-Joon; Lee, Jaehyoung; Lee, Joo Yong; Ahn, Taewoong; Seo, Yongwon; Lee, Huen

2016-01-01

Highlights: • The structural sustainability of sII hydrate is demonstrated during the replacement. • The experimental evidence of isostructural replacement is revealed. • The cage-specific replacement in sII hydrates allows long-term CO 2 storage. • The compositions and extent of replacement are cross-checked by GC and NMR analyses. - Abstract: A replacement technique has been regarded as a promising strategy for both CH 4 exploitation from gas hydrates and CO 2 sequestration into deep-ocean reservoirs. Most research has been focused on replacement reactions that occur in sI hydrates due to their prevalence in natural gas hydrates. However, sII hydrates in nature have been also discovered in some regions, and the replacement mechanism in sII hydrates significantly differs from that in sI hydrates. In this study, we have intensively investigated the replacement reaction of sII (C 3 H 8 + CH 4 ) hydrate by externally injecting CO 2 /N 2 (50:50) gas mixture with a primary focus on powder X-ray diffraction, Raman spectroscopy, NMR spectroscopy, and gas chromatography analyses. In particular, it was firstly confirmed that there was no structural transformation during the replacement of C 3 H 8 + CH 4 hydrate with CO 2 /N 2 gas injection, indicating that sII hydrate decomposition followed by sI hydrate formation did not occur. Furthermore, the cage-specific replacement pattern of the C 3 H 8 + CH 4 hydrate revealed that CH 4 replacement with N 2 in the small cages of sII was more significant than C 3 H 8 replacement with CO 2 in the large cages of sII. The total extent of the replacement for the C 3 H 8 + CH 4 hydrate was cross-checked by NMR and GC analyses and found to be approximately 54%. Compared to the replacement for CH 4 hydrate with CO 2 /N 2 gas, the lower extent of the replacement for the C 3 H 8 + CH 4 hydrate with CO 2 /N 2 gas was attributable to the persistent presence of C 3 H 8 in the large cages and the lower content of N 2 in the feed gas. The
Field comparison of CO, SO{sub 2}, NO, H{sub 2}S and O{sub 3} ambient air measurements and field audit 2006; Ulkoilman CO-, SO{sub 2}{sup -}, NO{sup -}, H{sub 2}2S - ja O{sub 3}-mittausten kansallinen vertailumittaus ja kenttaeauditointi 2006

Energy Technology Data Exchange (ETDEWEB)

Walden, J.; Bergius, J.; Pohjola, V.; Laurila, S.; Kuronen, P.; Wemberg, A.

2008-07-01

The second field comparison campaign of gaseous compound measurements by the air quality networks in Finland was carried out during 2006. The gaseous components used in the comparison studies were carbon monoxide (CO), sulphur dioxide (SO{sub 2}), nitrogen monoxide (Norway), hydrogen sulfide (H{sub 2}S) and ozone (O{sub 3}). Two reference concentrations, one representing a low concentration and the other a higher concentration than normal ambient air concentrations were used for carbon monoxide, sulphur dioxide, nitrogen monoxide, and hydrogen sulfide. For ozone three reference concentrations were used. The extent and functioning of the quality system of each measurement network was examined by a field audit. All Finnish air quality monitoring networks, a total of 30, participated in the comparison measurements. In total, 144 measurements were conducted at 44 different measurement stations. The results and conclusions of the comparison measurements and field audit are presented in this report. According to the analysis of the results all the 18 results were acceptable for ozone. In case of carbon monoxide 13 out of 14 results were acceptable and for nitrogen monoxide 49 out of 50 were acceptable. For sulphur dioxide there were 29 acceptable results, and 5 results were outside of the acceptable limit. For hydrogen sulfide there were 19 acceptable results, and 9 results were outside of the acceptable limit. Altogether (also hydrogen sulfide), 89 % of the results were acceptable. For carbon monoxide, sulphur dioxide, nitrogen monoxide and ozone, 94 % of the results were acceptable. This is a significant improvement in comparison with the previous results of the first comparison measurements in 2003. The results of the field audit were generally good. The measurement networks had prepared instructions concerning the location of the measurement stations, the measurement methods, training of personnel and the documentation of the operations. All networks have functional
Acidic gases (CO{sub 2}, NO{sub 2} and SO{sub 2}) capture and dissociation on metal decorated phosphorene

Energy Technology Data Exchange (ETDEWEB)

Kuang, Anlong, E-mail: alkuang@swu.edu.cn [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Kuang, Minquan; Yuan, Hongkuan; Wang, Guangzhao; Chen, Hong [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Yang, Xiaolan [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

2017-07-15

Highlights: • The light metal decorated phosphorene sheets are very effective for capture of CO{sub 2}, NO{sub 2} and SO{sub 2} because of large adsorption energies. • The adsorption energy is obviously dependent on the amount of electrons transferred between acidic gases and metal decorated phosphorene. • Pt-decorated phosphorene can effectively catalyze the dissociation of acidic gas. - Abstract: Density functional theory is employed to investigate the adsorption and dissociation of several acidic gases (CO{sub 2}, NO{sub 2} and SO{sub 2}) on metal (Li, Al, Ni and Pt) decorated phosphorene. The results show that light metal (Li, Al) decorated phosphorene exhibits a strong adsorption of acidic gases, i.e., the adsorption energy of CO{sub 2} on Li decorated phosphorene is 0.376 eV which is the largest in all adsorption of CO{sub 2} on metal decorated phosphorene and Al decorated phosphorene is most effective for capture of NO{sub 2} and SO{sub 2} due to large adsorption energies of 3.951 and 3.608 eV, respectively. Moreover, Li and Al light metals have stronger economic effectiveness and more friendly environment compared with the transition metals, the strong adsorption ability of acidic gases and low price suggest that Li, Al decorated phosphorene may be useful and promising for collection and filtration of exhaust gases. The reaction energy barriers of acidic gases dissociated process on Pt decorated phosphorene are relatively low and the reaction processes are significantly exothermic, indicating that the dissociation process is favorable.
40 CFR 75.19 - Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Optional SO2, NOX, and CO2 emissions... § 75.19 Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units. (a... input, NOX, SO2, and CO2 mass emissions, and NOX emission rate under this part. If the owner or operator...
A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

KAUST Repository

Eddaoudi, Mohamed; Shekhah, Osama; Belmabkhout, Youssef; Adil, Karim; Cairns, Amy J.; Bhatt, Prashant

2015-01-01

The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.
A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

KAUST Repository

Eddaoudi, Mohamed

2015-07-06

The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.
THE DETERMINATION THE POLLUTION EMISSIONS OF SO2, NOX, CO, CO2 AND O2 FROM THE CHANNELS OF BURNT GAS ON BOILER OF 420 T/H - STEAM, IN THE SIGHT APPLICATION PROCEEDING TO REDUCE OF THESE

Directory of Open Access Journals (Sweden)

Valentin Nedeff

2007-03-01

Full Text Available The work present the results obtained after dynamic analyze the pollution emissions of SO2, NOx, CO, CO2 and O2 on evacuation channels of burnt gas on boiler of 420 t/h steam, having right the basic combustible the lignite, and auxiliary combustible the fuel oil and the natural gas. The values of pollution emission was analyze beside the admissible maxims values required by European legislation for Romania in the year 2005. The conclusion elaborated it adverted to: the values of oxides azoth, carry they frame in the limits provide in Environmental Authorization, under 60 mg/Nmc on 6% oxygen, the concentration values of SO2 which was bigger in report with one authorized comprised between 3500-3900 mg/Nmc confronted by 3400 mg/Nm. For integration in the foresee Government Decision 541/2003 aren't sufficient just proceeding of below reduce SO2, must take and another measures such as: get the fuel with quantity of sulphur 0.5% and with a content of ash below 35%.
Anticorrosion performance of chromized coating prepared by pack cementation in simulated solution with H2S and CO2

Science.gov (United States)

Wang, Qin-Ying; Behnamian, Yashar; Luo, Hong; Wang, Xian-Zong; Leitch, Michael; Zeng, Hongbo; Luo, Jing-Li

2017-10-01

A hash service environment containing H2S and CO2 in oil industry usually causes corrosion of carbon steel. In this study, the chromized coatings with different deposited time were prepared on the surface of carbon steel by the method of pack cementation to enhance its corrosion resistance. Then the microstructure, hardness, corrosion resistance as well as the semiconductor behavior of coatings in the simulated solution with saturated H2S and CO2 were investigated. The results show that the content of Cr in coating was increased by prolonging deposited time, and both chromium carbides and chromium nitrides were formed. Furthermore, coatings display higher polarization resistance, Rp, than that of the substrate, indicating a higher resistance to charge transfer on coating surface. The corrosion rates of coatings with different deposited time were significantly lower than that of substrate. Chemical analysis showed the formation of heavy sulfides on the surface of substrates after corrosion, while the least corrosion products were detected on the surface of coating with deposited time of 12 h. Mott-Schottky results indicated that coating of 12 h displayed less defects than the other two coatings with deposited time of 4 h and 8 h, which will be beneficial to improve corrosion resistance. The investigation showed that chromized coatings exhibited high corrosion resistance and owned a potential application in oil industry for corrosion prevention.
Co3(PO4)2·4H2O

Science.gov (United States)

Lee, Young Hoon; Clegg, Jack K.; Lindoy, Leonard F.; Lu, G. Q. Max; Park, Yu-Chul; Kim, Yang

2008-01-01

Single crystals of Co3(PO4)2·4H2O, tricobalt(II) bis[orthophosphate(V)] tetrahydrate, were obtained under hydrothermal conditions. The title compound is isotypic with its zinc analogue Zn3(PO4)2·4H2O (mineral name hopeite) and contains two independent Co2+ cations. One Co2+ cation exhibits a slightly distorted tetrahedral coordination, while the second, located on a mirror plane, has a distorted octahedral coordination environment. The tetrahedrally coordinated Co2+ is bonded to four O atoms of four PO4 3− anions, whereas the six-coordinate Co2+ is cis-bonded to two phosphate groups and to four O atoms of four water molecules (two of which are located on mirror planes), forming a framework structure. In addition, hydrogen bonds of the type O—H⋯O are present throughout the crystal structure. PMID:21200978
The Relationship Between Emissions and Economic Growth for SO2, CO2, and BC

Science.gov (United States)

Ru, M.; Shindell, D. T.; Tao, S.; Zhong, Q.; Seltzer, K.

2017-12-01

We characterize the relationship between per person emissions of SO2, CO2, and black carbon (BC) and income using a global country-level emission inventory. Pollutant emissions of SO2 and BC from the power, industry, and transportation sectors largely follow an Environmental Kuznets Curve (EKC) pattern with peak emissions at income levels between 10,000 and 100,000 USD per capita. However, for CO2, any estimated turnover income is extremely high and unlikely to be reached in the near future in power, industry, and transportation. Residential emissions show a negatively sloped linear relationship for BC, a small positive slope for CO2, and a fairly flat trajectory for SO2. For the EKC-like trajectories, "turning point" incomes for each sector and pollutant are related to technological advances and the effectiveness of emission controls. These results suggest that policy targeting technological advances and emission controls could change future pathways by affecting the "turning point" incomes. For the linear trajectories in the residential sector, we show that transitions from biomass fuel to coal in low-income countries and from coal to natural gas in middle and high-income countries, in concert with electrification levels, are the main factors governing slopes. Thus, the three pollutants show different income-emission trajectories based on the sum of the four major sectors, and the residential sector in particular has a unique relationship with income growth. As one of the first studies to analyze historical emission trajectories of BC, we find that BC differs from SO2 and CO2 because of its significantly earlier turnover in the power and industry sectors due to control policies. Total BC emissions trajectories follow a unique shape due to the combination of linearly decreasing residential emissions with EKC-like patterns in industry and transportation. We compare these trajectories to those in three Integrated Assessment Models (IAMs), GCAM, AIM, and MESSAGE

Isoreticular rare earth fcu-MOFs for the selective removal of H 2 S from CO 2 containing gases

KAUST Repository

Bhatt, Prashant; Belmabkhout, Youssef; Assen, Ayalew Hussen Assen; Weselinski, Lukasz Jan; Jiang, Hao; Cadiau, Amandine; Xue, Dongxu; Eddaoudi, Mohamed

2017-01-01

. Markedly, RE-fcu-MOFs, having different pore apertures sizes in the range of 4.7-6.0 Å and different functionalities, showed excellent properties for the removal of H2S from CO2 and CH4 containing gases such as natural gas, biogas and landfill gas. A series
The Formation and Spatiotemporal Progress of the pH Wave Induced by the Temperature Gradient in the Thin-Layer H2O2-Na2S2O3-H2SO4-CuSO4 Dynamical System.

Science.gov (United States)

Jędrusiak, Mikołaj; Orlik, Marek

2016-03-31

The H2O2-S2O3(2-)-H(+)-Cu(2+) dynamical system exhibits sustained oscillations under flow conditions but reveals only a single initial peak of the indicator electrode potential and pH variation under batch isothermal conditions. Thus, in the latter case, there is no possibility of the coupling of the oscillations and diffusion which could lead to formation of sustained spatiotemporal patterns in this process. However, in the inhomogeneous temperature field, due to dependence of the local reaction kinetics on temperature, spatial inhomogeneities of pH distribution can develop which, in the presence of an appropriate indicator, thymol blue, manifest themselves as the color front traveling along the quasi-one-dimensional reactor. In this work, we describe the experimental conditions under which the above-mentioned phenomena can be observed and present their numerical model based on thermokinetic coupling and spatial coordinate introduced to earlier isothermal homogeneous kinetic mechanism.
Spectroscopic study on the intermolecular interaction of SO{sub 2} absorption in poly-ethylene glycol+H{sub 2}O systems

Energy Technology Data Exchange (ETDEWEB)

He, Zhiqiang; Liu, Jinrong; Zhang, Jianbin; Zhang, Na [Inner Mongolia University of Technology, Huhhot (China)

2014-03-15

Poly-Ethylene Glycol (PEG) 300+H{sub 2}O solutions (PEGWs) has been used as a promising medium for the absorption of SO{sub 2}. We investigated the UV, FTIR, {sup 1}H-NMR, and fluorescence spectra in the absorption processes of SO{sub 2} in PEGWs to present an important absorption mechanism. Based on the spectral results, the possibility of intermolecular hydrogen bond formation by hydroxyl oxygen atom in the PEG molecule with hydrogen atom in H{sub 2}O and S…O interaction formation by the oxygen atoms in PEG with the sulfur atom in SO{sub 2} are discussed. This shows that the spectral changes may be due to the formation of -CH{sub 2}CH{sub 2}O(H)…HOH… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-)…HOH… in PEGWs and the formation of -CH{sub 2}CH{sub 2}OH…OSO…, and intermolecular S…O interaction between PEG and SO{sub 2} as the formation of -CH{sub 2}CH{sub 2}OCH{sub 2}CH{sub 2}O(H)…(O)S(O)… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-) …(O)S(O)…. The existence of these bonds benefits the absorption and desorption processes of SO{sub 2} in PEGWs.
Decapado de un acero inoxidable austenítico mediante mezclas ecológicas basadas en H2O2 - H2SO4 - iones F-

Directory of Open Access Journals (Sweden)

Narváez, L.

2013-04-01

Full Text Available This study reports the pickling of 316L stainless steel using mixtures of hydrogen peroxide (H2O2, sulphuric acid (H2SO4 and fluoride ions as hydrofluoric acid (HF, sodium fluoride (NaF and potassium fluoride (KF. The decomposition of H2O2 in the mixtures was assessed at different temperatures 25 °C to 60 °C, with ferric ion contents from 0 to 40 g/l. According to the results obtained, were established the optimal condition pickling at 20 g/l of ferric ions, 25 °C and p-toluensulphonic acid as stabilizer of H2O2. The HF pickling mixture was the only capable to remove totally the oxide layer from the 316L stainless steel after 300 s. The fluoride salts pickling mixtures only remove partially the oxide layer (20 to 40 % aprox. after 300 s. When the pickling time was increased until 1200 s, the removal percentages were around to 80 %.En este estudio se presenta el decapado del acero inoxidable austenítico 316L utilizando mezclas de peróxido de hidrógeno (H2O2/ácido sulfúrico (H2SO4/iones fluoruro; los iones fluoruro provienen del ácido fluorhídrico (HF, fluoruro de sodio (NaF y fluoruro de potasio (KF. La estabilidad del H2O2 fue valorada modificando las concentraciones del ión férrico de 0 a 40 g/l y las temperaturas de 25 °C a 60 °C en las mezclas decapantes. Se establecieron las condiciones óptimas de decapado utilizando 20 g/l de iones férrico a 25 °C empleando el ácido p-toluensulfónico como estabilizante del H2O2. La mezcla que contenía HF fue la única capaz de eliminar completamente los óxidos superficiales del acero a tiempos de 300 s. Las mezclas a base de sales fluoradas eliminaron parcialmente los óxidos (20 y 40 % aprox. en 300 s. Al incrementar el tiempo de decapado hasta 1200 s se obtuvieron porcentajes de eliminación alrededor de un 80 %.
Photodissociation dynamics of gaseous CpCo(CO)2 and ligand exchange reactions of CpCoH2 with C3H4, C3H6, and NH3.

Science.gov (United States)

Oana, Melania; Nakatsuka, Yumiko; Albert, Daniel R; Davis, H Floyd

2012-05-31

The photodissociation dynamics of CpCo(CO)(2) was studied in a molecular beam using photofragment translational energy spectroscopy with 157 nm photoionization detection of the metallic products. At 532 and 355 nm excitation, the dominant one-photon channel involved loss of a single CO ligand producing CpCoCO. The product angular distributions were isotropic, and a large fraction of excess energy appeared as product vibrational excitation. Production of CpCO + 2CO resulted from two-photon absorption processes. The two-photon dissociation of mixtures containing CpCo(CO)(2) and H(2) at the orifice of a pulsed nozzle was used to produce a novel 16-electron unsaturated species, CpCoH(2). Transition metal ligand exchange reactions, CpCoH(2) + L → CpCoL + H(2) (L = propyne, propene, or ammonia), were studied under single-collision conditions for the first time. In all cases, ligand exchange occurred via 18-electron association complexes with lifetimes comparable to their rotational periods. Although ligand exchange reactions were not detected from CpCoH(2) collisions with methane or propane (L = CH(4) or C(3)H(8)), a molecular beam containing CpCoCH(4) was produced by photolysis of mixtures containing CpCo(CO)(2) and CH(4).
XPS study on the surface reaction of uranium metal in H2 and H2-CO atmospheres

International Nuclear Information System (INIS)

Wang Xiaolin; Fu Yibei; Xie Renshou

1996-04-01

The surface reactions of uranium metal in H 2 and H 2 -CO atmospheres and the effects of temperature and CO on the hydriding reaction have been studied by X-ray photoelectron spectroscopy (XPS). The reaction between commercial H 2 and uranium metal at 25 degree C leads mainly to the further oxidation of surface layer of metal due to traces of water vapour. At 200 degree C, it may lead to the hydriding reaction of uranium and the hydriding increases with increasing the exposure of H 2 . Investigation indicates CO inhibits both the hydriding reaction and oxidation on the condition of H 2 -CO atmospheres. (13 refs., 10 figs.)
Crystal structures of NiSO4·9H2O and NiSO4·8H2O: magnetic properties, stability with respect to morenosite (NiSO4·7H2O), the solid-solution series (Mg x Ni1-x )SO4·9H2O

Science.gov (United States)

Fortes, A. D.; Knight, K. S.; Gibbs, A. S.; Wood, I. G.

2018-02-01

Since being discovered initially in mixed-cation systems, a method of forming end-member NiSO4·9H2O and NiSO4·8H2O has been found. We have obtained powder diffraction data from protonated analogues (with X-rays) and deuterated analogues (using neutrons) of these compounds over a range of temperatures, allowing us to determine their crystal structures—including all H-atoms—and to characterise the transitions on warming from 220 to 278 K; glass → 9-hydrate → 8-hydrate + ice → 7-hydrate + ice → partial melt (7-hydrate + liquid). NiSO4·8D2O is triclinic, space-group P\\bar {1} , Z = 2, with unit cell parameters at 150 K, a = 6.12463(8) Å, b = 6.8401(1) Å, c = 12.5339(2) Å, α = 92.846(1)°, β = 97.822(1)°, γ = 96.627(1)° and V = 515.58(1) Å3. The structure consists of two symmetry-inequivalent Ni(D2O)6 octahedra on sites of \\bar {1} symmetry. These are directly joined by a water-water H-bond to form chains of octahedra parallel with the c-axis at x = 0. Two interstitial water molecules serve both to bridge the Ni(D2O)6 octahedral chains in the b-c plane and also to connect with the SO4 2- tetrahedral oxyanion. These tetrahedra are linked by the two interstitial water molecules in a reticular motif to form sheets perpendicular to c. NiSO4·9D2O is monoclinic, space-group P21/c, Z = 4, with unit-cell parameters at 150 K, a = 6.69739(6) Å, b = 11.8628(1) Å, c = 14.5667(1) Å, β = 94.9739(8)° and V = 1152.96(1) Å3. The structure is isotypic with the Mg analogue described elsewhere (Fortes et al., Acta Cryst B 73:47‒64, 2017b). It shares the motif of H-bonded octahedral chains with NiSO4·8D2O, although in the enneahydrate these run parallel with the b-axis at x = 0. Three interstitial water molecules bridge the Ni(D2O)6 octahedra to the SO4 2- tetrahedral oxyanion. The tetrahedra sit at x ≈ 0.5 and are linked by two of the three interstitial water molecules in a pentagonal motif to form ribbons parallel with b. A solid-solution series
The Cheshire-cat-like Behavior of 2nu(sub 3) Overtone of Co2 near 2.134 micron: NIR Lab Spectra of Solid CO2 in H2O and CH3OH

Science.gov (United States)

Bernstein, Max; Sandford, Scott; Cruikshank, Dale

2005-01-01

Infrared (IR) spectra have demonstrated that solid H2O is very common in the outer Solar System, and solid carbon dioxide (CO2) has been detected on icy satellites, comets, and planetismals throughout the outer Solar System. In such environments, CO2 and H2O must sometimes be mixed at a molecular level, changing their IR absorption features. In fact, the IR spectra of CO2-H2O mixtures are not equivalent to a linear combination of the spectra of the pure materials. Laboratory IR spectra of pure CO2 and H2O have been published but a lack of near-IR spectra of CO2-H2O mixtures has made the interpretation of outer Solar System spectra more difficult. We present near infrared (IR) spectra of CO2 in H2O and in CH3OH compared to that of pure solid CO2 and find significant differences. Peaks not present in either pure H2O or pure CO2 spectra become evident. First, the CO2 (2nu(sub 3)) overtone near 2.134 micron (4685/ cm) that is not seen in pure solid CO2 is prominent in the spectrum of a CO2/H2O = 25 mixture. Second, a 2.74 micron (3650/ cm) dangling OH feature of water (and a potentially related peak at 1.89 micron) appear in the spectra of CO2-H2O ice mixtures, but may not be specific to the presence of CO2. Other CO2 peaks display shifts in position and increased width because of intermolecular interactions with water. Changes in CO2 peak positions and profiles on warming of a CO2/H2O = 5 mixture are consistent with 'segregation' of the ice into nearly pure separate components. Absolute strengths for absorptions of CO2 in solid H2O are estimated. Similar results are observed for CO2 in solid CH3OH. Since the CO2 ( 2nu(sub 3)) overtone near 2.134 micron (4685/ cm) is not present in pure CO2 but prominent in mixtures it may be a good observational indicator of whether solid CO2 is a pure material or intimately mixed with other molecules. Significant changes in the near IR spectrum of solid CO2 in the presence of H2O and CH3OH means that the abundance of solid CO2 in the
First identification and thermodynamic characterization of the ternary U(VI) species, UO2(O2)(CO3)2(4-), in UO2-H2O2-K2CO3 solutions.

Science.gov (United States)

Goff, George S; Brodnax, Lia F; Cisneros, Michael R; Peper, Shane M; Field, Stephanie E; Scott, Brian L; Runde, Wolfgang H

2008-03-17

In alkaline carbonate solutions, hydrogen peroxide can selectively replace one of the carbonate ligands in UO2(CO3)3(4-) to form the ternary mixed U(VI) peroxo-carbonato species UO2(O2)(CO3)2(4-). Orange rectangular plates of K4[UO2(CO3)2(O2)].H2O were isolated and characterized by single crystal X-ray diffraction studies. Crystallographic data: monoclinic, space group P2(1)/ n, a = 6.9670(14) A, b = 9.2158(10) A, c = 18.052(4) A, Z = 4. Spectrophotometric titrations with H 2O 2 were performed in 0.5 M K 2CO 3, with UO2(O2)(CO3)2(4-) concentrations ranging from 0.1 to 0.55 mM. The molar absorptivities (M(-1) cm(-1)) for UO2(CO3)3(4-) and UO2(O2)(CO3)2(4-) were determined to be 23.3 +/- 0.3 at 448.5 nm and 1022.7 +/- 19.0 at 347.5 nm, respectively. Stoichiometric analyses coupled with spectroscopic comparisons between solution and solid state indicate that the stable solution species is UO2(O2)(CO3)2(4-), which has an apparent formation constant of log K' = 4.70 +/- 0.02 relative to the tris-carbonato complex.
Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H{sub 2}O){sub 2}SO{sub 4} and Cu(tn)Cl{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Baranová, Lucia [Civil Engineering Faculty, Department of Applied Mathematics, Technical University of Košice, Vysokoškolská 4 SK-042 00, Košice (Slovakia); Orendáčová, Alžbeta, E-mail: alzbeta.orendacova@upjs.sk [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Čižmár, Erik [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Tarasenko, Róbert; Tkáč, Vladimír [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5 12116, Prague (Czech Republic); Orendáč, Martin; Feher, Alexander [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia)

2016-04-15

Organo-metallic compounds Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (en=C{sub 2}H{sub 8}N{sub 2}) and Cu(tn)Cl{sub 2} (tn=C{sub 3}H{sub 10}N{sub 2}) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k{sub B}≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H{sub 2}O){sub 2}SO{sub 4} at T{sub C}=0.9 K while hidden in Cu(tn)Cl{sub 2}. A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (1) and Cu(tn)Cl{sub 2} (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.
BioCO2 - a multidisciplinary, biological approach using solar energy to capture CO2 while producing H2 and high value products.

Science.gov (United States)

Skjånes, Kari; Lindblad, Peter; Muller, Jiri

2007-10-01

Many areas of algae technology have developed over the last decades, and there is an established market for products derived from algae, dominated by health food and aquaculture. In addition, the interest for active biomolecules from algae is increasing rapidly. The need for CO(2) management, in particular capture and storage is currently an important technological, economical and global political issue and will continue to be so until alternative energy sources and energy carriers diminish the need for fossil fuels. This review summarizes in an integrated manner different technologies for use of algae, demonstrating the possibility of combining different areas of algae technology to capture CO(2) and using the obtained algal biomass for various industrial applications thus bringing added value to the capturing and storage processes. Furthermore, we emphasize the use of algae in a novel biological process which produces H(2) directly from solar energy in contrast to the conventional CO(2) neutral biological methods. This biological process is a part of the proposed integrated CO(2) management scheme.
Characterization a binderless particleboard of coffee husk using Hydrogen Peroxide (H2O2) and Ferrous Sulfate (FeSO4)

Science.gov (United States)

Milawarni; Nurlaili; Sariyadi

2018-05-01

Binderless particleboard is particleboard that can be made of a lignocellulose material which is formed into a board only by heat pressing without the addition of adhesive or resin. The particleboard in this study was made from coffee husk (endocarp) using H2O2 and FeSO4 catalyst to activate lignin coffee husk component by oxidation method. Initial treatment of coffee husk is the variation of steam then Oxidation (S + O) and Oxidation without steaming (O). In this study H2O2 and FeSO4 catalysts were varied, including H2O2 levels of 10,20,30 wt% based on particle dry weight and FeSO4 is 5 and 7.5 wt% based on H2O2 weight. From the results of the study, it can be concluded that the coffee husk particleboard whose raw material is treated oxidation without steam can improve the physical properties of binderless particleboard. Increased wt% of H2O2 and FeSO4 catalysts in the oxidation process of coffee husk particles produce binderless particleboard with good physical characteristics such as density, water content, water absorption and swelling thickness. Therefore, considering the efficient aspects of the use of chemicals, the combination of H2O2 and FeSO4 catalysts that can be made according to JIS A 5908 2003 standard are 20% H2O2 and 7.5% FeSO4. The ester linkages were detected by Fourier transform infrared spectroscopy, indicated that cross-link due to the incorporation of phenoxyl radicals.
Long-term stability of FeSO{sub 4} and H{sub 2}SO{sub 4} treated chromite ore processing residue (COPR): Importance of H{sup +} and SO{sub 4}{sup 2−}

Energy Technology Data Exchange (ETDEWEB)

Wang, Xin [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Jingdong [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Linling, E-mail: wanglinling@mail.hust.edu.cn [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Jing, E-mail: chenjing@mail.hust.edu.cn [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Hou, Huijie; Yang, Jiakuan [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Lu, Xiaohua [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2017-01-05

Highlights: • The long-term stability of the FeSO{sub 4}-H{sub 2}SO{sub 4} treated COPR was evaluated. • Reliable long-term stability for samples curing 400 days was achieved. • H{sub 2}SO{sub 4} significantly enhanced the stabilization efficiency of COPR using FeSO{sub 4}. • H{sup +} and SO{sub 4}{sup 2−} both reinforced Cr(VI) release from COPR core to react with Fe(II). - Abstract: In this study, the long-term stability of Cr(VI) in the FeSO{sub 4} and H{sub 2}SO{sub 4} (FeSO{sub 4}-H{sub 2}SO{sub 4}) treated chromite ore processing residue (COPR) after 400 curing days and the stabilization mechanisms were investigated. FeSO{sub 4}-H{sub 2}SO{sub 4} treatment significantly reduced toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) Cr(VI) concentrations to lower than the regulatory limit of 1.5 mg L{sup −1} (HJ/T 301-2007, China EPA) even for the samples curing 400 days, achieving an outstanding long-term stability. Our independent leaching tests revealed that H{sup +} and SO{sub 4}{sup 2−} have synergistic effect on promoting the release of Cr(VI), which would make Cr(VI) easier accessed by Fe(II) during stabilization. The contributions of H{sup +} and SO{sub 4}{sup 2−} to Cr(VI) release ratio were 25%–44% and 19%–38%, respectively, as 5 mol H{sub 2}SO{sub 4} per kg COPR was used. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and alkaline digestion analyses were also employed to interpret the possible stabilization mechanism. Cr(VI) released from COPR solid was reduced to Cr(III) by Fe(II), and then formed stable Fe{sub x}Cr{sub (1−x)}(OH){sub 3} precipitate. This study provides a facile and reliable scheme for COPR stabilization, and verifies the excellent long-term stability of the FeSO{sub 4}-H{sub 2}SO{sub 4} treated COPR.
The flight of Arcadia: spatial CO2/SO2 variations in a cross section above the Nord East crater of Etna volcano

Science.gov (United States)

Giuffrida, Giovanni; Calabrese, Sergio; Bobrowski, Nicole; Finkenzeller, Henning; Pecoraino, Giovannella; Scaglione, Sarah

2015-04-01

The CO2/SO2 ratio in volcanic plumes of open conduit volcanoes can provide useful information about the magma depth inside a conduit and the possible occurrence of an eruptive event. Moreover, the same CO2 measurement when combined with a SO2 flux measurement, commonly carried out at many volcanoes nowadays, is used to contribute to an improved estimate of global volcanic CO2 budget. Today worldwide at 13 volcanoes automated in-situ instruments (known as Multi-GAS stations) are applied to continuously determine CO2/SO2 ratios and to use this signal as additional parameter for volcanic monitoring. Usually these instruments carry out measurements of half an hour 4 - 6 times/day and thus provide continuous CO2/SO2 values and their variability. The stations are located at crater rims in a position that according to the prevailing winds is invested by the plume. Obviously, although the stations are carefully positioned, it is inevitable that other sources than the plume itself, e.g. soil degassing and surrounding fumaroles, contribute and will be measured as well, covering the 'real' values. Between July and September 2014 experiments were carried out on the North East crater (NEC) of Mount Etna, installing a self-made cable car that crossed the crater from one side to the other. The basket, called "Arcadia", was equipped with an automated standard Multi-GAS station and a GPS, which acquired at high frequency (0.5 Hz) the following parameters : CO2, SO2, H2S, Rh, T, P and geo-coordinates. The choice of NEC of the volcano Etna was based on its accessibility, the relative small diameter (about 230 m) and the presence of a relatively constant and rather concentrated plume. Actually, NEC belongs also to the monitoring network EtnaPlume (managed by the INGV of Palermo). The aim of these experiments was to observe variations of each parameter, in particular the fluctuation of the CO2/SO2 ratio within the plume, moving from the edge to the center of the crater. The gained
Densities and apparent molar volumes of atmospherically important electrolyte solutions. 2. The systems H(+)-HSO4(-)-SO4(2-)-H2O from 0 to 3 mol kg(-1) as a function of temperature and H(+)-NH4(+)-HSO4(-)-SO4)2-)-H2O from 0 to 6 mol kg(-1) at 25 °C using a Pitzer ion interaction model, and NH4HSO4-H2O and (NH4)3H(SO4)2-H2O over the entire concentration range.

Science.gov (United States)

Clegg, S L; Wexler, A S

2011-04-21

A Pitzer ion interaction model has been applied to the systems H(2)SO(4)-H(2)O (0-3 mol kg(-1), 0-55 °C) and H(2)SO(4)-(NH(4))(2)SO(4)-H(2)O (0-6 mol kg(-1), 25 °C) for the calculation of apparent molar volume and density. The dissociation reaction HSO(4)(-)((aq)) ↔ H(+)((aq)) + SO(4)(2-)((aq)) is treated explicitly. Apparent molar volumes of the SO(4)(2-) ion at infinite dilution were obtained from part 1 of this work, (1) and the value for the bisulfate ion was determined in this study from 0 to 55 °C. In dilute solutions of both systems, the change in the degree of dissociation of the HSO(4)(-) ion with concentration results in much larger variations of the apparent molar volumes of the solutes than for conventional strong (fully dissociated) electrolytes. Densities and apparent molar volumes are tabulated. Apparent molar volumes calculated using the model are combined with other data for the solutes NH(4)HSO(4) and (NH(4))(3)H(SO(4))(2) at 25 °C to obtain apparent molar volumes and densities over the entire concentration range (including solutions supersaturated with respect to the salts).
Model simulations of the competing climatic effects of SO2 and CO2

Science.gov (United States)

Kaufman, Yoram J.; Chou, Ming-Dah

1993-01-01

Sulfur dioxide-derived cloud condensation nuclei are expected to enhance the planetary albedo, thereby cooling the planet. This effect might counteract the global warming expected from enhanced greenhouse gases. A detailed treatment of the relationship between fossil fuel burning and the SO2 effect on cloud albedo is implemented in a two-dimensional model for assessing the climate impact. Using a conservative approach, results show that the cooling induced by the SO2 emission can presently counteract 50 percent of the CO2 greenhouse warming. Since 1980, a strong warming trend has been predicted by the model: 0.15 C during the 1980-1990 period alone. The model predicts that by the year 2060 the SO2 cooling reduces climate warming by 0.5 C or 25 percent for the Intergovernmental Panel on Climate Change (IPCC) business as usual (BAU) scenario and 0.2 C or 20 percent for scenario D (for a slow pace of fossil fuel burning). The hypothesis is examined that the different responses between the Northern Hemisphere and the Southern Hemisphere can be used to validate the presence of the SO2-induced cooling.
Photocatalytic degradation of water surface oils by CoPcS-TiO2-beads and TiO2-beads%CoPcS/TiO2/beads及TiO2/beads光催化降解水面浮油

Institute of Scientific and Technical Information of China (English)

张晓叶; 闰永胜; 孔峰; 赵瑞平; 陈林; 钱华伟

2008-01-01

以钛酸四丁酯为原料,空心玻璃微珠(beads)为载体,采用溶胶一凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads新型光催化剂.研究了利用TiO2/beads及CoPcS/TiO2/beads光催化剂降解水面漂浮植物油的最优条件.结果表明:(1)溶胶-凝胶法制备TiO2/beads的最佳条件为:空心玻璃微珠浸渍3次,450～550℃下焙烧2 h.用CoPcS对TiO2/beads进行改性时,TiO2/beads的最1圭浸渍时间为30 min.(2)在中性或酸性条件下,375 W中压汞灯光照2～3 h,TiO2/eads与CoPcS/TiO2/beads的最佳用量分别为3 g和1 g(植物油3 g),在此条件下,植物油的去除率都高达90%.(3)微量H2O2对TiO2/beads和CoPcS/TiO2/beads的光催化活性都有很大的提高.对于TiO2/beads催化剂,H2O2的最佳用量为5～11 mmol/L;对于CoPcS/TiO2/beads催化剂,H2O2的最佳用量为5～30 mmol/L.(4)新型光催化剂CoPcS/TiO2/aeads比TiO2/beads具有更好的除油性能.
Description and crystal structure of albrechtschraufite, MgCa{sub 4}F{sub 2}[UO{sub 2}(CO{sub 3}){sub 3}]{sub 2}.17-18H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Mereiter, K. [Vienna Univ. of Technology (Austria). Inst. of Chemical Technologies and Analytics

2013-04-15

Albrechtschraufite, MgCa{sub 4}F{sub 2}[UO{sub 2}(CO{sub 3}){sub 3}]{sub 2}.17-18H{sub 2}O, triclinic, space group P anti 1, a = 13.569(2), b = 13.419(2), c = 11.622(2) Aa, α = 115.82(1), β = 107.61(1), γ = 92.84(1) (structural unit cell, not reduced), V = 1774.6(5) Aa{sup 3}, Z = 2, Dc = 2.69 g/cm{sup 3} (for 17.5 H{sub 2}O), is a mineral that was found in small amounts with schroeckingerite, NaCa{sub 3}F[UO{sub 2}(CO{sub 3}){sub 3}](SO{sub 4}).10H{sub 2}O, on a museum specimen of uranium ore from Joachimsthal (Jachymov), Czech Republic. The mineral forms small grain-like subhedral crystals (= 0.2 mm) that resemble in appearance liebigite, Ca{sub 2}[UO{sub 2}(CO{sub 3}){sub 3}]. ∝ 11H{sub 2}O. Colour pale yellow-green, luster vitreous, transparent, pale bluish green fluorescence under ultraviolet light. Optical data: Biaxial negative, nX = 1.511(2), nY = 1.550(2), nZ = 1.566(2), 2V = 65(1) (λ = 589 nm), r < v weak. After qualitative tests had shown the presence of Ca, U, Mg, CO{sub 2} and H{sub 2}O, the chemical formula was determined by a crystal structure analysis based on X-ray four-circle diffractometer data. The structure was later on refined with data from a CCD diffractometer to R1 = 0.0206 and wR2 = 0.0429 for 9,236 independent observed reflections. The crystal structure contains two independent [UO{sub 2}(CO{sub 3}){sub 3}]{sup 4-} anions of which one is bonded to two Mg and six Ca while the second is bonded to only one Mg and three Ca. Magnesium forms a MgF{sub 2}(O{sub carbonate}){sub 3}(H{sub 2}O) octahedron that is linked via the F atoms with three Ca atoms so as to provide each F atom with a flat pyramidal coordination by one Mg and two Ca. Calcium is 7- and 8-coordinate forming CaFO{sub 6}, CaF{sub 2}O{sub 2}(H{sub 2}O){sub 4}, CaFO{sub 3}(H{sub 2}O){sub 4} and CaO{sub 2}(H{sub 2}O){sub 6} coordination polyhedra. The crystal structure is built up from MgCa{sub 3}F{sub 2}[UO{sub 2}(CO{sub 3}){sub 3}].8H{sub 2}O layers parallel to (001) which
The topotactic dehydration of monoclinic {[Co(pht)(bpy)(H2O)2]·2H2O}n into orthorhombic [Co(pht)(bpy)(H2O)2]n (pht is phthalate and bpy is 4,4'-bipyridine).

Science.gov (United States)

Harvey, Miguel Angel; Suarez, Sebastián; Cukiernik, Fabio D; Baggio, Ricardo

2014-10-01

Controlled heating of single crystals of the previously reported [Köferstein & Robl (2007). Z. Anorg. Allg. Chem. 633, 1127-1130] dihydrate {[Co(pht)(bpy)(H2O)2]·2H2O}n, (II) [where pht is phthalate (C8H4O4) and bpy is 4,4'-bipyridine (C10H8N2)], produced a topotactic transformation into an unreported diaqua anhydrate, namely poly[diaqua(μ2-benzene-1,2-dicarboxylato-κ(2)O(1):O(2))(μ2-4,4'-bipyridine-κ(2)N:N')cobalt(II)], [Co(C8H4O4)(C10H8N2)(H2O)2]n, (IIa). The structural change consists of the loss of the two solvent water molecules linking the original two-dimensional covalent substructures which are the `main frame' of the monoclinic P2/n hydrate (strictly preserved during the transformation), with further reaccommodation of the latter. The anhydrate organizes itself in the orthorhombic system (space group Pmn2(1)) in a disordered fashion, where the space-group-symmetry restrictions are achieved only in a statistical sense, with mirror-related two-dimensional planar substructures, mirrored in a plane perpendicular to [100]. Thus, the asymmetric unit in the refined model is composed of two superimposed mirror-related `ghosts' of half-occupancy each. Similarities and differences with the parent dihydrate and some other related structures in the literature are discussed.
A Novel Triple-Pulsed 2-micrometer Lidar for Simultaneous and Independent CO2 and H2O Column Measurement

Science.gov (United States)

Yu, Jirong; Singh, Upendra; Petros, Mulugeta; Refaat, Tamer

2015-01-01

The study of global warming needs precisely and accurately measuring greenhouse gases concentrations in the atmosphere. CO2 and H2O are important greenhouse gases that significantly contribute to the carbon cycle and global radiation budget on Earth. NRC Decadal Survey recommends a mission for Active Sensing of Carbon Dioxide (CO2) over Nights, Days and Seasons (ASCENDS). 2 micron laser is a viable IPDA transmitter to measure CO2 and H2O column density from space. The objective is to demonstrate a first airborne direct detection 2 micron IPDA lidar for CO2 and H2O measurements.

Measurements and modeling of absorption by CO2 + H2O mixtures in the spectral region beyond the CO2 ν3-band head

Science.gov (United States)

Tran, H.; Turbet, M.; Chelin, P.; Landsheere, X.

2018-05-01

In this work, we measured the absorption by CO2 + H2O mixtures from 2400 to 2600 cm-1 which corresponds to the spectral region beyond the ν3 band head of CO2. Transmission spectra of CO2 mixed with water vapor were recorded with a high-resolution Fourier-transform spectrometer for various pressure, temperature and concentration conditions. The continuum absorption by CO2 due to the presence of water vapor was determined by subtracting from measured spectra the contribution of local lines of both species, that of the continuum of pure CO2 as well as of the self- and CO2-continua of water vapor induced by the H2O-H2O and H2O-CO2 interactions. The obtained results are in very good agreement with the unique previous measurement (in a narrower spectral range). They confirm that the H2O-continuum of CO2 is significantly larger than that observed for pure CO2. This continuum thus must be taken into account in radiative transfer calculations for media involving CO2+ H2O mixture. An empirical model, using sub-Lorentzian line shapes based on some temperature-dependent correction factors χ is proposed which enables an accurate description of the experimental results.
H2 production by reforming route in reducing CO2 emissions

International Nuclear Information System (INIS)

Raphaelle Imbault

2006-01-01

Nowadays the most common way to produce hydrogen is the Steam Methane Reforming route from natural gas. With the pressure of new environmental rules, reducing CO 2 emissions becomes a key issue. The European project Ulcos (Ultra Low CO 2 Steelmaking) has targeted to reduce of at least 50% the CO 2 emissions in steelmaking. The H 2 route (and in particular the reforming process) is one of the solutions which have been explored. The results of this study have shown that the two main ways (which can be combined) of limiting CO 2 emissions in H 2 production are to improve the energetic efficiency of the plant or to capture CO 2 . With the first way, a reduction of 20% of emissions compared to conventional plant can be reached. The second one enables to achieve a decrease of 90%. However the CO 2 capture is much more expensive and this kind of solution can be economically competitive only if high CO 2 taxes are implemented (≥40 Euros/ton). (author)
Modeling Water Saturation Points in Natural Gas Streams Containing CO2 and H2S-Comparisons with Different Equations of State

DEFF Research Database (Denmark)

dos Santos, Leticia C.; Abunahman, Samir S.; Tavares, Frederico W.

2015-01-01

Since the discovery of the Pre-Salt layer in Brazilian waters, production of high gas-oil ratio (GOR) has increased considerably. This gas has a high content of water, CO2, and sometimes H2S. A study in different conditions was conducted using several equations of state (EoS) such as Peng...
Fumarole/plume and diffuse CO2 emission from Sierra Negra caldera, Galapagos archipelago

Science.gov (United States)

Padrón, Eleazar; Hernández, Pedro A.; Pérez, Nemesio M.; Toulkeridis, Theofilos; Melián, Gladys; Barrancos, José; Virgili, Giorgio; Sumino, Hirochika; Notsu, Kenji

2012-08-01

Measurements of visible and diffuse gas emission were conducted in 2006 at the summit of Sierra Negra volcano, Galapagos, with the aim to better characterize degassing after the 2005 eruption. A total SO2 emission of 11 ± 2 t day-1 was derived from miniature differential optical absorption spectrometer (mini-DOAS) ground-based measurements of the plume emanating from the Mini Azufral fumarolic area, the most important site of visible degassing at Sierra Negra volcano. Using a portable multigas system, the H2S/SO2, CO2/SO2, and H2O/SO2 molar ratios in the Mina Azufral plume emissions were found to be 0.41, 52.2, and 867.9, respectively. The corresponding H2O, CO2, and H2S emission rates were 562, 394, and 3 t day-1, respectively. The total output of diffuse CO2 emissions from the summit of Sierra Negra volcano was 990 ± 85 t day-1, with 605 t day-1 being released by a deep source. The diffuse-to-plume CO2 emission ratio was about 1.5. Mina Azufral fumaroles released gasses containing 73.6 mol% of H2O; the main noncondensable components amounted to 97.4 mol% CO2, 1.5 mol% SO2, 0.6 mol% H2S, and 0.35 mol% N2. The higher H2S/SO2 ratio values found in 2006 as compared to those reported before the 2005 eruption reveal a significant hydrothermal contribution to the fumarolic emissions. 3He/4He ratios measured at Mina Azufral fumarolic discharges showed values of 17.88 ± 0.25 R A , indicating a mid-ocean ridge basalts (MORB) and a Galapagos plume contribution of 53 and 47 %, respectively.
Formation of secondary aerosols from the ozonolysis of styrene: Effect of SO2 and H2O

Science.gov (United States)

Díaz-de-Mera, Yolanda; Aranda, Alfonso; Martínez, Ernesto; Rodríguez, Ana Angustias; Rodríguez, Diana; Rodríguez, Ana

2017-12-01

In this work we report the study of the ozonolysis of styrene and the reaction conditions leading to the formation of secondary aerosols. The reactions have been carried out in a Teflon chamber filled with synthetic air mixtures at atmospheric pressure and room temperature. We have found that the ozonolysis of styrene in the presence of low concentrations of SO2 readily produces new particles under concentrations of reactants lower than those required in experiments in the absence of SO2. Thus, nucleation events occur at concentrations around (5.6 ± 1.7) × 108molecule cm-3 (errors are 2σ±20%) and SO2 is consumed during the experiments. The reaction of the Criegee intermediates with SO2 to produce SO3 and then H2SO4 may explain (together with OH reactions' contribution) the high capacity of styrene to produce particulate matter in polluted atmospheres. The formation of secondary aerosols in the smog chamber is inhibited under high H2O concentrations. So, the potential formation of secondary aerosols under atmospheric conditions depends on the concentration of SO2 and relative humidity, with a water to SO2 rate constants ratio kH2O/kSO2 = (2.8 ± 0.7) × 10-5 (errors are 2σ±20%).
THE REACTION BETWEEN ZnO AND MOLTEN NA2S2O7 OR K2S2O7 FORMING NA2Zn(SO4)2 OR K2Zn(SO4)2, STUDIED BY RAMAN SPECTROSCOPY AND X-RAY DIFFRACTION

DEFF Research Database (Denmark)

Berg, Rolf W.; Thorup, Niels

2005-01-01

Reactions between solid ZnO and molten Na2S2O7 or K2S2O7 at 500 are shown by Raman spectroscopy to be 1:1 reactions leading to solns. By lowering the temp. of the soln. melts, colorless crystals form. Raman spectra of the crystals are given and tentatively assigned. Crystal structures of the mon...... the three-dimensional network of the M2Zn(SO4)2 structures. Bond distances and angles compare well with literature values. Empirical correlations between S-O bond distances and av. O-S-O bond angles follow a previously found trend....
Mechanisms of radical removal by SO2

DEFF Research Database (Denmark)

Rasmussen, Christian Lund; Glarborg, Peter; Marshall, Paul

2007-01-01

It is well established from experiments in premixed, laminar flames, jet-stirred reactors, flow reactors, and batch reactors that SO2 acts to catalyze hydrogen atom removal at stoichiometric and reducing conditions. However, the commonly accepted mechanism for radical removal, SO2 + H......(+M) reversible arrow HOSO(+M), HOSO + H/OH reversible arrow SO2 + H-2/H2O, has been challenged by recent theoretical and experimental results. Based on ab initio calculations for key reactions, we update the kinetic model for this chemistry and re-examine the mechanism of fuel/SO2 interactions. We find...... that the interaction of SO, with the radical pool is more complex than previously assumed, involving HOSO and SO, as well as, at high temperatures also HSO, SH, and S. The revised mechanism with a high rate constant for H + SO2 recombination and with SO + H2O, rather than SO2 + H-2, as major products of the HOSO + H...
(Solid + liquid) isothermal evaporation phase equilibria in the aqueous ternary system (Li{sub 2}SO{sub 4} + MgSO{sub 4} + H{sub 2}O) at T = 308.15 K

Energy Technology Data Exchange (ETDEWEB)

Wang Shiqiang [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Deng Tianlong [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); College of Materials, Chemistry and Chemical Engineering, Chengdu University Technology, Chengdu 610059 (China)], E-mail: dtl@cdut.edu.cn

2008-06-15

The solubility and the density in the aqueous ternary system (Li{sub 2}SO{sub 4} + MgSO{sub 4} + H{sub 2}O) at T = 308.15 K were determined by the isothermal evaporation. Our experimental results permitted the construction of the phase diagram and the plot of density against composition. It was found that there is one eutectic point for (Li{sub 2}SO{sub 4} . H{sub 2}O + MgSO{sub 4} . 7H{sub 2}O), two univariant curves, and two crystallization regions corresponding to lithium sulphate monohydrate (Li{sub 2}SO{sub 4} . H{sub 2}O) and epsomite (MgSO{sub 4} . 7H{sub 2}O). The system belongs to a simple co-saturated type, and neither double salts nor solid solution was found. Based on the Pitzer ion-interaction model and its extended HW models of aqueous electrolyte solution, the solubility of the ternary system at T = 308.15 K has been calculated. The predicted solubility agrees well with the experimental values.
Bis(2,2′-bipyridyl-κ2N,N′(sulfato-κ2O,O′cobalt(II ethane-1,2-diol monosolvate

Directory of Open Access Journals (Sweden)

Lin Chen

2011-01-01

Full Text Available The title compound, [Co(SO4(C10H8N22]·C2H6O2, has the Co2+ ion in a distorted octahedral CoN4O2 coordination geometry. A twofold rotation axis passes through the Co and S atoms, and through the mid-point of the C—C bond of the ethanediol molecule. In the crystal, the [CoSO4(C10H8N22] and C2H6O2 units are held together by a pair of O—H...O hydrogen bonds.
Mechano-chemical pathways to H2O and CO2 splitting

Science.gov (United States)

Vedadi, Mohammad H.; Haas, Stephan

2011-10-01

The shock-induced collapse of CO2-filled nanobubbles is investigated using molecular dynamics simulations based on a reactive force field. The energetic nanojet and high-pressure water hammer shock formed during and after collapse of the nanobubble trigger mechano-chemical H2O-CO2 reactions, some of which lead to splitting of water and formation of O2 molecules. The dominant pathways through which splitting of water molecules occur are identified.
Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2.

Science.gov (United States)

Kaiser, Jan; Röckmann, Thomas

2008-12-01

Gas isotope ratio mass spectrometers usually measure ion current ratios of molecules, not atoms. Often several isotopologues contribute to an ion current at a particular mass-to-charge ratio (m/z). Therefore, corrections have to be applied to derive the desired isotope ratios. These corrections are usually formulated in terms of isotope ratios (R), but this does not reflect the practice of measuring the ion current ratios of the sample relative to those of a reference material. Correspondingly, the relative ion current ratio differences (expressed as delta values) are first converted into isotopologue ratios, then into isotope ratios and finally back into elemental delta values. Here, we present a reformulation of this data reduction procedure entirely in terms of delta values and the 'absolute' isotope ratios of the reference material. This also shows that not the absolute isotope ratios of the reference material themselves, but only product and ratio combinations of them, are required for the data reduction. These combinations can be and, for carbon and oxygen have been, measured by conventional isotope ratio mass spectrometers. The frequently implied use of absolute isotope ratios measured by specially calibrated instruments is actually unnecessary. Following related work on CO2, we here derive data reduction equations for the species O2, CO, N2O and SO2. We also suggest experiments to measure the required absolute ratio combinations for N2O, SO2 and O2. As a prelude, we summarise historic and recent measurements of absolute isotope ratios in international isotope reference materials. Copyright 2008 John Wiley & Sons, Ltd.
PVTx properties of the CO2-H2O and CO2-H2O-NaCl systems below 647 K: assessment of experimental data and thermodynamic models

Science.gov (United States)

Hu, Jiawen; Duan, Zhenhao; Zhu, Chen; Chou, I.-Ming

2007-01-01

Evaluation of CO2 sequestration in formation brine or in seawater needs highly accurate experimental data or models of pressure–volume–temperature-composition (PVTx) properties for the CO2–H2O and CO2–H2O–NaCl systems. This paper presents a comprehensive review of the experimental PVTx properties and the thermodynamic models of these two systems. The following conclusions are drawn from the review: (1) About two-thirds of experimental data are consistent with each other, where the uncertainty in liquid volumes is within 0.5%, and that in gas volumes within 2%. However, this accuracy is not sufficient for assessing CO2 sequestration. Among the data sets for liquids, only a few are available for accurate modeling of CO2 sequestration. These data have an error of about 0.1% on average, roughly covering from 273 to 642 K and from 1 to 35 MPa; (2) There is a shortage of volumetric data of saturated vapor phase. (3) There are only a few data sets for the ternary liquids, and they are inconsistent with each other, where only a couple of data sets can be used to test a predictive density model for CO2 sequestration; (4) Although there are a few models with accuracy close to that of experiments, none of them is accurate enough for CO2 sequestration modeling, which normally needs an accuracy of density better than 0.1%. Some calculations are made available on www.geochem-model.org.
SO{sub 2} retention by reactivated CaO-based sorbent from multiple CO{sub 2} capture cycles

Energy Technology Data Exchange (ETDEWEB)

Vasilije Manovic; Edward J. Anthony [CANMET Energy Technology Centre-Ottawa, Ottawa, ON (Canada). Natural Resources Canada

2007-06-15

This paper examines the reactivation of spent sorbent, produced from multiple CO{sub 2} capture cycles, for use in SO{sub 2} capture. CaO-based sorbent samples were obtained from Kelly Rock limestone using three particle size ranges, each containing different impurities levels. Using a thermogravimetric analyzer (TGA), the sulfation behavior of partially sulfated and unsulfated samples obtained after multiple calcination-carbonation cycles in a tube furnace (TF), following steam reactivation in a pressurized reactor, is examined. In addition, samples calcined/sintered under different conditions after hydration are also examined. The results show that suitably treated spent sorbent has better sulfation characteristics than that of the original sorbent. Thus for example, after 2 h sulfation, {gt} 80% of the CaO was sulfated. In addition, the sorbent showed significant activity even after 4 h when {gt} 95% CaO was sulfated. The results were confirmed by X-ray diffraction (XRD) analysis, which showed that, by the end of the sulfation process, samples contained CaSO{sub 4} with only traces of unreacted CaO. The superior behavior of spent reactivated sorbent appears to be due to swelling of the sorbent particles during steam hydration. The surface area morphology of sorbent after reactivation was examined by scanning electron microscopy (SEM). Ca(OH){sub 2} crystals were seen, which displayed their regular shape, and their elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis. These results allow the proposal of a new process for the use of CaO-based sorbent in fluidized bed combustion (FBC) systems, which incorporates CO{sub 2} capture, sorbent reactivation, and SO{sub 2} retention. 26 refs., 4 figs., 2 tabs.
Catalytic combustion of the retentate gas from a CO2/H2 separation membrane reactor for further CO2 enrichment and energy recovery

International Nuclear Information System (INIS)

Hwang, Kyung-Ran; Park, Jin-Woo; Lee, Sung-Wook; Hong, Sungkook; Lee, Chun-Boo; Oh, Duck-Kyu; Jin, Min-Ho; Lee, Dong-Wook; Park, Jong-Soo

2015-01-01

The CCR (catalytic combustion reaction) of the retentate gas, consisting of 90% CO 2 and 10% H 2 obtained from a CO 2 /H 2 separation membrane reactor, was investigated using a porous Ni metal catalyst in order to recover energy and further enrich CO 2 . A disc-shaped porous Ni metal catalyst, namely Al[0.1]/Ni, was prepared by a simple method and a compact MCR (micro-channel reactor) equipped with a catalyst plate was designed for the CCR. CO 2 and H 2 concentrations of 98.68% and 0.46%, respectively, were achieved at an operating temperature of 400 °C, GHSV (gas-hourly space velocity) of 50,000 h −1 and a H 2 /O 2 ratio (R/O) of 2 in the unit module. In the case of the MCR, a sheet of the Ni metal catalyst was easily installed along with the other metal plates and the concentration of CO 2 in the retentate gas increased up to 96.7%. The differences in temperatures measured before and after the CCR were 31 °C at the product outlet and 19 °C at the N 2 outlet in the MCR. The disc-shaped porous metal catalyst and MCR configuration used in this study exhibit potential advantages, such as high thermal transfer resulting in improved energy recovery rate, simple catalyst preparation, and easy installation of the catalyst in the MCR. - Highlights: • The catalytic combustion of a retentate gas obtained from the H 2 /CO 2 separation membrane. • A disc-shaped porous nickel metal catalyst and a micro-channel reactor for catalytic hydrogen combustion. • CO 2 enrichment up to 98.68% at 400 °C, 50,000 h −1 and H 2 /O 2 ratio of 2.
Investigation into the dehydration of selenate doped Na2M(SO4)2·2H2O (M = Mn, Fe, Co and Ni): Stabilisation of the high Na content alluaudite phases Na3M1.5(SO4)3-1.5x(SeO4)1.5x (M = Mn, Co and Ni) through selenate incorporation

Science.gov (United States)

Driscoll, L. L.; Kendrick, E.; Knight, K. S.; Wright, A. J.; Slater, P. R.

2018-02-01

In this paper we report an investigation into the phases formed on dehydration of Na2M(SO4)2-x(SeO4)x·2H2O (0 ≤ x ≤ 1; M = Mn, Fe, Co and Ni). For the Fe series, all attempts to dehydrate the samples doped with selenate resulted in amorphous products, and it is suspected that a side redox reaction involving the Fe and selenate may be occurring leading to phase decomposition and hence the lack of a crystalline product on dehydration. For M = Mn, Co, Ni, the structure observed was shown to depend upon the transition metal cation and level of selenate doping. An alluaudite phase, Na3M1.5(SO4)3-1.5x(SeO4)1.5x, was observed for the selenate doped compositions, with this phase forming as a single phase for x ≥ 0.5 M = Co, and x = 1.0 M = Ni. For M = Mn, the alluaudite structure is obtained across the series, albeit with small impurities for lower selenate content samples. Although the alluaudite-type phases Na2+2y(Mn/Co)2-y(SO4)3 have recently been reported [1,2], doping with selenate appears to increase the maximum sodium content within the structure. Moreover, the selenate doped Ni based samples reported here are the first examples of a Ni sulfate/selenate containing system exhibiting the alluaudite structure.
Solar processing of CO2 and H2O, routes for solar fuels

International Nuclear Information System (INIS)

Flammant, G.; Abanades, St.

2008-01-01

Complete text of publication follows: Concentrated solar energy provides heat in the temperature range 200 C - 3000 C for concentration ratio variation from 10 to 10 000 (three orders of magnitude). Consequently, solar-driven thermochemical processes may be proposed to produce hydrogen from water decomposition and to reduce carbon dioxide. This lecture gives an overview of such processes. High temperature thermochemical cycles for hydrogen production by water splitting are currently studied at PROMES lab, particularly 2-step and 3-step cycles based on the following reaction scheme, MOox → MOred + 1/2 O 2 (high temperature solar step), MOred + H 2 O → MOox + H 2 (low temperature non solar step). Volatile and non-volatile oxide cycles are developed from the chemical and the engineering points of view. A similar reaction scheme may be proposed to reduce carbon dioxide with concentrated solar energy (Fig. 1), it comes, MOox → MOred + 1/2 O 2 (high temperature solar step), MOred + CO 2 → MOox + CO (low temperature non solar step). As a result gas mixtures such as CO 2 /H 2 and CO/H 2 may be produced by solar energy. Such mixtures are the reactants for liquid fuels production (solar fuels)
On synthesis of LiCe(SO4)2xH2O double salt in hydrothermal conditions

International Nuclear Information System (INIS)

Bondar', S.A.; Belokoskov, V.I.; Popova, R.A.; Nikitina, S.D.; Trofimov, G.V.; Korobejnikov, L.S.

1986-01-01

Conditions for LiCe(SO 4 ) 2 xH 2 O double sulfate crystallization are determined by investigation of Li 2 SO 4 -Ce 4 (SO 4 ) 3 -H 2 SO 4 -H 2 O system using the method of isothermal solubility at 150 and 200 deg C in the 35-85 mass % concentration range of sulfuric acid and ratios at mixture charge of Li 2 SO 4 :Ce(SO 4 ) 3 equal to 2:1 and 5:1 (g/mole). Derivatograms, infrared spectra and crystal optical characteristics of double lithium and cerium (3) sulphate are presented
Eddy Covariance measurements of stable CO2 and H2O isotopologues

Science.gov (United States)

Braden-Behrens, Jelka; Knohl, Alexander

2015-04-01

The analysis of the stable isotope composition of CO2 and H2O fluxes (such as 13C, 18O and 2H in H2O and CO2) has provided valuable insights into ecosystem gas exchange. The approach builds on differences in the isotope signature of different ecosystem components that are primarily caused by the preference for or the discrimination against respective isotope species by important processes within the ecosystem (e.g. photosynthesis or leaf water diffusion). With the ongoing development of laser spectrometric methods, fast and precise measurements of isotopologue mixing ratios became possible, hence also enabling Eddy Covariance (EC) based approaches to directly measure the isotopic composition of CO2 and H2Ov net fluxes on ecosystem scale. During an eight month long measurement campaign in 2015, we plan to simultaneously measure CO2 and H2Ov isotopologue fluxes using an EC approach in a managed beech forest in Thuringia, Germany. For this purpose, we will use two different laser spectrometers for high frequency measurements of isotopic compositions: For H2Ov measurements, we will use an off axis cavity output water vapour isotope analyser (WVIA, Los Gatos Research Inc.) with 5 Hz response; and for CO2 measurements, we will use a quantum cascade laser-based system (QCLAS, Aerodyne Research Inc.) with thermoelectrically cooled detectors and up to 10 Hz measurement capability. The resulting continuous isotopologue flux measurements will be accompanied by intensive sampling campaigns on the leaf scale: Water from leaf, twig, soil and precipitation samples will be analysed in the lab using isotope ratio mass spectrometry. During data analysis we will put a focus on (i) the influence of carbon and oxygen discrimination on the isotopic signature of respective net ecosystem exchange, (ii) on the relationship between evapotranspiration and leaf water enrichment, and (iii) on the 18O exchange between carbon dioxide and water. At present, we already carried out extensive
Attempts To Catalyze the Electrochemical CO2-to-Methanol Conversion by Biomimetic 2e(-) + 2H(+) Transferring Molecules.

Science.gov (United States)

Saveant, Jean-Michel; Tard, Cédric

2016-01-27

In the context of the electrochemical and photochemical conversion of CO2 to liquid fuels, one of the most important issues of contemporary energy and environmental issues, the possibility of pushing the reduction beyond the CO and formate level and catalytically generate products such as methanol is particularly attractive. Biomimetic 2e(-) + 2H(+) is often viewed as a potential hydride donor. This has been the object of a recent interesting attempt (J. Am. Chem. Soc. 2014, 136, 14007) in which 6,7-dimethyl-4-hydroxy-2-mercaptopteridine was reported as a catalyst of the electrochemical conversion of CO2 to methanol and formate, based on cyclic voltammetric, (13)C NMR, IR, and GC analyses. After checking electrolysis at the reported potential and at a more negative potential to speed up the reaction, it appears, on (1)H NMR and gas chromatographic grounds, that there is neither catalysis nor methanol and nor formate production. (1)H NMR (with H2O presaturation) brings about an unambiguous answer to the eventual production of methanol and formate, much more so than (13)C NMR, which can even be misleading when no internal standard is used as in the above-mentioned paper. IR analysis is even less conclusive. Use of a GC technique with sufficient sensitivity confirmed the lack of methanol formation. The direct or indirect hydride transfer electrochemical reduction of CO2 to formate and to methanol remains an open question. Original ideas and efforts such as those discussed here are certainly worth tempting. However, in view of the importance of the stakes, it appears necessary to carefully check reports in this area.
Molten V2O5/Cs0.9K0.9Na0.2S2O7 and V2O5/K2S2O7 catalysts as electrolytes in an electrocatalytic membrane separation device for SO2 removal

DEFF Research Database (Denmark)

Rasmussen, Søren Birk; Eriksen, Kim Michael; Fehrmann, Rasmus

2002-01-01

Bench scale fuel cell tests have been carried out on the SO2 oxidation catalyst systems V2O5/M2S2O7 (M = alkali) used as electrolytes in a standard molten carbonate fuel cell (MCFC) fuel cell setup for removal of SO2 from power plant flue gases. Porous LixNi(1-x)O electrodes were used both as anode...... and cathode. The cleaning cell removes SO2 when a potential is applied across the membrane, potentially providing cheap and ecological viable means for regeneration of SO2 from off-gases into high quality H2SO4. Results show that successful removal of up to 80% SO2 at 450 degreesC can be achieved...

Synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2.

Science.gov (United States)

Qian, Qingli; Zhang, Jingjing; Cui, Meng; Han, Buxing

2016-05-11

Acetic acid is an important bulk chemical that is currently produced via methanol carbonylation using fossil based CO. Synthesis of acetic acid from the renewable and cheap CO2 is of great importance, but state of the art routes encounter difficulties, especially in reaction selectivity and activity. Here we report a route to produce acetic acid from CO2, methanol and H2. The reaction can be efficiently catalysed by Ru-Rh bimetallic catalyst using imidazole as the ligand and LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) solvent. It is confirmed that methanol is hydrocarboxylated into acetic acid by CO2 and H2, which accounts for the outstanding reaction results. The reaction mechanism is proposed based on the control experiments. The strategy opens a new way for acetic acid production and CO2 transformation, and represents a significant progress in synthetic chemistry.
A novel CO>2- and SO>2-tolerant dual phase composite membrane for oxygen separation

DEFF Research Database (Denmark)

Cheng, Shiyang; Søgaard, Martin; Han, Li

2015-01-01

A novel dual phase composite oxygen membrane (Al0.02Ga0.02Zn0.96O1.02 – Gd0.1Ce0.9O1.95-δ) was successfully prepared and tested. The membrane shows chemical stability against CO2 and SO2, and a stable oxygen permeation over 300 hours in CO2 was demonstrated. ZnO is cheap and non-toxic...... and is therefore highly advantageous compared to other common materials used for the purpose....
H+ irradiation effect in Co-doped BaFe2As2 single crystals

International Nuclear Information System (INIS)

Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Tamegai, T.; Kitamura, H.; Murakami, T.

2011-01-01

The effect of H + irradiation on the suppression of Tc in Co-doped BaFe 2 As 2 . H + irradiation introduces nonmagnetic scattering centers. Critical Scattering rate is much higher than that expected in s±-pairing scenario. We report the suppression of the critical temperature T c in single crystalline Ba(Fe 1-x Co x ) 2 As 2 at under-, optimal-, and over-doping levels by 3 MeV proton irradiation. T c decreases and residual resistivity increases monotonically with increasing the dose. The low-temperature resistivity does not show the upturn in contrast with the α-particle irradiated NdFeAs(O,F), which suggests that proton irradiation introduces nonmagnetic scattering centers. Critical scattering rates for all samples obtained by three different ways are much higher than that expected in s±-pairing scenario based on inter-band scattering due to antiferro-magnetic spin fluctuations.
Adiabatic burning velocity of H2-O2 mixtures diluted with CO2/N2/Ar

International Nuclear Information System (INIS)

Ratna Kishore, V.; Muchahary, Ringkhang; Ray, Anjan; Ravi, M.R.

2009-01-01

Global warming due to CO 2 emissions has led to the projection of hydrogen as an important fuel for future. A lot of research has been going on to design combustion appliances for hydrogen as fuel. This has necessitated fundamental research on combustion characteristics of hydrogen fuel. In this work, a combination of experiments and computational simulations was employed to study the effects of diluents (CO 2 , N 2 , and Ar) on the laminar burning velocity of premixed hydrogen/oxygen flames using the heat flux method. The experiments were conducted to measure laminar burning velocity for a range of equivalence ratios at atmospheric pressure and temperature (300 K) with reactant mixtures containing varying concentrations of CO 2 , N 2 , and Ar as diluents. Measured burning velocities were compared with computed results obtained from one-dimensional laminar premixed flame code PREMIX with detailed chemical kinetics and good agreement was obtained. The effectiveness of diluents in reduction of laminar burning velocity for a given diluent concentration is in the increasing order of argon, nitrogen, carbon dioxide. This may be due to increased capabilities either to quench the reaction zone by increased specific heat or due to reduced transport rates. The lean and stoichiometric H 2 /O 2 /CO 2 flames with 65% CO 2 dilution exhibited cellular flame structures. Detailed three-dimensional simulation was performed to understand lean H 2 /O 2 /CO 2 cellular flame structure and cell count from computed flame matched well with the experimental cellular flame. (author)
Effects of O{sub 2} and SO{sub 2} on the Capture Capacity of a Primary-Amine Based Polymeric CO{sub 2} Sorbent

Energy Technology Data Exchange (ETDEWEB)

Hallenbeck, Alexander P; Kitchin, John R

2013-08-01

Post combustion CO{sub 2} capture is most commonly carried out using an amine solution that results in a high parasitic energy cost in the stripper unit due to the need to heat the water which comprises a majority of the amine solution. It is also well known that amine solvents suffer from stability issues due to amine leaching and poisoning by flue gas impurities. Solid sorbents provide an alternative to solvent systems that would potentially reduce the energy penalty of carbon capture. However, the cost of using a particular sorbent is greatly affected by the usable lifetime of the sorbent. This work investigated the stability of a primary amine-functionalized ion exchange resin in the presence of O{sub 2} and SO{sub 2}, both of which are constituents of flue gas that have been shown to cause degradation of various amines in solvent processes. The CO{sub 2} capture capacity was measured over multiple capture cycles under continuous exposure to two simulated flue gas streams, one containing 12 vol% CO{sub 2}, 4% O{sub 2}, 84% N{sub 2}, and the other containing 12.5 vol% CO{sub 2}, 4% O{sub 2}, 431 ppm SO{sub 2}, balance N{sub 2} using a custom-built packed bed reactor. The resin maintained its CO{sub 2} capture capacity of 1.31 mol/kg over 17 capture cycles in the presence of O{sub 2} without SO{sub 2}. However, the CO{sub 2} capture capacity of the resin decreased rapidly under exposure to SO{sub 2} by an amount of 1.3 mol/kg over 9 capture cycles. Elemental analysis revealed the resin adsorbed 1.0 mol/kg of SO{sub 2}. Thermal regeneration was determined to not be possible. The poisoned resin was, however, partially regenerated with exposure to 1.5M NaOH for 3 days resulting in a 43% removal of sulfur, determined through elemental analysis, and a 35% recovery of CO{sub 2} capture capacity. Evidence was also found for amine loss upon prolonged (7 days) continuous exposure to high temperatures (120 C) in air. It is concluded that desulfurization of the flue gas
Formation of Nanodroplets in N₂/H₂O/SO₂ under Irradiation of Fast Proton Beams

DEFF Research Database (Denmark)

Nakai, Youchi; Shigeoka, Tomita; Funada, Shuhei

of the droplet growth in thebinary nucleation process of water and H2SO4.We have performed irradiation of proton beam on the gas mixture of N2/H2O/SO2 andAir/H2O/SO2. The reduction of SO2 concentration by beam irradiation was monitored usingan SO2 meter and the size distributions of generated droplets were...
Crystal-field-driven redox reactions: How common minerals split H2O and CO2 into reduced H2 and C plus oxygen

Science.gov (United States)

Freund, F.; Batllo, F.; Leroy, R. C.; Lersky, S.; Masuda, M. M.; Chang, S.

1991-01-01

It is difficult to prove the presence of molecular H2 and reduced C in minerals containing dissolved H2 and CO2. A technique was developed which unambiguously shows that minerals grown in viciously reducing environments contain peroxy in their crystal structures. The peroxy represent interstitial oxygen atoms left behind when the solute H2O and/or CO2 split off H2 and C as a result of internal redox reactions, driven by the crystal field. The observation of peroxy affirms the presence of H2 and reduced C. It shows that the solid state is indeed an unusual reaction medium.
Production of H2 from aluminium/water reaction and its potential for CO2 methanation

Science.gov (United States)

Khai Phung, Khor; Sethupathi, Sumathi; Siang Piao, Chai

2018-04-01

Carbon dioxide (CO2) is a natural gas that presents in excess in the atmosphere. Owing to its ability to cause global warming, capturing and conversion of CO2 have attracted much attention worldwide. CO2 methanation using hydrogen (H2) is believed to be a promising route for CO2 removal. In the present work, H2 is produced using aluminum-water reaction and tested for its ability to convert CO2 to methane (CH4). Different type of water i.e. tap water, distilled water, deionized water and ultrapure water, concentration of sodium hydroxide (NaOH) (0.2 M to 1.0 M) and particle size of aluminum (45 m to 500 μm) were varied as parameter study. It was found that the highest yield of H2 was obtained using distilled water, 1.0 M of NaOH and 45μm particle size of aluminium. However, the highest yield of methane was achieved using a moderate and progressive H2 production (distilled water, 0.6 M of NaOH and 45 μm particle size of aluminium) which allowed sufficient time for H2 to react with CO2. It was concluded that 1130 ml of H2 can produce about 560 ppm of CH4 within 25 min of batch reaction using nickel catalyst.
Assembly of [Cu2(COO)4] and [M3(μ3-O)(COO)6] (M = Sc, Fe, Ga, and In) building blocks into porous frameworks towards ultra-high C2H2/CO2 and C2H2/CH4 separation performance.

Science.gov (United States)

Zhang, Jian-Wei; Hu, Man-Cheng; Li, Shu-Ni; Jiang, Yu-Cheng; Qu, Peng; Zhai, Quan-Guo

2018-02-20

A porous MOF platform (SNNU-65s) formed by creatively combining paddle-wheel-like [Cu 2 (COO) 4 ] and trigonal prismatic [M 3 (μ 3 -O)(COO) 6 ] building blocks was designed herein. The mixed and high-density open metal sites and the OH-functionalized pore surface promote SNNU-65s to exhibit ultra-high C 2 H 2 uptake and separation performance. Impressively, SNNU-65-Cu-Ga stands out for the highest C 2 H 2 /CO 2 (18.7) and C 2 H 2 /CH 4 (120.6) selectivity among all the reported MOFs at room temperature.
Virtual half-metallicity at the CoS2/FeS2 interface induced by strain

KAUST Repository

Nazir, Safdar

2013-01-01

Spin polarized ab initio calculations based on density functional theory are performed to investigate the electronic and magnetic properties of the interface between the ferromagnetic metal CoS2 and the nonmagnetic semiconductor FeS2. Relaxation of the interface structure is taken into account by atomic force minimization. We find that both Co and Fe are close to half-metallicity at the interface. Tensile strain is shown to strongly enhance the spin polarization so that a virtually half-metallic interface can be achieved, for comparably moderate strain. © 2012 The Royal Society of Chemistry.
Comparison of methods for calculating thermodynamic properties of binary mixtures in the sub and super critical state: Lee-Kesler and cubic equations of state for binary mixtures containing either CO2 or H2S

International Nuclear Information System (INIS)

Yang, Jyisy; Griffiths, Peter R.; Goodwin, Anthony R.H.

2003-01-01

The (ρ,T,p) and (vapor + liquid) equilibria for fluid mixtures containing either CO 2 or H 2 S have been determined from 13 equations of state. The estimated values have been compared with published experimental results. CO 2 and H 2 S were used to represent non-polar and polar fluids, respectively. The equations of state investigated were as follows: (a) the Lee-Kesler equation; (b) two equations that included new reference fluids for the Lee-Kesler method; (c) three so-called extended equations of state; and (d) seven cubic equations of state. After adjustment of the binary interaction parameters the predicted values differed from the experimental data by about 0.8% for CO 2 mixtures while for H 2 S mixtures the uncertainty was about ±2.8%. Somewhat larger errors, although still lower than ±5%, were obtained for co-existing phase densities; the Lee-Kesler method provided results of the highest accuracy. The cubic equations proposed by Schmidt and Wenzel and Valderrama provide the most reliable predictions of both single and co-existing phase densities. Comparison of the predicted (vapor + liquid) equilibrium with experiment shows that each of the seven cubic equations provides results of similar accuracy and all within ±6%
Remote sensing of volcanic CO2, HF, HCl, SO2, and BrO in the downwind plume of Mt. Etna

Science.gov (United States)

Butz, André; Solvejg Dinger, Anna; Bobrowski, Nicole; Kostinek, Julian; Fieber, Lukas; Fischerkeller, Constanze; Giuffrida, Giovanni Bruno; Hase, Frank; Klappenbach, Friedrich; Kuhn, Jonas; Lübcke, Peter; Tirpitz, Lukas; Tu, Qiansi

2017-01-01

Remote sensing of the gaseous composition of non-eruptive, passively degassing volcanic plumes can be a tool to gain insight into volcano interior processes. Here, we report on a field study in September 2015 that demonstrates the feasibility of remotely measuring the volcanic enhancements of carbon dioxide (CO2), hydrogen fluoride (HF), hydrogen chloride (HCl), sulfur dioxide (SO2), and bromine monoxide (BrO) in the downwind plume of Mt. Etna using portable and rugged spectroscopic instrumentation. To this end, we operated the Fourier transform spectrometer EM27/SUN for the shortwave-infrared (SWIR) spectral range together with a co-mounted UV spectrometer on a mobile platform in direct-sun view at 5 to 10 km distance from the summit craters. The 3 days reported here cover several plume traverses and a sunrise measurement. For all days, intra-plume HF, HCl, SO2, and BrO vertical column densities (VCDs) were reliably measured exceeding 5 × 1016, 2 × 1017, 5 × 1017, and 1 × 1014 molec cm-2, with an estimated precision of 2.2 × 1015, 1.3 × 1016, 3.6 × 1016, and 1.3 × 1013 molec cm-2, respectively. Given that CO2, unlike the other measured gases, has a large and well-mixed atmospheric background, derivation of volcanic CO2 VCD enhancements (ΔCO2) required compensating for changes in altitude of the observing platform and for background concentration variability. The first challenge was met by simultaneously measuring the overhead oxygen (O2) columns and assuming covariation of O2 and CO2 with altitude. The atmospheric CO2 background was found by identifying background soundings via the co-emitted volcanic gases. The inferred ΔCO2 occasionally exceeded 2 × 1019 molec cm-2 with an estimated precision of 3.7 × 1018 molec cm-2 given typical atmospheric background VCDs of 7 to 8 × 1021 molec cm-2. While the correlations of ΔCO2 with the other measured volcanic gases confirm the detection of volcanic CO2 enhancements, correlations were found of variable
H2S-mediated thermal and photochemical methane activation.

Science.gov (United States)

Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V

2013-12-02

Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with methane, deemed altogether as sub-quality or "sour" gas. We propose a unique method of activation to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3 , and an energy carrier such as H2. For this purpose, we investigated the H2S-mediated methane activation to form a reactive CH3SH species by means of direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4 + H2S complex resulted in a barrierless relaxation by a conical intersection to form a ground-state CH3SH + H2 complex. The resulting CH3SH could further be coupled over acidic catalysts to form higher hydrocarbons, and the resulting H2 used as a fuel. This process is very different from conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced control over the conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the current industrial steam methane reforming (SMR). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The surface chemistry of Cu in the presence of CO2 and H2O

Energy Technology Data Exchange (ETDEWEB)

Deng, Xingyi; Verdaguer, Albert; Herranz, Tirma; Weis, Christoph; Bluhm, Hendrik; Salmeron, Miquel

2008-07-16

The chemical nature of copper and copper oxide (Cu{sub 2}O) surfaces in the presence of CO{sub 2} and H{sub 2}O at room temperature was investigated using ambient pressure x-ray photoelectron spectroscopy. The studies reveal that in the presence of 0.1 torr CO{sub 2} several species form on the initially clean Cu, including carbonate CO{sub 3}{sup 2}, CO{sub 2}{sup {delta}-} and C{sup 0}, while no modifications occur on an oxidized surface. The addition of 0.1 ML Zn to the Cu results in the complete conversion of CO{sub 2}{sup {delta}-} to carbonate. In a mixture of 0.1 torr H{sub 2}O and 0.1 torr CO{sub 2}, new species are formed, including hydroxyl, formate and methoxy, with H{sub 2}O providing the hydrogen needed for the formation of hydrogenated species.
Decomposition of SO2, NOx and CO2 emissions from energy use of major economic sectors in Taiwan

International Nuclear Information System (INIS)

Sue J. Lin; Tzu C. Chang

1996-01-01

In this paper we use the Divisia index approach to decompose emission changes of SO 2 , NO, and CO 2 from major economic sectors in Taiwan during 1980 to 1992. The study highlights the interrelationships between energy use and environmental quality, and provides insights for policy making. The emission changes are decomposed into five components-pollution coefficient, fuel mix, energy intensity, economic growth and industrial structure. Of all components analyzed, economic growth had the largest positive effect on emission changes for Taiwan's major economic sectors. Emissions of SO 2 in industry and other sectors showed a decreasing trend due to fuel quality improvements antipollution control. However, NO, and CO 2 emissions increased sharply in all sectors. Comparisons were also made with Germany, Japan and USA. This study has shown that improvement in energy efficiency, pollution control and fuel substitution are major options to reduce SO 2 , NO, and CO 2 emissions
Simultaneous purifying of Hg0, SO2, and NOx from flue gas by Fe3+/H2O2: the performance and purifying mechanism.

Science.gov (United States)

Xing, Yi; Li, Liuliu; Lu, Pei; Cui, Jiansheng; Li, Qianli; Yan, Bojun; Jiang, Bo; Wang, Mengsi

2018-03-01

Hg 0 , SO 2 , and NOx result in heavily global environmental pollution and serious health hazards. Up to now, how to efficiently remove mercury with SO 2 and NOx from flue gas is still a tough task. In this study, series of high oxidizing Fenton systems were employed to purify the pollutants. The experimental results showed that Fe 3+ /H 2 O 2 was more suitable to purify Hg 0 than Fe 2+ /H 2 O 2 and Cu 2+ /H 2 O 2. The optimal condition includes Fe 3+ concentration of 0.008 mol/L, Hg 0 inlet concentration of 40 μg/m 3 , solution temperature of 50 °C, pH of 3, H 2 O 2 concentration of 0.7 mol/L, and O 2 percentage of 6%. When SO 2 and NOx were taken into account under the optimal condition, Hg 0 removal efficiency could be enhanced to 91.11% while the removal efficiency of both NOx and SO 2 was slightly declined, which was consistent to the analysis of purifying mechanism. The removal efficiency of Hg 0 was stimulated by accelerating the conversion of Fe 2+ to Fe 3+ , which resulted from the existence of SO 2 and NOx. The results of this study suggested that simultaneously purifying Hg 0 , SO 2 , and NOx from flue gas is feasible.
Vibrational spectra of Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·nH2O (n = 4, 6) with a crystal structure determination of the Tutton salt Cs2Cu(SeO4)2·6H2O

Science.gov (United States)

Wildner, M.; Marinova, D.; Stoilova, D.

2016-02-01

The solubility in the three-component systems Cs2SO4-CuSO4-H2O and Cs2SeO4-CuSeO4-H2O have been studied at 25 °C. The experimental results show that double salts, Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·4H2O, crystallize from the ternary solutions within large concentration ranges. Crystals of Cs2Cu(SeO4)2·6H2O were synthesized at somewhat lower temperatures (7-8 °C). The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the respective dehydration schemes are proposed. The calculated enthalpies of dehydration (ΔHdeh) have values of: 434.2 kJ mol-1 (Cs2Cu(SeO4)2·6H2O), 280.9 kJ mol-1 (Cs2Cu(SeO4)2·4H2O), and 420.2 kJ mol-1 (the phase transition of Cs2Cu(SO4)2·6H2O into Cs2Cu(SO4)2·H2O). The crystal structure of Cs2Cu(SeO4)2ṡ6H2O was determined from single crystal X-ray diffraction data. It belongs to the group of Tutton salts, crystallizing isotypic to the respective sulfate in a monoclinic structure which is characterized by isolated Cu(H2O)6 octahedra and SeO4 tetrahedra, interlinked by hydrogen bonds and [9]-coordinated Cs+ cations. Infrared spectra of the cesium copper compounds are presented and discussed with respect to both the normal modes of the tetrahedral ions and the water molecules. The analysis of the infrared spectra of the double compounds reveals that the distortion of the selenate tetrahedra in Cs2Cu(SeO4)2·4H2O is stronger than those in Cs2Cu(SeO4)2·6H2O in agreement with the structural data. Matrix-infrared spectroscopy was applied to confirm this claim - Δν3 for SO4 2 - ions matrix-isolated in Cs2Cu(SeO4)2·6H2O has a value of 35 cm-1 and that of the same ions included in Cs2Cu(SeO4)2·4H2O - 84 cm-1. This spectroscopic finding is due to the formation of strong covalent bands Cu-OSO3 on one hand, and on the other to the stronger deformation of the host SeO4 2 - tetrahedra in Cs2Cu(SeO4)2·4H2O as compared to those in Cs2Cu(SeO4)2·6H2O. The strength of the hydrogen bonds as deduced from the
Mechanism of SO2 removal by carbon

Science.gov (United States)

Lizzio, Anthony A.; DeBarr, Joseph A.

1997-01-01

The reaction of SO2 with carbon (C) in the presence of O2 and H2O involves a series of reactions that leads to the formation of sulfuric acid as the final product. The rate-determining step in the overall process is the oxidation of SO2 to SO3. Three SO2 oxidation reactions are possible. Adsorbed SO2 (C−SO2) can react either with gas phase O2 or with adsorbed oxygen (C−O complex) to form sulfur trioxide (SO3), or gas phase SO2 can react directly with the C−O complex. In optimizing the SO2 removal capabilities of carbon, most studies only assume a given mechanism for SO2 adsorption and conversion to H2SO4 to be operable. The appropriate SO2 oxidation step and role of the C−O complex in this mechanism remain to be determined. The ultimate goal of this study was to prepare activated char from Illinois coal with optimal properties for low-temperature (80−150°C) removal of sulfur dioxide from coal combustion flue gas. The SO2 adsorption capacity of activated char was found to be inversely proportional to the amount of oxygen adsorbed on its surface. A temperature-programmed desorption technique was developed to titrate those sites responsible for adsorption of SO2 and conversion to H2SO4. On the basis of these results, a mechanism for SO2 removal by carbon was proposed. The derived rate expression showed SO2 adsorption to be dependent only on the fundamental rate constant and concentration of carbon atoms designated as free sites. Recent studies indicate a similar relationship exists between the rate of carbon gasification (in CO2 or H2O) and the number of reactive sites as determined by transient kinetics experiments. Utilizing the concept of active or free sites, it was possible to produce a char from Illinois coal having an SO2 adsorption capacity surpassing that of a commercial catalytic activated carbon.
Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H2S and CO2

Directory of Open Access Journals (Sweden)

Yiyong Sui

2017-06-01

Full Text Available The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H2S/CO2 environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H2S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni3S2, NiS, or Ni3S4, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate.
La0.8Sr0.2Co0.8Ni0.2O3-δ impregnated oxygen electrode for H2O/CO2 co-electrolysis in solid oxide electrolysis cells

Science.gov (United States)

Zheng, Haoyu; Tian, Yunfeng; Zhang, Lingling; Chi, Bo; Pu, Jian; Jian, Li

2018-04-01

High-temperature H2O/CO2 co-electrolysis through reversible solid oxide electrolysis cell (SOEC) provides potentially a feasible and eco-friendly way to convert electrical energy into chemicals stored in syngas. In this work, La0.8Sr0.2Co0.8Ni0.2O3-δ (LSCN) impregnated Gd0.1Ce0.9O1.95 (GDC)-(La0.8Sr0.2)0.95MnO3-δ (LSM) composite oxygen electrode is studied as high-performance electrode for H2O/CO2 co-electrolysis. The LSCN impregnated cell exhibits competitive performance with the peak power density of 1057 mW cm-2 at 800 °C in solid oxide fuel cell (SOFC) mode; in co-electrolysis mode, the current density can reach 1.60 A cm-2 at 1.5 V at 800 °C with H2O/CO2 ratio of 2/1. With LSCN nanoparticles dispersed on the surface of GDC-LSM to maximize the reaction active sites, the LSCN impregnated cell shows significant enhanced electrochemical performance at both SOEC and SOFC modes. The influence of feed gas composition (H2O-H2-CO2) and operating voltages on the performance of co-electrolysis are discussed in detail. The cell shows a very stable performance without obvious degradation for more than 100 h. Post-test characterization is analyzed in detail by multiple measurements.

Carbon Deposition in Solid Oxide Cells during Co-Electrolysis of H2O and CO2

DEFF Research Database (Denmark)

Tao, Youkun; Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

2014-01-01

current densities from 1.5 to 2.25 A/cm2 and reactant (H2O + CO2) conversion of up to 67%. Delamination and carbon nano-fibers were observed at the Ni-YSZ|YSZ interface for two cells with a dense microstructure operated at electrolysis current densities of 2.0 and 2.25 A/cm2 and a conversion of 59% and 67...... and the active Ni-YSZ electrode. Carbon nano-fibers were only observed close to the YSZ electrolyte, indicating a very reducing atmosphere and a large over-potential gradient in the active electrode, being highest at the interface to the bulk electrolyte and decreasing toward the Ni-YSZ support.......Carbon formation during co-electrolysis of H2O and CO2 in Ni-YSZ supported Solid Oxide Electrolysis Cells (SOECs) may occur, especially at high current density and high conversion. In order to evaluate the carbon formation limits, five galvanostatic tests were performed in this work at electrolysis...
OMS, OM(η2-SO), and OM(η2-SO)(η2-SO2) molecules (M = Ti, Zr, Hf): infrared spectra and density functional calculations.

Science.gov (United States)

Liu, Xing; Wang, Xuefeng; Wang, Qiang; Andrews, Lester

2012-07-02

Infrared spectra of the matrix isolated OMS, OM(η(2)-SO), and OM(η(2)-SO)(η(2)-SO(2)) (M = Ti, Zr, Hf) molecules were observed following laser-ablated metal atom reactions with SO(2) during condensation in solid argon and neon. The assignments for the major vibrational modes were confirmed by appropriate S(18)O(2) and (34)SO(2) isotopic shifts, and density functional vibrational frequency calculations (B3LYP and BPW91). Bonding in the initial OM(η(2)-SO) reaction products and in the OM(η(2)-SO)(η(2)-SO(2)) adduct molecules with unusual chiral structures is discussed.
Magnetic structure and phase transitions of Co1-xMnxCl2.2H2O and Co1-xMnxCl2.2D2O

International Nuclear Information System (INIS)

Brueckel, T.; Lippert, M.; Kubo, H.; Zenmyo, K.; Mayer, H.M.; Pfeiffer, F.; Hohlwein, D.; Krimmel, A.

1995-01-01

We present neutron diffraction results of the magnetic structure, phase transitions and magnetic short-range order of Co 1-x Mn x Cl 2 .2H 2 O/D 2 O single crystals. For samples in an intermediate composition range, where a spin glass phase exists, we found the coexistence of spin glass and long-range antiferromagnetic order. ((orig.))
Tungsten phosphanylarylthiolato complexes [W{PhP(2-SC6H4)2-kappa3S,S',P} 2] and [W{P(2-SC6H4)3-kappa4S,S',S",P}2]: synthesis, structures and redox chemistry.

Science.gov (United States)

Hildebrand, Alexandra; Lönnecke, Peter; Silaghi-Dumitrescu, Luminita; Hey-Hawkins, Evamarie

2008-09-14

PhP(2-SHC6H4)2 (PS2H2) reacts with WCl6 with reduction of tungsten to give the air-sensitive tungsten(IV) complex [W{PhP(2-SC6H4)2-kappa(3)S,S',P}2] (1). 1 is oxidised in air to [WO{PhPO(2-SC6H4)2-kappa(3)S,S',O}{PhP(2-SC6H4)2-kappa(3)S,S',P}] (2). The attempted synthesis of 2 by reaction of 1 with iodosobenzene as oxidising agent was unsuccessful. [W{P(2-SC6H4)3-kappa(4)S,S',S",P}2] (3) was formed in the reaction of P(2-SHC6H4)3 (PS3H3) with WCl6. The W(VI) complex 3 contains two PS3(3-) ligands, each coordinated in a tetradentate fashion resulting in a tungsten coordination number of eight. The reaction of 3 with AgBF4 yields the dinuclear tungsten complex [W2{P(2-SC6H4)3-kappa(4)S,S',S",P}3]BF4 (4). Complexes 1-4 were characterised by spectral methods and X-ray structure determination.
GaAs micromachining in the 1 H2SO4:1 H2O2:8 H2O system. From anisotropy to simulation

Science.gov (United States)

Tellier, C. R.

2011-02-01

The bulk micromachining on (010), (110) and (111)A GaAs substrates in the 1 H2SO4:1 H2O2:8 H2O system is investigated. Focus is placed on anisotropy of 3D etching shapes with a special emphasis on convex and concave undercuts which are of prime importance in the wet micromachining of mechanical structures. Etched structures exhibit curved contours and more and less rounded sidewalls showing that the anisotropy is of type 2. This anisotropy can be conveniently described by a kinematic and tensorial model. Hence, a database composed of dissolution constants is further determined from experiments. A self-elaborated simulator which works with the proposed database is used to derive theoretical 3D shapes. Simulated shapes agree well with observed shapes of microstructures. The successful simulations open up two important applications for MEMS: CAD of mask patterns and meshing of simulated shapes for FEM simulation tools.
Treatment for GaSb surfaces using a sulphur blended (NH4)2S/(NH4)2SO4 solution

International Nuclear Information System (INIS)

Murape, D.M.; Eassa, N.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

2012-01-01

A sulphur based chemical, [(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na 2 S·9H 2 O and (NH 4 ) 2 S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) than with (NH 4 ) 2 S or Na 2 S·9H 2 O, as evidenced by the ratio of the O 506eV to Sb 457eV AES peaks. XPS results reveal that Sb 2 S 3 /Sb 2 S 5 “replaces” Sb 2 O 3 /Sb 2 O 5 , suggesting that sulphur atoms substitute oxygen atoms in Sb 2 O 3 /Sb 2 O 5 to form Sb-S. It seems sulphurization only partially removes Ga 2 O 3 . Treatment with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.
Preparation and Performance Analysis of Na2SO4·10H2O/EG Composite Phase-change Materials

Directory of Open Access Journals (Sweden)

LENG Cong-bin

2017-01-01

Full Text Available Sodium sulfate decahydrate/expanded graphite composite phase-change material (Na2SO4·10H2O/EG was prepared by vacuum adsorption method.The thermal properties of Na2SO4·10H2O/EG,such as melting-solidification,phase separation,supercooling and latent heat were tested and analyzed.The results show that with the addition of 2%(mass fraction borax and 8% EG,the composite phase-change materials Na2SO4·10H2O/EG obtain ideal properties.The phase separation is eliminated,the supercooling degree of Na2SO4·10H2O is reduced from 13.6℃ to below 0.6℃,the latent heat and the energy storage density of the phase-change materials reach 225.77kJ·kg-1 and 218.09MJ·m-3 respectively.The thermal conductivity is also greatly improved.Compared with Na2SO4·10H2O with the addition of the nucleating agent borax only,the time for heat storage is shortened by 52.6%,and the time for heat release is shortened by 55.1%.Even after 500 times of rapid heating and cooling cycles,the performance of Na2SO4·10H2O/EG does not deteriorate.The novel composite phase-change material has better storage/exothermic properties.
COMPARISON OF S-CO2 POWER CYCLES FOR NUCLEAR ENERGY

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Ladislav Vesely

2016-12-01

Full Text Available The supercritical carbon dioxide (S-CO2 is a possible cooling system for the new generations of nuclear reactors and fusion reactors. The S-CO2 power cycles have several advantages over other possible coolants such as water and helium. The advantages are the compression work, which is lower than in the case of helium, near the critical point and the S-CO2 is more compact than water and helium. The disadvantage is so called Pinch point which occurs in the regenerative heat exchanger. The pinch point can be eliminated by an arrangement of the cycle or using a mixture of CO2. This paper describes the S-CO2 power cycles for nuclear fission and fusion reactors.
Synthesis and structural characterization of two cobalt phosphites: 1-D (H3NC6H4NH3)Co(HPO3)2 and 2-D (NH4)2Co2(HPo3)3

International Nuclear Information System (INIS)

Cheng, C.-C.; Chang, W.-K.; Chiang, R.-K.; Wang, S.-L.

2010-01-01

Two new cobalt phosphites, (H 3 NC 6 H 4 NH 3 )Co(HPO 3 ) 2 (1) and (NH 4 ) 2 Co 2 (HPO 3 ) 3 (2), have been synthesized and characterized by single-crystal X-ray diffraction. All the cobalt atoms of 1 are in tetrahedral CoO 4 coordination. The structure of 1 comprises twisted square chains of four-rings, which contain alternating vertex-shared CoO 4 tetrahedra and HPO 3 groups. These chains are interlinked with trans-1,4-diaminocyclohexane cations by hydrogen bonds. The 2-D structure of 2 comprises anionic complex sheets with ammonium cations present between them. An anionic complex sheet contains three-deck phosphite units, which are interconnected by Co 2 O 9 to form complex layers. Magnetic susceptibility measurements of 1 and 2 showed that they have a weak antiferromagnetic interaction. - Graphical abstract: The 2-D structure of (NH 4 ) 2 Co 2 (HPO 3 ) 3 comprises anionic complex sheets with ammonium cations present between them. An anionic complex sheet contains three-deck phosphite units, which are interconnected by dimmeric Co 2 O 9 to form complex layers.
Effect of the greenhouse gases (CO2, H2O, SO2) on Martian paleoclimate

Science.gov (United States)

Postawko, S. E.; Kuhn, W. R.

1986-01-01

There is general agreement that certain surface features on Mars are indicative of the presence of liquid water at various times in the geologic past. In particular, the valley networks are difficult to explain by a mechanism other than the flow of liquid water. It has been suggested in several studies that a thick CO2 atmosphere on Mars early in its history could have provided a greenhouse warming that would have allowed the flow of water either on the surface or just below the surface. However, this effect was examined with a detailed radiation model, and it was found that if reduced solar luminosity early in the history of the solar system is taken into account, even three bars of CO2 will not provide sufficient greeenhouse warming. The addition of water vapor and sulflur dioxide (both plausible gases that may have been emitted by Martian volcanoes) to the atmosphere also fail to warm the surface above 273 K for reduced solar luminosity conditions. The increase in temperature may be large enough, however, for the formation of these features by brines.
Gaseous (DMS, MSA, SO2, H2SO4 and DMSO and particulate (sulfate and methanesulfonate sulfur species over the northeastern coast of Crete

Directory of Open Access Journals (Sweden)

H. Bardouki

2003-01-01

Full Text Available A detailed study of the levels, the temporal and diurnal variability of the main compounds involved in the biogenic sulfur cycle was carried out in Crete (Eastern Mediterranean during the Mediterranean Intensive Oxidant Study (MINOS field experiment in July-August 2001. Intensive measurements of gaseous dimethylsulfide (DMS, dimethylsulfoxide (DMSO, sulfur dioxide (SO2, sulfuric (H2SO4 and methanesulfonic acids (MSA and particulate sulfate (SO42- and methanesulfonate (MS- have been performed during the campaign. Dimethylsulfide (DMS levels ranged from 2.9 to 136 pmol·mol-1 (mean value of 21.7 pmol·mol-1 and showed a clear diurnal variation with daytime maximum. During nighttime DMS levels fall close or below the detection limit of 2 pmol·mol-1. Concurrent measurements of OH and NO3 radicals during the campaign indicate that NO3 levels can explain most of the observed diurnal variation of DMS. Dimethylsulfoxide (DMSO ranged between 0.02 and 10.1 pmol·mol-1 (mean value of 1.7 pmol·mol-1 and presents a diurnal variation similar to that of DMS. SO2 levels ranged from 220 to 2970 pmol·mol-1 (mean value of 1030 pmol·mol-1, while nss-SO42- and MS- ranged from 330 to 7100 pmol·mol-1, (mean value of 1440 pmol·mol-1 and 1.1 to 37.5 pmol·mol-1 (mean value of 11.5 pmol·mol-1 respectively. Of particular interest are the measurements of gaseous MSA and H2SO4. MSA ranged from below the detection limit (3x104 to 3.7x107 molecules cm-3, whereas H2SO4 ranged between 1x105 and 9.0x107 molecules cm-3. The measured H2SO4 maxima are among the highest reported in literature and can be attributed to high insolation, absence of precipitation and increased SO2 levels in the area. From the concurrent SO2, OH, and H2SO4 measurements a sticking coefficient of 0.52±0.28 was calculated for H2SO4. From the concurrent MSA, OH, and DMS measurements the yield of gaseous MSA from the OH-initiated oxidation of DMS was calculated to range between 0.1-0.4%. This low MSA
Synthesis and characterization of MoS{sub 2} cocatalysts for H{sub 2}-generation; Darstellung und Charakterisierung von MoS{sub 2} Cokatalysatoren fuer die H{sub 2}-Entwicklung

Energy Technology Data Exchange (ETDEWEB)

Djamil, John

2015-10-05

} nanoparticles as a function of milling time but with the same chemical composition. In doing so, the MoS{sub 2} stacking was reduced more rapidly than the slab length, yielding in increasing aspects ratios and thus affecting the particle shape. All nanosized cocatalysts exceeded bulk MoS{sub 2} in light driven hydrogen generation. The enhancement of H{sub 2} generation on MoS{sub 2} was achieved by addition of carbon, improving the electron conductivity and suppressing recombination processes. The positive influence of MoS{sub 2} edge sites on H{sub 2} generation was proofed by structural properties of the cocatalysts. Additionally, the importance of the particle shape on photocatalytic properties was demonstrated. Photocatalytic investigations on novel transition metal sulfides and -oxides for H{sub 2} evolution yielded in a rash of promising materials.
Synthèse de composés oxygénés à partir de CO et H2 Synthesis of Oxygenated Compounds from CO and H2

Directory of Open Access Journals (Sweden)

Chaumette P.

2006-11-01

Full Text Available Dans cet article sont passés en revue les principaux produits oxygénés qui peuvent être obtenus en utilisant exclusivement le gaz de synthèse, par voie directe ou par l'intermédiaire du méthanol, aisément synthétisé à partir de CO et H2. Une comparaison est effectuée, qui porte essentiellement sur les modes de synthèse, les différents catalyseurs employés et leurs performances. L'aspect mécanistique est abordé en présentant les divers mécanismes proposés pour ces réactions. Il apparaît, dès à présent, que ces voies d'accès vers les produits oxygénés permettraient de remplacer les procédés utilisant les oléfines par des procédés utilisant le méthanol et le gaz de synthèse. In this article are reviewed the principal oxygenated products that can be produced exclusively from synthesis gas either by a straight-run process or through the use of methanol that can be easily obtained from CO and H2. A comparison is made between the synthesis processes, the different catalysts and their performances. An approach of the mechanistic aspects is undertaken by considering the various mechanistic routes proposed for these reactions. It already now appears that such ways of obtaining these oxygenated products would allow to replace processes using olefins by processes using methanol and synthesis gas.
Carbon Disulfide (CS2) Mechanisms in Formation of Atmospheric Carbon Dioxide (CO2) Formation from Unconventional Shale Gas Extraction and Processing Operations and Global Climate Change.

Science.gov (United States)

Rich, Alisa L; Patel, Jay T

2015-01-01

Carbon disulfide (CS2) has been historically associated with the production of rayon, cellophane, and carbon tetrachloride. This study identifies multiple mechanisms by which CS2 contributes to the formation of CO2 in the atmosphere. CS2 and other associated sulfide compounds were found by this study to be present in emissions from unconventional shale gas extraction and processing (E&P) operations. The breakdown products of CS2; carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) are indirect greenhouse gases (GHGs) that contribute to CO2 levels in the atmosphere. The heat-trapping nature of CO2 has been found to increase the surface temperature, resulting in regional and global climate change. The purpose of this study is to identify five mechanisms by which CS2 and the breakdown products of CS2 contribute to atmospheric concentrations of CO2. The five mechanisms of CO2 formation are as follows: Chemical Interaction of CS2 and hydrogen sulfide (H2S) present in natural gas at high temperatures, resulting in CO2 formation;Combustion of CS2 in the presence of oxygen producing SO2 and CO2;Photolysis of CS2 leading to the formation of COS, CO, and SO2, which are indirect contributors to CO2 formation;One-step hydrolysis of CS2, producing reactive intermediates and ultimately forming H2S and CO2;Two-step hydrolysis of CS2 forming the reactive COS intermediate that reacts with an additional water molecule, ultimately forming H2S and CO2. CS2 and COS additionally are implicated in the formation of SO2 in the stratosphere and/or troposphere. SO2 is an indirect contributor to CO2 formation and is implicated in global climate change.
Specific IgE to peanut 2S albumin Ara h 7 has a discriminative ability comparable to Ara h 2 and 6.

Science.gov (United States)

Blankestijn, M A; Otten, H G; Suer, W; Weimann, A; Knol, E F; Knulst, A C

2018-01-01

Little is known on the clinical relevance of peanut 2S albumin Ara h 7. To investigate the discriminative ability of Ara h 7 in peanut allergy and assess the role of cross-reactivity between Ara h 2, 6 and Ara h 7 isoforms. Sensitization to recombinant peanut storage proteins Ara h 1, 2, 3, 6, and 7 was assessed using a line blot in sera from 40 peanut-tolerant and 40 peanut-allergic patients, based on food challenge outcome. A dose-dependent ELISA inhibition experiment was performed with recombinant Ara h 2, 6 and Ara h 7 isoforms. For Ara h 7.0201, an area under the ROC curve was found of 0.83, comparable to Ara h 2 (AUC 0.81) and Ara h 6 (AUC 0.85). Ara h 7 intensity values strongly correlated with those from Ara h 2 and 6 (r s = 0.81). Of all patients sensitized to 2S albumins Ara h 2, 6, or 7, the majority was co-sensitized to all three (n = 24, 68%), although mono-sensitization to either 2S albumin was also observed in selected patients (Ara h 2: n = 6, 17%; Ara h 6: n = 2, 6%; Ara h 7: n = 2, 6%). Binding to Ara h 7.0101 could be strongly inhibited by Ara h 7.0201, but not the other way around. Specific IgE against Ara h 7.0201 has a predictive ability for peanut allergy similar to Ara h 2 and 6 and possesses unique IgE epitopes as well as epitopes shared between the other Ara h 7 isoform and Ara h 2 and 6. While co-sensitization to all three 2S albumins is most common, mono-sensitization to either Ara h 2, 6, or 7 occurs in selected patients, leading to a risk of misdiagnosis when testing for a single 2S albumin. © 2017 John Wiley & Sons Ltd.
The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 - venting sediments (Milos Island, Greece).

Science.gov (United States)

Bayraktarov, Elisa; Price, Roy E; Ferdelman, Timothy G; Finster, Kai

2013-01-01

Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive (35)S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~40-75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity.
Tellurium sulfates from reactions in oleum and sulfur trioxide: syntheses and crystal structures of TeO(SO_4), Te_4O_3(SO_4)_5, and Te(S_2O_7)_2

International Nuclear Information System (INIS)

Logemann, Christian; Bruns, Joern; Schindler, Lisa Verena; Zimmermann, Vanessa; Wickleder, Mathias S.

2015-01-01

The reaction of K_2TeO_4 with fuming sulfuric acid (65 % SO_3) in sealed glass ampoules at 250 C led to colorless single crystals of TeO(SO_4) [triclinic, P anti 1, Z = 8, a = 819.89(3) pm, b = 836.95(4) pm, c = 1179.12(5) pm, α = 82.820(2) , β = 70.645(2) , γ = 81.897(2) , V = 753.11(6) x 10"6 pm"3]. A horseshoe type [Te_4O_3] fragment is the basic motif in the layer structure of the compound. The [Te_4O_3] moieties are linked to infinite chains by further oxide ions. Monomeric [Te_4O_3] horseshoes are found in the crystal structure of Te_4O_3(SO_4)_5 [trigonal, P3_221, Z = 3, a = 859.05(2) pm, c = 2230.66(7) pm, V = 1425.61(6) x 10"6 pm"3], which was obtained from TeO_2 and fuming sulfuric acid (65 % SO_3) at 200 C as colorless single crystals. By switching to neat SO_3 as reaction medium colorless crystals of Te(S_2O_7)_2 [P2_1/n, Z = 4, a = 1065.25(3) pm, b = 818.50(2) pm, c = 1206.27(3) pm, β = 102.097(1) , V = 1028.40(5) x 10"6 pm"3] form when ortho-telluric acid, H_6TeO_6, is used as the tellurium source. The compound was reported previously, however, obviously with a wrong crystallographic description. In the crystal structure the tellurium atoms are coordinated by two chelating disulfate ions. Further Te-O contacts link the [Te(S_2O_7)_2] units to an extended network. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Surface study and sensing activity of nanotubular indium trioxide to NH{sub 3}, H{sub 2}S, NO{sub 2} and CO environmental pollutants

Energy Technology Data Exchange (ETDEWEB)

Zamani, Mehdi, E-mail: m.zamani@du.ac.ir

2016-02-15

Graphical abstract: - Highlights: • Molecular and electronic structures of indium oxide nanotube were investigated. • Gas sensing performance of this compound was studied using DFT. • Interaction of environmental pollutants with nanotube surface was examined. - Abstract: Molecular and electronic structures of nanotubular indium trioxide were studied using B3LYP and CAM-B3LYP density functional methods. Three nanotube models including nanotubes with closed ends (CENT), one opened end (OOENT) and two opened ends (TOENT) were considered. The highest occupied molecular orbital (HOMO) of CENT is distributed over the entire nanotube; while it is distributed on the end cap of OOENT. In both CENT and OOENT, the distribution of the lowest unoccupied molecular orbital (LUMO) is on the end caps. HOMO and LUMO of TOENT are distributed on the center of nanotube. The sensing activity of OOENT to environmental pollutants was evaluated regarding the interaction of nanotube with NH{sub 3}, H{sub 2}S, NO{sub 2} and CO molecules. Adsorptions over different positions of OOENT are exothermic and the NH{sub 3} adsorption is thermodynamically more favorable. The selectivity of OOENT toward gaseous pollutants is investigated as NH{sub 3} > H{sub 2}S > CO > NO{sub 2}. Interaction of NO{sub 2} and CO over the closed end (end cap) of nanotube is preferred; while adsorption of NH{sub 3} and H{sub 2}S on the opened end is more favorable.
Calcium oxide doped sorbents for CO{sub 2} uptake in the presence of SO{sub 2} at high temperatures

Energy Technology Data Exchange (ETDEWEB)

Lu, H.; Smirniotis, P.G. [University of Cincinnati, Cincinnati, OH (United States)

2009-06-15

There is an urgent need to understand sorbent tolerance for capturing carbon dioxide (CO{sub 2}) in the presence of sulfur dioxide (SO{sub 2}). Sulfur oxide is emitted together with CO{sub 2} from various combustion systems and can cause severe air pollution. In this study, the behavior of different dopants on the performance of calcium oxide (CaO) sorbent for capturing CO{sub 2} in the presence of SO{sub 2} was investigated. Three main sets of experiments were carried out to study carbonation and sulfation both separately and simultaneously using a thermogravimetric analyzer (TGA). The results show that SO{sub 2} reduced the capability of the sorbents for capturing CO{sub 2} because of the competition between carbonation and sulfation reactions. Formation of calcium carbonate (CaCO{sub 3}) and calcium sulfate (CaSO{sub 4}) took place upon carbonation and sulfation, respectively. Our TGA and X-ray photoelectron spectroscopy (XPS) results indicate that the carbonation is totally reversible, while this is not the case with the sulfation. The permanent residual weight gained by the sorbents during the course of sulfation is attributed to the irreversible formation of sulfate species, which is confirmed by both the TGA and XPS results. The Ce promoted CaO sorbent exhibits the best performance for CO{sub 2} capture and is the most SO{sub 2} tolerant sorbent. On the other hand, the Mn doped dopant has the strongest affinity for SO{sub 2}.
SOFT X-RAY IRRADIATION OF H{sub 2}S ICE AND THE PRESENCE OF S{sub 2} IN COMETS

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Escobar, A.; Munoz Caro, G. M. [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Ciaravella, A.; Candia, R.; Micela, G. [INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Cecchi-Pestellini, C., E-mail: munozcg@cab.inta-csic.es [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Canada) (Italy)

2012-06-01

Little is known about the effects of X-rays in interstellar ices. To understand the sulfur depletion in dense clouds and the presence of S{sub 2} in comets, we simulated experimentally the soft X-ray processing (0.3 keV) of H{sub 2}S ice for the first time. Experiments were performed under ultrahigh vacuum conditions at 8 K using infrared and quadrupole mass spectrometry to monitor the solid and gas phases, respectively. A UV irradiation experiment using a similar dose was made for comparison. After X-ray irradiation, an infrared absorption appears near 4.0 {mu}m which is attributed to H{sub 2}S{sub 2} formation in the ice. This identification is also supported by the desorption at 133 K of m/z 66, 65, 64, corresponding to the mass fragments of H{sub 2}S{sub 2}. The H{sub 2}S{sub 2} species is expected to be present in interstellar and cometary ices that were processed by X-rays. Further irradiation leads to dissociation of this molecule forming S{sub 2} and larger S-molecules up to S{sub 8}, which may explain the depletion of sulfur in dense clouds. CS{sub 2} was so far the parent molecule proposed for S{sub 2} formation in comets. But the abundance of H{sub 2}S{sub 2}, formed by irradiation of pure H{sub 2}S or H{sub 2}S in an H{sub 2}O-ice matrix, should be larger than that of CS{sub 2} in the ice, the latter requiring a carbon source for its formation. Based on our experimental results, we propose that S{sub 2} in comets could be formed by dissociation of H{sub 2}S{sub 2} in the ice.

Descent Without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds

Science.gov (United States)

Loeffler, Mark Josiah; Hudson, Reggie Lester

2015-01-01

The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NHþ 4 and SO2 making SO2 4 by H+ and e - transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.
Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

International Nuclear Information System (INIS)

Modak, Arindam; Bhaumik, Asim

2015-01-01

Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.
Magnetic ordering in Sc{sub 2}CoSi{sub 2}-type R{sub 2}FeSi{sub 2} (R=Gd, Tb) and R{sub 2}CoSi{sub 2} (R=Y, Gd–Er) compounds

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Pani, M. [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, C. Perrone 24, 16152 Genova (Italy); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

2016-09-01

Magnetic and magnetocaloric properties of Sc{sub 2}CoSi{sub 2}-type R{sub 2}TSi{sub 2} (R=Gd–Er, T=Fe, Co) compounds have been studied using magnetization data. These indicate the presence of mixed ferromagnetic and antiferromagnetic interactions in these compounds. One observes a ferromagnetic transition followed by an antiferromagnetic order and a further possible spin-reorientation transition at low temperatures. Compared to Gd{sub 2}{Fe, Co}Si{sub 2}, the Tb{sub 2}FeSi{sub 2} and {Tb–Er}{sub 2}CoSi{sub 2} compounds exhibit remarkable hysteresis (for e.g. Tb{sub 2}FeSi{sub 2} shows residual magnetization M{sub res}/Tb=2.45 μ{sub B}, coercive field H{sub coer}=14.9 kOe, and critical field H{sub crit}~5 kOe at 5 K) possibly due to the magnetocrystalline anisotropy of the rare earth. The R{sub 2}{Fe, Co}Si{sub 2} show relatively small magnetocaloric effect (i.e. isothermal magnetic entropy change, ΔS{sub m}) around the magnetic transition temperature: the maximal value of MCE is demonstrated by Ho{sub 2}CoSi{sub 2} (ΔS{sub m}=−8.1 J/kg K at 72 K and ΔS{sub m}=−9.4 J/kg K at 23 K in field change of 50 kOe) and Er{sub 2}CoSi{sub 2} (ΔS{sub m}=−13.6 J/kg K at 32 K and ΔS{sub m}=−8.4 J/kg K at 12 K in field change of 50 kOe). - Highlights: • {Gd–Er}{sub 2}{Fe, Co}Si{sub 2} show high-temperature ferromagnetic-type transitions. • {Gd–Er}{sub 2}{Fe, Co}Si{sub 2} show low-temperature spin-reorientation transitions. • Tb{sub 2}FeSi{sub 2} and {Tb–Er}{sub 2}CoSi{sub 2} compounds exhibit low-temperature hysteresis. • Tb{sub 2}FeSi{sub 2} shows M{sub res}/Tb=2.45 μ{sub B}, H{sub coer}=14.9 kOe and H{sub crit} ~5 kOe at 5 K • Considerable magnetocaloric effect is exhibited by Ho{sub 2}CoSi{sub 2} and Er{sub 2}CoSi{sub 2}.
Studies on the relationship between Pitzer's equation and medium effect: the system of HCl + H2SO4 in {0.06455C2H5OH + 0.93545H2O}

International Nuclear Information System (INIS)

Lu Xingmei; Xu Weiguo; Chang Xiaohong; Lu Dianzhen; Yang Jiazhen

2004-01-01

The second ionization constant of sulfuric acid in mixed solvent, K 2 , was determined by e.m.f. of cell without liquid junction: (Pt,H 2 (101.325 kPa) vertical bar HCl(m 1 ),H 2 SO 4 (m 2 ),{ethanol(x=0.06455)+water(x=0.93545)} vertical bar AgCl-Ag))over the temperatures (278.15 to 318.15) K, where x is mole fraction. Combining Owen's definition of medium effect with Pitzer's equations, the values of combination parameters: (λ nHS +λ nCl -λ nS )+(3/2)m n (μ nnHS +μ nnCl -μ nnS ),(1/2)(ξ nHHS +ξ nHCl -ξ nHS ), that represent the interactions between ions and ethanol were obtained at 298.15 K.
Structure of Chloro bis(1,10-phenanthroline)Cobalt(II) Complex, [Co(phen)2(Cl)(H2O)]Cl · 2H2O

International Nuclear Information System (INIS)

Zhao, Pu Su; Lu, Lu De; Jian, Fang Fang

2003-01-01

The crystal structure of [Co(phen) 2 (Cl)(H 2 O)] Cl · 2H 2 O(phen=1,10-phenanthroline) has been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P 1 , with lattice parameters a=9.662(2), b=11.445(1), c=13.037(2)A, α=64.02(1), β=86.364(9), γ=78.58(2) .deg., and Z=2. The coordinated cations contain a six-coordinated cobalt atom chelated by two phen ligands and one chloride anion and one water ligand in cis arrangement. In addition to the chloride coordinated to the cobalt, there are one chloride ion and four water molecules which complete the crystal structure. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds, within which exists the strongest hydrogen bond (O(3)-O(4)=2.33A). The intermolecular hydrogen bonds connect the [Co(phen) 2 (Cl)(H 2 O)] 1+ , H 2 O moieties and chloride ion
H2, CO, and dust absorption through cold molecular clouds

Science.gov (United States)

Lacy, John H.; Sneden, Chris; Kim, Hwihyun; Jaffe, Daniel Thomas

2017-06-01

We have made observations with IGRINS on the Harlan J. Smith telescope at McDonald Observatory of near-infrared absorption by H2, CO, and dust toward stars behind molecular clouds, primarily the TMC. Prior to these observations, the abundance of H2 in molecular clouds, relative to the commonly used tracer CO, had only been measured toward a few embedded stars, which may be surrounded by atypical gas. The new observations provide a representative sample of these molecules in cold molecular gas. We find N(H2)/Av ~ 0.9e+21, N(CO)/Av ~ 1.6e+17, and H2/CO ~ 6000. The measured H2/CO ratio is consistent with that measured toward embedded stars in various molecular clouds, but half that derived from mm-wave observations of CO emission and star counts or other determinations of Av.
Theoretical Investigations of CO 2 and H 2 Sorption in an Interpenetrated Square-Pillared Metal–Organic Material

KAUST Repository

Pham, Tony

2013-05-16

Simulations of CO2 and H2 sorption and separation were performed in [Cu(dpa)2SiF6-i], a metal-organic material (MOM) consisting of an interpenetrated square grid of Cu2+ ions coordinated to 4,4′-dipyridylacetylene (dpa) rings and pillars of SiF6 2- ions. This class of water stable MOMs shows great promise in practical gas sorption/separation with especially high selectivity for CO2 and variable selectivity for other energy related gases. Simulated CO2 sorption isotherms and isosteric heats of adsorption, Qst, at ambient temperatures were in excellent agreement with the experimental measurements at all pressures considered. Further, it was observed that the Qst for CO2 increases as a function of uptake in [Cu(dpa)2SiF6-i]. This suggests that nascently sorbed CO2 molecules within a channel contribute to a more energetically favorable site for additional CO2 molecules, i.e., in stark contrast to typical behavior, sorbate intermolecular interactions enhance sorption energetics with increased loading. The simulated structure at CO2 saturation shows a loading with tight packing of 8 CO2 molecules per unit cell. The CO2 molecules can be seen alternating between a vertical and horizontal alignment within a channel, with each CO2 molecule coordinating to an equatorial fluorine MOM atom. Calculated H 2 sorption isotherms and Qst values were also in good agreement with the experimental measurements in [Cu(dpa)2SiF 6-i]. H2 saturation corresponds to 10 H2 molecules per unit cell for the studied structure. Moreover, there were two observed binding sites for hydrogen sorption in [Cu(dpa)2SiF 6-i]. Simulations of a 30:70 CO2/H2 mixture, typical of syngas, in [Cu(dpa)2SiF6-i] showed that the MOM exhibited a high uptake and selectivity for CO2. In addition, it was observed that the presence of H2O had a negligible effect on the CO2 uptake and selectivity in [Cu(dpa)2SiF6-i], as simulations of a mixture containing CO2, H2, and small amounts of CO, N2, and H2O produced comparable
Structural and physical properties of the NaxCoO2·yH2O superconducting system

International Nuclear Information System (INIS)

Shi, Y G; Li, J Q; Yu, H C; Zhou, Y Q; Zhang, H R; Dong, C

2004-01-01

The structural features and physical properties of Na x CoO 2 and Na x CoO 2 ·yH 2 O materials have been investigated. The Na x CoO 2 -yH 2 O samples, in general, undergo superconducting transitions at around 3.5 K. Energy dispersive x-ray analyses suggest that our samples have average compositions of Na 0.65 CoO 2 for the parent compounds and Na 0.26 CoO 2 ·yH 2 O for the superconducting oxyhydrates. Transmission electron microscopy observations reveal a new superstructure with wave vector q = in the parent material. This superstructure becomes very weak in the superconducting samples. Electron energy loss spectra analyses show that the Co ions have valence states of around +3.3 in Na 0.65 CoO 2 and around +3.7 in Na 0.26 CoO 2 -yH 2 O
The first 3D malonate bridged copper [Cu(O2C–CH2–CO2H)2·2H2O]: Structure, properties and electronic structure

International Nuclear Information System (INIS)

Seguatni, A.; Fakhfakh, M.; Smiri, L.S.; Gressier, P.; Boucher, F.; Jouini, N.

2012-01-01

A new inorganic-organic compound [Cu(O 2 C–CH 2 –CO 2 H) 2 ·2H 2 O] ([Cumal]) was hydrothermally synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray diffraction. [Cumal] is the first three-dimensional compound existing in the system Cu(II)–malonic acid–H 2 O. Its framework is built up through carboxyl bridged copper where CuO 6 octahedra are elongated with an almost D 4h symmetry (4+2) due to the Jahn–Teller effect. The magnetic properties were studied by measuring its magnetic susceptibility in the temperature range of 2–300 K indicating the existence of weak ferromagnetic interactions. The electronic structure of [Cumal] was calculated within the density functional theory (DFT) framework. Structural features are well reproduced using DFT structural optimizations and the optical spectra, calculated within the dielectric formalism, explain very well the light blue colour of the compound. It is shown that a GGA+U approach with a U eff value of about 6 eV is necessary for a better correlation with the experiment. - Graphical abstract: [Cu(O 2 C–CH 2 –CO 2 H) 2 ·2H 2 O]: the first 3D hybrid organic–inorganic compound built up carboxyl groups. The network presents a diamond-like structure achieved via carboxyl. Highlights: ► A new organic–inorganic material with an unprecedented topology is synthesized. ► Crystallographic structure is determined using single crystal X-ray diffraction. ► Electronic structure is obtained from DFT, GGA+U calculation. ► Framework can be described as formed from CuC 4 tetrahedron sharing four corners. ► This structure can be classified as an extended diamond structure.
Self-Driven Photoelectrochemical Splitting of H2S for S and H2 Recovery and Simultaneous Electricity Generation.

Science.gov (United States)

Luo, Tao; Bai, Jing; Li, Jinhua; Zeng, Qingyi; Ji, Youzhi; Qiao, Li; Li, Xiaoyan; Zhou, Baoxue

2017-11-07

A novel, facile self-driven photoelectrocatalytic (PEC) system was established for highly selective and efficient recovery of H 2 S and simultaneous electricity production. The key ideas were the self-bias function between a WO 3 photoanode and a Si/PVC photocathode due to their mismatched Fermi levels and the special cyclic redox reaction mechanism of I - /I 3 - . Under solar light, the system facilitated the separation of holes in the photoanode and electrons in the photocathode, which then generated electricity. Cyclic redox reactions were produced in the photoanode region as follows: I - was transformed into I 3 - by photoholes or hydroxyl radicals, H 2 S was oxidized to S by I 3 - , and I 3 - was then reduced to I - . Meanwhile, H + was efficiently converted to H 2 in the photocathode region. In the system, H 2 S was uniquely oxidized to sulfur but not to polysulfide (S x n- ) because of the mild oxidation capacity of I 3 - . High recovery rates for S and H 2 were obtained up to ∼1.04 mg h -1 cm -1 and ∼0.75 mL h -1 cm -1 , respectively, suggesting that H 2 S was completely converted into H 2 and S. In addition, the output power density of the system reached ∼0.11 mW cm -2 . The proposed PEC-H 2 S system provides a self-sustaining, energy-saving method for simultaneous H 2 S treatment and energy recovery.
Physicochemical effects of discrete CO2-SO2 mixtures on injection and storage in a sandstone aquifer

NARCIS (Netherlands)

Waldmann, S.; Hofstee, C.; Koenen, M.; Loeve, D.

2016-01-01

Geological storage of captured CO2, which typically will contain certain amounts of impurities, in salineaquifers is of potential to reduce greenhouse gas emissions into the atmosphere. The co-injection of theimpurity SO2has an effect on the chemical reactivity of the fluid and solid phases as well
The solubility of Ni in molten Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3} (52/48) in H{sub 2}/H{sub 2}O/CO{sub 2} atmosphere

Energy Technology Data Exchange (ETDEWEB)

Boden, Andreas; Lindbergh, Goeran [KTH Chemical Science and Engineering, Department of Chemical Engineering and Technology, SE-100 44 Stockholm (Sweden); Yoshikawa, Masahiro [Central Research Institute of Electric Power Industry, Sector, Energy Conversion Engineering, Energy Engineering Research Laboratory, Yokosuka-shi, Kanagawa 240-0196 (Japan)

2007-03-30

In this work the solubility of a Ni-Al anode for MCFC has been studied at atmospheric pressure and two different temperatures using various gas compositions containing H{sub 2}/H{sub 2}O/CO{sub 2}. It is well known that nickel is dissolved at cathode conditions in an MCFC. However, the results in this study show that nickel can be dissolved also at the anode, indicating that the solubility increases with increasing CO{sub 2} partial pressure of the inlet gas and decreasing with increasing temperature. This agrees with the results found by other authors concerning the solubility of NiO at cathode conditions. The dissolution of Ni into the melt can proceed in two ways, either by the reduction of water or by the reduction of carbon dioxide. (author)
Cationic polyhydrido cluster complexes. Crystal and molecular structures of (Ir3(Ph2P(CH2)3PPh2)3(H)7(CO))2+ and (Ir3(Ph2P(CH2)2(2-py))3(H)7)2+

International Nuclear Information System (INIS)

Hsienhau Wang; Casalnuovo, A.L.; Johnson, B.J.; Mueting, A.M.; Pignolet, L.H.

1988-01-01

Two new cationic polyhydrido cluster complexes of iridium have been synthesized and characterized by single-crystal x-ray diffraction and by ir and 1 H and 31 P NMR spectroscopy (Ir 3 (dppp) 3 (H) 7 (CO)) 2+ (2) and (Ir3 (PN) 3 (H) 7)2+ (5), where dppp = 1,3-bis(diphenylphosphino)propane and PN = 1-(2-pyridyl)-2-(diphenylphosphino)ethane, were synthesized by the reaction of CO with (Ir 3 (dppp) 3 (H) 7 ) 2+ (1) in CH 2 Cl 2 solution and H 2 with (Ir(PN)(COD)) + (4) in CH 3 OH solution, respectively. Crystal structures for both compounds is reported. The hydride positions were not located in the crystal structure analyses but were deduced from structural and 1 H NMR data. The molecular structure of 2 consists of a bilateral triangle of three iridium atoms with a carbonyl at the vertex and a chelating dppp ligand on each iridium atom. 1 H NMR data with use of acetone-d 6 as solvent showed that 2 possesses four doubly bridging hydrides and three terminal hydrides, yielding C 1 symmetry. The molecular structure of 5 consists of an approximately equilateral triangle of three iridium atoms (average Ir-Ir distance 2.746 (1) angstrom) with one PN ligand chelated to each iridium atom. 1 H NMR analysis, with use of CD 2 Cl 2 as solvent, showed that 5 has one triply bridging hydride and six terminal hydrides, giving C 3 symmetry. (Ir 3 (dppp) 3 (H) 7 (CH 3 C 6 H 4 NC)) 2+ (3) a complex structurally analogous to 2, was synthesized from 1 and p-tolyl isocyanide in CH 2 Cl 2 solution and characterized by ir and 1 H and 31 P NMR spectroscopy. 44 refs., 3 figs., 3 tabs
Seasonal change in CO2 and H2O exchange between grassland and atmosphere

Directory of Open Access Journals (Sweden)

T. Oikawa

Full Text Available The seasonal change in CO2 flux over an artificial grassland was analyzed from the ecological and meteorological point of view. This grassland contains C3 and C4 plants; the three dominant species belonging to the Gramineae; Festuca elatior (C3 dominated in early spring, and Imperata cylindrica (C4 and Andropogon virginicus (C4 grew during early summer and became dominant in mid-summer. CO2 flux was measured by the gradient method, and the routinely observed data for the surface-heat budget were used to analyze the CO2 and H2O exchange between the grassland and atmosphere. From August to October in 1993, CO2 flux was reduced to around half under the same solar-radiation conditions, while H2O flux decreased 20% during the same period. The monthly values of water use efficiency, i.e., ratio of CO2 flux to H2O flux decreased from 5.8 to 3.3 mg CO2/g H2O from August to October, the Bowen ratio increased from 0.20 to 0.30, and the ratio of the bulk latent heat transfer coefficient CE to the sensible heat transfer coefficient CH was maintained around 0.40-0.50. The increase in the Bowen ratio was explained by the decrease in air temperature from 22.3 °C in August to 16.6 °C in October without considering biological effects such as stomatal closure on the individual leaves. The nearly constant CE/CH ratios suggested that the contribution ratio of canopy resistance to aerodynamic resistance did not change markedly, although the meteorological conditions changed seasonally. The decrease in the water use efficiency, however, suggested that the photosynthetic rate decreased for individual leaves from August to October under the same radiation conditions. Diurnal variations of CO2 exchange were simulated by the multi-layer canopy model taking into account the differences in the stomatal conductance and photosynthetic pathway between C3 and C4 plants. The results suggested that C4 plants played a major role in the CO2 exchange in August, the contribution
Seasonal change in CO2 and H2O exchange between grassland and atmosphere

Directory of Open Access Journals (Sweden)

N. Saigusa

1996-03-01

Full Text Available The seasonal change in CO2 flux over an artificial grassland was analyzed from the ecological and meteorological point of view. This grassland contains C3 and C4 plants; the three dominant species belonging to the Gramineae; Festuca elatior (C3 dominated in early spring, and Imperata cylindrica (C4 and Andropogon virginicus (C4 grew during early summer and became dominant in mid-summer. CO2 flux was measured by the gradient method, and the routinely observed data for the surface-heat budget were used to analyze the CO2 and H2O exchange between the grassland and atmosphere. From August to October in 1993, CO2 flux was reduced to around half under the same solar-radiation conditions, while H2O flux decreased 20% during the same period. The monthly values of water use efficiency, i.e., ratio of CO2 flux to H2O flux decreased from 5.8 to 3.3 mg CO2/g H2O from August to October, the Bowen ratio increased from 0.20 to 0.30, and the ratio of the bulk latent heat transfer coefficient CE to the sensible heat transfer coefficient CH was maintained around 0.40-0.50. The increase in the Bowen ratio was explained by the decrease in air temperature from 22.3 °C in August to 16.6 °C in October without considering biological effects such as stomatal closure on the individual leaves. The nearly constant CE/CH ratios suggested that the contribution ratio of canopy resistance to aerodynamic resistance did not change markedly, although the meteorological conditions changed seasonally. The decrease in the water use efficiency, however, suggested that the photosynthetic rate decreased for individual leaves from August to October under the same radiation conditions. Diurnal variations of CO2 exchange were simulated by the multi-layer canopy model taking into account the differences in the stomatal conductance and photosynthetic pathway between C3 and C4 plants. The results suggested that C4 plants played a major role in the CO2 exchange in August, the contribution
Seasonal change in CO2 and H2O exchange between grassland and atmosphere

Science.gov (United States)

Saigusa, N.; Liu, S.; Oikawa, T.; Watanabe, T.

1996-03-01

The seasonal change in CO2 flux over an artificial grassland was analyzed from the ecological and meteorological point of view. This grassland contains C3 and C4 plants; the three dominant species belonging to the Gramineae; Festuca elatior (C3) dominated in early spring, and Imperata cylindrica (C4) and Andropogon virginicus (C4) grew during early summer and became dominant in mid-summer. CO2 flux was measured by the gradient method, and the routinely observed data for the surface-heat budget were used to analyze the CO2 and H2O exchange between the grassland and atmosphere. From August to October in 1993, CO2 flux was reduced to around half under the same solar-radiation conditions, while H2O flux decreased 20% during the same period. The monthly values of water use efficiency, i.e., ratio of CO2 flux to H2O flux decreased from 5.8 to 3.3 mg CO2/g H2O from August to October, the Bowen ratio increased from 0.20 to 0.30, and the ratio of the bulk latent heat transfer coefficient CE to the sensible heat transfer coefficient CH was maintained around 0.40-0.50. The increase in the Bowen ratio was explained by the decrease in air temperature from 22.3 °C in August to 16.6 °C in October without considering biological effects such as stomatal closure on the individual leaves. The nearly constant CE/CH ratios suggested that the contribution ratio of canopy resistance to aerodynamic resistance did not change markedly, although the meteorological conditions changed seasonally. The decrease in the water use efficiency, however, suggested that the photosynthetic rate decreased for individual leaves from August to October under the same radiation conditions. Diurnal variations of CO2 exchange were simulated by the multi-layer canopy model taking into account the differences in the stomatal conductance and photosynthetic pathway between C3 and C4 plants. The results suggested that C4 plants played a major role in the CO2 exchange in August, the contribution of C4 plants
Ion-molecule interactions in crossed-beams. [N/sup +/-H/sub 2/; F/sup +/-H; CO/sub 2//sup +/-D/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Hansen, S.G.

1980-09-01

Interactions of the ions N/sup +/, F/sup +/, and CO/sub 2//sup +/ with H/sub 2/ and/or its isotopes were examined using the crossed-beam technique in the low (< 4 eV) initial relative energy. For the reaction N/sup +/(/sup 3/P) + H/sub 2/ ..-->.. NH/sup +/ + H, complex formation dominates up to 1.9 eV and a substantial interaction occurs between all collision partners up to 3.6 eV. The distribution of N/sup +/ scattered nonreactively from H/sub 2/ also showed a long-lived complex channel below 1.9 eV. The reaction F/sup +/(/sup 3/P) + H/sub 2/ ..-->..FH/sup +/ + H proceeded by a direct reaction mechanism at 0.20 to 1.07 eV. The reaction CO/sub 2//sup +/ + D/sub 2/ ..-->.. DCO/sub 2//sup +/ + D gives asymmetric product distributions at 0.27 eV and above, indicating a direct reaction mechanism. Results indicated that there are probably barriers in the exit channels for DCO/sub 2//sup +/, DCO/sup +/, and D/sub 2/O/sup +/ products. The electronic state distributions of the N/sup +/, F/sup +/, and CO/sub 2//sup +/ beams was investigated using beam attenuation and total luminescence techniques.
Evaluation of in vitro and in vivo tests for surface-modified titanium by H2SO4 and H2O2 treatment

Science.gov (United States)

Lee, Min-Ho; Park, Il-Song; Min, Kwan-Sik; Ahn, Seung-Geun; Park, Ju-Mi; Song, Kwang-Yeob; Park, Charn-Woon

2007-04-01

Titanium is widely used as an implant material for artificial teeth. Furthermore, various studies have examined surface treatment with respect to the formation of a fine passive film on the surface of commercial titanium and its alloys and to improve the bioactivity with bone. However, there is insufficient data about the biocompatibility of implant materials in the body. The purpose of this study was to examine whether surface modification affects the precipitation of apatite on titanium metal. Specimens were chemically washed for 2 min in a 1∶1∶1.5 (vol.%) mixture of 48 %HF, 60%HNO3 and distilled water. The specimens were then chemically treated with a solution containing 97%H2SO4 and 30%H2O2 at the ratio of 1∶1 (vol.%) at 40°C for 1h, and subsequently heat-treated at 400°C for 1h. All the specimens were immersed in HBSS with pH 7.4 at 36.5°C for 15d, and the surface was examined with TF-XRD, SEM, EDX and XPS. In addition, specimens of commercial pure Ti, with and without surface treatment, were implanted in the abdominal connective tissue of mice for 28 d. Conventional aluminum and stainless steel 316L were also implanted for comparison. An amorphous titania gel layer was formed on the titanium surface after the titanium specimen was treated with a solution of H2SO4 and H2O2. The average roughness was 2.175 μm after chemical surface treatment. The amorphous titania was subsequently transformed into anatase by heat treatment at 400°C for 1h. The average thickness of the fibrous capsule surrounding the specimens implanted in the connective tissue was 47.1μm in the chemically treated Ti, and 52.2, 168.7 and 101.9μm, respectively, in the untreated commercial pure Ti, aluminum and stainless steel 316L.
SO{sub 2} Retention by CaO-Based Sorbent Spent in CO{sub 2} Looping Cycles

Energy Technology Data Exchange (ETDEWEB)

Manovic, V.; Anthony, E.J.; Loncarevic, D.

2009-07-15

CaO-based looping cycles are promising processes for CO{sub 2} Capture from both syngas and flue gas. The technology is based on cyclical carbonation of CaO and regeneration of CaCO{sub 3} in a dual fluidized-bed reactor to produce a pure CO{sub 2} stream suitable for sequestration. Use of spent sorbent from CO{sub 2} looping cycles for SO{sub 2} capture is investigated. Three limestones were investigated: Kelly Rock (Canada), La Blanca (Spain), and Katowice (Poland, Upper Silesia). Carbonation/calcination cycles were performed in a tube furnace with both the original limestones and samples thermally pretreated for different times (i.e., sintered). The spent sorbent samples were sulfated in a thermogravimetric analyzer (TGA). The changes in the resulting sorbent pore structure were then investigated using mercury porosimetry. It has been shown that the sulfation rates of both thermally pretreated and spent sorbent samples are lower in comparison with those of the original samples. However, final conversions of both spent and pretreated sorbents after longer sulfation time were comparable or higher than those observed for the original sorbents under comparable conditions. Maximum sulfation levels strongly depend on sorbent porosity and pore surface area. The results showed that spent sorbent samples from CO{sub 2} looping cycles can be used as sorbents for SO{sub 2} retention in cases where significant porosity loss does not occur during CO{sub 2} reaction cycles. In the case of spent Kelly Rock and Katowice samples, sorbent particles are practically uniformly sulfated, achieving final conversions that are determined by the total pore volume available for the bulky CaSO{sub 4} product.
Ionic strength dependence of the oxidation of SO2 by H2O2 in sodium chloride particles

Science.gov (United States)

Ali, H. M.; Iedema, M.; Yu, X.-Y.; Cowin, J. P.

2014-06-01

The reaction of sulfur dioxide and hydrogen peroxide in the presence of deliquesced (>75% RH) sodium chloride (brine) particles was studied by utilizing a cross flow mini-reactor. The reaction kinetics were followed by observing chloride depletion in particles by computer-controlled scanning electron microscope with energy dispersive X-ray analysis, namely CCSEM/EDX. The reactions take place in concentrated mixed salt brine aerosols, for which no complete kinetic equilibrium data previously existed. We measured the Henry's law solubility of H2O2 in brine solutions to close that gap. We also calculated the reaction rate as the particle transforms continuously from concentrated NaCl brine to, eventually, a mixed NaHSO4 plus H2SO4 brine solution. The reaction rate of the SO2 oxidation by H2O2 was found to be influenced by the change in ionic strength as the particle undergoes compositional transformation, following closely the dependence of the third order rate constant on ionic strength as predicted using established rate equations. This is the first study that has measured the ionic strength dependence of sulfate formation (in non-aqueous media) from oxidation of mixed salt brine aerosols in the presence of H2O2. It also gives the first report of the dependence of the Henry's law constant of H2O2 on ionic strength.

Factorizable S-matrix for SO(D)/SO(2) circle times SO(D - 2) non-linear σ models with fermions

International Nuclear Information System (INIS)

Abdalla, E.; Lima-Santos, A.

1988-01-01

The authors compute the exact S matrix for the non-linear sigma model with symmetry SO(D)/SO(2) circle times SO(D-2) coupled to fermions in a minimal or supersymmetric way. The model has some relevance in string theory with non-zero external curvature
A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2-N2 and CO2-CH4 gas mixtures with high CO2 loading.

Science.gov (United States)

Pal, Arun; Chand, Santanu; Elahi, Syed Meheboob; Das, Madhab C

2017-11-14

A microporous MOF {[Zn(SDB)(L) 0.5 ]·S} n (IITKGP-5) with a polar pore surface has been constructed by the combination of a V-shaped -SO 2 functionalized organic linker (H 2 SDB = 4,4'-sulfonyldibenzoic acid) with an N-rich spacer (L = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene), forming a network with sql(2,6L1) topology. IITKGP-5 is characterized by TGA, PXRD and single crystal X-ray diffraction. The framework exhibits lozenge-shaped channels of an approximate size of 4.2 × 5.6 Å 2 along the crystallographic b axis with a potential solvent accessible volume of 26%. The activated IITKGP-5a revealed a CO 2 uptake capacity of 56.4 and 49 cm 3 g -1 at 273 K/1 atm and 295 K/1 atm, respectively. On the contrary, it takes up a much smaller amount of CH 4 (17 cm 3 g -1 at 273 K and 13.6 cm 3 g -1 at 295 K) and N 2 (5.5 cm 3 g -1 at 273 K; 4 cm 3 g -1 at 295 K) under 1 atm pressure exhibiting its potential for a highly selective adsorption of CO 2 from flue gas as well as a landfill gas mixture. Based on the ideal adsorbed solution theory (IAST), a CO 2 /N 2 selectivity of 435.5 and a CO 2 /CH 4 selectivity of 151.6 have been realized at 273 K/100 kPa. The values at 295 K are 147.8 for CO 2 /N 2 and 23.8 for CO 2 /CH 4 gas mixtures under 100 kPa. In addition, this MOF nearly approaches the target values proposed for PSA and TSA processes for practical utility exhibiting its prospect for flue gas separation with a CO 2 loading capacity of 2.04 mmol g -1 .
SO4= uptake and catalase role in preconditioning after H2O2-induced oxidative stress in human erythrocytes.

Science.gov (United States)

Morabito, Rossana; Remigante, Alessia; Di Pietro, Maria Letizia; Giannetto, Antonino; La Spada, Giuseppina; Marino, Angela

2017-02-01

Preconditioning (PC) is an adaptive response to a mild and transient oxidative stress, shown for the first time in myocardial cells and not described in erythrocytes so far. The possible adaptation of human erythrocytes to hydrogen peroxide (H 2 O 2 )-induced oxidative stress has been here verified by monitoring one of band 3 protein functions, i.e., Cl - /HCO 3 - exchange, through rate constant for SO 4 = uptake measurement. With this aim, erythrocytes were exposed to a mild and transient oxidative stress (30 min to either 10 or 100 μM H 2 O 2 ), followed by a stronger oxidant condition (300- or, alternatively, 600-μM H 2 O 2 treatment). SO 4 = uptake was measured by a turbidimetric method, and the possible role of catalase (CAT, significantly contributing to the anti-oxidant system in erythrocytes) in PC response has been verified by measuring the rate of H 2 O 2 degradation. The preventive exposure of erythrocytes to 10 μM H 2 O 2 , and then to 300 μM H 2 O 2 , significantly ameliorated the rate constant for SO 4 = uptake with respect to 300 μM H 2 O 2 alone, showing thus an adaptive response to oxidative stress. Our results show that (i) SO 4 = uptake measurement is a suitable model to monitor the effects of a mild and transient oxidative stress in human erythrocytes, (ii) band 3 protein anion exchange capability is retained after 10 μM H 2 O 2 treatment, (iii) PC response induced by the 10 μM H 2 O 2 pretreatment is clearly detected, and (iv) PC response, elicited by low-concentrated H 2 O 2 , is mediated by CAT enzyme and does not involve band 3 protein tyrosine phosphorylation pathways. Erythrocyte adaptation to a short-term oxidative stress may serve as a basis for future studies about the impact of more prolonged oxidative events, often associated to aging, drug consumption, chronic alcoholism, hyperglycemia, or neurodegenerative diseases.
Axial zero-field splitting in mononuclear Co(ii) 2-N substituted N-confused porphyrin: Co(2-NC3H5-21-Y-CH2C6H4CH3-NCTPP)Cl (Y = o, m, p) and Co(2-NC3H5-21-CH2C6H5-NCTPP)Cl.

Science.gov (United States)

Lai, Ya-Yuan; Chang, Yu-Chang; Chen, Jyh-Horung; Wang, Shin-Shin; Tung, Jo-Yu

2016-03-21

The inner C-benzyl- and C-o-xylyl (or m-xylyl, p-xylyl)-substituted cobalt(ii) complexes of a 2-N-substituted N-confused porphyrin were synthesized from the reaction of 2-NC3H5NCTPPH (1) and CoCl2·6H2O in toluene (or o-xylene, m-xylene, p-xylene). The crystal structures of diamagnetic chloro(2-aza-2-allyl-5,10,15,20-tetraphenyl-21-hydrogen-21-carbaporphyrinato-N,N',N'')zinc(ii) [Zn(2-NC3H5-21-H-NCTPP)Cl; 3 ] and paramagnetic chloro(2-aza-2-allyl-5,10,15,20-tetraphenyl-21-benzyl-21-carbaporphyrinato-N,N',N'')cobalt(ii) [Co(2-NC3H5-21-CH2C6H5NCTPP)Cl; 7], and chloro(2-aza-2-allyl-5,10,15,20-tetraphenyl-21-Y-xylyl-21-carbaporphyrinato-N,N',N'')cobalt(ii) [Co(2-NC3H5-21-Y-CH2C6H4CH3NCTPP)Cl] [Y = o (8), m (9), p (10)] were determined. The coordination sphere around the Zn(2+) (or Co(2+)) ion in 3 (or 7-10) is a distorted tetrahedron (DT). The free energy of activation at the coalescence temperature Tc for the exchange of phenyl ortho protons o-H (26) with o-H (22) in 3 in a CDCl3 solvent is found to be ΔG = 61.4 kJ mol(-1) through (1)H NMR temperature-dependent measurements. The axial zero-field splitting parameter |D| was found to vary from 35.6 cm(-1) in 7 (or 30.7 cm(-1) in 8) to 42.0 cm(-1) in 9 and 46.9 cm(-1) in 10 through paramagnetic susceptibility measurements. The magnitude of |D| can be related to the coordination sphere at the cobalt sites.
Methane production from formate, acetate and H2/CO2; focusing on kinetics and microbial characterization

DEFF Research Database (Denmark)

Pan, Xiaofang; Angelidaki, Irini; Alvarado-Morales, Merlin

2016-01-01

For evaluating the methanogenesis from typical methanogenic precursors (formate, acetate and H-2/CO2), CH4 production kinetics were investigated at 37 +/- 1 degrees C in batch anaerobic digestion tests and stimulated by modified Gompertz model. The results showed that maximum methanation rate from...... formate, acetate and H-2/CO2 were 19.58 +/- 0.49, 42.65 +/- 1.17 and 314.64 +/- 3.58 N mL/gVS/d in digested manure system and 6.53 +/- 0.31, 132.04 +/- 3.96 and 640.16 +/- 19.92 N mL/gVS/d in sewage sludge system during second generation incubation. Meanwhile the model could not fit well in granular...... sludge system, while the rate of formate methanation was faster than from H-2/CO2 and acetate. Considering both the kinetic results and microbial assay we could conclude that H-2/CO2 methanation was the fastest methanogenic step in digested manure and sewage sludge system with Methanomicrobiales...
Hydrogen Dynamics in Cyanobacteria Dominated Microbial Mats Measured by Novel Combined H2/H2S and H2/O2 Microsensors

Directory of Open Access Journals (Sweden)

Karen Maegaard

2017-10-01

Full Text Available Hydrogen may accumulate to micromolar concentrations in cyanobacterial mat communities from various environments, but the governing factors for this accumulation are poorly described. We used newly developed sensors allowing for simultaneous measurement of H2S and H2 or O2 and H2 within the same point to elucidate the interactions between oxygen, sulfate reducing bacteria, and H2 producing microbes. After onset of darkness and subsequent change from oxic to anoxic conditions within the uppermost ∼1 mm of the mat, H2 accumulated to concentrations of up to 40 μmol L-1 in the formerly oxic layer, but with high variability among sites and sampling dates. The immediate onset of H2 production after darkening points to fermentation as the main H2 producing process in this mat. The measured profiles indicate that a gradual disappearance of the H2 peak was mainly due to the activity of sulfate reducing bacteria that invaded the formerly oxic surface layer from below, or persisted in an inactive state in the oxic mat during illumination. The absence of significant H2 consumption in the formerly oxic mat during the first ∼30 min after onset of anoxic conditions indicated absence of active sulfate reducers in this layer during the oxic period. Addition of the methanogenesis inhibitor BES led to increase in H2, indicating that methanogens contributed to the consumption of H2. Both H2 formation and consumption seemed unaffected by the presence/absence of H2S.
Unique edge-sharing sulfate-transition metal coordination in Na2M(SO4)2 (M=Ni and Co)

International Nuclear Information System (INIS)

Fry, Allyson M.; Sweeney, Owen T.; Adam Phelan, W.; Drichko, Natalia; Siegler, Maxime A.; McQueen, Tyrel M.

2015-01-01

Two compounds, Na 2 Ni(SO 4 ) 2 and Na 2 Co(SO 4 ) 2 , were synthesized and their structure and properties were characterized. They adopt a structure that contains a bidentate coordination of sulfate to the transition metal center, which was determined via single crystal X-ray diffraction combined with model refinements to both laboratory X-ray and time-of-flight neutron powder diffraction data. The compounds were both found to crystallize in the C2/c space group with Z=24 and a unit cell of a=23.3461(3) Å, b=10.3004(1) Å, c=17.4115(2) Å, β=98.8659(9)°, and V=4136.99(8) Å 3 for the cobalt analog and a=23.2253(1) Å, b=10.26155(6) Å, c=17.3353(1) Å, β=99.0376(5)°, and V=4080.20(5) Å 3 for the nickel analog. Magnetization measurements show that the transition metal centers have negligible interactions with neighboring sites. Infrared and Raman spectroscopies were used to further probe the unique sulfate-transition metal coordination, and confirm the bidentate binding motif. The resulting pseudo-trigonal bipyramidal coordination produces vivid violet, Na 2 Co(SO 4 ) 2 , and yellow, Na 2 Ni(SO 4 ) 2 , colors that were probed by diffuse reflectance. - Graphical abstract: Two blue distorted transition metal octahedra (oxygen in red) bridged by two sulfate tetrahedra are shown here. Each bridging sulfate tetrahedra shares an edge with one octahedron and a corner with the other. All of the remaining corners of the octahedra are corner sharing with four tetrahedra forming a polyhedral network. - Highlights: • Structure of Na2Ni(SO4)2 and Na2Co(SO4)2 is determined. • Unique sulfate-transition metal binding observed in the new structure. • Combined diffraction and spectroscopic techniques were used. • Magnetization measurements show negligible interactions between sites
Direct Coupling of Thermo- and Photocatalysis for Conversion of CO2 -H2 O into Fuels.

Science.gov (United States)

Zhang, Li; Kong, Guoguo; Meng, Yaping; Tian, Jinshu; Zhang, Lijie; Wan, Shaolong; Lin, Jingdong; Wang, Yong

2017-12-08

Photocatalytic CO 2 reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address global energy and environmental issues. This study focused on the direct coupling of photocatalytic water splitting and thermocatalytic hydrogenation of CO 2 in the conversion of CO 2 -H 2 O into fuels. Specifically, it was found that direct coupling of thermo- and photocatalysis over Au-Ru/TiO 2 leads to activity 15 times higher (T=358 K; ca. 99 % CH 4 selectivity) in the conversion of CO 2 -H 2 O into fuels than that of photocatalytic water splitting. This is ascribed to the promoting effect of thermocatalytic hydrogenation of CO 2 by hydrogen atoms generated in situ by photocatalytic water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
INFRARED ABSORPTION LINES TOWARD NGC 7538 IRS 1: ABUNDANCES OF H{sub 2}, H{sub 3}{sup +}, AND CO

Energy Technology Data Exchange (ETDEWEB)

Goto, Miwa [Universitäts-Sternwarte München, Scheinerstr. 1, D-81679 Munich (Germany); Geballe, T. R. [Gemini Observatory, 670 North A‘ohoku Place, Hilo, HI 96720 (United States); Usuda, Tomonori, E-mail: mgoto@usm.lmu.de, E-mail: tgeballe@gemini.edu, E-mail: usuda@naoj.org [Subaru Telescope, 650 North A‘ohoku Place, Hilo, HI 96720 (United States)

2015-06-10

We report high-resolution near-infrared absorption spectroscopy of H{sub 2}, H{sub 3}{sup +}, and CO toward the young high mass object NGC 7538 IRS 1. The v = 1–0 H{sub 2} S(0) line and lines in the CO v = 2–0 band were detected; the v = 1–0 H{sub 2} S(1) line and the v = 1–0 H{sub 3}{sup +} lines [R(1, 1){sup l}, R(1, 0), R(1, 1){sup u}] were not detected. The line of sight traverses two clouds, with temperatures 45 and 259 K and with roughly equal column densities of CO. Assuming that H{sub 2} is at the same temperature as CO and that the two species are uniformly mixed, [H{sub 2}]/[CO] = 3600 ± 1200. NGC 7538 is the most distant object from the Galactic center for which [H{sub 2}]/[CO] has been directly measured using infrared absorption spectroscopy.
Summit CO2 emission rates by the CO2/SO2 ratio method at Kīlauea Volcano, Hawaiʻi, during a period of sustained inflation

Science.gov (United States)

Hager, S.A.; Gerlach, T.M.; Wallace, P.J.

2008-01-01

The emission rate of carbon dioxide escaping from the summit of Kīlauea Volcano, Hawaiʻi, proved highly variable, averaging 4900 ± 2000 metric tons per day (t/d) in June–July 2003 during a period of summit inflation. These results were obtained by combining over 90 measurements of COSPEC-derived SO2emission rates with synchronous CO2/SO2 ratios of the volcanic gas plume along the summit COSPEC traverse. The results are lower than the CO2 emission rate of 8500 ± 300 t/d measured by the same method in 1995–1999 during a period of long-term summit deflation [Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J. and Doukas, M.P., 2002. Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir. Journal of Geophysical Research-Solid Earth, 107(B9): art. no.-2189.]. Analysis of the data indicates that the emission rates of the present study likely reflect changes in the magma supply rate and residence time in the summit reservoir. It is also likely that emission rates during the inflation period were heavily influenced by SO2 pulses emitted adjacent to the COSPEC traverse, which biased CO2/SO2 ratios towards low values that may be unrepresentative of the global summit gas plume. We conclude that the SO2 pulses are consequences of summit re-inflation under way since 2003 and that CO2 emission rates remain comparable to, but more variable than, those measured prior to re-inflation.
One-dimensional ferromagnetic array compound [Co3(SBA)2(OH)2(H2O)2]n, (SBA = 4-sulfobenzoate)

Science.gov (United States)

Honda, Zentaro; Nomoto, Naoyuki; Fujihara, Takashi; Hagiwara, Masayuki; Kida, Takanori; Sawada, Yuya; Fukuda, Takeshi; Kamata, Norihiko

2018-06-01

We report on the syntheses, crystal structure, and magnetic properties of the transition metal coordination polymer [Co3(SBA)2(OH)2(H2O)2]n, (SBA = 4-sulfobenzoate) in which CoO6 octahedra are linked through their edges, forming one-dimensional (1D) Co(II) arrays running along the crystal a-axis. These arrays are further perpendicularly bridged by SBA ligand to construct a three-dimensional framework. Its magnetic properties have been investigated, and ferromagnetic interactions within the arrays have been found. From heat capacity measurements, we have found that this compound exhibits a three-dimensional ferromagnetic phase transition at TC = 1.54 K, and the specific heat just above TC shows a Schottky anomaly which originates from an energy gap caused by uniaxial magnetic anisotropy. These results suggest that [Co3(SBA)2(OH)2(H2O)2]n consists of weakly coupled 1D ferromagnetic Ising arrays.
Selective removal of Cs and Re by precipitation in a Na2CO3-H2O2 solution

International Nuclear Information System (INIS)

Eil-Hee Lee; Jae-Gwan Lim; Dong-Yong Chung; Han-Beom Yang; Kwang-Wook Kim

2010-01-01

The removal of Cs and Re (as a surrogate for Tc) by selective precipitation from the simulated fission products which were co-dissolved with uranium during the oxidative dissolution of spent fuel in a Na 2 CO 3 -H 2 O 2 solution was investigated in this study. The precipitations of Cs and Re were examined by introducing sodium tetraphenylborate (NaTPB) and tetraphenylohosponium chloride (TPPCl), respectively. The precipitation of Cs by NaTPB and that of Re by TPPCl each took place within 5 min, and an increase in temperature up to 50 deg C and a stirring speed up to 1000 rpm hardly affected their precipitation rates. The most important factor in the precipitation with NaTPB and TPPCl was found to be a pH of the solution after precipitation. Since Mo tends to co-precipitate with Cs or Re at a lower pH, an effective precipitation with NaTPB and TPPCl was done at pH of above 9 without the co-precipitation of Mo. More than 99% of Cs and Re were precipitated when the initial concentration ratio of NaTPB to Cs was above 1 and when that of TPPCl to Re was above 1. The precipitation of Cs and Re was never affected by the concentration of Na 2 CO 3 and H 2 O 2 , even though they were raised up to 1.5 and 1.0 M, respectively. Precipitation yields of Cs and Re in a Na 2 CO 3 -H 2 O 2 solution were found to be dependent on the concentration ratios of [NaTBP]/[Cs] and [TPPCl]/[Re]. (author)
Syngas (CO-H2) production using high temperature micro-tubular solid oxide electrolysers

International Nuclear Information System (INIS)

Kleiminger, L.; Li, T.; Li, K.; Kelsall, G.H.

2015-01-01

Highlights: • CO 2 and/or H 2 O reduced to CO/H 2 in micro-tubular solid oxide electrolyser (MT-SOE). • MT-SOE: CO 2 , H 2 O | Ni-(ZrO 2 ) 0.92 (Y 2 O 3 ) 0.08 (YSZ) | YSZ | YSZ- La 0.8 Sr 0.2 MnO 3-δ |O 2. • −0.76 A cm −2 achieved at 1.5V and ca. 820°C for H 2 O electrolysis. • Ni wire cathode current collector gave better performance than (Ag wire+Ag paste). • C 18 O 2 in co-electrolysis could not distinguish cathodic and chemical reduction. - Abstract: CO 2 and/or H 2 O were reduced to CO/H 2 in micro-tubular solid oxide electrolysers with yttria-stabilized zirconia (YSZ) electrolyte, Ni-YSZ cermet cathode and strontium(II)-doped lanthanum manganite (LSM) oxygen-evolving anode. At 822 °C, the kinetics of CO 2 reduction were slower (ca. −0.49 A cm −2 at 1.8 V) than H 2 O reduction or co-reduction of CO 2 and H 2 O, which were comparable (ca. −0.83 to −0.77 A cm −2 at 1.8 V). Performances were improved (−0.85 and −1.1 A cm −2 for CO 2 and H 2 O electrolysis, respectively) by substituting the silver current collector with nickel and avoiding blockage of entrances to pores on the inner lumen of micro-tubes induced by silver paste applied previously to decrease contact losses. The change in current collector materials increased ohmic potential losses due to substituting the lower resistance Ag with Ni wire, but decreased electrode polarization losses by 80–93%. For co-electrolysis of CO 2 and H 2 O, isotopically-labelled C 18 O 2 was used to try to distinguish between direct cathodic reduction of CO 2 and its Ni-catalysed chemical reaction with hydrogen from reduction of steam. Unfortunately, oxygen was exchanged between C 18 O 2 and H 2 16 O, enriching oxygen-18 in the steam and substituting oxygen-16 in the carbon dioxide, so the anode off-gas isotopic fractions were meaningless. This occurred even in alumina and YSZ tubes without the micro-tubular reactor, i.e. in the absence of Ni catalyst, though not in quartz tubes
Photosynthetic responses to elevated CO2 and O3 in Quercus ilex leaves at a natural CO2 spring

International Nuclear Information System (INIS)

Paoletti, E.; Seufert, G.; Della Rocca, G.; Thomsen, H.

2007-01-01

Photosynthetic stimulation and stomatal conductance (Gs) depression in Quercus ilex leaves at a CO 2 spring suggested no down-regulation. The insensitivity of Gs to a CO 2 increase (from ambient 1500 to 2000 μmol mol -1 ) suggested stomatal acclimation. Both responses are likely adaptations to the special environment of CO 2 springs. At the CO 2 -enriched site, not at the control site, photosynthesis decreased 9% in leaves exposed to 2x ambient O 3 concentrations in branch enclosures, compared to controls in charcoal-filtered air. The stomatal density reduction at high CO 2 was one-third lower than the concomitant Gs reduction, so that the O 3 uptake per single stoma was lower than at ambient CO 2 . No significant variation in monoterpene emission was measured. Higher trichome and mesophyll density were recorded at the CO 2 -enriched site, accounting for lower O 3 sensitivity. A long-term exposure to H 2 S, reflected by higher foliar S-content, and CO 2 might depress the antioxidant capacity of leaves close to the vent and increase their O 3 sensitivity. - Very high CO 2 concentrations did not compensate for the effects of O 3 on holm oak photosynthesis
Photoacoustic-based sO2 estimation through excised bovine prostate tissue with interstitial light delivery.

Science.gov (United States)

Mitcham, Trevor; Taghavi, Houra; Long, James; Wood, Cayla; Fuentes, David; Stefan, Wolfgang; Ward, John; Bouchard, Richard

2017-09-01

Photoacoustic (PA) imaging is capable of probing blood oxygen saturation (sO 2 ), which has been shown to correlate with tissue hypoxia, a promising cancer biomarker. However, wavelength-dependent local fluence changes can compromise sO 2 estimation accuracy in tissue. This work investigates using PA imaging with interstitial irradiation and local fluence correction to assess precision and accuracy of sO 2 estimation of blood samples through ex vivo bovine prostate tissue ranging from 14% to 100% sO 2 . Study results for bovine blood samples at distances up to 20 mm from the irradiation source show that local fluence correction improved average sO 2 estimation error from 16.8% to 3.2% and maintained an average precision of 2.3% when compared to matched CO-oximeter sO 2 measurements. This work demonstrates the potential for future clinical translation of using fluence-corrected and interstitially driven PA imaging to accurately and precisely assess sO 2 at depth in tissue with high resolution.
Quantitative analysis of H2O and CO2 in cordierite using polarized FTIR spectroscopy

Science.gov (United States)

Della Ventura, Giancarlo; Radica, Francesco; Bellatreccia, Fabio; Cavallo, Andrea; Capitelli, Francesco; Harley, Simon

2012-11-01

We report a FTIR (Fourier transform infrared) study of a set of cordierite samples from different occurrence and with different H2O/CO2 content. The specimens were fully characterized by a combination of techniques including optical microscopy, single-crystal X-ray diffraction, EMPA (electron microprobe analysis), SIMS (secondary ion mass spectrometry), and FTIR spectroscopy. All cordierites are orthorhombic Ccmm. According to the EMPA data, the Si/Al ratio is always close to 5:4; X Mg ranges from 76.31 to 96.63, and additional octahedral constituents occur in very small amounts. Extraframework K and Ca are negligible, while Na reaches the values up to 0.84 apfu. SIMS shows H2O up to 1.52 and CO2 up to 1.11 wt%. Optically transparent single crystals were oriented using the spindle stage and examined by FTIR micro-spectroscopy under polarized light. On the basis of the polarizing behaviour, the observed bands were assigned to water molecules in two different orientations and to CO2 molecules in the structural channels. The IR spectra also show the presence of small amounts of CO in the samples. Refined integrated molar absorption coefficients were calibrated for the quantitative microanalysis of both H2O and CO2 in cordierite based on single-crystal polarized-light FTIR spectroscopy. For H2O the integrated molar coefficients for type I and type II water molecules (ν3 modes) were calculated separately and are [I]ɛ = 5,200 ± 700 l mol-1 cm-2 and [II]ɛ = 13,000 ± 3,000 l mol-1 cm-2, respectively. For CO2 the integrated coefficient is \\varepsilon_{{{{CO}}_{ 2} }} = 19,000 ± 2,000 l mol-1 cm-2.
H₂ production through electro-oxidation of SO₂

DEFF Research Database (Denmark)

Kriek, Roelof J.; Rossmeisl, Jan; Siahrostami, Samira

2014-01-01

one volt lower than that of a regular water electrolyser. In taking this technology forward the greatest improvement to be made is in developing a suitable electrocatalyst, which is also the 'lowest hanging fruit' in that very limited research and development has been conducted on the electrocatalyst....... The electrolysis of aqueous solutions of dissolved SO2 holds huge environmental potential in that SO2 is converted to sulphuric acid (H2SO4) and at the same time hydrogen gas is produced. A further benefit or incentive is that a sulphur depolarised electrolyser (SDE) operates at an applied potential that is about...... are found to scale with the surface reactivity (measured as the adsorption of OH). Irrespective of the pathway water needs to be activated and reduction of SO2 to elemental sulphur must be avoided. This requirement alone calls for an electrode potential of at least 0.7-0.8 V for all the investigated...
The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece)

Science.gov (United States)

Bayraktarov, Elisa; Price, Roy E.; Ferdelman, Timothy G.; Finster, Kai

2013-01-01

Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~40–75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity. PMID:23658555
Synthesis and Crystal Structure of an Unprecedented Supramolecular Complex[Co(μ2-ClO4)2(H2O)2]·2MA

Institute of Scientific and Technical Information of China (English)

XU,Jing; BAI,Zhengshuai; SUN,Weiyin

2009-01-01

A new supramolecular framework[Co(μ2-C104)2(H2O)2]·2MA(1)[MA=melamine(C3H6N6)]has been syn-thesized by a hydrothermal method.Interestingly,there ale inorganic and organic building blocks with two different supramolecular synthons:(a)2D(4,4)network constructed by infinite inorganic 1D chains through interchain hy-drogen bonding interactions;(b)1D zigzag organic chains formed by hydrogen bonds, which further stack up through,ππ-interactions between the two adjacent MA molecules.The entire structure of 1 is a 3D supramolecular framework resulting from the presence of abundant hydrogen bonds between infinite[CO(μ2-C1O4)2(H2O)2]n chains and zigzag MA chains in different sheets.1 gives a nice example of supramolecular framework based on non-covalent interactions including hydrogen bonding and π-π interactions.
Electron capture, electron loss, and deexcitation of fast H(2 2S) and H(1 2S) atoms in collisions with molecular hydrogen and inert gases

International Nuclear Information System (INIS)

Roussel, F.; Pradel, P.; Spiess, G.

1977-01-01

Collisions of ground-state (1 2 S) and metastable (2 2 S) hydrogen atoms with rare gases and molecular hydrogen have been studied in the energy range 0.5--3.0 keV. For an acceptance angle of 55 mrad, the electron loss and the electron-capture cross sections of both H(1 2 S) and H(2 2 S) have been measured and compared with previous experimental values. The deexcitation cross section for H(2 2 S) has been deduced with the help of previously measured total-quenching cross sections for H(2 2 S). The ratio of the electron-capture cross sections for H(2 2 S) relative to H(1 2 S) is found to be very large for argon at low energies. The effects of large-angle scattering and of highly excited states of H are discussed

CO2 storage in deep underground strata. Integrity of deep wells under the influence of CO2; CO{sub 2} Lagerung im Geogrund. Integritaet von Tiefbohrungen unter Einfluss von CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Reinicke, K.M.; Franz, O. [Technische Univ. Clausthal (Germany). Inst. fuer Erdoel- und Erdgastechnik; Nangue Donfack, R. [Baker Hughes GmbH, Houston, TX (United States); Shinde, S. [Shell (Germany)

2007-09-13

Deep underground storage of CO2 is possible in petroleum reservoirs, gas reservoirs, aquifers and coal seams. Two aspects must be considered for safety: First, the technical integrity of the production and injection systems must be ensured during the operating phase of, typically, 10 to 50 years. Secondly, the technical integrity of the boreholes must be ensured for the whole storage period of 100 to 5000 years in order to prevent release of CO2 through the boreholes after sealing. The industry has long years of experience with injection of CO2 gained in CO2 enhanced oil recovery (EOR), in the production of high-pressure acid gas from natural gas wells, and in the injection of the acid components H2S and CO2 separated during acid gas production. Completion equipment and components of CO2 EOR and acid gas projects were analyzed, and detailed information on potential failure processes and their consequences. There are no major problems in ensuring safe injection and production during the operating phase. In contrast, the proof of technical stability over a period of 1000 years and more is a challenge as the experience so far covers only a few decades. This is the focus of research projects worldwide. The contribution presents the state of the art and shows how safe storage of CO2 may be possible. The results presented are part of the activities carried out in the CSEGR project (Carbon Sequestration with Enhanced Gas REcovery). The partners of Clausthal University are: Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hanover, EEG - Erdgas Erdoel GmbH Berlin, Wintershall AG Kassel, Vattenfall AB, and E.ON Ruhrgas GmbH, Essen. The project receives BMBF funds from the GEOTECHNOLOGIEN programme. (orig.)
Synthesis, structure, optical, photoluminescence and magnetic properties of K2[Co(C2O4)2(H2O)2]·4H2O

Science.gov (United States)

Narsimhulu, M.; Hussain, K. A.

2018-06-01

The synthesis, crystal structure, optical, photoluminescence and magnetic behaviour of potassium bis(oxalato)cobaltate(II)tertrahydrate{K2[Co(C2O4)2(H2O)2]·4H2O} are described. The compound was grown at room temperature from mixture of aqueous solutions by slow evaporation method. The X-ray crystallographic data showed that the compound belongs to the monoclinic crystal system with P21/n space group and Z = 4. The UV-visible diffuse absorbance spectra exhibited bands at 253, 285 and 541 nm in the visible and ultraviolet regions. The optical band gap of the compound was estimated as 3.4 eV. At room temperature, an intense photoluminescence was observed from this material around 392 nm when it excited at 254 nm. The variable temperature dc magnetic susceptibility measurements exposed paramagnetic behaviour at high temperatures and antiferromagnetic ordering at low temperatures.
Modeling Plasma-based CO2 and CH4 Conversion in Mixtures with N2, O2 and H2O: the Bigger Plasma Chemistry Picture

KAUST Repository

Wang, Weizong; Snoeckx, Ramses; Zhang, Xuming; Cha, Min; Bogaerts, Annemie

2018-01-01

performed regarding the single component gases, i.e. CO2 splitting and CH4 reforming, as well as for two component mixtures, i.e. dry reforming of methane (CO2/CH4), partial oxidation of methane (CH4/O2), artificial photosynthesis (CO2/H2O), CO2
Crystal structure of strontium aqua(ethylenediaminetetraacetato)cobaltate(II) tetrahydrate Sr[CoEdta(H2O)] · 4H2O

International Nuclear Information System (INIS)

Zasurskaya, L.A.; Polynova, T.N.; Polyakova, I.N.; Sergienko, V.S.; Poznyak, A.L.

2001-01-01

The complex Sr[Co II Edta] · 5H 2 O (I) (where Edta 4- is the ethylenediaminetetraacetate ion) has been synthesized. The crystal structure of this compound is determined by X-ray diffraction. Crystals are monoclinic, a = 7.906(2) A, b = 12.768(2) A, c = 18.254(3) A, β = 95.30(3) deg., V 1834.8 A 3 , space group P2 1 /n, Z = 4, and R = 0.036. The structure is built up of the binuclear complex fragments {Sr(H 2 O) 3 [CoEdta(H 2 O)]}, which consist of the anionic [CoEdta(H 2 O)] 2- and cationic [Sr(H 2 O) 3 ] 2+ units linked by the Sr-O bonds into a three-dimensional framework. The coordination polyhedra of the Co and Sr atoms are mono- and bicapped trigonal prisms. The coordination sphere of the Co atom (the coordination number is equal to 6 + 1) involves six donor atoms (2N and 4O) of the Edta 4- ligand and the O w atom of water molecule. One of the Co-O distances (2.718 A) is considerably longer than the other Co-O lig distances (2.092-2.190 A) and the Co-O w (1) distance (2.079 A). The Sr coordination polyhedron (the coordination number is eight) contains three water molecules, three carbonyl O atoms of the three different anionic complexes, and two O atoms of one acetate group of the fourth anionic complex. The Sr-O distances fall in the range 2.535-2.674 A. The structural formula of the compound is {Sr(H 2 O) 3 [CoEdta(H 2 O)]} 3∞ · H 2 O
Activation of SO2 with [(η(5) -C5 Me5 )2 Ln(THF)2 ] (Ln=Eu, Yb) leading to dithionite and sulfinate complexes.

Science.gov (United States)

Klementyeva, Svetlana V; Gamer, Michael T; Schmidt, Anna-Corina; Meyer, Karsten; Konchenko, Sergey N; Roesky, Peter W

2014-10-13

The reaction of decamethylytterbocene [(η(5) -C5 Me5 )2 Yb(THF)2 ] with SO2 at low temperature gave two new compounds, namely, the Yb(III) dithionite/sulfinate complex [{(η(5) -C5 Me5 )2 Yb(μ3 ,1κ(2) O(1,3) ,2κ(3) O(2,2',4) -S2 O4 )}2 {(η(5) -C5 Me5 )Yb(μ,1κO,2κO'-C5 Me5 SO2 )}2 ] (1) and the Yb(III) dithionite complex [{(η(5) -C5 Me5 )2 Yb}2 (μ,1κ(2) O(1,3) ,2κ(2) O(2,4) -S2 O4 )] (2). After extraction of 1, the mixture was heated to give the dinuclear tetrasulfinate complex [{(η(5) -C5 Me5 )Yb}2 (μ,κO,κO'-C5 Me5 SO2 )4 ] (3 a). In contrast, from the reaction of [(η(5) -C5 Me5 )2 Eu(THF)2 ] with SO2 only the tetrasulfinate complex [{(η(5) -C5 Me5 )Eu}2 (μ,κO,κO'-C5 Me5 SO2 )4 ] (3 b) was isolated. Two major reaction pathways were observed: 1) reductive coupling of two SO2 molecules to form the dithionite anion S2 O4 (2-) ; and 2) nucleophilic attack of one metallocene C5 Me5 ligand on the sulfur atom of SO2 . The compounds presented are the first dithionite and sulfinate complexes of the f-elements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Hard-X-ray photoelectron spectroscopy of NaxCoO2.yH2O

International Nuclear Information System (INIS)

Chainani, A.; Yokoya, T.; Takata, Y.; Tamasaku, K.; Taguchi, M.; Shimojima, T.; Kamakura, N.; Horiba, K.; Tsuda, S.; Shin, S.; Miwa, D.; Nishino, Y.; Ishikawa, T.; Yabashi, M.; Kobayashi, K.; Namatame, H.; Taniguchi, M.; Takada, K.; Sasaki, T.; Sakurai, H.; Takayama-Muromachi, E.

2005-01-01

We study the bulk electronic structure of Na x CoO 2 .yH 2 O using Hard X-ray (HX, hν = 5.95KeV) synchrotron photoelectron spectroscopy (PES). The Co 2p core level spectra show well-separated Co 3+ and Co 4+ ions. Cluster calculations suggest low spin Co 3+ and Co 4+ character, and a moderate on-site Coulomb correlation energy U dd ∼3-5.5eV. Photon-dependent valence band PES identifies Co 3d and O 2p derived states, in near agreement with band structure calculations. We discuss the importance of HX-PES for studying correlated transition metal oxides
Ionothermal Synthesis of a Novel 3D Cobalt Coordination Polymer with a Uniquely Reported Framework: [BMI]2[Co2(BTC2(H2O2

Directory of Open Access Journals (Sweden)

Il-Ju Ko

2017-01-01

Full Text Available The framework of [RMI]2[Co2(BTC2(H2O2] (RMI = 1-alkyl-3-methylimidazolium, alkyl; ethyl (EMI; propyl (PMI; butyl (BMI, which has uniquely occurred in ionothermal reactions of metal salts and H3BTC (1,3,5-benzenetricarboxylic acid, an organic ligand, reappeared in this work. Ionothermal reaction of cobalt acetate and H3BTC with [BMI]Br ionic liquid as the reaction medium yielded the novel coordination polymer [BMI]2[Co2(BTC2(H2O2] (compound B2. Similar ionothermal reactions with different [EMI]Br and [PMI]Br as the reaction media have been previously reported to produce [EMI]2[Co3(BTC2(OAc2] (compound A1 and [PMI]2[Co2(BTC2(H2O2] (compound B1, respectively. In contrast with the trinuclear secondary building unit of A1, the framework structure of B1 and B2 consists of dinuclear secondary building units in common, but with subtle distinction posed by the different size of the incorporated cations. These structural differences amidst the frameworks showed interesting aspects, including guest and void volume, and were used to explain the chemical trend observed in the system. Moreover, the physicochemical properties of the newly synthesized compound have been briefly discussed.
Polysulfides and products of H2S/S-nitrosoglutathione in comparison to H2S, glutathione and antioxidant Trolox are potent scavengers of superoxide anion radical and produce hydroxyl radical by decomposition of H2O2.

Science.gov (United States)

Misak, Anton; Grman, Marian; Bacova, Zuzana; Rezuchova, Ingeborg; Hudecova, Sona; Ondriasova, Elena; Krizanova, Olga; Brezova, Vlasta; Chovanec, Miroslav; Ondrias, Karol

2018-06-01

Exogenous and endogenously produced sulfide derivatives, such as H 2 S/HS - /S 2- , polysulfides and products of the H 2 S/S-nitrosoglutathione interaction (S/GSNO), affect numerous biological processes in which superoxide anion (O 2 - ) and hydroxyl (OH) radicals play an important role. Their cytoprotective-antioxidant and contrasting pro-oxidant-toxic effects have been reported. Therefore, the aim of our work was to contribute to resolving this apparent inconsistency by studying sulfide derivatives/free radical interactions and their consequent biological effects compared to the antioxidants glutathione (GSH) and Trolox. Using the electron paramagnetic resonance (EPR) spin trapping technique and O 2 - , we found that a polysulfide (Na 2 S 4 ) and S/GSNO were potent scavengers of O 2 - and cPTIO radicals compared to H 2 S (Na 2 S), GSH and Trolox, and S/GSNO scavenged the DEPMPO-OH radical. As detected by the EPR spectra of DEPMPO-OH, the formation of OH in physiological solution by S/GSNO was suggested. All the studied sulfide derivatives, but not Trolox or GSH, had a bell-shaped potency to decompose H 2 O 2 and produced OH in the following order: S/GSNO > Na 2 S 4 ≥ Na 2 S > GSH = Trolox = 0, but they scavenged OH at higher concentrations. In studies of the biological consequences of these sulfide derivatives/H 2 O 2 properties, we found the following: (i) S/GSNO alone and all sulfide derivatives in the presence of H 2 O 2 cleaved plasmid DNA; (ii) S/GSNO interfered with viral replication and consequently decreased the infectivity of viruses; (iii) the sulfide derivatives induced apoptosis in A2780 cells but inhibited apoptosis induced by H 2 O 2 ; and (iv) Na 2 S 4 modulated intracellular calcium in A87MG cells, which depended on the order of Na 2 S 4 /H 2 O 2 application. We suggest that the apparent inconsistency of the cytoprotective-antioxidant and contrasting pro-oxidant-toxic biological effects of sulfide derivatives results from their time
Effect of Uncertainties in CO2 Property Databases on the S-CO2 Compressor Performance

International Nuclear Information System (INIS)

Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu; Cha, Je Eun

2013-01-01

Various S-CO 2 Brayton cycle experiment facilities are on the state of construction or operation for demonstration of the technology. However, during the data analysis, S-CO 2 property databases are widely used to predict the performance and characteristics of S-CO 2 Brayton cycle. Thus, a reliable property database is very important before any experiment data analyses or calculation. In this paper, deviation of two different property databases which are widely used for the data analysis will be identified by using three selected properties for comparison, C p , density and enthalpy. Furthermore, effect of above mentioned deviation on the analysis of test data will be briefly discussed. From this deviation, results of the test data analysis can have critical error. As the S-CO 2 Brayton cycle researcher knows, CO 2 near the critical point has dramatic change on thermodynamic properties. Thus, it is true that a potential error source of property prediction exists in CO 2 properties near the critical point. During an experiment data analysis with the S-CO 2 Brayton cycle experiment facility, thermodynamic properties are always involved to predict the component performance and characteristics. Thus, construction or defining of precise CO 2 property database should be carried out to develop Korean S-CO 2 Brayton cycle technology
Production of Excess CO2 relative to methane in peatlands: a new H2 sink

Science.gov (United States)

Wilson, R.; Woodcroft, B. J.; Varner, R. K.; Tyson, G. W.; Tfaily, M. M.; Sebestyen, S.; Saleska, S. R.; Rogers, K.; Rich, V. I.; McFarlane, K. J.; Kostka, J. E.; Kolka, R. K.; Keller, J.; Iversen, C. M.; Hodgkins, S. B.; Hanson, P. J.; Guilderson, T. P.; Griffiths, N.; de La Cruz, F.; Crill, P. M.; Chanton, J.; Bridgham, S. D.; Barlaz, M.

2015-12-01

Methane is generated as the end product of anaerobic organic matter degradation following a series of reaction pathways including fermentation and syntrophy. Along with acetate and CO2, syntrophic reactions generate H2 and are only thermodynamically feasible when coupled to an exothermic reaction that consumes H2. The usual model of organic matter degradation in peatlands has assumed that methanogenesis is that exothermic H2-consuming reaction. If correct, this paradigm should ultimately result in equimolar production of CO2 and methane from the degradation of the model organic compound cellulose: i.e. C6H12O6 à 3CO2 + 3CH4. However, dissolved gas measurement and modeling results from field and incubation experiments spanning peatlands across the northern hemisphere have failed to demonstrate equimolar production of CO2 and methane. Instead, in a flagrant violation of thermodynamics, these studies show a large bias favoring CO2 production over methane generation. In this talk, we will use an array of complementary analytical techniques including FT-IR, cellulose and lignin measurements, 13C-NMR, fluorescence spectroscopy, and ultra-high resolution mass spectrometry to describe organic matter degradation within a peat column and identify the important degradation mechanisms. Hydrogenation was the most common transformation observed in the ultra-high resolution mass spectrometry data. From these results we propose a new mechanism for consuming H2 generated during CO2 production, without concomitant methane formation, consistent with observed high CO2/CH4 ratios. While homoacetogenesis is a known sink for H2 in these systems, this process also consumes CO2 and therefore does not explain the excess CO2 measured in field and incubation samples. Not only does the newly proposed mechanism consume H2 without generating methane, but it also yields enough energy to balance the coupled syntrophic reactions, thereby restoring thermodynamic order. Schematic of organic matter
Promotion of H2 production by microwave-assisted treatment of water hyacinth with dilute H2SO4 through combined dark fermentation and photofermentation

International Nuclear Information System (INIS)

Cheng, Jun; Xia, Ao; Su, Huibo; Song, Wenlu; Zhou, Junhu; Cen, Kefa

2013-01-01

Highlights: • Water hyacinth is microwaved with dilute H 2 SO 4 to improve enzymatic hydrolysis. • Hydrolyzed hyacinth is fermented by hydrogenogens to improve dark H 2 yield. • Nearly 100% glucose and most arabinose in hydrolysate are used in dark fermentation. • H 2 yield from hyacinth via combined fermentation is 75.2% of theoretical H 2 yield. - Abstract: Water hyacinth was treated with microwave-assisted dilute H 2 SO 4 to improve saccharification before enzymatic hydrolysis and H 2 production during dark fermentation. A maximum reducing sugar (RS) yield of 64.4 g/100 g total volatile solid (TVS) (96.1% of the theoretical RS yield) was achieved when water hyacinth was treated through microwave heating with 1% dilute H 2 SO 4 for 15 min at 140 °C and then enzymatically hydrolyzed for 72 h. During enzymatic hydrolysis, glucose was efficiently produced from the hydrolysis of cellulose that resulted from the disruption of the lignocellulosic structure of water hyacinth after microwave-assisted H 2 SO 4 treatment. When the hydrolyzed water hyacinth was inoculated with H 2 -producing bacteria to produce H 2 during dark fermentation, a maximum H 2 yield of 112.3 ml/g TVS was obtained. The major sugar compositions in the residual solution from dark fermentation were xylose and cellobiose (total RS utilization efficiency: 88.5%). Through a combination of dark fermentation and photofermentation, the maximum H 2 yield from water hyacinth was significantly increased from 112.3 ml/g TVS to 751.5 ml/g TVS, which is 75.2% of the theoretical H 2 yield
SO2 and NO removal from flue gas over V2O5/AC at lower temperatures - role of V2O5 on SO2 removal

International Nuclear Information System (INIS)

Ma, Jianrong; Liu, Zhenyu; Liu, Qingya; Guo, Shijie; Huang, Zhanggen; Xiao, Yong

2008-01-01

Supporting V 2 O 5 onto an activated coke (AC) has been reported to significantly increase the AC's activity in simultaneous SO 2 and NO removal from flue gas. To understand the role of V 2 O 5 on SO 2 removal, V 2 O 5 /AC is studied through SO 2 removal reaction, surface analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) techniques. It is found that the main role of V 2 O 5 in SO 2 removal over V 2 O 5 /AC is to catalyze SO 2 oxidation through a VOSO 4 -like intermediate species, which reacts with O 2 to form SO 3 and V 2 O 5 . The SO 3 formed transfers from the V sites to AC sites and then reacts with H 2 O to form H 2 SO 4 . At low V 2 O 5 loadings, a V atom is able to catalyze as many as 8 SO 2 molecules to SO 3 . At high V 2 O 5 loadings, however, the number of SO 2 molecules catalyzed by a V atom is much less, due possibly to excessive amounts of V 2 O 5 sites in comparison to the pores available for SO 3 and H 2 SO 4 storage. (author)
Decoloration Kinetics of Waste Cooking Oil by 60Co γ-ray/H2O2

Science.gov (United States)

Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng

2016-03-01

In order to decolorize, waste cooking oil, a dark red close to black solution from homes and restaurants, was subjected to 60Co γ-ray/H2O2 treatment. By virtue of UV/Vis spectrophotometric method, the influence of Gamma irradiation to decoloration kinetics and rate constants of the waste cooking oil in the presence of H2O2 was researched. In addition, the influence of different factors such as H2O2 concentration and irradiation dose on the decoloration rate of waste cooking oil was investigated. Results indicated that the decoloration kinetics of waste cooking oil conformed to the first-order reaction. The decoloration rate increased with the increase of irradiation dose and H2O2 concentration. Saponification analysis and sensory evaluation showed that the sample by 60Co γ-ray/H2O2 treatment presented better saponification performance and sensory score. Furthermore, according to cost estimate, the cost of the 60Co γ-ray/H2O2 was lower and more feasible than the H2O2 alone for decoloration of waste cooking oil.
Synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2

OpenAIRE

Qian, Qingli; Zhang, Jingjing; Cui, Meng; Han, Buxing

2016-01-01

Acetic acid is an important bulk chemical that is currently produced via methanol carbonylation using fossil based CO. Synthesis of acetic acid from the renewable and cheap CO2 is of great importance, but state of the art routes encounter difficulties, especially in reaction selectivity and activity. Here we report a route to produce acetic acid from CO2, methanol and H2. The reaction can be efficiently catalysed by Ru?Rh bimetallic catalyst using imidazole as the ligand and LiI as the promot...
Densities, viscosities, and refractive indexes for {C2H5CO2(CH2)2CH3+C6H13OH+C6H6} at T=308.15 K

International Nuclear Information System (INIS)

Casas, Herminio; Garcia-Garabal, Sandra; Segade, Luisa; Cabeza, Oscar.; Franjo, Carlos; Jimenez, Eulogio

2003-01-01

In this work we present densities, kinematic viscosities, and refractive indexes of the ternary system {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 13 OH+C 6 H 6 } and the corresponding binary mixtures {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 6 }, {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 13 OH}, and {C 6 H 13 OH+C 6 H 6 }. All data have been measured at T=308.15 K and atmospheric pressure over the whole composition range. The excess molar volumes, dynamic viscosity deviations, and changes of the refractive index on mixing were calculated from experimental measurements. The results for binary mixtures were fitted to a polynomial relationship to estimate the coefficients and standard deviations. The Cibulka equation has been used to correlate the experimental values of ternary mixtures. Also, the experimental values obtained for the ternary mixture were used to test the empirical methods of Kohler, Jacob and Fitzner, Colinet, Tsao and Smith, Toop, Scatchard et al., and Hillert. These methods predict excess properties of the ternary mixtures from those of the involved binary mixtures. The results obtained for dynamic viscosities of the binary mixtures were used to test the semi-empirical relations of Grunberg-Nissan, McAllister, Auslaender, and Teja-Rice. Finally, the experimental refractive indexes were compared with the predicted results for the Lorentz-Lorenz, Gladstone-Dale, Wiener, Heller, and Arago-Biot equations. In all cases, we give the standard deviation between the experimental data and that calculated with the above named relations
Comparative study of CO2 and H2O activation in the synthesis of carbon electrode for supercapacitors

Science.gov (United States)

Taer, E.; Apriwandi, Yusriwandi, Mustika, W. S.; Zulkifli, Taslim, R.; Sugianto, Kurniasih, B.; Agustino, Dewi, P.

2018-02-01

The physical activation for the comparative study of carbon electrode synthesized for supercapacitor applications made from rubber wood sawdust has been performed successfully. Comparison of physical activation used in this research is based on the different gas activation such as CO2 and H2O. The CO2 and H2O activation are made by using an integrated carbonization and activation system. The carbonization process is performed in N2 atmosphere followed by CO2 and H2O activation process. The carbonization process at temperature of 600°C, the CO2 and H2O activation process at a temperature of 900°C and maintained at this condition for 2 h and 3 h. The electrochemical properties were analyzed using cyclic voltammetric (CV) method. The CV results show that the carbon electrode with CO2 activation has better capacitive properties than H2O, the highest specific capacitance obtained is 93.22 F/g for 3 h of activation time. In addition, the analysis of physical properties such as surface morphology and degree of crystallinity was also performed.
Superconductivity in Na{sub 1-x}CoO{sub 2}.yH{sub 2}O thin films

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Sandra; Komissinkiy, Philipp; Alff, Lambert [Institute for Materials Science, TU Darmstadt (Germany); Fritsch, Ingo; Habermeier, Hanns-Ulrich [Max-Planck-Institute for Solid State Research, Stuttgart (Germany); Lemmens, Peter [Institute for Condensed Matter Physics, TU Braunschweig (Germany)

2010-07-01

Sodium cobaltate (Na{sub 1-x}CoO{sub 2}) is a novel material with thermoelectric behavior, charge and spin ordered states dependent on the sodium content in the composition. A superconducting phase was found in water intercalated sodium cobaltate (Na{sub 1-x}CoO{sub 2}.yH{sub 2}O) with x=0.65-0.7 and y=0.9-1.3. The pairing state is still under debate, but there are some indications for a spin-triplet or p-wave superconducting pairing state. First films of Na{sub 1-x}CoO{sub 2}.yH{sub 2}O with a superconducting transition temperature near 5 K have been successfully grown. Here we report on thin films of Na{sub 1-x}CoO{sub 2} grown by pulsed laser deposition technique. The deposition parameters, sodium deintercalation and water intercalation conditions are tuned in order to obtain the superconducting phase. The instability of this phase might be an indication for triplet superconductivity, which is known to be affected strongly by impurities and defects.This observation is in agreement with the fact that so far also no superconducting thin films of the most famous triplet superconductor Sr{sub 2}RuO{sub 4} have been reported.
Ultrahigh and Selective SO2 Uptake in Inorganic Anion-Pillared Hybrid Porous Materials.

Science.gov (United States)

Cui, Xili; Yang, Qiwei; Yang, Lifeng; Krishna, Rajamani; Zhang, Zhiguo; Bao, Zongbi; Wu, Hui; Ren, Qilong; Zhou, Wei; Chen, Banglin; Xing, Huabin

2017-07-01

The efficient capture of SO 2 is of great significance in gas-purification processes including flue-gas desulfurization and natural-gas purification, but the design of porous materials with high adsorption capacity and selectivity of SO 2 remains very challenging. Herein, the selective recognition and dense packing of SO 2 clusters through multiple synergistic host-guest and guest-guest interactions by controlling the pore chemistry and size in inorganic anion (SiF 6 2- , SIFSIX) pillared metal-organic frameworks is reported. The binding sites of anions and aromatic rings in SIFSIX materials grasp every atom of SO 2 firmly via S δ+ ···F δ- electrostatic interactions and O δ- ···H δ+ dipole-dipole interactions, while the guest-guest interactions between SO 2 molecules further promote gas trapping within the pore space, which is elucidated by first-principles density functional theory calculations and powder X-ray diffraction experiments. These interactions afford new benchmarks for the highly efficient removal of SO 2 from other gases, even if at a very low SO 2 concentration. Exceptionally high SO 2 capacity of 11.01 mmol g -1 is achieved at atmosphere pressure by SIFSIX-1-Cu, and unprecedented low-pressure SO 2 capacity is obtained in SIFSIX-2-Cu-i (4.16 mmol g -1 SO 2 at 0.01 bar and 2.31 mmol g -1 at 0.002 bar). More importantly, record SO 2 /CO 2 selectivity (86-89) and excellent SO 2 /N 2 selectivity (1285-3145) are also achieved. Experimental breakthrough curves further demonstrate the excellent performance of these hybrid porous materials in removing low-concentration SO 2 . © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
pCO2 And pH regulation of cerebral blood flow

Directory of Open Access Journals (Sweden)

SeongHun eYoon

2012-09-01

Full Text Available CO2 Serves as one of the fundamental regulators of cerebral blood flow. It is widely considered that this regulation occurs through pCO2-driven changes in pH of the cerebral spinal fluid, with elevated and lowered pH causing direct relaxation and contraction of the smooth muscle, respectively. However, some findings also suggest that pCO2 acts independently of and/or in conjunction with altered pH. This action may be due to a direct effect of cerebral spinal fluid pCO2 on the smooth muscle as well as on the endothelium, nerves, and astrocytes. Findings may also point to an action of arterial pCO2 on the endothelium to regulate smooth muscle contractility. Thus, the effects of pH and pCO2 may be influenced by the absence/presence of different cell types in the various experimental preparations. Results may also be influenced by experimental parameters including myogenic tone as well as solutions containing significantly altered HCO3- concentrations, i.e., solutions routinely employed to differentiate the effects of pH from pCO2. In sum, it appears that pCO2, independently and in conjunction with pH, may regulate cerebral blood flow.
Atomic and molecular data for H2O, CO and CO2 relevant to edge plasma impurities

International Nuclear Information System (INIS)

Tawara, Hiro.

1992-10-01

The present status of atomic and molecular data under electron impact involving the most relevant plasma impurity species (H 2 O, CO and CO 2 ) has been surveyed and some data have been compiled and evaluated. The emphasis is the cross sections for ionization, dissociation, excitation, photon emission and recombination processes. (author)

Zeolitic Imidazolate Framework-8 Membrane for H2/CO2 Separation: Experimental and Modeling

Science.gov (United States)

Lai, L. S.; Yeong, Y. F.; Lau, K. K.; Azmi, M. S.; Chew, T. L.

2018-03-01

In this work, ZIF-8 membrane synthesized through solvent evaporation secondary seeded growth was tested for single gas permeation and binary gases separation of H2 and CO2. Subsequently, a modified mathematical modeling combining the effects of membrane and support layers was applied to represent the gas transport properties of ZIF-8 membrane. Results showed that, the membrane has exhibited H2/CO2 ideal selectivity of 5.83 and separation factor of 3.28 at 100 kPa and 303 K. Besides, the experimental results were fitted well with the simulated results by demonstrating means absolute error (MAE) values ranged from 1.13 % to 3.88 % for single gas permeation and 10.81 % to 21.22 % for binary gases separation. Based on the simulated data, most of the H2 and CO2 gas molecules have transported through the molecular pores of membrane layer, which was up to 70 %. Thus, the gas transport of the gases is mainly dominated by adsorption and diffusion across the membrane.
Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

KAUST Repository

Zhu, Xiuping; Hatzell, Marta C; Logan, Bruce E

2014-01-01

Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.
Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

KAUST Repository

Zhu, Xiuping

2014-03-24

Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.
Laboratory Study of H2SO4 / H2O Nucleation Using a New Technique - a Laminar Co-Flow Tube.

Czech Academy of Sciences Publication Activity Database

Trávníčková, Tereza; Škrabalová, Lenka; Havlica, Jaromír; Krejčí, A. Petr; Hrubý, Jan; Ždímal, Vladimír

2018-01-01

Roč. 70, č. 1 (2018), s. 1446643 ISSN 0280-6509 R&D Projects: GA ČR(CZ) GAP105/12/0664; GA ČR(CZ) GA17-19798S; GA MŠk(CZ) EF16_013/0001315 EU Projects: European Commission(XE) 315760 - HEXACOMM; European Commission(XE) 654109 - ACTRIS-2 Institutional support: RVO:67985858 ; RVO:61388998 Keywords : co-flow * nucleation * sulphuric acid Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry
Neutron scattering studies of K3H(SO4)2 and K3D(SO4)2: the particle-in-a-box model for the quantum phase transition.

Science.gov (United States)

Fillaux, François; Cousson, Alain

2012-08-21

In the crystal of K(3)H(SO(4))(2) or K(3)D(SO(4))(2), dimers SO(4)···H···SO(4) or SO(4)···D···SO(4) are linked by strong centrosymmetric hydrogen or deuterium bonds whose O···O length is ≈2.50 Å. We address two open questions. (i) Are H or D sites split or not? (ii) Is there any structural counterpart to the phase transition observed for K(3)D(SO(4))(2) at T(c) ≈ 85.5 K, which does not exist for K(3)H(SO(4))(2)? Neutron diffraction by single-crystals at cryogenic or room temperature reveals no structural transition and no resolvable splitting of H or D sites. However, the width of the probability densities suggest unresolved splitting of the wavefunctions suggesting rigid entities H(L1/2)-H(R1/2) or D(L1/2)-D(R1/2) whose separation lengths are l(H) ≈ 0.16 Å or l(D) ≈ 0.25 Å. The vibrational eigenstates for the center of mass of H(L1/2)-H(R1/2) revealed by inelastic neutron scattering are amenable to a square-well and we suppose the same potential holds for D(L1/2)-D(R1/2). In order to explain dielectric and calorimetric measurements of mixed crystals K(3)D((1-ρ))H(ρ)(SO(4))(2) (0 ≤ ρ ≤ 1), we replace the classical notion of order-disorder by the quantum notion of discernible (e.g., D(L1/2)-D(R1/2)) or indiscernible (e.g., H(L1/2)-H(R1/2)) components depending on the separation length of the split wavefunction. The discernible-indiscernible isostructural transition at finite temperatures is induced by a thermal pure quantum state or at 0 K by ρ.
Thermal decomposition of RE(C2H5CO2)3·H2O (RE = Dy, Tb, Gd, Eu and Sm)

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2014-01-01

The thermal decomposition of Dy(III), Tb(III), Gd(III), Eu(III), and Sm(III) propionate monohydrates was studied in argon by means of simultaneous differential thermal analysis and thermogravimetry, infrared-spectroscopy, X-ray diffraction, and optical microscopy. After dehydration, which takes......, an intermediate stage involving a RE2O(C2H5CO2)4 composition was evidenced in the case of the Eu- and Sm-propionates. For all compounds, further decomposition of RE2O2CO3 into the corresponding sesquioxides (RE2O3) is accompanied by the release of CO2. The thermal decomposition of Dy- and Tb-propionates occurs...
Methanesulfonates of high-valent metals. Syntheses and structural features of MoO{sub 2}(CH{sub 3}SO{sub 3}){sub 2}, UO{sub 2}(CH{sub 3}SO{sub 3}){sub 2}, ReO{sub 3}(CH{sub 3}SO{sub 3}), VO(CH{sub 3}SO{sub 3}){sub 2}, and V{sub 2}O{sub 3}(CH{sub 3}SO{sub 3}){sub 4} and their thermal decomposition under N{sub 2} and O{sub 2} atmosphere

Energy Technology Data Exchange (ETDEWEB)

Betke, Ulf; Neuschulz, Kai; Wickleder, Mathias S. [Carl von Ossietzky University of Oldenburg, Institute of Pure and Applied Chemistry (Germany)

2011-11-04

with reduction of the metal leading to the oxides MoO{sub 2}, U{sub 3}O{sub 7}, V{sub 4}O{sub 7}, and VO{sub 2}; for MoO{sub 2}(CH{sub 3}SO{sub 3}){sub 2}, a small amount of MoS{sub 2} is formed. If the thermal decomposition is carried out in a atmosphere of O{sub 2} the oxides MoO{sub 3} and V{sub 2}O{sub 5} are formed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Facile synthesis of MoS{sub 2}/Bi{sub 2}WO{sub 6} nanocomposites for enhanced CO{sub 2} photoreduction activity under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Dai, Weili, E-mail: wldai81@126.com [Key Laboratory of Jiangxi Province for Persistant Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, Jiangxi (China); Yu, Juanjuan [Key Laboratory of Jiangxi Province for Persistant Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, Jiangxi (China); Deng, Yiqiang, E-mail: dyq3211@126.com [College of Chemical Engineering, Guangdong University of Petrochemical Technology, Maoming 525000 Guangdong (China); Hu, Xu; Wang, Tengyao; Luo, Xubiao [Key Laboratory of Jiangxi Province for Persistant Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, Jiangxi (China)

2017-05-01

Highlights: • MoS{sub 2}/Bi{sub 2}WO{sub 6} nanocomposites (MB) were fabricated by a facile two-step approach. • MoS{sub 2} was first used as a cocatalyst coupling with Bi{sub 2}WO{sub 6} for CO{sub 2} photoreduction. • MoS{sub 2} significantly enhanced the photoelectric properties and photoactivity. • The CO{sub 3}{sup 2−}, HCO{sub 3}{sup −} and H{sub 2}CO{sub 3} in CO{sub 2} solution actually act as the reactive substrates. - Abstract: A novel composite material, MoS{sub 2}/Bi{sub 2}WO{sub 6}, has been fabricated via a facile two-step approach. The few layered MoS{sub 2} as a cocatalyst has intimate interactions with the hierarchical flower-like Bi{sub 2}WO{sub 6} microspheres, which boosts the visible light harvesting and charge transferring, and promotes the separation of electron-hole pairs, thus leading to the superior photocatalytic activity. It was found that the as-synthesized MoS{sub 2}/Bi{sub 2}WO{sub 6} nanocomposites exhibited significantly enhanced performance for the photoreduction of CO{sub 2} into hydrocarbons, i.e. methanol and ethanol, as compared with pure Bi{sub 2}WO{sub 6}. The yields of methanol and ethanol obtained over the composite with optimal content of MoS{sub 2} (0.4 wt%) were 36.7 and 36.6 μmol gcat{sup −1} after 4 h of visible light irradiation, respectively, which were 1.94 times higher than that over pure Bi{sub 2}WO{sub 6}. Furthermore, the mechanism of CO{sub 2} photoreduction was also investigated. It indicates that the CO{sub 3}{sup 2−}, HCO{sub 3}{sup −} and H{sub 2}CO{sub 3} generated in CO{sub 2} aqueous solution would be the reactive substrates during the photoreduction reaction, proving the thermodynamic feasibility of CO{sub 2} photoreduction. This work demonstrated that MoS{sub 2} is a very promising candidate for development of highly active photocatalysts, and supplied a facile and simple strategy for designing environmentally benign, cheap non-noble metal, and highly efficient semiconductor
Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-[2H]- and (2R)-[2H]-sparteine

International Nuclear Information System (INIS)

Ebner, T.; Meese, C.O.; Rebell, J.

1989-01-01

Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)(β)-deuterated (-)-sparteine and the (2R)(α)-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label (≥98%) are established unequivocally by 1 H, 2 H and 13 C NMR spectroscopy. (author)
Relaxation of photogenerated carriers under He, H sub 2 , CO sub 2 and O sub 2 on ZnO

CERN Document Server

Han, C S; Jun, J

1998-01-01

The relaxation process of photogenerated carriers was investigated using conductivity measurement on ZnO under He,H sub 2 ,CO sub 2 and O sub 2. The process was well explained with the rate constant of reaction or recombination of hole and electron, k sub h and k sub e (k sub h >k sub e), respectively. Generally, k sub h increased with the pressure of the gases. The slope of k sub h with respect to the pressure increased in the order of H sub 2<=He<CO sub 2 , while k sub h of O sub 2 was sensitive to the history of the sample. The relaxation process on ZnO which was exposed to oxygen at 298 K and 573 K was observed during the illumination time. From the result, it was suggested that the rate constant of photo generated excess carriers was affected by the surface barrier of the semiconductor.
Preliminary Studies of Two-Phase Reactive Process of Sodium-CO2 in S-CO2 Power Conversion Cycle Coupled to SFR System

International Nuclear Information System (INIS)

Jung, Hwa Young; Ahn, Yoon Han; Lee, You Ho; Lee, Jeong Ik

2013-01-01

As a competing alternative to the steam Rankine cycle, the supercritical CO 2 (S-CO 2 ) Brayton cycle has been highlighted due to its high thermal efficiency, compact turbomachinery and heat exchangers sizes, and the reduced risk of SWRs. While the reduced risk of an SWR is considered as the one of most pronounced benefits of S-CO 2 Brayton cycle, there is still an interaction problem between liquid sodium and CO 2 . Although the chemical interaction between liquid sodium and CO 2 demonstrates less serious potential risks than those of a SWR, the Na/CO 2 interaction should be understood to evaluate safety and reliability of Intermediate Heat eXchanger (IHX). A noticeable characteristic of the reaction environment is that there is a large pressure difference between the liquid sodium and CO 2 side by about 1 and 200 bar, respectively. This would imply that the presence of a micro-crack in a heat exchanger tube will cause a high-pressure leak of CO 2 into liquid sodium side. Although the Na/CO 2 interaction may play an important role in the safety of the SFR reactor system, there has not yet been any research on understanding Na/CO 2 reaction by leakage through IHX. For this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is studying the mechanism of CO 2 leakage and Na/CO 2 interaction in more details. The KAIST research team developed the MATLAB code, KAIST H XD, which can be used to design and evaluate performance of a heat exchanger of an S-CO 2 cycle. The size of heat exchanger and the amount of CO 2 in the cycle are calculated from the KAIST H XD code to estimate the amount of reaction products in Na/CO 2 interaction as well as liquid sodium
Li2S/Carbon Nanocomposite Strips from a Low-Temperature Conversion of Li2SO4 as High-Performance Lithium-Sulfur Cathodes

Energy Technology Data Exchange (ETDEWEB)

Ye, Fangmin; Noh, Hyungjun; Lee, Jin Hong; Lee, Hongkyung; Kim, Hee-Tak

2018-03-12

Carbothermal conversion of Li2SO4 provides a cost-effective strategy to fabricate high-capacity Li2S cathodes, however, Li2S cathodes derived from Li2SO4 at high temperatures (> 800 oC), having high crystallinity and large crystal size, result in a low utilization of Li2S. Here, we report a Li2SO4/poly(vinyl alcohol)-derived Li2S/Carbon nanocomposite (Li2S@C) strips at a record low temperature of 635 oC. These Li2S@C nanocomposite strips as a cathode shows a low initial activation potential (2.63 V), a high initial discharge capacity (805 mAh g-1 Li2S) and a high cycling stability (0.2 C and 1 C). These improvedresults could be ascribed to the nano-sized Li2S particles as well as their low crystallinity due to the PVA-induced carbon network and the low conversion temperature, respectively. An XPS analysis reveals that the C=C and C=O bonds derived from the carbonization of PVA can promote the conversion of Li2SO4 at the low temperature.
Evolution of H2O, CO, and CO2 production in Comet C/2009 P1 Garradd during the 2011-2012 apparition

Science.gov (United States)

McKay, Adam J.; Cochran, Anita L.; DiSanti, Michael A.; Villanueva, Geronimo; Russo, Neil Dello; Vervack, Ronald J.; Morgenthaler, Jeffrey P.; Harris, Walter M.; Chanover, Nancy J.

2015-04-01

We present analysis of high spectral resolution NIR spectra of CO and H2O in Comet C/2009 P1 (Garradd) taken during its 2011-2012 apparition with the CSHELL instrument on NASA's Infrared Telescope Facility (IRTF). We also present analysis of observations of atomic oxygen in Comet Garradd obtained with the ARCES echelle spectrometer mounted on the ARC 3.5-m telescope at Apache Point Observatory and the Tull Coude spectrograph on the Harlan J. Smith 2.7-m telescope at McDonald Observatory. The observations of atomic oxygen serve as a proxy for H2O and CO2. We confirm the high CO abundance in Comet Garradd and the asymmetry in the CO/H2O ratio with respect to perihelion reported by previous studies. From the oxygen observations, we infer that the CO2/H2O ratio decreased as the comet moved towards the Sun, which is expected based on current sublimation models. We also infer that the CO2/H2O ratio was higher pre-perihelion than post-perihelion. We observe evidence for the icy grain source of H2O reported by several studies pre-perihelion, and argue that this source is significantly less abundant post-perihelion. Since H2O, CO2, and CO are the primary ices in comets, they drive the activity. We use our measurements of these important volatiles in an attempt to explain the evolution of Garradd's activity over the apparition.
Simultaneous Reduction of CO 2 and Splitting of H 2 O by a Single Immobilized Cobalt Phthalocyanine Electrocatalyst

KAUST Repository

Morlanés, Natalia

2016-04-12

Perfluorinated cobalt phthalocyanine (CoFPc) immobilized on carbon electrodes was found to electrocatalyze the reduction of CO2 selectively to CO in an aqueous solution. The conversion of CO2 became apparent at -0.5 V vs RHE, and the Faradaic efficiency for the CO production reached as high as 93% at -0.8 V vs RHE. Highly stable electrolysis of CO2/H2O into CO/O2 was achieved for 12 h by applying the same catalyst as the cathode for CO2 reduction and the anode for water oxidation. This result indicates the highly robust nature of the CoFPc at wide range of potentials from -0.9 V to +2.2 V vs RHE, demonstrating the potential bipolar electrolytic system for CO2/H2O electrolysis, using the single-site molecular CoFPc-based electrocatalyst, which is simple, inexpensive, robust, and efficient. © 2016 American Chemical Society.
Effect of the Amide Bond Diamine Structure on the CO 2 , H 2 S, and CH 4 Transport Properties of a Series of Novel 6FDA-Based Polyamide–Imides for Natural Gas Purification

KAUST Repository

Vaughn, J.

2012-09-11

A series of higher permeability polyamide-imides based on 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride with comparable plasticization resistance to Torlon were synthesized and formed into dense film membranes. Polymers possessing 2,4-diamino mesitylene (DAM) were stable up to 56 atm of pure CO 2, which is due to enhanced charge transfer complex formation compared to polymers containing 4,4′- (hexafluoroisopropylidene) dianiline (6FpDA) and 2,3,5,6-tetramethyl-1,4- phenylenediamine (TmPDA). The new polymers containing DAM and TmPDA showed ideal CO 2/CH 4 selectivities of near 50 with CO 2 and H 2S permeabilities over an order of magnitude higher than Torlon. CO 2 and CH 4 sorption in the DAM- and TmPDA-based materials was reduced, whereas H 2S sorption was enhanced relative to membranes containing fluorinated 6FpDA. Consequently, DAM- and TmPDA-based membranes showed increased stability toward high pressure CO 2 but lower plasticization resistance toward pure H 2S. These results highlight the differences between CO 2 and H 2S that challenge the rational design of materials targeting simultaneous separation of both contaminants. © 2012 American Chemical Society.
The use of sulphite solutions for studying the effects of SO2 on higher plants

International Nuclear Information System (INIS)

Garsed, S.G.

1981-01-01

The effects of sulphite concentration and pH on 14 CO 2 fixation or the uptake of 35 S by needle segments of Pinus sylvestris were studied in factorial experiments. In addition, changes in the chemical composition of the sulphite solutions during the experiment were measured. Uptake of 14 CO 2 was increased and standard errors decreased by incorporating 1.0 to 10 ppm of Tween 80 into the solutions used. Inhibition of 14 CO 2 fixation by sulphite was significantly greater at low pH and high sulphite concentration, with a significant interaction. Uptake of Na 2 35 SO 3 was greater at low pH and was linear with respect to the concentration of Na 2 SO 3 carrier added between 10 -3 and 10 -4 M. In the absence of carrier, recovery of 35 S at the end of the experiment was reduced. Oxidation of the sulphite solutions was rapid at high pH and low concentration, with a significant interaction. It was also accelerated by the presence of plant material. The use of sulphite solutions to predict responses of higher plants to SO 2 is discussed. (author)
Non-Controlled Biogenic Emission of CO, H2S, NH3 and Hg0 from Lazareto's Landfill, Tenerife, Canary Islands

Science.gov (United States)

Nolasco, D.; Lima, R.; Salazar, J.; Hernández, P. A.; Pérez, N. M.

2002-12-01

Landfills are important sources of contaminant gases to the surrounding environment and a significant amount of them could be released to the atmosphere through the surface environment in a diffuse form, also known as non-controlled emission of landfill gases. CH4 and CO2 are major components in landfill gases and other gas species are only present in minor amounts. Trace compounds include both inorganic and a large number of volatile organic components. The goal of this study is to evaluate the non-controlled biogenic emission of inorganic toxic gases from Lazareto's landfill. Which is located in the city of Santa Cruz de Tenerife, with a population of about 150,000, and is used as a Palm tree park. Lazareto's landfill has an extension of 0.22 Km2 and it is not operative since 1980. A non-controlled biogenic gas emission survey of 281 sampling sites was carried out from February tod March, 2002. Surface CO2 efflux measurements were performed by means of a portable NDIR sensor according with the accumulation chamber method. Surface CO2 efflux ranged from negligible values up to 30,600 gm-2d-1. At each sampling site, surface landfill gas samples were collected at 40 cm depth using a metallic soil probe. These gas samples were analyzed within 24 hours for major and inorganic toxic gas species by means of microGC and specific electrochemical sensors. The highest concentrations of CO, H2S, NH3 and Hg0 were 3, 20, 2,227, 0.010 ppmV, respectively. Non-controlled biogenic emission rate of CO, H2S, NH3, and Hg0 were estimated by multiplying the observed surface CO2 efflux times (Inorganic Toxic Gas)i/CO2 weight ratio at each sampling site, respectively. The highest surface inorganic toxic gas efllux rates were 699 gm-2d-1 for NH3, 81, 431 and 4 mgm-2d-1 for CO, H2S and Hg0, respectively. Taking into consideration the spatial distribution of the inorganic toxic gas efflux values as well as the extension of the landfill, the non-controlled biogenic emission of CO, H2S, NH3
Surface studies of UFe2 and evaluation of its catalytic properties with a 2H2:CO mixture

International Nuclear Information System (INIS)

Schultz, J.; Naegele, J.; Spirlet, J.C.; Colmenares, C.

1987-01-01

The reactivity of UFe 2 with O 2 , CO and CO 2 were studied using x-ray photoelectron spectroscopy (XPS). Adsorption of O 2 on clean UFe 2 surfaces (Fe/U ≅ 2.0), produced by argon-ion sputtering, leads to the formation of UO 2 and depletion of Fe from the surface layer probed by XPS (Fe/U ≅ 0.8). The oxidation state of Fe in this layer, as determined by XPS (Fe 2p/sub 3/2/ = 710.4 eV), is between Fe +2 and Fe +3 of pure Fe oxides. Exposure of sputtered-clean UFe 2 to CO and CO 2 results in a slight broadening of the U 4f peaks, indicating U oxidation, and some Fe depletion in the analyzed layer (Fe/U ≅ 1.7). The O ls (530.2 and 530.4 eV for CO and CO 2 , respectively) and C ls (282.7 and 282.6 eV for CO and CO 2 , respectively) indicate that dissociative chemisorption to O and C atoms occurs. UFe 2 ground into a fine powder was tested as a catalyst in a differential high-pressure flow reactor with a 2H 2 :CO gas mixture. A significant amount of methanol and hydrocarbons are produced at 577K; while hydrocarbons are the main products (>99%) at 739K. XPS analysis of the used catalyst indicates that U is present as UO/sub 2+x/ and Fe as Fe 2 O 3
A kinetic study on the catalysis of KCl, K2SO4, and K2CO3 during oxy-biomass combustion.

Science.gov (United States)

Deng, Shuanghui; Wang, Xuebin; Zhang, Jiaye; Liu, Zihan; Mikulčić, Hrvoje; Vujanović, Milan; Tan, Houzhang; Duić, Neven

2018-07-15

Biomass combustion under the oxy-fuel conditions (Oxy-biomass combustion) is one of the approaches achieving negative CO 2 emissions. KCl, K 2 CO 3 and K 2 SO 4 , as the major potassium species in biomass ash, can catalytically affect biomass combustion. In this paper, the catalysis of the representative potassium salts on oxy-biomass combustion was studied using a thermogravimetric analyzer (TGA). Effects of potassium salt types (KCl, K 2 CO 3 and K 2 SO 4 ), loading concentrations (0, 1, 3, 5, 8 wt%), replacing N 2 by CO 2 , and O 2 concentrations (5, 20, 30 vol%) on the catalysis degree were discussed. The comparison between TG-DTG curves of biomass combustion before and after water washing in both the 20%O 2 /80%N 2 and 20%O 2 /80%CO 2 atmospheres indicates that the water-soluble minerals in biomass play a role in promoting the devolatilization and accelerating the char-oxidation; and the replacement of N 2 by CO 2 inhibits the devolatilization and char-oxidation processes during oxy-biomass combustion. In the devolatilization stage, the catalysis degree of potassium monotonously increases with the increase of potassium salt loaded concentration. The catalysis degree order of the studied potassium salts is K 2 CO 3  > KCl > K 2 SO 4 . In the char-oxidation stage, with the increase of loading concentration the three kinds of potassium salts present inconsistent change tendencies of the catalysis degree. In the studied loading concentrations from 0 to 8 wt%, there is an optimal loading concentration for KCl and K 2 CO 3 , at 3 and 5 wt%, respectively; while for K 2 SO 4 , the catalysis degree on char-oxidation monotonically increases with the loading potassium concentration. For most studied conditions, regardless of the potassium salt types or the loading concentrations or the combustion stages, the catalysis degree in the O 2 /CO 2 atmosphere is stronger than that in the O 2 /N 2 atmosphere. The catalysis degree is also affected by the O 2
Novel 2D or 3D alkaline-earth metal sulfonate-phosphonates based on [O 3S-C 2H 4-PO 3H] 2- ligand

Science.gov (United States)

Du, Zi-Yi; Wen, He-Rui; Xie, Yong-Rong

2008-11-01

Three novel alkaline-earth metal sulfonate-phosphonates based on [O 3S-C 2H 4-PO 3H] 2- ligand, namely, [Ca(O 3SC 2H 4PO 3H)(H 2O) 2] ( 1), [Sr(O 3SC 2H 4PO 3H)] ( 2) and [Ba 2(O 3SC 2H 4PO 3H) 2] ( 3), have been synthesized by hydrothermal reactions. They represent the first structurally characterized alkaline-earth metal complexes of phosphonic acid attached with a sulfonate group. The structure of compound 1 features a 2D layer based on 1D chains of [Ca 2(PO 3) 2] bridged by -CH 2-CH 2-SO 3- groups. Compounds 2 and 3 show pillar-layer architecture based on two different inorganic layers linked by -CH 2-CH 2- groups. The inorganic layer in compound 2 features a 1D chain of edge-sharing SrO 8 polyhedra whereas that in compound 3 features an edge-sharing Ba 2O 14 di-polyhedral unit which is further corner-shared with four neighboring ones. The [O 3S-C 2H 4-PO 3H] 2- ligand shows diverse coordination modes in the three alkaline-earth metal sulfonate-phosphonates.

Hydrothermal Valorization of Steel Slags—Part I: Coupled H2 Production and CO2 Mineral Sequestration

Directory of Open Access Journals (Sweden)

Camille Crouzet

2017-10-01

Full Text Available A new process route for the valorization of BOF steel slags combining H2 production and CO2 mineral sequestration is investigated at 300°C (HT under hydrothermal conditions. A BOF steel slag stored several weeks outdoor on the production site was used as starting material. To serve as a reference, room temperature (RT carbonation of the same BOF steel slag has been monitored with in situ Raman spectroscopy and by measuring pH and PCO2 on a time-resolved basis. CO2 uptake under RT and HT are, respectively, 243 and 327 kg CO2/t of fresh steel slag, which add up with the 63 kg of atmospheric CO2 per ton already uptaken by the starting steel slag on the storage site. The CO2 gained by the sample at HT is bounded to the carbonation of brownmillerite. H2 yield decreased by about 30% in comparison to the same experiment performed without added CO2, due to sequestration of ferrous iron in a Mg-rich siderite phase. Ferric iron, initially present in brownmillerite, is partitioned between an Fe-rich clay mineral of saponite type and metastable hematite. Saponite is likely stabilized by the presence of Al, whereas hematite may represent a metastable product of brownmillerite carbonation. Mg-rich wüstite is involved in at least two competing reactions, i.e., oxidation into magnetite and carbonation into siderite. Results of both water-slag and water-CO2-slag experiments after 72 h are consistent with a kinetics enhancement of the former reaction when a CO2 partial pressure imposes a pH between 5 and 6. Three possible valorization routes, (1 RT carbonation prior to hydrothermal oxidation, (2 RT carbonation after hydrothermal treatment, and (3 combined HT carbonation and oxidation are discussed in light of the present results and literature data.
Studies on the relationship between Pitzer's equation and medium effect: the system of HCl + H{sub 2}SO{sub 4} in {l_brace}0.06455C{sub 2}H{sub 5}OH + 0.93545H{sub 2}O{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Lu Xingmei E-mail: lxmqt@sohu.com; Xu Weiguo; Chang Xiaohong; Lu Dianzhen; Yang Jiazhen

2004-03-01

The second ionization constant of sulfuric acid in mixed solvent, K{sub 2}, was determined by e.m.f. of cell without liquid junction: (Pt,H{sub 2}(101.325 kPa) vertical bar HCl(m{sub 1}),H{sub 2}SO{sub 4}(m{sub 2}),{l_brace}ethanol(x=0.06455)+water(x=0.93545){r_brace} vertical bar AgCl-Ag))over the temperatures (278.15 to 318.15) K, where x is mole fraction. Combining Owen's definition of medium effect with Pitzer's equations, the values of combination parameters: ({lambda}{sub nHS}+{lambda}{sub nCl}-{lambda}{sub nS})+(3/2)m{sub n}({mu}{sub nnHS}+{mu}{sub nnC=} l-{mu}{sub nnS}),(1/2)({xi}{sub nHHS}+{xi}{sub nHCl}-{xi}{sub nHS}), that represent the interactions between ions and ethanol were obtained at 298.15 K.
Sustainable hydrocarbon fuels by recycling CO2 and H2O with renewable or nuclear energy

DEFF Research Database (Denmark)

Graves, Christopher R.; Ebbesen, Sune; Mogensen, Mogens Bjerg

2011-01-01

) and biofuels have received the most attention, similar hydrocarbons can be produced without using fossil fuels or biomass. Using renewable and/or nuclear energy, carbon dioxide and water can be recycled into liquid hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse...... of fuel combustion). Capture of CO2 from the atmosphere would enable a closed-loop carbon-neutral fuel cycle. This article critically reviews the many possible technological pathways for recycling CO2 into fuels using renewable or nuclear energy, considering three stages—CO2 capture, H2O and CO2...... by Fischer–Tropsch synthesis is identified as one of the most promising, feasible routes. An analysis of the energy balance and economics of this CO2 recycling process is presented. We estimate that the full system can feasibly operate at 70% electricity-to-liquid fuel efficiency (higher heating value basis...
Enhancement of CO Evolution by Modification of Ga2O3 with Rare-Earth Elements for the Photocatalytic Conversion of CO2 by H2O.

Science.gov (United States)

Tatsumi, Hiroyuki; Teramura, Kentaro; Huang, Zeai; Wang, Zheng; Asakura, Hiroyuki; Hosokawa, Saburo; Tanaka, Tsunehiro

2017-12-12

Modification of the surface of Ga 2 O 3 with rare-earth elements enhanced the evolution of CO as a reduction product in the photocatalytic conversion of CO 2 using H 2 O as an electron donor under UV irradiation in aqueous NaHCO 3 as a pH buffer, with the rare-earth species functioning as a CO 2 capture and storage material. Isotope experiments using 13 CO 2 as a substrate clearly revealed that CO was generated from the introduced gaseous CO 2 . In the presence of the NaHCO 3 additive, the rare-earth (RE) species on the Ga 2 O 3 surface are transformed into carbonate hydrates (RE 2 (CO 3 ) 3 ·nH 2 O) and/or hydroxycarbonates (RE 2 (OH) 2(3-x) (CO 3 ) x ) which are decomposed upon photoirradiation. Consequently, Ag-loaded Yb-modified Ga 2 O 3 exhibits much higher activity (209 μmol h -1 of CO) than the pristine Ag-loaded Ga 2 O 3 . The further modification of the surface of the Yb-modified Ga 2 O 3 with Zn afforded a selectivity toward CO evolution of 80%. Thus, we successfully achieved an efficient Ag-loaded Yb- and Zn-modified Ga 2 O 3 photocatalyst with high activity and controllable selectivity, suitable for use in artificial photosynthesis.
Co3(PO42·4H2O

Directory of Open Access Journals (Sweden)

Yang Kim

2008-10-01

Full Text Available Single crystals of Co3(PO42·4H2O, tricobalt(II bis[orthophosphate(V] tetrahydrate, were obtained under hydrothermal conditions. The title compound is isotypic with its zinc analogue Zn3(PO42·4H2O (mineral name hopeite and contains two independent Co2+ cations. One Co2+ cation exhibits a slightly distorted tetrahedral coordination, while the second, located on a mirror plane, has a distorted octahedral coordination environment. The tetrahedrally coordinated Co2+ is bonded to four O atoms of four PO43− anions, whereas the six-coordinate Co2+ is cis-bonded to two phosphate groups and to four O atoms of four water molecules (two of which are located on mirror planes, forming a framework structure. In addition, hydrogen bonds of the type O—H...O are present throughout the crystal structure.
New family of lanthanide-based inorganic-organic hybrid frameworks: Ln2(OH)4[O3S(CH2)nSO3]·2H2O (Ln = La, Ce, Pr, Nd, Sm; n = 3, 4) and their derivatives.

Science.gov (United States)

Liang, Jianbo; Ma, Renzhi; Ebina, Yasuo; Geng, Fengxia; Sasaki, Takayoshi

2013-02-18

We report the synthesis and structure characterization of a new family of lanthanide-based inorganic-organic hybrid frameworks, Ln(2)(OH)(4)[O(3)S(CH(2))(n)SO(3)]·2H(2)O (Ln = La, Ce, Pr, Nd, Sm; n = 3, 4), and their oxide derivatives. Highly crystallized samples were synthesized by homogeneous precipitation of Ln(3+) ions from a solution containing α,ω-organodisulfonate salts promoted by slow hydrolysis of hexamethylenetetramine. The crystal structure solved from powder X-ray diffraction data revealed that this material comprises two-dimensional cationic lanthanide hydroxide {[Ln(OH)(2)(H(2)O)](+)}(∞) layers, which are cross-linked by α,ω-organodisulfonate ligands into a three-dimensional pillared framework. This hybrid framework can be regarded as a derivative of UCl(3)-type Ln(OH)(3) involving penetration of organic chains into two {LnO(9)} polyhedra. Substitutional modification of the lanthanide coordination promotes a 2D arrangement of the {LnO(9)} polyhedra. A new hybrid oxide, Ln(2)O(2)[O(3)S(CH(2))(n)SO(3)], which is supposed to consist of alternating {[Ln(2)O(2)](2+)}(∞) layers and α,ω-organodisulfonate ligands, can be derived from the hydroxide form upon dehydration/dehydroxylation. These hybrid frameworks provide new opportunities to engineer the interlayer chemistry of layered structures and achieve advanced functionalities coupled with the advantages of lanthanide elements.
Dispersion capacitive de l'interface H 2 SO 4 /Pt | Hammadi ...

African Journals Online (AJOL)

Capacitive dispersion of Pt/H2SO4 interface. Impedance measurements by EIS and voltammograms measurements by CV on pretreated Pt electrodes immersed in an electrolytic solution of 0.5M H2SO4 are presented. Two electrochemical pretreatment techniques of the WE (thin Pt wire) are used: cleaning and etching.
H2S mediated thermal and photochemical methane activation

Science.gov (United States)

Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric

2013-01-01

Sustainable, low temperature methods of natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) in mixture with methane, CH4, altogether deemed as sub-quality or “sour” gas. We propose a unique method for activating this “sour” gas to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3, and an energy carrier, such as H2. For this purpose, we computationally investigated H2S mediated methane activation to form a reactive CH3SH species via direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4+H2S complex results in a barrier-less relaxation via a conical intersection to form a ground state CH3SH+H2 complex. The resulting CH3SH can further be heterogeneously coupled over acidic catalysts to form higher hydrocarbons while the H2 can be used as a fuel. This process is very different from a conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced controllability over the process conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the currently industrially used methane steam reforming (SMR). PMID:24150813
FTIR imaging in diffusion studies: CO2 and H2O in a synthetic sector-zoned beryl

Directory of Open Access Journals (Sweden)

Giancarlo eDella Ventura

2015-06-01

Full Text Available In this work we investigate the strongly inhomogeneous distribution of CO2 and H2O in a synthetic beryl having a peculiar hourglass zoning of Cr due to the crystal growth. The sample was treated at 800°C, 500 MPa, in a CO2-rich atmosphere. High-resolution FESEM images revealed that the hourglass boundary is not correlated to physical discontinuities, at least at the scale of tens of nanometers. Polarized FPA-FTIR imaging, on the other side, revealed that the chemical zoning acts as a fast pathway for carbon dioxide diffusion, a feature never observed so far in minerals. The hourglass zone boundary may be thus considered as a structural defect possibly due to the mismatch induced by the different growth rates of each sector. High-resolution synchrotron-light FTIR imaging, in addition, also allows enhancement of CO2 diffusion along the hourglass boundary to be distinguished from diffusion along fractures in the grain. Therefore, FTIR imaging provides evidence that different diffusion mechanisms may locally combine, suggesting that the distribution of the target molecules needs to be be carefully characterized in experimental studies. This piece of information is mandatory when the study is aimed at extracting diffusion coefficients from analytical profiles. Combination of TOF-SIMS and FPA data shows a significant depletion of type II H2O along the hourglass boundary, indicating that water diffusion could be controlled by the distribution of alkali cations within channels, coupled to a plug effect of CO2.
A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

Science.gov (United States)

Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

2017-08-02

In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.
Hollow mesoporous CuCo2O4 microspheres derived from metal organic framework: A novel functional materials for simultaneous H2O2 biosensing and glucose biofuel cell.

Science.gov (United States)

Cui, Shiqiang; Gu, Shuqing; Ding, Yaping; Zhang, Jiangjiang; Zhang, Zhen; Hu, Zongqian

2018-02-01

Hollow mesoporous CuCo 2 O 4 (meso-CuCo 2 O 4 ) microspheres were successfully synthesized by decomposing metal-organic frameworks (MOFs) as the template. The as-prepared CuCo 2 O 4 microspheres were first simultaneously used for H 2 O 2 biosensing and glucose biofuel cell (GFC) as the enzyme mimic. The resulting of meso-CuCo 2 O 4 displayed not only excellent catalytic performances to H 2 O 2 including a super-fast response time (within 2s), a super-high sensitivity (654.23 μA mM -1 cm -2 ) and a super-low detection limit (3nM at S/N = 3) on the sensor, but also great values in GFC as anode material with an open circuit voltage of 0.85V, a maximum power density of 0.33 mWcm -2 and a limiting current density of 1.27 mAcm -2 , respectively. The preeminent catalytic abilities to H 2 O 2 and glucose may be attributed to the surpassing intrinsic catalytic activity of CuCo 2 O 4 and large specific area of mesoporous structure. These significant findings deriving from this work not only provided a novel exploration for the fabrication of hollow spherical mesoporous bimetallic oxides, but also promoted the development of the supersensitive detection of H 2 O 2 and non-enzymatic biofuel cell. Copyright © 2017. Published by Elsevier B.V.
Synthesis of new dithiacobaltaborane clusters derived from arachno-6,8-S2B7H9

International Nuclear Information System (INIS)

Kang, S.O.; Sneddon, L.G.

1988-01-01

A series of air-stable dithiacobaltaborane clusters has been isolated from either the reaction of the arachno-S 2 B 7 H 8 - anion with cobalt chloride and pentamethylcyclopentadienide or the reaction of neutral arachno-6,8-S 2 B 7 H 9 with cobalt atoms and pentamethylcyclopentadiene. Thus, the reaction of arachno-S 2 B 7 H 8 - with CoCl 2 and C 5 (CH 3 ) 5 - in THF gave, as the major products, the triple-decker compound nido-4,6-η-C 5 (CH 3 ) 52 Co 2 -3,5-S 2 B 2 H 2 (I) and the 11-vertex cluster nido-8,10(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (III). Also isolated in smaller amounts were a chloride derivative of I, nido-1-Cl-4,6-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -3,5-S 2 B 2 H (II), two isomers of III, nido-3,10-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (IV) and nido-3,5-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (V), and the eight-boron cluster nido-8-(η-C 5 (CH 3 ) 5 )Co-7,9-S 2 B 8 H 8 (VI). Other trace products of the reaction included the six-boron clusters nido-5,8-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -6,9-S 2 B 6 H 6 (VII) and arachno-7-(η-C 5 (CH 3 ) 5 )Co-6,8-S 2 B 6 H 8 (VIII). Compound III was found to isomerize at 250 degree C to IV, which could then be converted to V at 300 degree C. The reaction of cobalt atoms with arachno-6,8-S 2 B 7 H 9 in the presence of pentamethylcyclopentadiene gave VIII as the major product; however, a number of other clusters including I, V, VI, and [(η-C 5 (CH 3 ) 5 ) 2 Co] + [(SB 10 H 10 ) 2 Co] - were isolated in trace amounts. 16 references, 6 figures, 3 tables
Improved method to determine the molar volume and compositions of the NaCl-H2O-CO2 system inclusion

Institute of Scientific and Technical Information of China (English)

2007-01-01

On the basis of Parry’s method (1986), an improved method was established to determine the molar volume (Vm) and compositions (X) of the NaCl-H2O-CO2 (NHC) system inclusion. To use this method, the determination of Vm-X only requires three microthermometric data of a NHC inclusion: partial homog-enization temperature (Th ,CO2), salinity (S) and total homogenization temperature (Th). Theoretically, four associated equations are needed containing four unknown parameters: X CO2, XNaCl, Vm and F (volume fraction of CO2 phase in total inclusion when occurring partial homogenization). When they are released, the Vm-X are determined. The former three equations, only correlated with Th ,CO2, S and F, have simplified expressions:XCO2=f1(Th,CO2,S,F),XNaCl=f2(Th,CO2,S,F),Vm=f3(Th,CO2,S,F). The last one is the thermodynamic relationship of X CO2, XNaCl, Vm and Th:f4(XCO2,XNaCl,Vm,Th)=0.Since the above four associated equations are complicated, it is necessary to adopt iterative technique to release them. The technique can be described by:(i) Freely input a F value (0≤F≤1),with Th ,CO2 and S, into the former three equations. As a result,X CO 2,XNaCl and the molar volume value recorded as Vm1 are derived. (ii) Input the X CO2 and XNaCl gotten in the step above into the last equation, and another molar volume value recorded as Vm2 is determined. (iii) If Vm1 is unequal to Vm2, the calculation will be restarted from “(i)”. The iteration is completed until Vm1 is equal to Vm2, which means that the four associated equations are released. Compared to Parry’s (1986) solution method, the improved method is more convenient to use, as well as more accurate to determine X CO 2. It is available for a NHC inlusion whose partial homogenization temperature is higher than clatherate melting temperature and there are no solid salt crystals in the inclusion at parital homogenization.
Double C-H activation of ethane by metal-free SO2*+ radical cations.

Science.gov (United States)

de Petris, Giulia; Cartoni, Antonella; Troiani, Anna; Barone, Vincenzo; Cimino, Paola; Angelini, Giancarlo; Ursini, Ornella

2010-06-01

The room-temperature C-H activation of ethane by metal-free SO(2)(*+) radical cations has been investigated under different pressure regimes by mass spectrometric techniques. The major reaction channel is the conversion of ethane to ethylene accompanied by the formation of H(2)SO(2)(*+), the radical cation of sulfoxylic acid. The mechanism of the double C-H activation, in the absence of the single activation product HSO(2)(+), is elucidated by kinetic studies and quantum chemical calculations. Under near single-collision conditions the reaction occurs with rate constant k=1.0 x 10(-9) (+/-30%) cm(3) s(-1) molecule(-1), efficiency=90%, kinetic isotope effect k(H)/k(D)=1.1, and partial H/D scrambling. The theoretical analysis shows that the interaction of SO(2)(*+) with ethane through an oxygen atom directly leads to the C-H activation intermediate. The interaction through sulfur leads to an encounter complex that rapidly converts to the same intermediate. The double C-H activation occurs by a reaction path that lies below the reactants and involves intermediates separated by very low energy barriers, which include a complex of the ethyl cation suitable to undergo H/D scrambling. Key issues in the observed reactivity are electron-transfer processes, in which a crucial role is played by geometrical constraints. The work shows how mechanistic details disclosed by the reactions of metal-free electrophiles may contribute to the current understanding of the C-H activation of ethane.
A feasible process for simultaneous removal of CO2, SO2 and NOx in the cement industry by NH3 scrubbing

International Nuclear Information System (INIS)

Dong, Ruifeng; Lu, Hongfang; Yu, Yunsong; Zhang, Zaoxiao

2012-01-01

Highlights: ► Simultaneous removal of CO 2 , SO 2 and NO x is realized by NH 3 scrubbing with NaClO 2 . ► The crystallization process of NH 4 HCO 3 is employed instead of CO 2 regeneration. ► Energy consumption reduces hugely while CO 2 removal rate remains higher than 90%. ► Exergy calculation reveals that a higher thermodynamic perfection degree is achieved. -- Abstract: With the rapid economic and industrial development, the concentration of carbon dioxide in the atmosphere is increasing enormously, which has greatly affected the global climate and human living environment. At present, a lot of technologies have been applied to CO 2 removal in fossil fuel-fired power plants, which are one of the main CO 2 emission sources. But few researches have been done in the cement industry, which is the third largest CO 2 emission source. There is no mature technology of CO 2 removal in cement industry mentioned before. This paper proposes a feasible process for simultaneous removal of CO 2 , SO 2 and NO x in the cement industry by NH 3 scrubbing. As there is no ready steam source for the regeneration of CO 2 -rich loading solvent after absorption, a process with the final product of ammonium bicarbonate is developed. With the oxidative additive of NaClO 2 added in the aqueous ammonium absorbent, the simultaneous removal of CO 2 , SO 2 and NO x is feasible by NH 3 scrubbing. The products of the process are mainly ammonium bicarbonate, ammonium sulfate and ammonium nitrate, which are all good fertilizers for crops and plants. The crystallization of NH 4 HCO 3 is easier for storage and transportation than that for liquid carbon dioxide, which becomes more stable when dicyandiamide (DCD) is added. The thermodynamic analysis proves that the proposed process has the advantages of energy conservation and high thermodynamic perfection degree compared with the traditional ones.
Photocatalytic degradation of vegetable oil floating on water by CoPcS/TiO2/beads and TiO2/beads%CoPcS/TiO2/beads及TiO2/beads光催化降解水面漂浮植物油

Institute of Scientific and Technical Information of China (English)

张晓叶; 闫永胜; 孔峰; 王赟

2007-01-01

以钛酸四丁酯为原料,以空心玻璃微珠为载体,采用溶胶-凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads光催化剂.研究了TiO2/beads及CoPcS/TiO2/beads光催化降解水面漂浮植物油的最优条件.结果表明,酸性或中性条件下,375 W中压汞灯照射2～3 h,TiO2/beads与CoPcS/TiO2/beads的投加量分别为3 g与1 g时,植物油的去除率达90%以上,投加微量的H2O2,可大大提高两者的光催化去除率.
Hard target LIDAR calibration for SO2

CSIR Research Space (South Africa)

Du Plessis, A

2006-01-01

Full Text Available calibration for SO2 A du Plessis, DE Roberts CSIR National Laser Centre, Pretoria Slide 2 © CSIR 2006 www.csir.co.za Project background • Las-R-MAP: Laser – Remote – Measurement of Atmospheric Pollutants • Mobile laser system....csir.co.za Hard target backscatter ∫ = − R dRRn p e R RcE RS 0 )(2 2 )()( λσ λ β S R Slide 10 © CSIR 2006 www.csir.co.za Las-R-MAP hardware: laser system Slide 11 © CSIR 2006 www.csir.co.za Las-R...
C-A-S-H synthesis and thermodynamics modelling in CaO-Al2O3-SiO2-H2O system

International Nuclear Information System (INIS)

Haas, J.; Pochard, I.; Nonat, A.

2015-01-01

Ordinary Portland cement (OPC) is being increasingly replaced by blended cements, where part of the clinker is replaced by secondary cementitious materials (SCM) such as blast furnace or fly ash. The use of SCM enables to achieve various aims as the cost reduction by recovery of by-products, the CO 2 emission reduction, the obtaining of specific properties as low pH. So, blended cements are more and more current in different fields as civil engineering and nuclear waste repository. The use of silica and/or aluminium rich SCMs directly impacts the amount and the kind of hydrates formed, hence the volume and the porosity and finally the durability of these materials. Aluminates containing hydrates formation is not well understood. Al content can result from Al-uptake in C-S-H due to Al-substitution of Si-tetrahedra to well crystallised hydrates like straetlingite or katoite phases. This study proposes a surface dependant thermodynamic model to predict and to correlate the Al-uptake (substitution) of C-A-S-H with solutions representative of that of cement pores chemistry. For this purpose, pure C-A-S-H alkali-free were synthesized in diluted suspensions. On one hand, hydrates and their solutions were characterized at equilibrium. On the other hand, thermodynamics modelling were performed from these collected data to describe C-A-S-H in the equilibrium solutions. These results allowed evaluating the Al-availability in the cementitious system and especially for aluminates containing hydrates precipitation. (authors)
Synthesis, characterization and thermal decomposition of [Pd2 (C2-dmba (µ-SO4 (SO22

Directory of Open Access Journals (Sweden)

Caires Antonio Carlos Fávero

1998-01-01

Full Text Available The bridged sulphate complex [Pd2 (C²,dmba (µ-SO4 (SO22] has been obtained by reacting a saturated solution of SO2 in methanol and the cyclometallated compound [Pd(C²,N-dmba(µ-N3] 2; (dmba = N,N-dimethylbenzylamine, at room temperature for 24 h. Reaction product was characterized by elemental analysis, NMR comprising 13C{¹H} and ¹H nuclei and I.R. spectrum's measurements. Thermal behavior has been investigated and residual products identified by X-ray powder diffraction.
Are CO Observations of Interstellar Clouds Tracing the H2?

Science.gov (United States)

Federrath, Christoph; Glover, S. C. O.; Klessen, R. S.; Mac Low, M.

2010-01-01

Interstellar clouds are commonly observed through the emission of rotational transitions from carbon monoxide (CO). However, the abundance ratio of CO to molecular hydrogen (H2), which is the most abundant molecule in molecular clouds is only about 10-4. This raises the important question of whether the observed CO emission is actually tracing the bulk of the gas in these clouds, and whether it can be used to derive quantities like the total mass of the cloud, the gas density distribution function, the fractal dimension, and the velocity dispersion--size relation. To evaluate the usability and accuracy of CO as a tracer for H2 gas, we generate synthetic observations of hydrodynamical models that include a detailed chemical network to follow the formation and photo-dissociation of H2 and CO. These three-dimensional models of turbulent interstellar cloud formation self-consistently follow the coupled thermal, dynamical and chemical evolution of 32 species, with a particular focus on H2 and CO (Glover et al. 2009). We find that CO primarily traces the dense gas in the clouds, however, with a significant scatter due to turbulent mixing and self-shielding of H2 and CO. The H2 probability distribution function (PDF) is well-described by a log-normal distribution. In contrast, the CO column density PDF has a strongly non-Gaussian low-density wing, not at all consistent with a log-normal distribution. Centroid velocity statistics show that CO is more intermittent than H2, leading to an overestimate of the velocity scaling exponent in the velocity dispersion--size relation. With our systematic comparison of H2 and CO data from the numerical models, we hope to provide a statistical formula to correct for the bias of CO observations. CF acknowledges financial support from a Kade Fellowship of the American Museum of Natural History.

Detailed H2 and CO Electrochemistry for a MEA Model Fueled by Syngas

KAUST Repository

Lee, W. Y.

2015-07-17

© The Electrochemical Society. SOFCs can directly oxidize CO in addition to H2, which allows them to be coupled to a gasifier. Many membrane-electrode-assembly (MEA) models neglect CO electrochemistry due to sluggish kinetics and the water-gas-shift reaction, but CO oxidation may be important for high CO-content syngas. The 1D-MEA model presented here incorporates detailed mechanisms for both H2 and CO oxidation, individually fitted to experimental data. These mechanisms are then combined into a single model, which provides a good fit to experimental data for H2/CO mixtures. Furthermore, the model fits H2/CO data best when a single chargetransfer step in the H2 mechanism is assumed to be rate-limiting for all current densities. This differs from the result for H2/H2O mixtures, where H2 adsorption becomes rate-limiting at high current densities. These results indicate that CO oxidation cannot be neglected in MEA models running on CO-rich syngas, and that CO oxidation can alter the H2 oxidation mechanism.
Diversity of H2/CO2-utilizing acetogenic bacteria from feces of non-methane-producing humans.

Science.gov (United States)

Bernalier, A; Rochet, V; Leclerc, M; Doré, J; Pochart, P

1996-08-01

The purpose of this work was to study H2/CO2-utilizing acetogenic population in the colons of non-methane-producing individuals harboring low numbers of methanogenic archaea. Among the 50 H2-consuming acetogenic strains isolated from four fecal samples and an in vitro semi-continuous culture enrichment, with H2/CO2 as sole energy source, 20 were chosen for further studies. All isolates were Gram-positive strict anaerobes. Different morphological types were identified, providing evidence of generic diversity. All acetogenic strains characterized used H2/CO2 to form acetate as the sole metabolite, following the stoichiometric equation of reductive acetogenesis. These bacteria were also able to use a variety of organic compounds for growth. The major end product of glucose fermentation was acetate, except for strains of cocci that mainly produced lactate. Yeast extract was not necessary, but was stimulatory for growth and acetogenesis from H2/CO2.
Advances in Geological CO{sub 2} Sequestration and Co-Sequestration with O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Verba, Circe A; O& #x27; Connor, William K.; Ideker, J.H.

2012-10-28

The injection of CO{sub 2} for Enhanced Oil Recovery (EOR) and sequestration in brine-bearing formations for long term storage has been in practice or under investigation in many locations globally. This study focused on the assessment of cement wellbore seal integrity in CO{sub 2}- and CO{sub 2}-O{sub 2}-saturated brine and supercritical CO{sub 2} environments. Brine chemistries (NaCl, MgCl{sub 2}, CaCl{sub 2}) at various saline concentrations were investigated at a pressure of 28.9 MPa (4200 psi) at both 50{degree}C and 85{degree}C. These parameters were selected to simulate downhole conditions at several potential CO{sub 2} injection sites in the United States. Class H portland cement is not thermodynamically stable under these conditions and the formation of carbonic acid degrades the cement. Dissociation occurs and leaches cations, forming a CaCO{sub 3} buffered zone, amorphous silica, and other secondary minerals. Increased temperature affected the structure of C-S-H and the hydration of the cement leading to higher degradation rates.
High-temperature removal of H2S from syngas by means of zinc-contaminated soils

International Nuclear Information System (INIS)

Tzu-Hsing Ko; Hsin-Ta Hsueh

2006-01-01

Hydrogen sulfide (H 2 S) is one of the most common compounds and can be easily found in advanced power generation plants, such as integrated gasification combined cycle (IGCC) and molten-carbonate fuel cell (MCFC) plants. Generally, in these systems raw materials with high heating value (HHV) or biomass were gasified under high temperature and produced a useful mixture gas. During the gasification, hydrogen sulfide accompanies with a great quantity of reductive gases at high temperature including CO, H 2 , CH 4 and N 2 , etc. This mixture gas is so-call syngas. Syngas is a valuable resource for electric power generation. Prior to using, H 2 S needs to be removed because its harmful effect. In addition, H 2 S is not only the malodorous and corrosive gas but also is the sources of the acid rain when it is oxidized into SO 2 and reacted with water. It has been known for many years that certain soils have the ability to absorb reductive sulfur-containing species such as hydrogen sulfide (H 2 S), carbonyl sulfide (COS), carbon disulfide (CS 2 ), dimethyl sulfide (CH 3 SCH 3 ) and dimethyl disulfide (CH 3 SSCH 3 ) at room temperature. Therefore, soils could act as an important sorption media for the removal of waste gases before they are released into the atmosphere. In this study, we further use the contaminated soils as regenerable sorbent for the removal of H 2 S from syngas under high temperature. Results indicate that contaminated soils could be used to remove H 2 S as well as maintain at least 90% regeneration efficiency after regeneration cycles. Additionally, zinc and iron appeared to be the major active species to react with H 2 S. The chemical structure of zinc and iron after removal of H 2 S could be expressed as ZnS and FeS. In addition to removal of H 2 S, it is also established that contaminated soil can be used for application which reduce the problem of heavy metal contaminated soils (Full text of contribution)
Investigating the effect of graphene nanoplatelets on the thermal conductivity of KAl(SO4)2 · 12H2O

Science.gov (United States)

Sun, Mingjie; Liu, Liqiang; Ma, Fukun; Jing, Min; Cui, Kaixuan; Lin, Liangkan

2018-04-01

This article, taking phase change material (PCM) aluminum potassium sulfate dodecahydrate (KAl(SO4)2 · 12H2O) as the object of study, researches the effects of graphene nanoplatelets (GN) on the thermal conductivity of KAl(SO4)2 · 12H2O. Correlated analysis shows that KAl(SO4)2 · 12H2O can be combined with GN to form KAl(SO4)2 · 12H2O/GN composites. The thermal conductivity of KAl(SO4)2 · 12H2O/GN composites improves significantly with the increase of GN contents. When the content of GN up to 2.5 wt%, the thermal conductivity of the composites is 1.311 W/m · k, increasing by 120% compared with the pure KAl(SO4)2 · 12H2O, the thermal storage time reduces by 31.9%. Meanwhile, GN can improve the undercooling of KAl(SO4)2 · 12H2O. When the content of GN is 2.5 wt%, the minimum undercooling is 31.1 °C, reducing by 28.5% compared with the pure KAl(SO4)2 · 12H2O. X-ray diffractometry (XRD) analysis shows that the crystal structure of KAl(SO4)2 · 12H2O is basically unchanged with the composite of GN after circulation. In general, GN have a great effect on improving the thermal conductivity of KAl(SO4)2 · 12H2O and have a good application prospect in the field of phase change thermal storage.
Molecular structures and excited states of CpM(CO)(2) (Cp = eta(5)-C(5)H(5); M = Rh, Ir) and [Cl(2)Rh(CO)(2)](-). Theoretical evidence for a competitive charge transfer mechanism.

Science.gov (United States)

Hu, Zhenming; Boyd, Russell J; Nakatsuji, Hiroshi

2002-03-20

Molecular structures and excited states of CpM(CO)(2) (Cp = eta(5)-C(5)H(5); M = Rh, Ir) and [Cl(2)Rh(CO)(2)](-) complexes have been investigated using the B3LYP and the symmetry-adapted cluster (SAC)/SAC-configuration interaction (SAC-CI) theoretical methods. All the dicarbonyl complexes have singlet ground electronic states with large singlet-triplet separations. Thermal dissociations of CO from the parent dicarbonyls are energetically unfavorable. CO thermal dissociation is an activation process for [Cl(2)Rh(CO)(2)](-) while it is a repulsive potential for CpM(CO)(2). The natures of the main excited states of CpM(CO)(2) and [Cl(2)Rh(CO)(2)](-) are found to be quite different. For [Cl(2)Rh(CO)(2)](-), all the strong transitions are identified to be metal to ligand CO charge transfer (MLCT) excitations. A significant feature of the excited states of CpM(CO)(2) is that both MLCT excitation and a ligand Cp to metal and CO charge transfer excitation are strongly mixed in the higher energy states with the latter having the largest oscillator strength. A competitive charge transfer excited state has therefore been identified theoretically for CpRh(CO)(2) and CpIr(CO)(2). The wavelength dependence of the quantum efficiencies for the photoreactions of CpM(CO)(2) reported by Lees et al. can be explained by the existence of two different types of excited states. The origin of the low quantum efficiencies for the C-H/S-H bond activations of CpM(CO)(2) can be attributed to the smaller proportion of the MLCT excitation in the higher energy states.
Experimental determination and modeling of the solubility phase diagram of the ternary system (Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O) at 288.15 K

Energy Technology Data Exchange (ETDEWEB)

Wang, Shiqiang, E-mail: wangshiqiang@tust.edu.cn [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Guo, Yafei [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Li, Dongchan [Engineering Research Center of Seawater Utilization Technology of Ministry of Education, Hebei University of Technology, Tianjin 300130 (China); Tang, Peng; Deng, Tianlong [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China)

2015-02-10

Highlights: • Solubility of the ternary system Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O at 288.15 K has been measured. • Phase diagram of this system was simulated and calculated by a thermodynamic model. • Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4} belongs to the incongruent double salt in this system. • Solution density was calculated using empirical equation. - Abstract: The solubility and density in the thermodynamic phase equilibria ternary system (Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O) at 288.15 K and 0.1 MPa were investigated experimentally with the method of isothermal dissolution equilibrium. This system at 288.15 K consists of two invariant points, three univariant isothermal dissolution curves; and three crystallization regions. The salt Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4} belongs to the incongruent double salt, and no solid solution was found. Based on the Pitzer model and its extended Harvie–Weare (HW) model, the mixing ion-interaction parameters of θ{sub Li,K}, ψ{sub Li,K,SO4} at 288.15 K and the solubility equilibrium constants K{sub sp} of solid phases Li{sub 2}SO{sub 4}·H{sub 2}O and Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4}, which are not reported in the literature were acquired. A comparison between the calculated and experimental results at 288.15 K for the ternary system shows that the calculated solubilities obtained with the extended HW model agree well with experimental data.
Hydrogen-bonded Three-Dimensional Networks Encapsulating One-dimensional Covalent Chains: [Cu(3-ampy)(H2O)4](SO4)·(H2O) (3-ampy = 3-Aminopyridine)

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

A three-dimensional complex [Cu(3-ampy)(H2O)4](SO4)·(H2O) (3-ampy = 3-aminopyridine) has been synthesized. Crystallographic data: C5H16CuN2O9S, Mr = 343.80, triclinic, space group P, a = 7.675(2), b = 8.225(3), c = 10.845(3) (A), α= 86.996(4), β = 76.292(4),γ = 68.890(4)°, V = 620.0(3) (A)3, Z = 2, Dc = 1.841 g/cm3, F(000) = 354 and μ = 1.971 mm-1. The structure was refined to R = 0.0269 and wR = 0.0659 for 1838 observed reflections (I ＞ 2σ(Ⅰ)). The structure consists of [Cu(3-ampy)(H2O)4]2+ cations, SO42- anions and lattice water molecules. 3-Ampy acting as a bidentate bridging ligand generates a 1D covalent chain. A supramolecular 2D framework is formed through π-π stacking of pyridine rings. The lattice water molecules and SO42- anions are located between the adjacent 2D frameworks. The hydrogen bonding interactions from lattice water molecules and SO42- anions to coordinate water extend the 2D framework into a 3D network.
Photoexcitation, photoionization and photofragmentation studies on Pyrosulfuryl chloride, (ClSO{sub 2}){sub 2}O, between 12 and 300 eV

Energy Technology Data Exchange (ETDEWEB)

Betancourt, Angelica Moreno; Romano, Rosana M.; Erben, Mauricio F.; Gerones, Mariana; Berrueta Martinez, Y.; Rodriguez Pirani, Lucas; Della Vedova, Carlos O. [Universidad Nacional de La Plata, La PLata B.A. (Argentina); Cavasso Filho, R.L. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

2012-07-01

Full text: Recent investigations in our research group have been dedicated to the elucidation of photochemical reaction mechanisms between small molecules, relevant as atmospheric contaminants or components. For example the photochemical gas-phase reaction between SO{sub 2}, O{sub 2} and Cl{sub 2} was studied and the reaction mechanisms were proposed on the basis of the isolation and identification of the products [1]. Molecules of the type ClSO{sub 2} (OSO{sub 2}){sub n}Cl, with n=1,2 and the novel peroxide ClSO{sub 2}OOSO{sub 2}Cl were determined, among others, as the main photoproducts. It was proposed that this reaction could play an important role in atmospheric chemistry, particularly in regions of high Cl{sub 2} and SO{sub 2} abundances. It was also suggested that it could account for chemical processes to explain the unexpectedly low oxygen content of the Venus stratosphere [2]. Pyrosulfuryl chloride, was prepared by the reaction of SO{sub 3} and CCl{sub 4},1 and subsequently purified by fractional distillation first, and then by trap-to-trap distillations in vacuum conditions. The identity and purity of the sample were checked by IR and Raman spectroscopy. The photoexcitation and photofragmentation in the energy region between 12 and 300 eV was studied. The Total Ion Yield (TIY) spectra show the S 2p, Cl 2p and S 2s edges, at 182.4, 212.4 and 236.6 eV, respectively. The most abundant ion detected in the PEPICO spectra, after the photoexcitation of the sample in the 12-21 eV energy region, was the ClSO{sub 2}{sup +} fragment (43.4% at 13 eV and 44.0% at 21 eV). At higher ionization energies, the atomization processes dominate the PEPICO spectra, being the abundances of O{sup +}, S{sup +} and Cl{sup +} 46.5, 15.9 and 22.2. [1] R. M. Romano, C.O. Della Vedova, H. Beckers, H. Willner. Inorganic Chemistry. 2009. 48 (5), 1906. [2] W. B. Demore, M.-T. Leu, R. H. Smith, Y. L. Yung., 1985, 63, 347-353. (author)
CO2/H2O adsorption equilibrium and rates on metal-organic frameworks: HKUST-1 and Ni/DOBDC.

Science.gov (United States)

Liu, Jian; Wang, Yu; Benin, Annabelle I; Jakubczak, Paulina; Willis, Richard R; LeVan, M Douglas

2010-09-07

Metal-organic frameworks (MOFs) have recently attracted intense research interest because of their permanent porous structures, huge surface areas, and potential applications as novel adsorbents and catalysts. In order to provide a basis for consideration of MOFs for removal of carbon dioxide from gases containing water vapor, such as flue gas, we have studied adsorption equilibrium of CO(2), H(2)O vapor, and their mixtures and also rates of CO(2) adsorption in two MOFs: HKUST-1 (CuBTC) and Ni/DOBDC (CPO-27-Ni or Ni/MOF-74). The MOFs were synthesized via solvothermal methods, and the as-synthesized products were solvent exchanged and regenerated before experiments. Pure component adsorption equilibria and CO(2)/H(2)O binary adsorption equilibria were studied using a volumetric system. The effects of H(2)O adsorption on CO(2) adsorption for both MOF samples were determined, and the results for 5A and NaX zeolites were included for comparison. The hydrothermal stabilities for the two MOFs over the course of repetitive measurements of H(2)O and CO(2)/H(2)O mixture equilibria were also studied. CO(2) adsorption rates from helium for the MOF samples were investigated by using a unique concentration-swing frequency response (CSFR) system. Mass transfer into the MOFs is rapid with the controlling resistance found to be macropore diffusion, and rate parameters were established for the mechanism.
Fluid geochemistry and soil gas fluxes (CO2-CH4-H2S) at a promissory Hot Dry Rock Geothermal System: The Acoculco caldera, Mexico

Science.gov (United States)

Peiffer, L.; Bernard-Romero, R.; Mazot, A.; Taran, Y. A.; Guevara, M.; Santoyo, E.

2014-09-01

The Acoculco caldera has been recognized by the Mexican Federal Electricity Company (CFE) as a Hot Dry Rock Geothermal System (HDR) and could be a potential candidate for developing an Enhanced Geothermal System (EGS). Apart from hydrothermally altered rocks, geothermal manifestations within the Acoculco caldera are scarce. Close to ambient temperature bubbling springs and soil degassing are reported inside the caldera while a few springs discharge warm water on the periphery of the caldera. In this study, we infer the origin of fluids and we characterize for the first time the soil degassing dynamic. Chemical and isotopic (δ18O-δD) analyses of spring waters indicate a meteoric origin and the dissolution of CO2 and H2S gases, while gas chemical and isotopic compositions (N2/He, 3He/4He, 13C, 15N) reveal a magmatic contribution with both MORB- and arc-type signatures which could be explained by an extension regime created by local and regional fault systems. Gas geothermometry results are in agreement with temperature measured during well drilling (260 °C-300 °C). Absence of well-developed water reservoir at depth impedes re-equilibration of gases upon surface. A multi-gas flux survey including CO2, CH4 and H2S measurements was performed within the caldera. Using the graphical statistical analysis (GSA) approach, CO2 flux measurements were classified in two populations. Population A, representing 95% of measured fluxes is characterized by low values (mean: 18 g m- 2 day- 1) while the remaining 5% fluxes belonging to Population B are much higher (mean: 5543 g m- 2 day- 1). This low degassing rate probably reflects the low permeability of the system, a consequence of the intense hydrothermal alteration observed in the upper 800 m of volcanic rocks. An attempt to interpret the origin and transport mechanism of these fluxes is proposed by means of flux ratios as well as by numerical modeling. Measurements with CO2/CH4 and CO2/H2S flux ratios similar to mass ratios
Enhanced competitive adsorption of CO2 and H2 on graphyne: A density functional theory study

Directory of Open Access Journals (Sweden)

Hyuk Jae Kwon

2017-12-01

Full Text Available Adsorption using carbon-based materials has been established to be a feasible method for separating carbon dioxide and hydrogen to mitigate the emission of carbon dioxide into the atmosphere and for the collection of fuel for energy sources, simultaneously. We carried out density functional theory calculation with dispersion correction to investigate the physisorption characteristics of carbon allotropes such as graphene and graphyne for the competitive adsorption of CO2 and H2. It is worth noting that the graphyne represented preferable adsorption energies, short bond lengths and energy charges for both gases, compared with the characteristics observed with graphene. We found that in graphyne, both the affinitive adsorption of CO2, and the competitive adsorption of CO2 and H2, took place at the hollow site between acetylene links, which do not exist in graphene. We demonstrate that in the presence of H2, the CO2 adsorption selectivity of graphyne is higher than that of graphene, because of the improved electronic properties resulting from the acetylene links.
Amine–mixed oxide hybrid materials for carbon dioxide adsorption from CO2/H2 mixture

Science.gov (United States)

Ravi, Navin; Aishah Anuar, Siti; Yusuf, Nur Yusra Mt; Isahak, Wan Nor Roslam Wan; Shahbudin Masdar, Mohd

2018-05-01

Bio-hydrogen mainly contains hydrogen and high level of carbon dioxide (CO2). High concentration of CO2 lead to a limitation especially in fuel cell application. In this study, the amine-mixed oxide hybrid materials for CO2 separation from bio-hydrogen model (50% CO2:50% H2) have been studied. Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) characterizations showed that the amine–mixed oxide hybrid materials successfully adsorbed CO2 physically with no chemical adsorption evidence. The dry gas of CO2/H2 mixture adsorbed physically on amine–CuO–MgO hybrid material. No carbonates were detected after several times of adsorption, which indicated the good recyclability of adsorbents. The adsorbent system of diethanolamine (DEA)/15% CuO–75% MgO showed the highest CO2 adsorption capacity of 21.2 wt% due to the presence of polar substance on MgO surface, which can adsorb CO2 at ambient condition. The alcohol group of DEA can enhance the CO2 solubility on the adsorbent surface. In the 20% CuO–50% MgO adsorbent system, DEA as amine type showed a high CO2 adsorption of 19.4 wt%. The 10% amine loading system showed that the DEA adsorption system provided high CO2 adsorption. The BET analysis confirmed that a high amine loading contributed to the decrease in CO2 adsorption due to the low surface area of the adsorbent system.
Oxidation of SO2 and formation of water droplets under irradiation of 20MeV protons in N2/H2O/SO2

DEFF Research Database (Denmark)

Tomita, Shigeo; Nakai, Yoichi; Funada, Shuhei

2015-01-01

We have performed an experiment on charged droplet formation in a humidified N2 gas with trace SO2 concentration and induced by 20MeV proton irradiation. It is thought that SO2 reacts with the chemical species, such as OH radicals, generated through the reactions triggered by N2+ production. Both...
A novel highly efficient adsorbent {[Co4(L)2(μ3-OH)2(H2O)3(4,4‧-bipy)2]·(H2O)2}n: Synthesis, crystal structure, magnetic and arsenic (V) absorption capacity

Science.gov (United States)

Zhang, Chong; Xiao, Yu; Qin, Yan; Sun, Quanchun; Zhang, Shuhua

2018-05-01

A novel highly efficient adsorbent-microporous tetranuclear Co(II)-based polymer, {[Co4(L)2(μ3-OH)2(H2O)3(4,4‧-bipy)2]·(H2O)2}n (1, H3L = 4-(N,N‧-bis(4-carboxybenzyl)amino) benzenesulfonic acid, 4,4‧-bipy = 4,4‧-bipyridine), was hydrothermally synthesized. The complex 1 is a metal-organic framework (MOF) material which was characterized by single-crystal X-ray diffraction, BET and platon software. Co-MOF (complex 1) reveals excellent adsorption property. The capacity of Co-MOF to remove arsenic As(V) from sodium arsenate aqueous solutions was investigated (The form of As(V) is AsO43-). The experimental results showed that Co-MOF had a higher stable and relatively high As(V) removal rate (> 98%) at pH 4-10. The adsorption kinetics followed a pseudo-second-order kinetic model, and the adsorption isotherm followed the Langmuir equation. Co-MOF exhibits a very high adsorption capacity of As(V) in aqueous solution (Qmax of 96.08 mg/g). Finally, the optimal adsorption conditions for the model were obtained through a Box-Behnken response surface experiment which was designed with adsorption time, dose, temperature and rotational speed of the shaker as the influencing factors to determine two-factor interaction effects. Co-MOF was further characterized using FTIR, PXRD, X-ray photoelectron spectroscopy before and after adsorption As (V). The magnetism of Co-MOF was also discussed.
Conteúdo lipídico e composição de ácidos graxos de microalgas expostas aos gases CO2, SO2 e NO Lipid content and fatty acids composition variation of microalgae exposed to CO2, SO2 and NO

Directory of Open Access Journals (Sweden)

Elisangela Martha Radmann

2008-01-01

Full Text Available The objective of the present work was to verify the lipid content and the fatty acid composition of the microalgae Spirulina sp., Scenedesmus obliquus, Synechococcus nidulans and Chlorella vulgaris cultivated in a medium containing CO2, SO2 and NO. The microalga Scenedesmus obliquus presented the highest lipid content (6.18%. For the other microalgae the lipid content ranged from 4.56 to 5.97%. The major monounsaturated fatty acids content was 66.01% for S. obliquus. The PUFA were obtained in major amount by the microalgae Spirulina sp. (29.37% and S. nidulans (29.54%. The palmitoleic acid was in larger amount, with 41.02% concentration (Spirulina sp..
B_2S_2O_9. A boron sulfate with phyllosilicate topology

International Nuclear Information System (INIS)

Logemann, Christian; Wickleder, Mathias S.

2013-01-01

The condensation of [BO_4] and [SO_4] tetrahedra in the first binary boron sulfate B_2S_2O_9, leads to a structure with typical layered phyllosilicate topology. The compound is obtained from the hydrolysis of B(OH)_3 and HSO_3Cl. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Combined production of synthetic liquid fuel and electricity from coal using H2S and CO2 removal systems

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Elina A. Tyurina

2015-11-01

Full Text Available The main aim of the research is to continue the studies on promising technologies of coal conversion into synthetic liquid fuel (methanol. The object of study is the plants for combined production of electricity and synthetic liquid fuel (PCPs, which are eco-friendly and more efficient as compared to the plants for separate production. The previous studies on PCPs consider the systems for fine cleaning of gasification products in a simplified way. This study presents the detailed mathematical modeling of the aforementioned systems and determines the values of energy consumption and investment in them. The obtained values are used to carry out the optimization studies and find the optimal parameters of PCPs with different degree of CO2 removal from gasification products providing fine cleaning of gasification products from H2S.
Lanthanite-(Nd), Nd2(CO3)3·8H2O

Science.gov (United States)

Morrison, Shaunna M.; Andrade, Marcelo B.; Wenz, Michelle D.; Domanik, Kenneth J.; Downs, Robert T.

2013-01-01

Lanthanite-(Nd), ideally Nd2(CO3)3·8H2O [dineodymium(III) tricarbonate octahydrate], is a member of the lanthanite mineral group characterized by the general formula REE 2(CO3)3·8H2O, where REE is a 10-coordinated rare earth element. Based on single-crystal X-ray diffraction of a natural sample from Mitsukoshi, Hizen-cho, Karatsu City, Saga Prefecture, Japan, this study presents the first structure determination of lanthanite-(Nd). Its structure is very similar to that of other members of the lanthanite group. It is composed of infinite sheets made up of corner- and edge-sharing of two NdO10-polyhedra (both with site symmetry ..2) and two carbonate triangles (site symmetries ..2 and 1) parallel to the ab plane, and stacked perpendicular to c. These layers are linked to one another only through hydrogen bonding involving the water molecules. PMID:23476479
Differential cross sections for transfer into the 2S state of hydrogen: H+ + H2, H+ + D2

International Nuclear Information System (INIS)

Williams, D.G.; Lee, A.R.; Butcher, E.C.

1986-01-01

Differential cross sections for electron capture into the 2S state of hydrogen are presented for the reactions H + + H 2 and H + + D 2 . The results are for laboratory collision energies between 3.3 and 24 keV and scattering angles between 30 and 90'. The measurements expand on the results previously presented. (author)

Hybridized 1T/2H MoS2 Having Controlled 1T Concentrations and its use in Supercapacitors.

Science.gov (United States)

Thi Xuyen, Nguyen; Ting, Jyh-Ming

2017-12-06

Molybdenum disulfide (MoS 2 ) nanoflowers consisting of hybridized 1T/2H phases have been synthesized by using a microwave-assisted hydrothermal (MTH) method. The concentration of the 1T phase, ranging from 40 % to 73 %, is controlled by simply adjusting the ratio of the Mo and S precursors. By using the hybridized 1T/2H MoS 2 as an electrode material, it was demonstrated that the resulting supercapacitor performance is dominated by the 1T phase concentration. It was found that a supercapacitor with 73 % 1T phase exhibits excellent capacitance of 259 F g -1 and great cyclic stability after 1000 cycles. The formation mechanism of the MHT-synthesized hybridized 1T/2H MoS 2 is also reported. More importantly, the mechanism also explains the observed relationship between the 1T phase concentration and the ratio of the Mo and S precursors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Dimethyl 2,2′-[Carbonylbis(azanediyl](2S,2′S-bis[3-(4-hydroxyphenylpropanoate

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Raffaella Mancuso

2018-02-01

Full Text Available The thus-far unknown ureic derivative dimethyl 2,2′-[carbonylbis(azanediyl](2S,2′S-bis[3-(4-hydroxyphenylpropanoate] has been efficiently synthesized by enantiospecific oxidative carbonylation of readily available l-tyrosine methyl ester, using a very simple catalytic system (PdI2 in conjunction with KI under relatively mild conditions (100 °C for 5 h in DME as the solvent and under 20 atm of a 4:1 mixture CO-air.
Symmetrical synergy of hybrid CoS2-WS2 electrocatalysts for hydrogen evolution reaction

KAUST Repository

Zhou, Xiaofeng; Yang, Xiulin; Li, Henan; Hedhili, Mohamed N.; Huang, Kuo-Wei; Li, Lain-Jong; Zhang, Wenjing

2017-01-01

A highly active and stable hybrid electrocatalyst 3D hierarchical CoS2 nanosheets incorporated with WS2 (CoS2@WS2) has been developed via a one-step sulfurization method for the first time, where the contents of WS2 can be adjusted easily. We first prove the addition of small amounts of WS2 enhances the hydrogen evolution reaction (HER) performance of CoS2, and vise versa. In other words, we validated the symmetric synergy for HER between the Co- and W-based sulfide hybrid catalysts. In addition, we confirmed that the formation of nanointerfaces of Co-S-W between CoS2 and WS2 was responsible for the excellent HER activity (an overpotential of -97.2 mV at -10 mA/cm2, a small Tafel slope of 66.0 mV/dec, and prominent electrochemical stability) of hybrid electrocatalyst CoS2@WS2.
Symmetrical synergy of hybrid CoS2-WS2 electrocatalysts for hydrogen evolution reaction

KAUST Repository

Zhou, Xiaofeng

2017-06-05

A highly active and stable hybrid electrocatalyst 3D hierarchical CoS2 nanosheets incorporated with WS2 (CoS2@WS2) has been developed via a one-step sulfurization method for the first time, where the contents of WS2 can be adjusted easily. We first prove the addition of small amounts of WS2 enhances the hydrogen evolution reaction (HER) performance of CoS2, and vise versa. In other words, we validated the symmetric synergy for HER between the Co- and W-based sulfide hybrid catalysts. In addition, we confirmed that the formation of nanointerfaces of Co-S-W between CoS2 and WS2 was responsible for the excellent HER activity (an overpotential of -97.2 mV at -10 mA/cm2, a small Tafel slope of 66.0 mV/dec, and prominent electrochemical stability) of hybrid electrocatalyst CoS2@WS2.
Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

KAUST Repository

Babarao, Ravichandar

2010-07-06

The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.
Effect of Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O Promoter Catalysts on H2, CO and CH4 Concentration by CO2 Gasification of Rosa Multiflora Biomass

Directory of Open Access Journals (Sweden)

Tursunov Obid

2017-11-01

Full Text Available The thermal behaviour of the Rosa mutiflora biomass by thermogravimetric analysis was studied at heating rate 3 K min−1 from ambient temperature to 950 °C. TGA tests were performed in high purity carbon dioxide (99 998% with a flow rate 200 ml/min and 100 mg of sample, milled and sieved to a particle size below 250 µm. Moreover, yields of gasification products such as hydrogen (H2, carbon monoxide (CO and methane (CH4 were determined based on the thermovolumetric measurements of catalytic (Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O promoter catalysts and non-catalytic gasification of the Rosa multiflora biomass. Additionally, carbon conversion degrees are presented. Calculations were made of the kinetic parameters of carbon monoxide and hydrogen formation reaction in the catalytic and non-catalytic CO2 gasification processes. A high temperature of 950 °C along with Ni/Al2O3-SiO2and Ni/Al2O3-SiO2 with K2O promoter catalysts resulted in a higher conversion of Rosa multiflora biomass into gaseous yield production with greatly increasing of H2 and CO contents. Consequently, H2 and CO are the key factors to produce renewable energy and bio-gases (synthesis gas. The parameters obtained during the experimental examinations enable a tentative assessment of plant biomasses for the process of large-scale gasification in industrial sectors.
Plant-Sediment Interactions in Salt Marshes - An Optode Imaging Study of O2, pH, and CO 2 Gradients in the Rhizosphere.

Science.gov (United States)

Koop-Jakobsen, Ketil; Mueller, Peter; Meier, Robert J; Liebsch, Gregor; Jensen, Kai

2018-01-01

In many wetland plants, belowground transport of O 2 via aerenchyma tissue and subsequent O 2 loss across root surfaces generates small oxic root zones at depth in the rhizosphere with important consequences for carbon and nutrient cycling. This study demonstrates how roots of the intertidal salt-marsh plant Spartina anglica affect not only O 2 , but also pH and CO 2 dynamics, resulting in distinct gradients of O 2 , pH, and CO 2 in the rhizosphere. A novel planar optode system (VisiSens TD ® , PreSens GmbH) was used for taking high-resolution 2D-images of the O 2 , pH, and CO 2 distribution around roots during alternating light-dark cycles. Belowground sediment oxygenation was detected in the immediate vicinity of the roots, resulting in oxic root zones with a 1.7 mm radius from the root surface. CO 2 accumulated around the roots, reaching a concentration up to threefold higher than the background concentration, and generally affected a larger area within a radius of 12.6 mm from the root surface. This contributed to a lowering of pH by 0.6 units around the roots. The O 2 , pH, and CO 2 distribution was recorded on the same individual roots over diurnal light cycles in order to investigate the interlinkage between sediment oxygenation and CO 2 and pH patterns. In the rhizosphere, oxic root zones showed higher oxygen concentrations during illumination of the aboveground biomass. In darkness, intraspecific differences were observed, where some plants maintained oxic root zones in darkness, while others did not. However, the temporal variation in sediment oxygenation was not reflected in the temporal variations of pH and CO 2 around the roots, which were unaffected by changing light conditions at all times. This demonstrates that plant-mediated sediment oxygenation fueling microbial decomposition and chemical oxidation has limited impact on the dynamics of pH and CO 2 in S. anglica rhizospheres, which may in turn be controlled by other processes such as root
Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

International Nuclear Information System (INIS)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-01-01

Two one-dimensional bismuth-coordination materials, Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 ) x F (x=1 and 2), have been synthesized by hydrothermal reactions using Bi 2 O 3 , 2,6-NC 5 H 3 (CO 2 H) 2 , HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi 3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C led to α-Bi 2 O 3 that maintained the same morphology of the original crystals. - Graphical abstract: Calcination of the Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C results in the α-Bi 2 O 3 rods that maintain the original morphology of the crystals. Highlights: ► Synthesis of one-dimensional chain Bi-organic frameworks. ► Reversible hydration reactions of Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F. ► Topotactic decomposition maintaining the same morphology of the original crystals.
Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254 nm irradiation

International Nuclear Information System (INIS)

He, Xuexiang; Mezyk, Stephen P.; Michael, Irene; Fatta-Kassinos, Despo; Dionysiou, Dionysios D.

2014-01-01

Graphical abstract: - Highlights: • Removal efficiency was comparable at different UV fluence rates but same fluence. • Reducing pH to 3 or 2 did not inhibit the removal of nitrobenzene by UV/S 2 O 8 2− . • 1.84 × 10 −14 M [HO • ] ss and 3.10 × 10 −13 M [SO 4 • − ] ss in UV/S 2 O 8 2− were estimated. • HO • reacted faster with the β-lactams than SO 4 • − but sharing similar byproducts. • Transformation pathways included hydroxylation, hydrolysis and decarboxylation. - Abstract: The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254 nm activated H 2 O 2 and S 2 O 8 2− photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S 2 O 8 2− system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO 4 2− and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the β-lactam ring and decarboxylation (–44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H 2 O 2 and UV/S 2 O 8 2− advanced oxidation processes (AOPs) are capable of degrading β-lactam antibiotics decreasing consequently the antibiotic activity of treated waters
Synthesis of 9H-Indeno [1, 2-b] Pyrazine and 11H-Indeno [1, 2-b ...

African Journals Online (AJOL)

NICO

Synthesis of 9H-Indeno [1, 2-b] Pyrazine and. 11H-Indeno [1, 2-b] Quinoxaline Derivatives in. One-step Reaction from 2-Bromo-4-chloro-1-indanone. S. Jasouri1,2, J. Khalafy1,*, M. Badali2 and R.H. Prager3. 1Department of Chemistry, Urmia University, Urmia 57154, Iran. 2Daana Pharmaceutical Co., P.O. Box 5181, Tabriz ...
A neodymium(III)-ammonium complex involving oxalate and carbonate ligands: (NH4)2[Nd2(C2O4)3(CO3)(H2O)].H2O.

Science.gov (United States)

Trombe, Jean-Christian; Galy, Jean; Enjalbert, Renée

2002-10-01

The title compound, diammonium aqua-mu-carbonato-tri-mu-oxalato-dineodymium(III) hydrate, (NH(4))(2)[Nd(2)(CO(3))(C(2)O(4))(3)(H(2)O)].H(2)O, involving the two ligands oxalate and carbonate, has been prepared hydrothermally as single crystals. The Nd atoms form a tetranuclear unit across the inversion centre at (1/2, 1/2, 1/2). Starting from this tetranuclear unit, the oxalate ligands serve to develop a three-dimensional network. The carbonate group acts as a bis-chelating ligand to two Nd atoms, and is monodentate to a third Nd atom. The oxalate groups are all bis-chelating. The two independent Nd atoms are ninefold coordinated and the coordination polyhedron of these atoms is a distorted monocapped antiprism.
The first 3D malonate bridged copper [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O]: Structure, properties and electronic structure

Energy Technology Data Exchange (ETDEWEB)

Seguatni, A., E-mail: seguatni@gmail.com [LBPC-INSERM U 698, Institut Galilee, Universite Paris XIII, 99, avenue J. B. Clement 93430, Villetaneuse (France); Fakhfakh, M. [Unite de recherche UR 12-30, Synthese et Structure de Materiaux Inorganiques, Faculte des Sciences de Bizerte, 7021 Zarzouna (Tunisia); Departement de Chimie, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-ville, Montreal, Que., H3C 3P8 (Canada); Smiri, L.S. [Unite de recherche UR 12-30, Synthese et Structure de Materiaux Inorganiques, Faculte des Sciences de Bizerte, 7021 Zarzouna (Tunisia); Gressier, P.; Boucher, F. [Institut des Materiaux Jean Rouxel, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3 (France); Jouini, N. [Departement de Chimie, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-ville, Montreal, Que., H3C 3P8 (Canada)

2012-03-15

A new inorganic-organic compound [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O] ([Cumal]) was hydrothermally synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray diffraction. [Cumal] is the first three-dimensional compound existing in the system Cu(II)-malonic acid-H{sub 2}O. Its framework is built up through carboxyl bridged copper where CuO{sub 6} octahedra are elongated with an almost D{sub 4h} symmetry (4+2) due to the Jahn-Teller effect. The magnetic properties were studied by measuring its magnetic susceptibility in the temperature range of 2-300 K indicating the existence of weak ferromagnetic interactions. The electronic structure of [Cumal] was calculated within the density functional theory (DFT) framework. Structural features are well reproduced using DFT structural optimizations and the optical spectra, calculated within the dielectric formalism, explain very well the light blue colour of the compound. It is shown that a GGA+U approach with a U{sub eff} value of about 6 eV is necessary for a better correlation with the experiment. - Graphical abstract: [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O]: the first 3D hybrid organic-inorganic compound built up carboxyl groups. The network presents a diamond-like structure achieved via carboxyl. Highlights: Black-Right-Pointing-Pointer A new organic-inorganic material with an unprecedented topology is synthesized. Black-Right-Pointing-Pointer Crystallographic structure is determined using single crystal X-ray diffraction. Black-Right-Pointing-Pointer Electronic structure is obtained from DFT, GGA+U calculation. Black-Right-Pointing-Pointer Framework can be described as formed from CuC{sub 4} tetrahedron sharing four corners. Black-Right-Pointing-Pointer This structure can be classified as an extended diamond structure.
The conversion of SO{sub 2} to SO{sub 3} in gas turbine engines

Energy Technology Data Exchange (ETDEWEB)

Miake-Lye, R C; Anderson, M R; Brown, R C; Kolb, C E [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A A; Buriko, Y I [Scientific Research Center ` Ecolen` , Moscow (Russian Federation)

1998-12-31

The oxidation of fuel sulfur to S(6) (SO{sub 3}+H{sub 2}SO{sub 4}) in a supersonic (Concorde) and a subsonic (ATTAS) aircraft engine is estimated numerically. The results indicate between 2% and 10% of the fuel sulfur is emitted as S(6). It is also shown that conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, resulting in a higher oxidation efficiency as the sulfur mass loading is decreased. SO{sub 2} and SO{sub 3} are the primary sulfur oxidation products, with less than 1% of fuel sulfur converted to H{sub 2}SO{sub 4}. For the Concorde, H{sub 2}SO{sub 4} was primarily formed during the supersonic expansion through the divergent nozzle. (author) 20 refs.
The conversion of SO{sub 2} to SO{sub 3} in gas turbine engines

Energy Technology Data Exchange (ETDEWEB)

Miake-Lye, R.C.; Anderson, M.R.; Brown, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

1997-12-31

The oxidation of fuel sulfur to S(6) (SO{sub 3}+H{sub 2}SO{sub 4}) in a supersonic (Concorde) and a subsonic (ATTAS) aircraft engine is estimated numerically. The results indicate between 2% and 10% of the fuel sulfur is emitted as S(6). It is also shown that conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, resulting in a higher oxidation efficiency as the sulfur mass loading is decreased. SO{sub 2} and SO{sub 3} are the primary sulfur oxidation products, with less than 1% of fuel sulfur converted to H{sub 2}SO{sub 4}. For the Concorde, H{sub 2}SO{sub 4} was primarily formed during the supersonic expansion through the divergent nozzle. (author) 20 refs.
Ab initio molecular dynamics simulations reveal localization and time evolution dynamics of an excess electron in heterogeneous CO2-H2O systems.

Science.gov (United States)

Liu, Ping; Zhao, Jing; Liu, Jinxiang; Zhang, Meng; Bu, Yuxiang

2014-01-28

In view of the important implications of excess electrons (EEs) interacting with CO2-H2O clusters in many fields, using ab initio molecular dynamics simulation technique, we reveal the structures and dynamics of an EE associated with its localization and subsequent time evolution in heterogeneous CO2-H2O mixed media. Our results indicate that although hydration can increase the electron-binding ability of a CO2 molecule, it only plays an assisting role. Instead, it is the bending vibrations that play the major role in localizing the EE. Due to enhanced attraction of CO2, an EE can stably reside in the empty, low-lying π(*) orbital of a CO2 molecule via a localization process arising from its initial binding state. The localization is completed within a few tens of femtoseconds. After EE trapping, the ∠OCO angle of the core CO2 (-) oscillates in the range of 127°∼142°, with an oscillation period of about 48 fs. The corresponding vertical detachment energy of the EE is about 4.0 eV, which indicates extreme stability of such a CO2-bound solvated EE in [CO2(H2O)n](-) systems. Interestingly, hydration occurs not only on the O atoms of the core CO2 (-) through formation of O⋯H-O H-bond(s), but also on the C atom, through formation of a C⋯H-O H-bond. In the latter binding mode, the EE cloud exhibits considerable penetration to the solvent water molecules, and its IR characteristic peak is relatively red-shifted compared with the former. Hydration on the C site can increase the EE distribution at the C atom and thus reduce the C⋯H distance in the C⋯H-O H-bonds, and vice versa. The number of water molecules associated with the CO2 (-) anion in the first hydration shell is about 4∼7. No dimer-core (C2O4 (-)) and core-switching were observed in the double CO2 aqueous media. This work provides molecular dynamics insights into the localization and time evolution dynamics of an EE in heterogeneous CO2-H2O media.
Human organic cation transporter 2 (hOCT2): Inhibitor studies using S2-hOCT2 cells

International Nuclear Information System (INIS)

Chiba, Shoetsu; Ikawa, Toru; Takeshita, Hiroshi; Kanno, Sanae; Nagai, Tomonori; Takada, Meri; Mukai, Toshiji; Wempe, Michael F.

2013-01-01

Highly expressed in kidney and located on the basolateral membrane, human organic cation transporter 2 (hOCT2) can transport various compounds (i.e. drugs and toxins) into the proximal tubular cell. Using cultured proximal tubule cells stably expressing hOCT2 (i.e. S2-hOCT2 cells), we sought to probe different compound classes (e.g. analgesics, anti-depressants, anti-psychotics, disinfectant, herbicides, insecticides, local anesthetic, muscarinic acetylcholine receptor antagonist, sedatives, steroid hormone, stimulants and toxins) for their ability to inhibit 14 C-TEA uptake, a prototypical OCT2 substrate. Aconitine, amitriptyline, atropine, chlorpyrifos, diazepam, fenitrothion, haloperidol, lidocaine, malathion, mianserin, nicotine and triazolam significantly inhibited 14 C-TEA uptake; IC 50 values were 59.2, 2.4, 2.0, 20.7, 32.3, 13.2, 32.5, 104.6, 71.1, 17.7, 52.8 and 65.5 μM, respectively. In addition, aconitine, amitriptyline, atropine, chlorpyrifos, fenitrothion, haloperidol, lidocaine, and nicotine displayed competitive inhibition with K i values of 145.6, 2.5, 2.4, 24.8, 16.9, 51.6, 86.8 and 57.7 μM, respectively. These in vitro data support the notion that compounds pertaining to a wide variety of different drug classes have the potential to decrease renal clearance of drugs transported via hOCT2. Consequently, these data warrant additional studies to probe hOCT2 and its role to influence drug pharmacokinetics
Re-evaluating the 1940s CO2 plateau

Science.gov (United States)

Bastos, Ana; Ciais, Philippe; Barichivich, Jonathan; Bopp, Laurent; Brovkin, Victor; Gasser, Thomas; Peng, Shushi; Pongratz, Julia; Viovy, Nicolas; Trudinger, Cathy M.

2016-09-01

The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940-1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940-1950 ranges between 0.9 and 2.0 Pg C yr-1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr-1 uptake, but it is unlikely to be higher. The impact of the 1940-1942 El Niño on the
An experimental study on premixed CNG/H2/CO2 mixture flames

Science.gov (United States)

Yilmaz, Ilker; Yilmaz, Harun; Cam, Omer

2018-03-01

In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.
The interface of the ferromagnetic metal CoS2 and the nonmagnetic semiconductor FeS2

KAUST Repository

Nazir, S.

2010-11-05

The electronic and magnetic properties of the cubic pyriteCoS2/FeS2interface are studied using the all-electron full-potential linearized augmented plane wave method. We find that this contact between a ferromagneticmetal and a nonmagnetic semiconductor shows a metallic character. The CoS2 stays close to half-metallicity at the interface, while the FeS2 becomes metallic. The magnetic moment of the Co atoms at the interface slightly decreases as compared to the bulk value and a small moment is induced on the Fe atoms. Furthermore, at the interfaceferromagnetic ordering is found to be energetically favorable as compared to antiferromagnetic ordering.
Synthesis, crystal structure and properties of [Co(L2](ClO42 (L=1,3-bis(1H-benzimidazol-2-yl-2-oxapropane

Directory of Open Access Journals (Sweden)

Tavman Aydin

2015-01-01

Full Text Available The reaction of 1,3-bis(1H-benzimidazol-2-yl-2-oxapropane (L with Co(ClO42•6H2O in absolute ethanol produces di[1,3-bis(1H-benzimidazol-2-yl-2-oxapropane-k2N,N’]cobalt(IIdiperchlorate chelate complex ([Co(L2](ClO42, 1. The complex 1 was characterized by elemental analysis, magnetic moment, molar conductivity, thermogravimetric analysis, FT-IR, UV-visible, mass spectrometry, and its solid state structure was determined by single crystal X-ray diffraction. According to the thermogravimetric analysis data, there is no any water coordinated or uncoordinated in 1 as well as elemental analysis. The complex 1 has 1:2 M:L ionic characteristic according to the molar conductivity. In the complex, the distances between the cobalt and the ethereal oxygen atoms (Co1-O2: 2.805(3; Co2-O1: 2.752(2 Å show the semi-coordination bonding and the Co(II ion is six-coordinated with a N4O2 ligand set, resulting in a distorted octahedron.

Theory of gastric CO2 ventilation and its control during respiratory acidosis: implications for central chemosensitivity, pH regulation, and diseases causing chronic CO2 retention.

Science.gov (United States)

Dean, Jay B

2011-02-15

The theory of gastric CO(2) ventilation describes a previously unrecognized reflex mechanism controlled by neurons in the caudal solitary complex (cSC) for non-alveolar elimination of systemic CO(2) during respiratory acidosis. Neurons in the cSC, which is a site of CO(2) chemosensitivity for cardiorespiratory control, also control various gastroesophageal reflexes that remove CO(2) from blood. CO(2) is consumed in the production of gastric acid and bicarbonate in the gastric epithelium and then reconstituted as CO(2) in the stomach lumen from the reaction between H(+) and HCO(3)(-). Respiratory acidosis and gastric CO(2) distension induce cSC/vagovagal mediated transient relaxations of the lower esophageal sphincter to vent gastric CO(2) upwards by bulk flow along an abdominal-to-esophageal (=intrapleural) pressure gradient the magnitude of which increases during abdominal (gastric) compression caused by increased contractions of respiratory muscles. Esophageal distension induces cSC/nucleus ambiguus/vagovagal reflex relaxation of the upper esophageal sphincter and CO(2) is vented into the pharynx and mixed with pulmonary gas during expiration or, alternatively, during eructation. It is proposed that gastric CO(2) ventilation provides explanations for (1) the postprandial increase in expired CO(2) and (2) the negative P(blood - expired)CO₂difference that occurs with increased inspired CO(2). Furthermore, it is postulated that gastric CO(2) ventilation and alveolar CO(2) ventilation are coordinated under dual control by CO(2) chemosensitive neurons in the cSC. This new theory, therefore, presupposes a level of neural control and coordination between two previously presumed dissimilar organ systems and supports the notion that different sites of CO(2) chemosensitivity address different aspects of whole body pH regulation. Consequently, not all sites of central chemosensitivity are equal regarding the mechanism(s) activated for CO(2) elimination. A distributed CO(2
CO2-SO3-rich (carbonate-sulfate) melt/fluids in the lithosphere beneath El Hierro, Canary Islands.

Science.gov (United States)

Oglialoro, E.; Ferrando, S.; Malaspina, N.; Villa, I. M.; Frezzotti, M. L.

2015-12-01

Mantle xenoliths from the island of El Hierro, the youngest of the Canary Islands, have been studied to characterize fluxes of carbon in the lithosphere of an OIB volcanism region. Fifteen xenoliths (4-10 cm in diameter) were collected in a rift lava flow (15-41 ka) at a new xenolith locality in El Julan cliff (S-SW of the island). Peridotites consist of protogranular to porphyroblastic spinel harzburgites, lherzolites, and subordinate dunites. One spinel clinopyroxenite, and one olivine-websterite were also analyzed. Ultramafic xenoliths were classified as HEXO (harzburgite and dunite with exsolved orthopyroxene), HLCO (harzburgite and lherzolite containing orthopyroxene without visible exsolution lamellae), and HTR (transitional harzburgite with exsolved orthopyroxene porphyroclasts, and poikilitic orthopyroxene) following [1]. While HLCO and HTR peridotites contain mostly CO2 fluid inclusions, HEXO peridotites preserve an early association of melt/fluid inclusions containing dominantly carbonate/sulfate/silicate glass, evolving to carbonate/sulfate/phosphate/spinel aggregates, with exsolved CO2 (± carbonates, anhydrite and H2O). Chemical and Raman analyses identify dolomite, Mg-calcite, anhydrite, sulfohalite [Na6(SO4)2FCl] (± other anhydrous and hydrous alkali-sulfates), apatite, and Cr-spinel in the inclusions. Sulfides are noticeably absent. The microstructure and chemical composition of the metasomatic fluids indicate that the peridotites were infiltrated by a carbonate-sulfate-silicate melt/fluid enriched in CO2, H2O, and P. A mantle origin for this fluid is supported by high densities of CO2inclusions (> 1g/cm3), determined by Raman microspectroscopy and cross-checked by microthermometry. Consequently, El Julan peridotites provide the first evidence for liberating oxidized C and S fluxes from the Earth lithosphere in an OIB source region, and suggest that oxidation of sulfide to sulfate can occur during small-degree partial melting of the upper mantle
Synthesis and Characterisation of Tris(1-carboxyl-2-phenyl-1,2-ethyl eno dithiol enic-S,S') Tungsten Complex as Photo catalyst for Photolysis of H2O Molecules

International Nuclear Information System (INIS)

Fadhli Hadana Rahman; Rusli Daik; Mohammad Kassim; Khuzaimah; Wan Ramli Wan Daud

2008-01-01

Tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex is one of the most promising photo catalyst to be used in photolysis of water to produce hydrogen. The first step of the synthesis involves a metathesis reaction of tetrapropylammonium bromide [((C 3 H 7 ) 4 N)Br] and ammonium tetrathiotungstate [(NH 4 ) 2 WS 4 ] to form a tetrapropylammonium tetrathiotungstate [((C 3 H 7 ) 4 N) 2 WS 4 ] (precursor). Then, the precursor was reacted with phenyl acetylenecarboxylic acid (C 9 H 6 O 2 ) to form tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex (C 27 H 18 O 2 S 6 W). The infra-red, ultra violet/ visible (UV/ Vis) spectrum, nuclear magnetic resonance (NMR) and elemental micro-analysis of C, H, N and S agreed with the characteristic of the tris(1-carboxyl-2-phenyl-1,2-ethylenodithiolenic-S,S ' ) tungsten complex. The (W-S), (C-S) and (C=O) stretching frequencies were detected at 511, (1470 and 1035) and 1655 cm -1 , respectively. The 1 H NMR spectrum showed six protons in the complex. The 13 C NMR showed only 7 signals for carbon atom in the benzene ring, ethylene groups and carboxylic acid pendant group due to the symmetry of the molecules. The reaction yield was about 50 percent. Photolysis of acetone spiked H 2 O showed that the catalyst was able to produced 1.8 μmol/ h hydrogen. (author)
Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-( sup 2 H)- and (2R)-( sup 2 H)-sparteine

Energy Technology Data Exchange (ETDEWEB)

Ebner, T.; Meese, C.O. (Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.)); Rebell, J. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie); Fischer, P. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.))

1989-04-01

Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)({beta})-deuterated (-)-sparteine and the (2R)({alpha})-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label ({>=}98%) are established unequivocally by {sup 1}H, {sup 2}H and {sup 13}C NMR spectroscopy. (author).
Tuning patterning conditions by co-adsorption of gases: Br2 and H2 on Si(001).

Science.gov (United States)

Biswas, Sananda; Deshpande, Sadanand V; Dunn, Derren N; Narasimhan, Shobhana

2013-11-14

We have studied the co-adsorption of Br2 and H2 on Si(001), and obtained co-adsorption energies and the surface phase diagram as a function of the chemical potential and pressure of the two gases. To do this, we have used density functional theory calculations in combination with ab initio atomistic thermodynamics. Over large ranges of bromine and hydrogen chemical potentials, the favored configuration is found to be either one with only Br atoms adsorbed on the surface, at full coverage, in a (3 × 2) pattern, or a fully H-covered surface in a (2 × 1) structure. However, we also find regions of the phase diagram where there are configurations with either only Br atoms, or Br and H atoms, arranged in a two-atom-wide checkerboard pattern with a (4 × 2) surface unit cell. Most interestingly, we find that by co-adsorbing with H2, we bring this pattern into a region of the phase diagram corresponding to pressures that are significantly higher than those where it is observed with Br2 alone. We also find small regions of the phase diagram with several other interesting patterns.
Analysis of (NH4)2SO4/(NH4)H2PO4 mixtures by thermogravimetry and X-ray diffraction

International Nuclear Information System (INIS)

Perez, Jose; Perez, Eduardo; Vas, Beatriz del; Garcia, Luis; Serrano, Jose Luis

2006-01-01

(NH 4 ) 2 SO 4 and (NH 4 )H 2 PO 4 are the principal components in the powder material used in fire extinguishers. In this paper the mutual influence in their thermal decomposition is investigated by thermogravimetry. Two methods for the quantification of both salts in mixtures (NH 4 ) 2 SO 4 /(NH 4 )H 2 PO 4 are proposed. The first employs thermogravimetry and is based on the measurement of the mass fraction in the 500-550 deg. C interval, once (NH 4 ) 2 SO 4 has totally decomposed to yield gaseous products. The second uses some selected peaks in the X-ray diffractogram
CO2 solubility in aqueous solutions containing Na+, Ca2+, Cl−, SO42− and HCO3-: The effects of electrostricted water and ion hydration thermodynamics

International Nuclear Information System (INIS)

Gilbert, Kimberly; Bennett, Philip C.; Wolfe, Will; Zhang, Tongwei; Romanak, Katherine D.

2016-01-01

Dissolution of CO 2 into deep subsurface brines for carbon sequestration is regarded as one of the few viable means of reducing the amount of CO 2 entering the atmosphere. Ions in solution partially control the amount of CO 2 that dissolves, but the mechanisms of the ion's influence are not clearly understood and thus CO 2 solubility is difficult to predict. In this study, CO 2 solubility was experimentally determined in water, NaCl, CaCl 2 , Na 2 SO 4, and NaHCO 3 solutions and a mixed brine similar to the Bravo Dome natural CO 2 reservoir; ionic strengths ranged up to 3.4 molal, temperatures to 140 °C, and CO 2 pressures to 35.5 MPa. Increasing ionic strength decreased CO 2 solubility for all solutions when the salt type remained unchanged, but ionic strength was a poor predictor of CO 2 solubility in solutions with different salts. A new equation was developed to use ion hydration number to calculate the concentration of electrostricted water molecules in solution. Dissolved CO 2 was strongly correlated (R 2 = 0.96) to electrostricted water concentration. Strong correlations were also identified between CO 2 solubility and hydration enthalpy and hydration entropy. These linear correlation equations predicted CO 2 solubility within 1% of the Bravo Dome brine and within 10% of two mixed brines from literature (a 10 wt % NaCl + KCl + CaCl 2 brine and a natural Na + , Ca 2+ , Cl − type brine with minor amounts of Mg 2+ , K + , Sr 2+ and Br − ). - Highlights: • Measured CO 2 solubility in Na + , Cl − , HCO 3 - , Ca 2+ and SO 4 2− solutions at high PCO 2 . • A new equation calculates electrostricted water (mol/kgw) from hydration number. • CO 2 solubility strongly correlates (R 2 = 0.96) to electrostricted water. • Ion electrostriction of water limits its availability for CO 2 caging and solvation. • Correlations predict CO 2 solubility of several mixed brines to within 1–9%.
Oxidative Addition Reactions of I2 with [HIr4(CO10-n(PPh3 n(m-PPh2] (n = 1 and 2 and Crystal and Molecular Structure of [HIr4(m-I2(CO7 (PPh3(m-PPh2

Directory of Open Access Journals (Sweden)

Braga Dario

2002-01-01

Full Text Available The reactions of the cluster compounds [HIr4(CO10-n(PPh3 n(mu-PPh2] [n = 0, (1; 1, (2 and 2, (3] with I2 have been investigated. Compound 1 does not react, however, the presence of PPh3 in place of CO ligand(s activates the cluster. Both compounds 2 and 3 react with I2 under mild conditions to give [HIr4(mu-I2(CO7(PPh3(mu-PPh 2] (4, as the result of oxidative addition of I2 and dissociation of two CO ligands, or one CO and one PPh3 ligands, respectively. The molecular structure of 4, determined by an X-ray diffraction study, exhibits a butterfly arrangement of iridium atoms with the wings spanned by a mu-PPh2 ligand, the hinge bridged by a mu-H ligand, two hinge to wing tip edges bridged by iodine atoms and all metal atoms bearing two CO ligands, with the exception of one of the hinge atoms that contains a CO and a PPh3 ligands. This cluster exhibits the shortest average Irfraction three-quartersIr bond length [2.698(2 Å] observed so far for a derivative of 1 and this is in accord with the relatively high average oxidation state of its metal atoms (+1 for a carbonyl cluster compound.
Synthesis of MoS2 and MoO2 for their applications in H2 generation and lithium ion batteries: a review

International Nuclear Information System (INIS)

Zhao Yufei; Zhang Yuxia; Yang Zhiyu; Yan Yiming; Sun Kening

2013-01-01

Scientists increasingly witness the applications of MoS 2 and MoO 2 in the field of energy conversion and energy storage. On the one hand, MoS 2 and MoO 2 have been widely utilized as promising catalysts for electrocatalytic or photocatalytic hydrogen evolution in aqueous solution. On the other hand, MoS 2 and MoO 2 have also been verified as efficient electrode material for lithium ion batteries. In this review, the synthesis, structure and properties of MoS 2 and MoO 2 are briefly summarized according to their applications for H 2 generation and lithium ion batteries. Firstly, we overview the recent advancements in the morphology control of MoS 2 and MoO 2 and their applications as electrocatalysts for hydrogen evolution reactions. Secondly, we focus on the photo-induced water splitting for H 2 generation, in which MoS 2 acts as an important co-catalyst when combined with other semiconductor catalysts. The newly reported research results of the significant functions of MoS 2 nanocomposites in photo-induced water splitting are presented. Thirdly, we introduce the advantages of MoS 2 and MoO 2 for their enhanced cyclic performance and high capacity as electrode materials of lithium ion batteries. Recent key achievements in MoS 2 - and MoO 2 -based lithium ion batteries are highlighted. Finally, we discuss the future scope and the important challenges emerging from these fascinating materials. (review)
Fumarole/plume and diffuse CO2 emission from Sierra Negra volcano, Galapagos archipelago

Science.gov (United States)

Padron, E.; Hernandez Perez, P. A.; Perez, N.; Theofilos, T.; Melian, G.; Barrancos, J.; Virgil, G.; Sumino, H.; Notsu, K.

2009-12-01

The active shield-volcano Sierra Negra is part of the Galapagos hotspot. Sierra Negra is the largest shield volcano of Isabela Island, hosting a 10 km diameter caldera. Ten historic eruptions have occurred and some involved a frequently visited east caldera rim fissure zone called Volcan Chico. The last volcanic event occurred in October 2005 and lasted for about a week, covering approximately twenty percent of the eastern caldera floor. Sierra Negra volcano has experienced some significant changes in the chemical composition of its volcanic gas discharges after the 2005 eruption. This volcanic event produced an important SO2 degassing that depleted the magmatic content of this gas. Not significant changes in the MORB and plume-type helium contribution were observed after the 2005 eruption, with a 65.5 % of MORB and 35.5 % of plume contribution. In 2006 a visible and diffuse gas emission study was performed at the summit of Sierra Negra volcano, Galapagos, to evaluate degassing rate from this volcanic system. Diffuse degassing at Sierra Negra was mainly confined in three different DDS: Volcan Chico, the southern inner margin of the caldera, and Mina Azufral. These areas showed also visible degassing, which indicates highly fractured areas where volcano-hydrothermal fluids migrate towards surface. A total fumarole/plume SO2 emission of 11 ± 2 td-1 was calculated by mini-DOAS ground-based measurements at Mina Azufral fumarolic area. Molar ratios of major volcanic gas components were also measured in-situ at Mina Azufral with a portable multisensor. The results showed H2S/SO2, CO2/SO2 and H2O/SO2 molar ratios of 0.41, 52.2 and 867.9, respectively. Multiplying the observed SO2 emission rate times the observed (gas)i/SO2 mass ratio we have estimated other volatiles emission rates. The results showed that H2O, CO2 and H2S emission rates from Sierra Negra are 562, 394, and 2.4 t d-1, respectively. The estimated total output of diffuse CO2 emission from the summit of
Isotopic equilibrium constants of the deuterium exchange between HDO and H2S, H2Se and H2Te

International Nuclear Information System (INIS)

Marx, D.

1959-11-01

We have determined experimentally the equilibrium constant K of each of the following isotope exchanges: SH 2 + OHD ↔ SHD + OH 2 ; SeH 2 + OHD ↔ SeHD + OH 2 ; TeH 2 + OHD ↔ TeHD + OH 2 . In gaseous phase, statistical thermodynamics leads to the expression: K (Z OHD x Z RH 2 )/(Z OH 2 x Z RHD ) x e W/T (R being the elements S, Se or Te). Z, the partition functions, have been calculated and, through our experimental results, the constant W has been determined. Having obtained W, the equilibrium constant K has been calculated for a series of temperatures. (author) [fr
An experimental study on premixed CNG/H2/CO2 mixture flames

Directory of Open Access Journals (Sweden)

Yilmaz Ilker

2018-03-01

Full Text Available In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW. All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.
Increased H2CO production in the outer disk around HD 163296

Science.gov (United States)

Carney, M. T.; Hogerheijde, M. R.; Loomis, R. A.; Salinas, V. N.; Öberg, K. I.; Qi, C.; Wilner, D. J.

2017-09-01

Context. The gas and dust in circumstellar disks provide the raw materials to form planets. The study of organic molecules and their building blocks in such disks offers insight into the origin of the prebiotic environment of terrestrial planets. Aims: We aim to determine the distribution of formaldehyde, H2CO, in the disk around HD 163296 to assess the contribution of gas- and solid-phase formation routes of this simple organic. Methods: Three formaldehyde lines were observed (H2CO 303-202, H2CO 322-221, and H2CO 321-220) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5″ (60 AU) spatial resolution. Different parameterizations of the H2CO abundance were compared to the observed visibilities, using either a characteristic temperature, a characteristic radius or a radial power law index to describe the H2CO chemistry. Similar models were applied to ALMA Science Verification data of C18O. In each scenario, χ2 minimization on the visibilities was used to determine the best-fit model in each scenario. Results: H2CO 303-202 was readily detected via imaging, while the weaker H2CO 322-221 and H2CO 321-220 lines required matched filter analysis to detect. H2CO is present throughout most of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of the H2CO emission is likely caused by an optically thick dust continuum. The H2CO radial intensity profile shows a peak at 100 AU and a secondary bump at 300 AU, suggesting increased production in the outer disk. In all modeling scenarios, fits to the H2CO data show an increased abundance in the outer disk. The overall best-fit H2CO model shows a factor of two enhancement beyond a radius of 270 ± 20 AU, with an inner abundance (relative to H2) of 2 - 5 × 10-12. The H2CO emitting region has a lower limit on the kinetic temperature of T> 20 K. The C18O modeling suggests an order of magnitude depletion of C18O in the outer disk and an abundance of 4 - 12 × 10-8 in the inner disk
Hydrothermal stability of adenine under controlled fugacities of N2, CO2 and H2.

Science.gov (United States)

Franiatte, Michael; Richard, Laurent; Elie, Marcel; Nguyen-Trung, Chinh; Perfetti, Erwan; LaRowe, Douglas E

2008-04-01

An experimental study has been carried out on the stability of adenine (one of the five nucleic acid bases) under hydrothermal conditions. The experiments were performed in sealed autoclaves at 300 degrees C under fugacities of CO(2), N(2) and H(2) supposedly representative of those in marine hydrothermal systems on the early Earth. The composition of the gas phase was obtained from the degradation of oxalic acid, sodium nitrite and ammonium chloride, and the oxidation of metallic iron. The results of the experiments indicate that after 200 h, adenine is still present in detectable concentration in the aqueous phase. In fact, the concentration of adenine does not seem to be decreasing after approximately 24 h, which suggests that an equilibrium state may have been established with the inorganic constituents of the hydrothermal fluid. Such a conclusion is corroborated by independent thermodynamic calculations.
Room temperature CO and H2 sensing with carbon nanoparticles

International Nuclear Information System (INIS)

Kim, Daegyu; Pikhitsa, Peter V; Yang, Hongjoo; Choi, Mansoo

2011-01-01

We report on a shell-shaped carbon nanoparticle (SCNP)-based gas sensor that reversibly detects reducing gas molecules such as CO and H 2 at room temperature both in air and inert atmosphere. Crystalline SCNPs were synthesized by laser-assisted reactions in pure acetylene gas flow, chemically treated to obtain well-dispersed SCNPs and then patterned on a substrate by the ion-induced focusing method. Our chemically functionalized SCNP-based gas sensor works for low concentrations of CO and H 2 at room temperature even without Pd or Pt catalysts commonly used for splitting H 2 molecules into reactive H atoms, while metal oxide gas sensors and bare carbon-nanotube-based gas sensors for sensing CO and H 2 molecules can operate only at elevated temperatures. A pristine SCNP-based gas sensor was also examined to prove the role of functional groups formed on the surface of functionalized SCNPs. A pristine SCNP gas sensor showed no response to reducing gases at room temperature but a significant response at elevated temperature, indicating a different sensing mechanism from a chemically functionalized SCNP sensor.
SO/sub 2/ injury to forests

Energy Technology Data Exchange (ETDEWEB)

Hontvedt, R

1970-01-01

Sulfur dioxide is one of the most important of the air pollutants which has produced damage to trees and other vegetation. This article gives some examples of SO/sub 2/ damage to forests: At Rjukan in Norway, at Naerkes-Kvarntorp in Sweden and in German industrial regions. Then a brief summary is given of the factors which determine the effects of SO/sub 2/ on plants. Significant differences in SO/sub 2/ resistance exist, both between species and between individuals of the same species. Deciduous trees are more resistant than conifers. There appears to be a positive correlation between CO/sub 2/ assimilation and SO/sub 2/ damage in some individuals. Factors which influence co2 assimilation include, for example, the leaf development state and environmental factors (light, water, temperature, etc.). High SO/sub 2/ concentrations in the air over a brief time period are distinctly more injurious than low concentrations over a long time. Fertilization may increase the resistance of forest trees to SO/sub 2/. Some insect types predispose to SO/sub 2/, partly by increasing the number of dead and weakened trees and partially by increasing parasitization by insects.
Solubility Modeling of the Binary Systems Fe(NO3)3–H2O, Co(NO3)2–H2O and the Ternary System Fe(NO3)3–Co(NO3)2–H2O with the Extended Universal Quasichemical (UNIQUAC) Model

DEFF Research Database (Denmark)

Arrad, Mouad; Kaddami, Mohammed; Goundali, Bahija El

2016-01-01

Solubility modeling in the binary system Fe(NO3)3–H2O, Co(NO3)2–H2O and the ternary system Fe(NO3)3–Co(NO3)2–H2O is presented. The extended UNIQUAC model was applied to the thermodynamic assessment of the investigated systems. The model parameters obtained were regressed simultaneously using...... the available databank but with more experimental points, recently published in the open literature. A revision of previously published parameters for the cobalt ion and new parameters for the iron(III) nitrate system are presented. Based on this set of parameters, the equilibrium constants of hydrates...
Relaxation phenomena in CsCoCl3·2 H2O

NARCIS (Netherlands)

Flokstra, Jakob; Gerritsma, G.J.; Vermeulen, A.J.W.A; Botterman, A.C.

1973-01-01

Dynamic susceptibility measurements have been performed on a single crystal of CsCoCl3·2H2O at liquid temperatures by means of a Hartshorn mutual inductance bridge. At the magnetic phase transition a maximum in τabs(H) has been observed. A jump in τabs(T) has been found at the λ-point of liquid
Relative importance of H2 and H2S as energy sources for primary production in geothermal springs.

Science.gov (United States)

D'Imperio, Seth; Lehr, Corinne R; Oduro, Harry; Druschel, Greg; Kühl, Michael; McDermott, Timothy R

2008-09-01

Geothermal waters contain numerous potential electron donors capable of supporting chemolithotrophy-based primary production. Thermodynamic predictions of energy yields for specific electron donor and acceptor pairs in such systems are available, although direct assessments of these predictions are rare. This study assessed the relative importance of dissolved H(2) and H(2)S as energy sources for the support of chemolithotrophic metabolism in an acidic geothermal spring in Yellowstone National Park. H(2)S and H(2) concentration gradients were observed in the outflow channel, and vertical H(2)S and O(2) gradients were evident within the microbial mat. H(2)S levels and microbial consumption rates were approximately three orders of magnitude greater than those of H(2). Hydrogenobaculum-like organisms dominated the bacterial component of the microbial community, and isolates representing three distinct 16S rRNA gene phylotypes (phylotype = 100% identity) were isolated and characterized. Within a phylotype, O(2) requirements varied, as did energy source utilization: some isolates could grow only with H(2)S, some only with H(2), while others could utilize either as an energy source. These metabolic phenotypes were consistent with in situ geochemical conditions measured using aqueous chemical analysis and in-field measurements made by using gas chromatography and microelectrodes. Pure-culture experiments with an isolate that could utilize H(2)S and H(2) and that represented the dominant phylotype (70% of the PCR clones) showed that H(2)S and H(2) were used simultaneously, without evidence of induction or catabolite repression, and at relative rate differences comparable to those measured in ex situ field assays. Under in situ-relevant concentrations, growth of this isolate with H(2)S was better than that with H(2). The major conclusions drawn from this study are that phylogeny may not necessarily be reliable for predicting physiology and that H(2)S can dominate over H(2
The electrochemical oxidation of lead in various H/sub 2/O-H/sub 2/SO/sub 4/ mixtures-II. Ring-disc electrode study

Energy Technology Data Exchange (ETDEWEB)

Danel, V; Plichon, V

1983-06-01

The rotating ring-disc electrode technique was used to study the generation of soluble Pb(II) species during the anodic oxidation of the lead electrode in various H/sub 2/O-H/sub 2/SO/sub 4/ media. The concentration range extended from 0.06 to 10.3 M H/sub 2/SO/sub 4/. For every concentration it was possible to detect small cathodic ring current variation which was attributable to the reduction of Pb(II) to Pb. Quantitative measurements of the collection efficiency showed that the small cycle life of the lead-acid batter in 5.6 M H/sub 2/SO/sub 4/ cannot be ascribed to the dissolution step.

MoS2 Nanocube structures as catalysts for electrochemical H2 evolution from acidic aqueous solutions

NARCIS (Netherlands)

Maijenburg, A.W.; Regis, M.; Hattori, A.N.; Tanaka, H.; Choi, K.-S.; ten Elshof, Johan E.

2014-01-01

Core–shell PMMA–Au nanocube structures made by a combination of nanoimprint lithography and sidewall deposition were used as template for electrodeposition of MoS2, Ni, and Pt. Linear sweep voltammetry experiments obtained in an aqueous solution containing 0.29 M H2SO4 (pH 0.24) showed that the
Development of Novel CO2 Adsorbents for Capture of CO2 from Flue Gas

Energy Technology Data Exchange (ETDEWEB)

Fauth, D.J.; Filburn, T.P. (University of Hartford, West Hartford, CT); Gray, M.L.; Hedges, S.W.; Hoffman, J.; Pennline, H.W.; Filburn, T.

2007-06-01

Capturing CO2 emissions generated from fossil fuel-based power plants has received widespread attention and is considered a vital course of action for CO2 emission abatement. Efforts are underway at the Department of Energy’s National Energy Technology Laboratory to develop viable energy technologies enabling the CO2 capture from large stationary point sources. Solid, immobilized amine sorbents (IAS) formulated by impregnation of liquid amines within porous substrates are reactive towards CO2 and offer an alternative means for cyclic capture of CO2 eliminating, to some degree, inadequacies related to chemical absorption by aqueous alkanolamine solutions. This paper describes synthesis, characterization, and CO2 adsorption properties for IAS materials previously tested to bind and release CO2 and water vapor in a closed loop life support system. Tetraethylenepentamine (TEPA), acrylonitrile-modified tetraethylenepentamine (TEPAN), and a single formulation consisting of TEPAN and N, N’-bis(2-hydroxyethyl)ethylenediamine (BED) were individually supported on a poly (methyl methacrylate) (PMMA) substrate and examined. CO2 adsorption profiles leading to reversible CO2 adsorption capacities were obtained using thermogravimetry. Under 10% CO2 in nitrogen at 25°C and 1 atm, TEPA supported on PMMA over 60 minutes adsorbed ~3.2 mmol/g{sorbent} whereas, TEPAN supported on PMMA along with TEPAN and BED supported on PMMA adsorbed ~1.7 mmol/g{sorbent} and ~2.3 mmol/g{sorbent} respectively. Cyclic experiments with a 1:1 weight ratio of TEPAN and BED supported on poly (methyl methacrylate) beads utilizing a fixed-bed flow system with 9% CO2, 3.5% O2, nitrogen balance with trace gas constituents were studied. CO2 adsorption capacity was ~ 3 mmols CO2/g{sorbent} at 40°C and 1.4 atm. No beneficial effect on IAS performance was found using a moisture-laden flue gas mixture. Tests with 750 ppmv NO in a humidified gas stream revealed negligible NO sorption onto the IAS. A high SO2
Tailoring of TiO2 films by H2SO4 treatment and UV irradiation to improve anticoagulant ability and endothelial cell compatibility.

Science.gov (United States)

Liao, Yuzhen; Li, Linhua; Chen, Jiang; Yang, Ping; Zhao, Ansha; Sun, Hong; Huang, Nan

2017-07-01

Surfaces with dual functions that simultaneously exhibit good anticoagulant ability and endothelial cell (EC) compatibility are desirable for blood contact materials. However, these dual functions have rarely been achieved by inorganic materials. In this study, titanium dioxide (TiO 2 ) films were treated by sulphuric acid (H 2 SO 4 ) and ultraviolet (UV) irradiation successively (TiO 2 H 2 SO 4 -UV), resulting in good anticoagulant ability and EC compatibility simultaneously. We found that UV irradiation improved the anticoagulant ability of TiO 2 films significantly while enhancing EC compatibility, though not significantly. The enhanced anticoagulant ability could be related to the oxidation of surface-adsorbed hydrocarbons and increased hydrophilicity. The H 2 SO 4 treatment improved the anticoagulant ability of TiO 2 films slightly, while UV irradiation improved the anticoagulant ability strongly. The enhanced EC compatibility could be related to the increased surface roughness and positive charges on the surface of the TiO 2 films. Furthermore, the time-dependent degradation of the enhanced EC compatibility and anticoagulant ability of TiO 2 H 2 SO 4 -UV was observed. In summary, TiO 2 H 2 SO 4 -UV expressed both excellent anticoagulant ability and good EC compatibility at the same time, which could be desirable for blood contact materials. However, the compatibility of TiO 2 H 2 SO 4 -UV with smooth muscle cells (SMCs) and macrophages was also improved. More effort is still needed to selectively improve EC compatibility on TiO 2 films for better re-endothelialization. Copyright © 2017 Elsevier B.V. All rights reserved.
Improved method to determine the molar volume and compositions of the NaCl-H2O-CO2 system inclusion

Institute of Scientific and Technical Information of China (English)

SONG YuCai; HU WenXuan; NI Pei; DUAN ZhenHao; ZHANG XueFeng

2007-01-01

On the basis of Parry's method (1986),an improved method was established to determine the molar volume(Vm)and compositions(X)of the NaCl-H2O-CO2(NHC)system inclusion.To use this method,the determination of Vm-X only requires three microthermometric data of a NHC inclusion:partial homogenization temperature(Th,CO2),salinity(s)and total homogenization temperature(Th).Theoretically,four associated equations are needed containing four unknown parameters:Xco2,XNcl,Vm and F (volume fraction of CO2 phase in total inclusion when occurring partial homogenization).When they are released,the Vm-X are determined.The former three equations,only correlated with Th,co2,S and F,have simplified expressions:XCO2=f1(Th,CO2,S,F),XNaCl=f2(Th,CO2,S,F),Vm=f3(Th,CO2,S,F).The last one is the thermodynamic relationship of Xco2,Xnacl,vm and Th:f4(XCO2,XNacl,Vm,Th)=0. Since the above four associated equations are complicated,it is necessary to adopt iterative technique to release them.The technique can be described by:(i)Freely input a F value(0≤F≤1),with Th,co2 and S,into the former three equations.As a result,Xco2,XNacl and the molar volume value recorded as Vm1 are derived.(ii)Input the Xco2 and XNacl gotten in the step above into the last equation,and another molar volume value recorded as Vm2 is determined.(iii) If Vm1 is unequal to Vm2,the calculation will be restarted from"(i)".The iteration is completed until Vm1 is equal to Vm2,which means that the four associated equations are released.Compared to Parry's (1986) solution method,the improved method is more convenient to use,as well as more accurate to determine Xco2.It is available for a NHC inlusion whose partial homogenization temperature is higher than clatherate melting temperature and there are no solid salt crystals in the inclusion at parital homogenization.
Solid-liquid stable phase equilibria of the ternary systems MgCl2 + MgB6O10+ H2O AND MgSO4 + MgB6O10 + H2O at 308.15 K

Directory of Open Access Journals (Sweden)

Lingzong Meng

2014-03-01

Full Text Available The solubilities and the relevant physicochemical properties of the ternary systems MgCl2 + MgB6O10 + H2O and MgSO4 + MgB6O10 + H2O at 308.15 K were investigated using an isothermal dissolution method. It was found that there is one invariant point, two univariant curves, and two crystallization regions of the systems. The systems belong to a simple co-saturated type, and neither double salts nor solid solutions were found. Based on the extended HW model and its temperature-dependent equations, the single-salt Pitzer parameters β(0, β(1, β(2 and CØ for MgCl2, MgSO4, and Mg(B6O7(OH6, the mixed ion-interaction parameters θCl,B6O10, θSO4,B6O10, ΨMg,Cl,B6O10, ΨMg,SO4,B6O10 of the systems at 308.15 K were fitted, In addition, the average equilibrium constants of the stable equilibrium solids at 308.15 K were obtained by a method using the activity product constant. Then the solubilities of the ternary systems are calculated. The calculated solubilities agree well with the experimental values.
Isotope ratios of H, C, and O in CO2 and H2O of the martian atmosphere.

Science.gov (United States)

Webster, Chris R; Mahaffy, Paul R; Flesch, Gregory J; Niles, Paul B; Jones, John H; Leshin, Laurie A; Atreya, Sushil K; Stern, Jennifer C; Christensen, Lance E; Owen, Tobias; Franz, Heather; Pepin, Robert O; Steele, Andrew; Achilles, Cherie; Agard, Christophe; Alves Verdasca, José Alexandre; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Bish, David; Blake, David F; Blanco Avalos, Juan J; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John; Cantor, Bruce; Caplinger, Michael; Caride Rodríguez, Javier; Carmosino, Marco; Carrasco Blázquez, Isaías; Charpentier, Antoine; Chipera, Steve; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Crisp, Joy; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie; de la Torre Juarez, Manuel; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; DesMarais, David; Dietrich, William; Dingler, Robert; Donny, Christophe; Downs, Bob; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; François, Pascaline; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez Gómez, Felipe; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Lepinette Malvitte, Alain; Léveillé, Richard; Lewin-Carpintier, Éric; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gérard; Manning, Heidi; Marchand, Geneviève; Marín Jiménez, Mercedes; Martín García, César; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F Javier; Mauchien, Patrick; Maurice, Sylvestre; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McLennan, Scott; McNair, Sean; Melikechi, Noureddine; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Ming, Douglas; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Molina Jurado, Antonio; Moores, John; Mora-Sotomayor, Luis; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Muñoz Caro, Guillermo; Nachon, Marion; Navarro López, Sara; Navarro-González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Nixon, Brian; Noe Dobrea, Eldar; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; de Pablo Hernández, Miguel Ángel; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Rampe, Elizabeth; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Robert, François; Robertson, Kevin; Rodriguez Manfredi, José Antonio; Romeral-Planelló, Julio J; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Sans Fuentes, Sara Alejandra; Saper, Lee; Sarrazin, Philippe; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne; Sebastian Martinez, Eduardo; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sobrón Sánchez, Pablo; Spanovich, Nicole; Spray, John; Squyres, Steven; Stack, Katie; Stalport, Fabien; Stein, Thomas; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Stolper, Ed; Sucharski, Bob; Sullivan, Rob; Summons, Roger; Sumner, Dawn; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Torres Redondo, Josefina; Trainer, Melissa; Treiman, Allan; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Vaniman, David; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Yen, Albert; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Zorzano Mier, María-Paz

2013-07-19

Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and (18)O/(16)O in water and (13)C/(12)C, (18)O/(16)O, (17)O/(16)O, and (13)C(18)O/(12)C(16)O in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.
VOLATILECALC: A silicate melt-H2O-CO2 solution model written in Visual Basic for excel

Science.gov (United States)

Newman, S.; Lowenstern, J. B.

2002-01-01

We present solution models for the rhyolite-H2O-CO2 and basalt-H2O-CO2 systems at magmatic temperatures and pressures below ~ 5000 bar. The models are coded as macros written in Visual Basic for Applications, for use within MicrosoftR Excel (Office'98 and 2000). The series of macros, entitled VOLATILECALC, can calculate the following: (1) Saturation pressures for silicate melt of known dissolved H2O and CO2 concentrations and the corresponding equilibrium vapor composition; (2) open- and closed-system degassing paths (melt and vapor composition) for depressurizing rhyolitic and basaltic melts; (3) isobaric solubility curves for rhyolitic and basaltic melts; (4) isoplethic solubility curves (constant vapor composition) for rhyolitic and basaltic melts; (5) polybaric solubility curves for the two end members and (6) end member fugacities of H2O and CO2 vapors at magmatic temperatures. The basalt-H2O-CO2 macros in VOLATILECALC are capable of calculating melt-vapor solubility over a range of silicate-melt compositions by using the relationships provided by Dixon (American Mineralogist 82 (1997) 368). The output agrees well with the published solution models and experimental data for silicate melt-vapor systems for pressures below 5000 bar. ?? 2002 Elsevier Science Ltd. All rights reserved.
Synthesis and chemistry of the open-cage cobaltaheteroborane cluster [{(η(5)-C5Me5)Co}2B2H2Se2]: a combined experimental and theoretical study.

Science.gov (United States)

Barik, Subrat Kumar; Dorcet, Vincent; Roisnel, Thierry; Halet, Jean-François; Ghosh, Sundargopal

2015-08-28

Reaction of [(η(5)-C5Me5)CoCl]2 with a two-fold excess of [LiBH4·thf] followed by heating with an excess of Se powder produces the dicobaltaselenaborane species [{(η(5)-C5Me5)Co}2B2H2Se2], , in good yield. The geometry of resembles a nido pentagonal [Co2B2Se2] bipyramid with a missing equatorial vertex. It can alternatively be seen as an open cage triple-decker cluster. Isolation of permits its reaction with [Fe2(CO)9] to give heterometallic diselenametallaborane [{(η(5)-C5Me5)Co}Fe(CO)3B2H2Se2], . The geometry of is similar to that of with one of the [(η(5)-C5Me5)Co] groups replaced by the isolobal, two-electron fragment [Fe(CO)3]. Both new compounds have been characterized by mass spectrometry, and by (1)H, (11)B and (13)C NMR spectroscopy. The structural architectures have been unequivocally established by crystallographic analysis. In addition, density functional theory calculations were performed to investigate the bonding and electronic properties. The large HOMO-LUMO gaps computed for both clusters are consistent with their thermodynamic stability. Natural bond order calculations predict the absence of metal-metal bonding interaction.
Geothermal-brine modeling - prediction of mineral solubilities in natural waters: the Na-K-Mg-Ca-H-Cl-SO{sub 4}-OH-HCO{sub 3} CO{sub 3}-CO{sub 2}-H{sub 2}O system to high ionic strengths at 25{sup 0}C

Energy Technology Data Exchange (ETDEWEB)

Weare, J.H.

1981-01-01

The mineral solubility model of Harvie and Weare (1980) is extended to the eight component system, Na-K-Ca-Mg-H-Cl-SO{sub 4}-OH-HCO{sub 3}-CO{sub 3}-CO{sub 2}-H{sub 2}O at 25{sup 0}C to high concentrations. The model is based on the semi-empirical equations of Pitzer (1973) and co-workers for the thermodynamics of aqueous electrolyte solutions. The model is parameterized using many of the available isopiestic, electromotive force, and solubility data available for many of the subsystems. The predictive abilities of the model are demonstrated by comparison to experimental data in systems more complex than those used in parameterization. The essential features of a chemical model for aqueous electrolyte solutions and the relationship between pH and the equilibrium properties of a solution are discussed.
Abundances and Excitation of H2, H3+ & CO in Star-Forming Regions

Science.gov (United States)

Kulesa, Craig A.

Although most of the 123 reported interstellar molecules to date have been detected through millimeter-wave emission-line spectroscopy, this technique is inapplicable to non-polar molecules like H2 and H3+, which are central to our understanding of interstellar chemistry. Thus high resolution infrared absorption-line spectroscopy bears an important role in interstellar studies: chemically important non-polar molecules can be observed, and their abundances and excitation conditions can be referred to the same ``pencil beam'' absorbing column. In particular, through a weak quadrupole absorption line spectrum at near-infrared wavelengths, the abundance of cold H2 in dark molecular clouds and star forming regions can now be accurately measured and compared along the same ``pencil beam'' line of sight with the abundance of its most commonly cited surrogate, CO, and its rare isotopomers. Also detected via infrared line absorption is the pivotal molecular ion H3+, whose abundance provides the most direct measurement of the cosmic ray ionization rate in dark molecular clouds, a process that initiates the formation of many other observed molecules there. Our growing sample of H2 and CO detections now includes detailed multi-beam studies of the ρ Ophiuchi molecular cloud and NGC 2024 in Orion. We explore the excitation and degree of ortho- and para-H2 thermalization in dark clouds, variation of the CO abundance over a cloud, and the relation of H2 column density to infrared extinction mapping, far-infrared/submillimeter dust continuum emission, and large scale submillimeter CO, [C I] and HCO+ line emission -- all commonly invoked to indirectly trace H2 during the past 30+ years. For each of the distinct velocity components seen toward some embedded young stellar objects, we are also able to determine the temperature, density, and a CO/H2 abundance ratio, thus unraveling some of the internal structure of a star-forming cloud. H2 and H3+ continue to surprise and delight us
Hydrothermal Valorization of Steel Slags—Part I: Coupled H{sub 2} Production and CO{sub 2} Mineral Sequestration

Energy Technology Data Exchange (ETDEWEB)

Crouzet, Camille [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); LRCS and RS2E, CNRS-UMR7314, University Picardie Jules Verne, Amiens (France); Aix Marseille University, CNRS, Centrale Marseille, M2P2, Marseille (France); Brunet, Fabrice, E-mail: fabrice.brunet@univ-grenoble-alpes.fr; Montes-Hernandez, German [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); Recham, Nadir [LRCS and RS2E, CNRS-UMR7314, University Picardie Jules Verne, Amiens (France); Findling, Nathaniel [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); Ferrasse, Jean-Henry [Aix Marseille University, CNRS, Centrale Marseille, M2P2, Marseille (France); Goffé, Bruno [Aix-Marseille University, CNRS, IRD, Coll. de France, CEREGE, Aix-en-Provence (France)

2017-10-30

A new process route for the valorization of BOF steel slags combining H{sub 2} production and CO{sub 2} mineral sequestration is investigated at 300°C (HT) under hydrothermal conditions. A BOF steel slag stored several weeks outdoor on the production site was used as starting material. To serve as a reference, room temperature (RT) carbonation of the same BOF steel slag has been monitored with in situ Raman spectroscopy and by measuring pH and P{sub CO2} on a time-resolved basis. CO{sub 2} uptake under RT and HT are, respectively, 243 and 327 kg CO{sub 2}/t of fresh steel slag, which add up with the 63 kg of atmospheric CO{sub 2} per ton already uptaken by the starting steel slag on the storage site. The CO{sub 2} gained by the sample at HT is bounded to the carbonation of brownmillerite. H{sub 2} yield decreased by about 30% in comparison to the same experiment performed without added CO{sub 2}, due to sequestration of ferrous iron in a Mg-rich siderite phase. Ferric iron, initially present in brownmillerite, is partitioned between an Fe-rich clay mineral of saponite type and metastable hematite. Saponite is likely stabilized by the presence of Al, whereas hematite may represent a metastable product of brownmillerite carbonation. Mg-rich wüstite is involved in at least two competing reactions, i.e., oxidation into magnetite and carbonation into siderite. Results of both water-slag and water-CO{sub 2}-slag experiments after 72 h are consistent with a kinetics enhancement of the former reaction when a CO{sub 2} partial pressure imposes a pH between 5 and 6. Three possible valorization routes, (1) RT carbonation prior to hydrothermal oxidation, (2) RT carbonation after hydrothermal treatment, and (3) combined HT carbonation and oxidation are discussed in light of the present results and literature data.
Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO{sub 2}, CH{sub 4}, H{sub 2} adsorptions and high CO{sub 2}/N{sub 2} selectivity

Energy Technology Data Exchange (ETDEWEB)

Modak, Arindam; Bhaumik, Asim, E-mail: msab@iacs.res.in

2015-12-15

Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m{sup 2} g{sup −1} and micropore volume of 0.85 cm{sup 3} g{sup −1} has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}) and CH{sub 4} (2.4 mmol g{sup −1}) at 1 atm, 273 K together with very good selectivity for the CO{sub 2}/N{sub 2} (30.2) separation. Furthermore, low pressure (1 atm) H{sub 2} (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m{sup 2} g{sup −1} has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO{sub 2} (7.6 mmol g{sup −1}), CH{sub 4} (2.4 mmol g{sup −1}) and H{sub 2} (2.6 wt%) at 1 atm together with very good selectivity for CO{sub 2}. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m{sup 2} g{sup −1}. • High CO2 uptake (7.6 mmol g{sup −1}) and CO{sub 2}/N{sub 2} selectivity (30.2). • Porous carbon also showed high H{sub 2} (2.6 wt%) and H{sub 2}O (57.4 wt%) uptakes.
High efficient removal of molybdenum from water by Fe{sub 2}(SO{sub 4}){sub 3}: Effects of pH and affecting factors in the presence of co-existing background constituents

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiang; Ma, Jun, E-mail: majunhit@126.com; Lu, Xixin; Huangfu, Xiaoliu; Zou, Jing

2015-12-30

Highlights: • Proposed high efficient Mo (VI) removal with Fe{sub 2}(SO{sub 4}){sub 3} coagulation-filtration. • Studied different effects of Fe{sub 2}(SO{sub 4}){sub 3} and FeCl{sub 3} due to different anionic portions. • Reported the adverse effect of calcium on the removal of Mo (VI). • Proposed factors affecting Mo (VI) removal: intercepted Fe and adsorption affinity. - Abstract: Comparatively investigated the different effects of Fe{sub 2}(SO{sub 4}){sub 3} coagulation-filtration and FeCl{sub 3} coagulation-filtration on the removal of Mo (VI). And the influence of calcium, sulfate, silicate, phosphate and humic acid (HA) were also studied. The following conclusions can be obtained: (1) compared with the case of FeCl{sub 3}, Fe{sub 2}(SO{sub 4}){sub 3} showed a higher Mo (VI) removal efficiency at pH 4.00–5.00, but an equal removal efficiency at pH 6.00–9.00. (2) The optimum Mo (VI) removal by Fe{sub 2}(SO{sub 4}){sub 3} was achieved at pH 5.00–6.00; (3) The presence of calcium can reduce the removal of Mo (VI) over the entire pH range in the present study; (4) The effect of co-existing background anions (including HA) was dominated by three factors: Firstly the influence of co-existing background anions on the content of Fe intercepted from water (intercepted Fe). Secondly the competition of co-existing anions with Mo (VI) for adsorption sites. Thirdly the influence of co-existing background anions on the Zeta potential of the iron flocs.
Nido-Carborane building-block reagents. 2. Bulky-substituent (alkyl)2C2B4H6 derivatives and (C6H5)2C2B4H6: synthesis and properties

International Nuclear Information System (INIS)

Boyter, H.A. Jr.; Grimes, R.N.

1988-01-01

The preparation and chemistry of nido-2,3-R 2 C 2 C 2 B 4 H 6 carboranes in which R is n-butyl, isopentyl, n-hexyl, and phenyl was investigated in order to further assess the steric and electronic influence of the R groups on the properties of the nido-C 2 B 4 cage, especially with respect to metal complexation at the C 2 B 3 face and metal-promoted oxidative fusion. The three dialkyl derivatives were prepared from the corresponding dialkylacetylenes via reaction with B 5 H 9 and triethylamine, but the diphenyl compound could not be prepared in this manner and was obtained instead in a thermal reaction of B 5 H 9 with diphenylacetylene in the absence of amine. All four carboranes are readily bridge-deprotonated by NaH in THF, and the anions of the dialkyl species, on treatment with FeCl 2 and air oxidation, generate the respective R 4 C 4 B 8 H 8 carborane fusion products were R = n-C 4 H 9 , i-C 5 H 11 or n-C 6 H 13 . The diphenylcarborane anion Ph 2 C 2 B 4 H 5 - did not form detectable metal complexes with Fe 2+ , Co 2+ , or Ni 2+ , and no evidence of a Ph 4 C 4 B 8 H 8 fusion product has been found. Treatment of Ph 2 C 2 B 4 H 6 with Cr(CO) 6 did not lead to metal coordination of the phenyl rings, unlike (PhCH 2 ) 2 C 2 B 4 H 6 , which had previously been shown to form mono- and bis(tricarbonylchromium) complexes. However, the reaction of Ph 2 C 2 B 4 H 5 - , CoCl 2 , and (PhPCH 2 ) 2 did give 1,1-(Ph 2 PCH 2 ) 2 -1-Cl-1,2,3-Co(Ph 2 C 2 B 4 H 4 ), the only case in which metal complexation of the diphenylcarborane was observed. 14 references, 3 figures, 3 tables
The effects of CO addition on the autoignition of H-2, CH4 and CH4/H-2 fuels at high pressure in an RCM

NARCIS (Netherlands)

Gersen, Sander; Darmeveil, Harry; Levinsky, Howard

2012-01-01

Autoignition delay times of stoichiometric and fuel-lean (phi = 0.5) H-2, H-2/CO, CH4, CH4/CO, CH4/H-2 and CH4/CO/H-2 mixtures have been measured in an Rapid Compression Machine at pressures ranging from 20 to 80 bar and in the temperature range 900-1100K. The effects of CO addition on the ignition
Molecular Dynamics Simulations for Loading-Dependent Diffusion of CO2, SO2, CH4, and Their Binary Mixtures in ZIF-10: The Role of Hydrogen Bond.

Science.gov (United States)

Li, Li; Yang, Deshuai; Fisher, Trevor R; Qiao, Qi; Yang, Zhen; Hu, Na; Chen, Xiangshu; Huang, Liangliang

2017-10-24

The loading-dependent diffusion behavior of CH 4 , CO 2 , SO 2 , and their binary mixtures in ZIF-10 has been investigated in detail by using classical molecular dynamics simulations. Our simulation results demonstrate that the self-diffusion coefficient D i of CH 4 molecules decreases sharply and monotonically with the loading while those of both CO 2 and SO 2 molecules initially display a slight increase at low uptakes and follow a slow decrease at high uptakes. Accordingly, the interaction energies between CH 4 molecules and ZIF-10 remain nearly constant regardless of the loading due to the absence of hydrogen bonds (HBs), while the interaction energies between CO 2 (or SO 2 ) and ZIF-10 decease rapidly with the loading, especially at small amounts of gas molecules. Such different loading-dependent diffusion and interaction mechanisms can be attributed to the relevant HB behavior between gas molecules and ZIF-10. At low loadings, both the number and strength of HBs between CO 2 (or SO 2 ) molecules and ZIF-10 decrease obviously as the loading increases, which is responsible for the slight increase of their diffusion coefficients. However, at high loadings, their HB strength increases with the loading. Similar loading-dependent phenomena of diffusion, interaction, and HB behavior can be observed for CH 4, CO 2 , and SO 2 binary mixtures in ZIF-10, only associated with some HB competition between CO 2 and SO 2 molecules in the case of the CO 2 /SO 2 mixture.
Absorption of CO2 and H2S in Aqueous Alkanolamine Solutions using a Fixed-Bed Reactor with Cocurrent Downflow Operation in the Pulsing Flow Regime

NARCIS (Netherlands)

Versteeg, G.F.; Swaaij, W.P.M. van

1988-01-01

Absorption rates of H2S and CO2 in several aqueous alkanolamines in a cocurrent downflow fixed-bed reactor operated in the pulse flow regime have been measured in order to obtain information on the potential selectivity and on the mass transfer parameters. From these experiments it can be concluded
New compounds bearing [M(S_2O_7)_3]"2"- anions (M = Si, Ge, Sn): Syntheses and characterization of A_2[Si(S_2O_7)_3] (A = Na, K, Rb), A_2[Ge(S_2O_7)_3] (A = Li, Na, K, Rb, Cs), A_2[Sn(S_2O_7)_3] (A = Na, K), and the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 with cationic "1_∞[HgCl_2_/_2]"+ chains

International Nuclear Information System (INIS)

Logemann, Christian; Witt, Julia; Wickleder, Mathias S.; Gunzelmann, Daniel; Senker, Juergen

2012-01-01

The reaction of the group 14 tetrachlorides MCl_4 (M = Si, Ge, Sn) with oleum (65 % SO_3) at elevated temperatures led to the unique anionic complexes [M(S_2O_7)_3]"2"- that show the central M atoms in coordination of three chelating S_2O_7"2"- groups. The mean distances M-O within the complexes increase from 175 pm (M = Si) via 186 pm (M = Ge) up to 200 pm (M = Sn). The charge balance for the [M(S_2O_7)_3]"2"- anions is achieved by alkaline metal ions A"+ (A = Li, Na, K, Rb, Cs) which were implemented in the syntheses in form of their sulfates. The size of the A"+ ions, i.e. their coordination requirement causes the crystallographic differences in the crystal structures, while the structure of the complex [M(S_2O_7)_3]"2"- anions remains essentially unaffected. Furthermore, we were able to characterize the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 which forms when HgCl_2 is added as a source for the counter cation. The Hg"2"+ and the Cl"- ions form infinite cationic chains according to "1_∞[HgCl_2_/_2]"+ which take care for the charge compensation. For selected examples of the compounds the thermal behavior has been monitored by means of thermal analyses and X-ray powder diffraction. For A being an alkaline metal the decomposition product is a mixture of the sulfates A_2SO_4 and the dioxides MO_2, whereas Hg_2[Ge(S_2O_7)_3]Cl_2 shows a more complicated decomposition. The tris-(disulfato)-silicate Na_2[Si(S_2O_7)_3] has additionally been examined by solid state "2"9Si and "2"3Na NMR spectroscopic measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Reactions between olivine and CO2-rich seawater at 300 °C: Implications for H2 generation and CO2 sequestration on the early Earth

Directory of Open Access Journals (Sweden)

Hisahiro Ueda

2017-03-01

Full Text Available To understand the influence of fluid CO2 on ultramafic rock-hosted seafloor hydrothermal systems on the early Earth, we monitored the reaction between San Carlos olivine and a CO2-rich NaCl fluid at 300 °C and 500 bars. During the experiments, the total carbonic acid concentration (ΣCO2 in the fluid decreased from approximately 65 to 9 mmol/kg. Carbonate minerals, magnesite, and subordinate amount of dolomite were formed via the water-rock interaction. The H2 concentration in the fluid reached approximately 39 mmol/kg within 2736 h, which is relatively lower than the concentration generated by the reaction between olivine and a CO2-free NaCl solution at the same temperature. As seen in previous hydrothermal experiments using komatiite, ferrous iron incorporation into Mg-bearing carbonate minerals likely limited iron oxidation in the fluids and the resulting H2 generation during the olivine alteration. Considering carbonate mineralogy over the temperature range of natural hydrothermal fields, H2 generation is likely suppressed at temperatures below approximately 300 °C due to the formation of the Mg-bearing carbonates. Nevertheless, H2 concentration in fluid at 300 °C could be still high due to the temperature dependency of magnetite stability in ultramafic systems. Moreover, the Mg-bearing carbonates may play a key role in the ocean-atmosphere system on the early Earth. Recent studies suggest that the subduction of carbonated ultramafic rocks may transport surface CO2 species into the deep mantle. This process may have reduced the huge initial amount of CO2 on the surface of the early Earth. Our approximate calculations demonstrate that the subduction of the Mg-bearing carbonates formed in komatiite likely played a crucial role as one of the CO2 carriers from the surface to the deep mantle, even in hot subduction zones.
Thermodinamically stable phases in the CaO-SiO2-Al2O3-CaSO4-H2O closed system at 25 ºC. Application to cementitious systems

Directory of Open Access Journals (Sweden)

Blanco-Varela, M. T.

2009-06-01

Full Text Available One of the chief causes of cement and concrete deterioration is the loss of durability prompted by sulphate attack. The existing standards call for long test periods (2- 12 months. Thermodynamic modelling is a particularly appropriate technique for studying systems that only reach equilibrium in the long term. Used in the present study to establish the fields of thermodynamic stability for the phases in the CaO-SiO2-Al2O3-CaSO4-H2O system at 25 ºC. According to the model, gypsum is stable at sulphate ion concentrations of 1.23e-2 mol/kg and over, while ettringite exhibits stability at concentrations ranging from 7.64e-6 to 1.54e-2 mol/kg. Ettringite is compatible with all system phases except SH and gypsum only with ettringite, the C-S-H gels, AH3 and SH. None of the calcium aluminates or silicoaluminates in the system is compatible with gypsum: in its presence, they all decompose to cement deteriorating ettringite. Finally, the model revealed that the maximum sulphate concentration at which C-S-H gel is stable is slightly higher in systems with than without Al2O3.Uno de los principales problemas asociados al deterioro de cementos y hormigones es la pérdida de durabilidad por ataque de sulfatos. La normativa existente requiere largos tiempos de ensayo (2-12 meses. La modelización termodinámica es una técnica particularmente adecuada para el estudio de sistemas que alcanzan el equilibrio en tiempos largos. Aplicando esta metodología se han establecido los campos de estabilidad termodinámica de las fases del sistema CaO-SiO2-Al2O3-CaSO4-H2O a 25 ºC. El yeso es estable a partir de la [SO42-] = 1,23e-2 mol/kg, y la ettringita es estable en un rango de [SO42-] = 7,64e-6 -1,54e-2 mol/kg. La ettringita es compatible con todas las fases del sistema excepto con SH y el yeso sólo con la ettringita, los geles C-S-H, el AH3 y el SH. Ninguno de los aluminatos o silicoaluminatos cálcicos son compatibles con el yeso, en su presencia se descomponen

Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

Science.gov (United States)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-03-01

Two one-dimensional bismuth-coordination materials, Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2), have been synthesized by hydrothermal reactions using Bi2O3, 2,6-NC5H3(CO2H)2, HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC5H3(CO2)2](OH2)F single crystals at 800 °C led to α-Bi2O3 that maintained the same morphology of the original crystals.
NMR Spectroscopic Characterization of Methylcobalt(III) Compounds with Classical Ligands. Crystal Structures of [Co(NH(3))(5)(CH(3))]S(2)O(6), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (en = 1,2-Ethanediamine), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(

DEFF Research Database (Denmark)

Kofod, Pauli; Harris, Pernille; Larsen, Sine

1997-01-01

magnetic resonance spectroscopy and by absorption spectroscopy. Single-crystal X-ray structure determinations at 122.0(5) K were performed on [Co(NH(3))(5)(CH(3))]S(2)O(6) (1), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (2), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(3))(2)(CH(3))](2)-trans-[Co(NO(2...
Enhancement in CO2 Adsorption Capacity and Selectivity in the Chalcogenide Aerogel CuSb2S4 by Post-synthetic Modification with LiCl

KAUST Repository

Ahmed, Ejaz

2015-09-11

The new chalcogel CuSb2S4 was obtained by reacting Cu(OAc)2·H2O with KSbS2 in a water/formamide mixture at room temperature. In order to modify the gas adsorption capacity the synthesized CuSb2S4 aerogel was loaded with different amounts of LiCl. CO2 adsorption measurements on the CuSb2S4 aerogel before and after treatment with LiCl showed more than three times increased uptake of the LiCl-modified chalcogel. The selectivities of the gas pairs CO2/H2 and CO2/CH4 in the LiCl-treated chalcogel are 235 and 105 respectively and amongst the highest reported for chalcogenide-based aerogels. In comparison with other porous materials like zeolites, activated carbon and most of the Metal Organic Frameworks (MOFs) or Porous Organic Frameworks (POFs), our synthesized aerogels show good air and moisture stability. Although, the CO2 storage capacity of our aerogels is relatively low, however the selectivity of CO2 over H2 or CH4 in LiCl-loaded aerogels are higher than in zeolites, activated carbon as well as some MOFs like Cu-BTC and MOF-5 etc.
Detection of transient infrared absorption of SO3 and 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH2)O(SO2)O] in the reaction CH2OO+SO2

Science.gov (United States)

Wang, Yi-Ying; Dash, Manas Ranjan; Chung, Chao-Yu; Lee, Yuan-Pern

2018-02-01

We recorded time-resolved infrared absorption spectra of transient species produced on irradiation at 308 nm of a flowing mixture of CH2I2/O2/N2/SO2 at 298 K. Bands of CH2OO were observed initially upon irradiation; their decrease in intensity was accompanied by the appearance of an intense band at 1391.5 cm-1 that is associated with the degenerate SO-stretching mode of SO3, two major bands of HCHO at 1502 and 1745 cm-1, and five new bands near >1340, 1225, 1100, 940, and 880 cm-1. The band near 1340 cm-1 was interfered by absorption of SO2 and SO3, so its band maximum might be greater than 1340 cm-1. SO3 in its internally excited states was produced initially and became thermalized at a later period. The rotational contour of the band of thermalized SO3 agrees satisfactorily with the reported spectrum of SO3. These five new bands are tentatively assigned to an intermediate 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH2)O(SO2)O] according to comparison with anharmonic vibrational wavenumbers and relative IR intensities predicted for this intermediate. Observation of a small amount of cyc-(CH2)O(SO2)O is consistent with the expected reaction according to the potential energy scheme predicted previously. SO3+HCHO are the major products of the title reaction. The other predicted product channel HCOOH+SO2 was unobserved and its branching ratio was estimated to be <5%.
Comprehensive cluster-theory analysis of the magnetic structures and excitations in CoCl2·2H2O

DEFF Research Database (Denmark)

Jensen, Jens; Larsen, Jacob; Hansen, Ursula B.

2018-01-01

The magnetic properties of CoCl2·2H2O are analyzed in the mean-field/random-phase approximation using a basis of clusters with four spins along the c-axis chains of Co ions. The model gives a unifying account of the bulk properties, the spin waves, and the higher-order cluster-spin excitations...... at a transverse field of 160 kOe and is found to agree closely with their observations....
MoS2 Nanocube structures as catalysts for electrochemical H2 evolution from acidic aqueous solutions

OpenAIRE

Maijenburg, A.W.; Regis, M.; Hattori, A.N.; Tanaka, H.; Choi, K.-S.; ten Elshof, Johan E.

2014-01-01

Core–shell PMMA–Au nanocube structures made by a combination of nanoimprint lithography and sidewall deposition were used as template for electrodeposition of MoS2, Ni, and Pt. Linear sweep voltammetry experiments obtained in an aqueous solution containing 0.29 M H2SO4 (pH 0.24) showed that the onset potential of the core–shell–shell PMMA–Au–MoS2 nanocube electrode for the hydrogen evolution reaction (HER) was shifted to the positive direction (i.e., requiring a lower overpotential) by 20–40 ...
The solubility of gold in H 2 O-H 2 S vapour at elevated temperature and pressure

Science.gov (United States)

Zezin, Denis Yu.; Migdisov, Artashes A.; Williams-Jones, Anthony E.

2011-09-01

This experimental study sheds light on the complexation of gold in reduced sulphur-bearing vapour, specifically, in H 2O-H 2S gas mixtures. The solubility of gold was determined in experiments at temperatures of 300, 350 and 365 °C and reached 2.2, 6.6 and 6.3 μg/kg, respectively. The density of the vapour varied from 0.02 to 0.22 g/cm 3, the mole fraction of H 2S varied from 0.03 to 0.96, and the pressure in the cell reached 263 bar. Statistically significant correlations of the amount of gold dissolved in the fluid with the fugacity of H 2O and H 2S permit the experimental data to be fitted to a solvation/hydration model. According to this model, the solubility of gold in H 2O-H 2S gas mixtures is controlled by the formation of sulphide or bisulphide species solvated by H 2S or H 2O molecules. Formation of gold sulphide species is favoured statistically over gold bisulphide species and thus the gold is interpreted to dissolve according to reactions of the form: Au(s)+(n+1)HS(g)=AuS·(HS)n(g)+H(g) Au(s)+HS(g)+mHO(g)=AuS·(HO)m(g)+H(g) Equilibrium constants for Reaction (A1) and the corresponding solvation numbers ( K A1 and n) were evaluated from the study of Zezin et al. (2007). The equilibrium constants as well as the hydration numbers for Reaction (A2) ( K A2 and m) were adjusted simultaneously by a custom-designed optimization algorithm and were tested statistically. The resulting values of log K A2 and m are -15.3 and 2.3 at 300 and 350 °C and -15.1 and 2.2 at 365 °C, respectively. Using the calculated stoichiometry and stability of Reactions (A1) and (A2), it is now possible to quantitatively evaluate the contribution of reduced sulphur species to the transport of gold in aqueous vapour at temperatures up to 365 °C. This information will find application in modelling gold ore-forming processes in vapour-bearing magmatic hydrothermal systems, notably those of epithermal environments.
Concurrent separation of CO2 and H2O from air by a temperature-vacuum swing adsorption/desorption cycle.

Science.gov (United States)

Wurzbacher, Jan Andre; Gebald, Christoph; Piatkowski, Nicolas; Steinfeld, Aldo

2012-08-21

A temperature-vacuum swing (TVS) cyclic process is applied to an amine-functionalized nanofibrilated cellulose sorbent to concurrently extract CO(2) and water vapor from ambient air. The promoting effect of the relative humidity on the CO(2) capture capacity and on the amount of coadsorbed water is quantified. The measured specific CO(2) capacities range from 0.32 to 0.65 mmol/g, and the corresponding specific H(2)O capacities range from 0.87 to 4.76 mmol/g for adsorption temperatures varying between 10 and 30 °C and relative humidities varying between 20 and 80%. Desorption of CO(2) is achieved at 95 °C and 50 mbar(abs) without dilution by a purge gas, yielding a purity exceeding 94.4%. Sorbent stability and a closed mass balance for both H(2)O and CO(2) are demonstrated for ten consecutive adsorption-desorption cycles. The specific energy requirements of the TVS process based on the measured H(2)O and CO(2) capacities are estimated to be 12.5 kJ/mol(CO2) of mechanical (pumping) work and between 493 and 640 kJ/mol(CO2) of heat at below 100 °C, depending on the air relative humidity. For a targeted CO(2) capacity of 2 mmol/g, the heat requirement would be reduced to between 272 and 530 kJ/mol(CO2), depending strongly on the amount of coadsorbed water.
Facile one-pot synthesis of CoS_2-MoS_2/CNTs as efficient electrocatalyst for hydrogen evolution reaction

International Nuclear Information System (INIS)

Liu, Yan-Ru; Hu, Wen-Hui; Li, Xiao; Dong, Bin; Shang, Xiao; Han, Guan-Qun; Chai, Yong-Ming; Liu, Yun-Qi; Liu, Chen-Guang

2016-01-01

Highlights: • Ternary hybrid CoS_2-MoS_2/CNTs electrocatalysts have been prepared. • CNTs as support may provide good conductivity and low the agglomeration of MoS_2. • CoS_2 with intrinsic metallic conductivity may enhance the activity for HER. • Ternary CoS_2-MoS_2/CNTs have the better activity and stability for HER. - Abstract: Ternary hybrid cobalt disulfide-molybdenum disulfides supported on carbon nanotubes (CoS_2-MoS_2/CNTs) electrocatalysts have been prepared via a simple hydrothermal method. CNTs as support may provide good conductivity and low the agglomeration of layered MoS_2 structure. CoS_2 with intrinsic metallic conductivity may enhance the activity of the ternary hybrid electrocatalysts for hydrogen evolution reaction (HER). X-ray diffraction (XRD) data confirm the formation of ternary hybrid nanocomposites composed of CNTs, CoS_2 and amorphous MoS_2. Scanning electron microscopy (SEM) images show that strong combination between MoS_2, CNTs and regular orthohexagonal CoS_2 has been obtained. The dispersion of each component is good and no obvious agglomeration can be observed. It is found that compared with CoS_2/CNTs and MoS_2/CNTs, the ternary CoS_2-MoS_2/CNTs have the better activity for HER with a low onset potential of 70 mV (vs. RHE) and a small Talel slope of 67 mV dec"−"1, and are extremely stable after 1000 cycles. In addition, the optimal doping ratio of Co to Mo is 2:1, which have better HER activity. It is proved that the introduction of carbon materials and Co atoms could improve the performances of MoS_2-based electrocatalysts for HER.
The interface of the ferromagnetic metal CoS2 and the nonmagnetic semiconductor FeS2

KAUST Repository

Nazir, S.; Schwingenschlö gl, Udo

2010-01-01

semiconductor shows a metallic character. The CoS2 stays close to half-metallicity at the interface, while the FeS2 becomes metallic. The magnetic moment of the Co atoms at the interface slightly decreases as compared to the bulk value and a small moment
One step hydrothermal synthesis of 3D CoS2@MoS2-NG for high performance supercapacitors.

Science.gov (United States)

Meng, Qi; Chen, Yizhi; Zhu, Wenkun; Zhang, Ling; Yang, Xiaoyong; Duan, Tao

2018-05-03

A three-dimensional (3D) MoS 2 coated CoS 2 -nitrogen doped graphene (NG) (CoS 2 @MoS 2 -NG) hybrid has been synthesized by a one step hydrothermal method as supercapacitor (SC) electrode material for the first time. Such a composite consists of NG embedded with stacked CoS 2 @MoS 2 sheets. With a 3D skeleton, it prevents the agglomeration of CoS 2 @MoS 2 nanoparticles, resulting in sound conductivity, rich porous structures and a large surface area. The results indicate that CoS 2 @MoS 2 -NG has higher specific capacitance (198 F g -1 at 1 A g -1 ), better rate performance (with about 56.57% from 1 to 16 A g -1 ) and an improved cycle stability (with about 96.97% after 1000 cycles). It is an ideal candidate for SC electrode materials.
Biological H{sub 2} from syngas and from H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Weaver, P.; Maness, P.C.; Markov, S.; Martin, S. [National Renewable Energy Lab., Golden, CO (United States)

1996-10-01

The two stand-alone objectives of the research are to economically produce neat H{sub 2} in the near term from biomass (thermally gasified to syngas) and in the mid term from H{sub 2}O using cyanobacteria or algae with an oxygen-tolerant bacterial hydrogenase. Photosynthetic bacteria have four different terminal enzymes that mediate their H{sub 2} metabolisms-nitrogenase, uptake hydrogenase, fermentative hydrogenase, and carbon monoxide-linked hydrogenase. Each has been microbiologically and biochemically examined for their potential to specifically generate H{sub 2} in large-scale processes. Based on measurements of maximal activities, stabilities, energy requirements, equilibria, and partial pressures of the H{sub 2} producing reactions, the CO-linked hydrogenase is easily the most suited for practical applications. The enzyme mediates H{sub 2} production from CO at rates up to 1.5 mmol/min/g cell dry weight at near ambient temperature and pressure. Hydrogen can be produced and evolved at linear rates up to at least 2 atmospheres of partial pressure (100% CO). The rate-limiting step with high cell density suspensions is the mass transfer of CO into the aqueous phase. Bioreactor designs have been examined which enhance the mass transfer. Hollow-fiber bioreactors with bacterial cells immobilized on the fiber surfaces evolve H{sub 2} at ambient pressure at rates of about 0.3-0.7 mmol/min/g cdw. One such reactor has been producing H{sub 2} from CO continuously for 9 months with only occasional changes of liquid medium. A trickle-filter reactor with bacteria immobilized on beads removed from a bulk water phase and a pumped-bubble coil reactor with bacteria in suspension are also being examined.
Hydrothermal synthesis, thermal, structural, spectroscopic and magnetic studies of the Mn5-x Co x (HPO4)2(PO4)2(H2O)4 (x=1.25, 2, 2.5 and 3) finite solid solution

International Nuclear Information System (INIS)

Larrea, Edurne S.; Mesa, Jose L.; Pizarro, Jose L.; Arriortua, Maria I.; Rojo, Teofilo

2007-01-01

The Mn 5- x Co x (HPO 4 ) 2 (PO 4 ) 2 (H 2 O) 4 (x=1.25, 2, 2.5, 3) finite solid solution has been synthesized by mild hydrothermal conditions under autogeneous pressure. The phases crystallize in the C2/c space group with Z=4, belonging to the monoclinic system. The unit-cell parameters obtained from single crystal X-ray diffraction are: a=17.525(1), b=9.0535(6), c=9.4517(7) A, β=96.633(5) o being R1=0.0436, wR2=0.0454 for Mn75Co25; a=17.444(2), b=9.0093(9), c=9.400(1) A, β=96.76(1) o being R1=0.0381, wR2=0.0490 for Mn60Co40; a=17.433(2), b=8.9989(9), c=9.405(1) A, β=96.662(9) o being R1=0.0438, wR2=0.0515 for Mn50Co50 and a=17.4257(9), b=8.9869(5), c=9.3935(5) A, β=96.685(4) o being R1=0.0296, wR2=0.0460 for Mn40Co60. The structure consists of a three dimensional network formed by octahedral pentameric entities (Mn,Co) 5 O 16 (H 2 O) 6 sharing vertices with the (PO 4 ) 3- and (HPO 4 ) 2- tetrahedra. The limit of thermal stability of these compounds is, approximately, 165 deg. C, near to this mean temperature the phases loose their water content in two successive steps. IR spectra show the characteristic bands of the water molecules and the phosphate and hydrogen-phosphate oxoanions. The diffuse reflectance spectra are consistent with the presence of MO 6 octahedra environments in slightly distorted octahedral geometry, except for the M(3)O 6 octahedron which presents a remarkable distortion and so a higher Dq parameter. The mean value for the Dq and B-Racah parameter for the M(1),(2)O 6 octahedra is 685 and 850 cm -1 , respectively. These parameters for the most distorted M(3)O 6 polyhedron are 825 and 880 cm -1 , respectively. The four phases exhibit antiferromagnetic couplings as the major magnetic interactions. However, a small spin canting phenomenon is observed at low temperatures for the two phases with major content in the anisotropic-Co(II) cation. - Graphical abstract: Crystal structure of the finite solid solution Mn 5-x Co x (HPO 4 ) 2 (PO 4 ) 2 (H
The synthesis of [2-3H2] taurine and [2-3H2] hypotaurine

International Nuclear Information System (INIS)

Fellman, J.H.

1981-01-01

The synthesis of [2- 3 H 2 ]-2-aminoethanesulfonate [2- 3 H]-taurine by the reduction of cyanomethanesulfonic acid with tritium gas is described. The conversion of [2- 3 H]-taurine and its 14 C and 35 S isotopic forms to 2-aminoethanesulfinate (hypotaurine) was accomplished by converting taurine to its corresponding sulfonyl chloride and reducing the latter with metallic zinc. (author)
The crystal structure of galgenbergite-(Ce), CaCe2(CO3)4•H2O

Science.gov (United States)

Walter, Franz; Bojar, Hans-Peter; Hollerer, Christine E.; Mereiter, Kurt

2013-04-01

Galgenbergite-(Ce) from the type locality, the railroad tunnel Galgenberg between Leoben and St. Michael, Styria, Austria, was investigated. There it occurs in small fissures of an albite-chlorite schist as very thin tabular crystals building rosette-shaped aggregates associated with siderite, ancylite-(Ce), pyrite and calcite. Electron microprobe analyses gave CaO 9.49, Ce2O3 28.95, La2O3 11.70, Nd2O3 11.86, Pr2O3 3.48, CO2 30.00, H2O 3.07, total 98.55 wt.%. CO2 and H2O calculated by stoichiometry. The empirical formula (based on Ca + REE ∑3.0) is C{{a}_{1.00 }}{{( {C{{e}_{1.04 }}L{{a}_{0.42 }}N{{d}_{0.42 }}P{{r}_{0.12 }}} )}_{2.00 }}{{( {C{{O}_3}} )}_4}\\cdot {{H}_2}O , and the simplified formula is CaC{{e}_2}{{( {C{{O}_3}} )}_4}\\cdot {{H}_2}O . According to X-ray single crystal diffraction galgenbergite-(Ce) is triclinic, space group Poverline{1},a=6.3916(5) , b = 6.4005(4), c = 12.3898(9) Å, α = 100.884(4), β = 96.525(4), γ = 100.492(4)°, V = 483.64(6) Å3, Z = 2. The eight strongest lines in the powder X-ray diffraction pattern are [ d calc in Å/( I)/ hkl]: 5.052/(100)/011; 3.011/(70)/0-22; 3.006/(66)/004; 5.899/(59)/-101; 3.900/(51)/1-12; 3.125/(46)/-201; 2.526/(42)/022; 4.694/(38)/-102. The infrared absorption spectrum reveals H2O (OH-stretching mode at 3,489 cm-1, HOH bending mode at 1,607 cm-1) and indicates the presence of distinctly non-equivalent CO3-groups by double and quadruple peaks of their ν1, ν2, ν3 and ν4 modes. The crystal structure of galgenbergite-(Ce) was refined with X-ray single crystal data to R1 = 0.019 for 2,448 unique reflections ( I > 2 σ( I)) and 193 parameters. The three cation sites of the structure Ca(1), Ce(2) and Ce(3) have a modest mixed site occupation by Ca and small amount of REE (Ce, La, Pr, Nd) and vice versa. The structure is based on double layers parallel to (001), which are composed of Ca(1)Ce(2)(CO3)2 single layers with an ordered chessboard like arrangement of Ca and Ce, and with a roof tile
Brine/CO2 Interfacial Properties and Effects on CO2 Storage in Deep Saline Aquifers Propriétés interfaciales saumure/CO2 et effets sur le stockage du CO2 dans des aquifères salins profonds

Directory of Open Access Journals (Sweden)

Chalbaud C.

2010-05-01

Full Text Available It has been long recognized that interfacial interactions (interfacial tension, wettability, capillarity and interfacial mass transfer govern fluid distribution and behaviour in porous media. Therefore the interfacial interactions between CO2, brine and reservoir oil and/or gas have an important influence on the effectiveness of any CO2 storage operation. There is a lack of experimental data related to interfacial properties for all the geological storage options (oil & gas reservoirs, coalbeds, deep saline aquifers. In the case of deep saline aquifers, there is a gap in data and knowledge of brine-CO2 interfacial properties at storage conditions. More specifically, experimental interfacial tension values and experimental tests in porous media are necessary to better understand the wettability evolution as a function of thermodynamic conditions and it’s effects on fluid flow in the porous media. In this paper, a complete set of experimental values of brine-CO2 Interfaciale Tension (IFT at pressure, temperature and salt concentration conditions representative of those of a CO2 storage operation. A correlation is derived from experimental data published in a companion paper [Chalbaud C., Robin M., Lombard J.-M., Egermann P., Bertin H. (2009 Interfacial Tension Measurements and Wettability Evaluation for Geological CO2 Storage, Adv. Water Resour. 32, 1, 1-109] to model IFT values. This paper pays particular attention to coreflooding experiments showing that the CO2 partially wets the surface in a Intermediate-Wet (IW or Oil-Wet (OW limestone rock. This wetting behavior of CO2 is coherent with observations at the pore scale in glass micromodels and presents a negative impact on the storage capacity of a given site. Il est admis depuis longtemps que les propriétés interfaciales (tension interfaciale, mouillabilité, capillarité et transfert de masse régissent la distribution et le comportement des fluides au sein des milieux poreux. Par cons
Method for heavy-water production by H2S--H2O chemical exchange process

International Nuclear Information System (INIS)

Strathdee, G.G.

1978-01-01

The invention discloses a heavy water production stage in a bithermal H 2 S gas H 2 O liquid exchange plant wherein the cold tower is operated under temperature and pressure conditions such that H 2 S in the liquid phase is formed and is maintained in the separation units (sieve trays or plates) of the cold tower. It has been found that the presence of liquid H 2 S acts as an efficient anti-foaming agent
Comparative study on catalytic behavior of polynuclear Mg-Mo-complex and FeMo-co-factor of nitrogenase in reactions with C2H2, N2 and CO

International Nuclear Information System (INIS)

Bardina, N.V.; Bazhenova, T.A.; Petrova, G.N.; Shilova, A.K.; Shilov, A.E.

2006-01-01

Catalytic reduction kinetics of C 2 H 2 in the presence of the Mg-Mo-cluster {[Mg 2 Mo 8 O 22 (MeO) 6 (MeOH) 4 ] 2- [Mg(MeOH) 6 ] 2+ }·6MeOH 1 is studied. Several interdependent coordinating centers are active in reference to substrates and inhibitors in the polynuclear Mg-Mo-complex, as in the reduced by europium amalgam (μ 6 -N)MoFe 7 S 9 ·homocitrate (FeMoco, 2). Comparison of regularities in reduction mechanism of C 2 H 2 , N 2 and CO with the participation of synthetic polynuclear complex 1 and natural cluster 2 is conducted. Regularities of the studied reactions in the systems involving natural catalytic cluster FeMoco and the synthetic Mg-Mo-complex modelling of its effect are noted to be similar. The main variations the systems show as regards to the reaction with molecular nitrogen [ru
Novel CO{sub 2} capture. Final CRADA Report.

Energy Technology Data Exchange (ETDEWEB)

Snyder, S. W.; Energy Systems

2009-11-30

The goal of this work was to use electrochemically driven pH control to develop a second generation, enzyme-based contained liquid membrane (CLM) permeator to extract CO{sub 2} from a variety of coal-based flue gas streams more efficiently than does the CLM current design, while achieving performance coincident with DOE targets of less than 45% Cost of electricity (COE) in 2007 and less than 20% COE in 2012. Central to this goal the CLM would be alkaline (>pH 8) at the feed gas side and acid (H 6) at the permeate side. Argonne demonstrated the technical feasibility for CO{sub 2} capture and release using Argonne's resin-wafer electrode ionization (RW-EDI) system integrated with Carbozyme's carbonic anhydrase (CA) enzyme. Argonne developed RW-EDI for pH controlled desalination of process streams (e.g. Patents 7,452,920 & 7,306,934). In the current work, Argonne captured CO{sub 2} as HCO{sub 3}{sup -} and released it as CO{sub 2}. The goal is to both capture CO{sub 2} from a simulated flue gas stream and release it within the DOE targets for increase in COE. Initial performance results indicate that the 2012 COE targets are achievable with the developed technology. The design is subject to patent-hold. This task was funded in an exploratory phase, so no process optimization was attempted. Argonne believes that with optimization this performance could be significantly improved.
Potassium Capture by Kaolin, Part 2: K2CO3, KCI, and K2SO4

DEFF Research Database (Denmark)

Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

2018-01-01

residence time on the reaction was investigated. The results showed that the K-capture level (C-K) (g potassium reacted by per g kaolin available) of K2CO3 and KCI by kaolin generally followed the equilibrium predictions at temperatures above 1100 degrees C, when using a kaolin particle size of D50 = 5.......47 mu m and a residence time of 1.2 s. This revealed that a nearly full conversion was obtained without kinetic or transport limitations at the conditions applied. At 800 and 900 degrees C, the measured conversions were lower than the equilibrium predictions, indicating that the reactions were either...

Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

Science.gov (United States)

Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

2008-01-01

Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.
NO emission characteristics in counterflow diffusion flame of blended fuel of H2/CO2/Ar

International Nuclear Information System (INIS)

Jeong Park; Kyunghwan Lee; Keeman Lee

2002-01-01

Flame structure and NO emission characteristics in counterflow diffusion flame of blended fuel of H 2 /CO 2 /Ar have been numerically simulated with detailed chemistry. The combination of H 2 , CO 2 and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of CO 2 . A radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. The detailed chemistry adopts the reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions. All mechanisms including thermal, NO 2 , N 2 O and Fenimore are taken into account to separately evaluate the effects of CO 2 addition on NO emission characteristics. The increase of added CO 2 quantity causes flame temperature to fall since at high strain rates a diluent effect is prevailing and at low strain rates the breakdown of CO 2 produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the contribution of NO production by N 2 O and NO 2 mechanisms are negligible and that thermal mechanism is concentrated on only the reaction zone. As strain rate and CO 2 quantity increase, NO production is remarkably augmented. (Author)
A new metal-organic framework for separation of C2H2/CH4 and CO2/CH4 at room temperature

Science.gov (United States)

Duan, Xing; Zhou, You; Lv, Ran; Yu, Ben; Chen, Haodong; Ji, Zhenguo; Cui, Yuanjing; Yang, Yu; Qian, Guodong

2018-04-01

A 3D microporous metal-organic framework with open Cu2+ sites and suitable pore space, [Cu2(L)(H2O)2]·(H2O)4(DMF)8 (ZJU-15, H4L = 5,5‧-(9H-carbazole-2,7-diyl)diisophthalic acid; DMF = N,N-dimethylformamide; ZJU = Zhejiang University), has been constructed and characterized. The activated ZJU-15a has three different types of cages and exhibits BET surface area of 1660 m2 g-1, and can separate gas mixture of C2H2/CH4 and CO2/CH4 at room temperature.
Ni substitution effect on magnetic and transport properties in metallic ferromagnet Co3Sn2S2

Science.gov (United States)

Kubodera, Takashi; Okabe, Hirotaka; Kamihara, Yoichi; Matoba, Masanori

2006-05-01

We investigated the magnetic and transport properties of polycrystalline (Co1-xNix)3Sn2S2(0⩽x⩽1) to ascertain the magnetism of the new metallic ferromagnet Co3Sn2S2. In Co3Sn2S2 magnetization does not saturate up to 5.5 T at 10 K, and the estimated saturation moment ( ps) is small ( ≅0.2μB per Co atom). In ( Co1-xNix)3Sn2S2, the electrical resistivity shows metallic behavior without a hump but has a kink at TC. The TC and magnetic susceptibility gradually decrease with increasing x, and there is no antiferromagnetic phase throughout the full range of composition. These results indicate that Co3Sn2S2 is a weak itinerant ferromagnet; while, the same order of the Rhodes-Wohlfarth pc/ps value as CoS2 suggests the existence of a localized moment.
Absolute measurements of light emission from CO2/+/ and CO in the interaction of He/2 super 3 S/ with CO2.

Science.gov (United States)

Wauchop, T. S.; Broida, H. P.

1972-01-01

A flowing afterglow has been used to produce metastable He(2 super 3 S). It is shown that when He(2 super 3 S) interacts with a diatomic or triatomic molecule, its electronic excitation energy can be transferred to electronic and vibrational excitation of the molecule. To examine this mechanism, the rates for the production of electronically excited molecules, observed spectroscopically between 190 and 750 nm in the reaction of He(2 super 3 S) with CO2, have been measured. Results are tabulated.
Weather resistance of CaSO4 ṡ 1/2H2O-based sand-fixation material

Science.gov (United States)

Liu, Xin; Tie, Shengnian

2017-07-01

Searching for an economical and effective sand-fixing material and technology is of great importance in Northwest China. This paper described the use of a semihydrated gypsum-(CaSO4 ṡ 1/2H2O-)based composite as a sand-fixing material. Its morphology and composition were characterized by SEM, and its water resistance, freezing-thawing resistance and wind erosion resistance were tested in the field. The results indicated that semihydrated gypsum-(CaSO4 ṡ 1/2H2O-)based sand-fixing composite has good water resistance and water-holding capacity. Its strength is maintained at 1.42 MPa after 50 freezing and thawing cycles, and its wind erosion increases with increasing wind speed and slope. Its compressive strength starts to decrease after nine months of field tests with no change in appearance, but it still satisfies the requirements of fixation technology. This sand-fixing material should have wide application owing to its good weather resistance.
Large-area MoS2 grown using H2S as the sulphur source

International Nuclear Information System (INIS)

Dumcenco, Dumitru; Ovchinnikov, Dmitry; Lopez Sanchez, Oriol; Kis, Andras; Gillet, Philippe; Alexander, Duncan T L; Lazar, Sorin; Radenovic, Aleksandra

2015-01-01

We report on the growth of molybdenum disulphide (MoS 2 ) using H 2 S as a gas-phase sulfur precursor that allows controlling the domain growth direction of domains in both vertical (perpendicular to the substrate plane) and horizontal (within the substrate plane), depending on the H 2 S:H 2 ratio in the reaction gas mixture and temperature at which they are introduced during growth. Optical and atomic force microscopy measurements on horizontal MoS 2 demonstrate the formation of monolayer triangular-shape domains that merge into a continuous film. Scanning transmission electron microscopy of monolayer MoS 2 shows a regular atomic structure with a hexagonal symmetry. Raman and photoluminescence spectra confirm the monolayer thickness of the material. Field-effect transistors fabricated on MoS 2 domains that are transferred onto Si/SiO 2 substrates show a mobility similar to previously reported exfoliated and chemical vapor deposition-grown materials. (paper)
Vanadium Flow Battery Electrolyte Synthesis via Chemical Reduction of V2O5 in Aqueous HCl and H2SO4.

Energy Technology Data Exchange (ETDEWEB)

Small, Leo J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pratt, Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Staiger, Chad [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Rachel Irene [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Travis Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chalamala, Babu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soundappan, Thiagarajan [Univ. of Washington, Seattle, WA (United States); Tiwari, Monika [Univ. of Washington, Seattle, WA (United States); Subarmanian, Venkat R. [Univ. of Washington, Seattle, WA (United States)

2017-01-01

We report a simple method to synthesize V 4+ (VO 2+ ) electrolytes as feedstock for all- vanadium redox flow batteries (RFB). By dissolving V 2 O 5 in aqueous HCl and H 2 SO 4 , subsequently adding glycerol as a reducing agent, we have demonstrated an inexpensive route for electrolyte synthesis to concentrations >2.5 M V 4+ (VO 2+ ). Electrochemical analysis and testing of laboratory scale RFB demonstrate improved thermal stability across a wider temperature range (-10-65 degC) for V 4+ (VO 2+ ) electrolytes in HCl compared to in H 2 SO 4 electrolytes.
Plant-Sediment Interactions in Salt Marshes – An Optode Imaging Study of O2, pH, and CO2 Gradients in the Rhizosphere

Directory of Open Access Journals (Sweden)

Ketil Koop-Jakobsen

2018-05-01

Full Text Available In many wetland plants, belowground transport of O2 via aerenchyma tissue and subsequent O2 loss across root surfaces generates small oxic root zones at depth in the rhizosphere with important consequences for carbon and nutrient cycling. This study demonstrates how roots of the intertidal salt-marsh plant Spartina anglica affect not only O2, but also pH and CO2 dynamics, resulting in distinct gradients of O2, pH, and CO2 in the rhizosphere. A novel planar optode system (VisiSens TD®, PreSens GmbH was used for taking high-resolution 2D-images of the O2, pH, and CO2 distribution around roots during alternating light–dark cycles. Belowground sediment oxygenation was detected in the immediate vicinity of the roots, resulting in oxic root zones with a 1.7 mm radius from the root surface. CO2 accumulated around the roots, reaching a concentration up to threefold higher than the background concentration, and generally affected a larger area within a radius of 12.6 mm from the root surface. This contributed to a lowering of pH by 0.6 units around the roots. The O2, pH, and CO2 distribution was recorded on the same individual roots over diurnal light cycles in order to investigate the interlinkage between sediment oxygenation and CO2 and pH patterns. In the rhizosphere, oxic root zones showed higher oxygen concentrations during illumination of the aboveground biomass. In darkness, intraspecific differences were observed, where some plants maintained oxic root zones in darkness, while others did not. However, the temporal variation in sediment oxygenation was not reflected in the temporal variations of pH and CO2 around the roots, which were unaffected by changing light conditions at all times. This demonstrates that plant-mediated sediment oxygenation fueling microbial decomposition and chemical oxidation has limited impact on the dynamics of pH and CO2 in S. anglica rhizospheres, which may in turn be controlled by other processes such as root
The stability evaluation of lime mud as transesterification catalyst in resisting CO2 and H2O for biodiesel production

International Nuclear Information System (INIS)

Li, Hui; Niu, Sheng-li; Lu, Chun-mei; Cheng, Shi-qing

2015-01-01

Highlights: • Lime mud (LM) is pretreated with calcination, hydration and desiccation. • The alkali solubility is the amount of alkali compounds dissolved in methanol. • The soluble alkali amount in LM700-H is higher than that of CaO–H. • LM700 possesses a stronger capability than CaO in resisting H 2 O and CO 2 . - Abstract: The most outstanding property of the heterogeneous transesterification catalysts is recyclable, but their catalytic activity may be depressed for the absorption of moisture (H 2 O) and carbon dioxide (CO 2 ) in air, especially for the basic ones. Lime mud (LM) is effective in catalyzing transesterification, yet its property in resisting H 2 O and CO 2 is indistinct, which should be emphasized. In this study, the LM based transesterification catalyst is prepared through calcinations. Then, it is hydrated and desiccated to simulate the contamination by H 2 O and CO 2 . Further, the fresh and the contaminated catalysts are characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Hammette indicator, Brunauer–Emmett–Teller (BET) surface area and soluble alkali examination, to reveal the mechanism of LM in resisting H 2 O and CO 2 . Meanwhile, the analytical grade calcium oxide (CaO) is chosen for comparison. Finally, to comprehensively investigate the influences of H 2 O and CO 2 on LM in catalyzing transesterification, the factors of the catalyst addition percentage, molar ratio of methanol to oil and transesterification temperature are evaluated
Two-component, ab initio potential energy surface for CO2-H2O, extension to the hydrate clathrate, CO2@(H2O)20, and VSCF/VCI vibrational analyses of both.

Science.gov (United States)

Wang, Qingfeng Kee; Bowman, Joel M

2017-10-28

We report an ab initio, full-dimensional, potential energy surface (PES) for CO 2 -H 2 O, in which two-body interaction energies are fit using a basis of permutationally invariant polynomials and combined with accurate potentials for the non-interacting monomers. This approach which we have termed "plug and play" is extended here to improve the precision of the 2-body fit in the long range. This is done by combining two separate fits. One is a fit to 47 593 2-body energies in the region of strong interaction and approaching the long range, and the second one is a fit to 6244 2-body energies in the long range. The two fits have a region of overlap which permits a smooth switch from one to the other. All energies are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory. Properties of the full PES, i.e., stationary points, harmonic frequencies of the global minimum, etc., are shown to be in excellent agreement with direct CCSD(T)-F12b/aug-cc-pVTZ results. Diffusion Monte Carlo calculations of the dimer zero-point energy (ZPE) are performed, and a dissociation energy, D 0 , of 787 cm -1 is obtained using that ZPE, D e , and the rigorous ZPEs of the monomers. Using a benchmark D e , D 0 is 758 cm -1 . Vibrational self-consistent field (VSCF)/virtual state configuration interaction (VCI) MULTIMODE calculations of intramolecular fundamentals are reported and are in good agreement with available experimental results. Finally, the full dimer PES is combined with an existing ab initio water potential to develop a potential for the CO 2 hydrate clathrate CO 2 (H 2 O) 20 (5 12 water cage). A full normal-mode analysis of this hydrate clathrate is reported as are local-monomer VSCF/VCI calculations of the fundamentals of CO 2 .
Zr powder and Zr-16% Al alloy as getters for O sub 2 , H sub 2 , H sub 2 O, CO and CO sub 2 gases

Energy Technology Data Exchange (ETDEWEB)

Garg, S P [CRM Jat Coll., Hisar (India); Gulbransen, E A [Pittsburgh Univ., PA (USA); Vijendran, P [Bhabha Atomic Research Centre, Bombay (India)

1990-01-01

Both zirconium and its 16 wt% aluminium alloy react with the common gases O{sub 2}, H{sub 2}, H{sub 2}O, CO and CO{sub 2} to form zirconium oxide, hydride and carbide or carbon and a thermochemical and stoichiometric analysis has been made of the several reactions. The capacity and reactivity of 30-40 {mu} zirconium powder and pellets of a 16 wt% aluminium-zirconium alloy, ST 101 getter, were studied using a sensitive vacuum microbalance, a mass spectrometer and Debye-Scherrer X-ray diffraction. The direct hydrogen reaction at 400{sup 0}C and 10 torr pressure and a slow oxidation reaction at 250-600{sup 0}C were used to measure the availability of the materials (capacity) for getter reactions. Special care must be taken to remove water vapour and any other reactive gas from the vacuum system in using the hydrogen method. The hydrogen-getter reaction must be carried out well below 400{sup 0}C if hydrogen is to be removed completely. The reactivity of water vapour in the presence of 10 torr of hydrogen gas was studied at 400{sup 0}C. Fourteen micrograms of water vapour in the reaction system could be detected. The carbon monoxide and carbon dioxide-getter reactions were studied at 500{sup 0}C and 600{sup 0}C at 10 torr pressure. Zirconium powder reacts much faster with both gases as compared to that with St 101 getter, activity of which with oxygen has been stabilized by adding aluminium. Carbon monoxide is produced in the carbon dioxide-getter reaction under conditions of excess gas in the reaction. Carbon and carbide were not observed in the carbon monoxide-getter reaction under excess gas conditions. (author).
ENDOR determination of the proton positions around Gd3+ in La(C2H5SO4)3.9H2O

International Nuclear Information System (INIS)

Beer, R. de; Biesboer, F.; Ormondt, D. van

1976-01-01

The water proton positions around Gd 3+ in La(C 2 H 5 SO 4 ) 3 .9H 2 O have been determined by means of ENDOR. The positions of the nearest neighbour water oxygens are discussed on the basis of a superposition model analysis of the ratios b 2 0 /A 2 0 2 >, b 6 6 /b 6 0 and mod(A 6 6 )modA 6 0 . (Auth.)
DNA-Binding Study of Tetraaqua-bis(p-nitrobenzoatocobalt(II Dihydrate Complex: [Co(H2O4(p-NO2C6H4COO2]Ã‚Â·2H2O

Directory of Open Access Journals (Sweden)

Hacali Necefoglu

2007-06-01

Full Text Available The interaction of [Co(H2O4(p-NO2C6H4COO2]. 2H2O with sheep genomicDNA has been investigated by spectroscopic studies and electrophoresis measurements.The interaction between cobalt(II p-nitrobenzoate and DNA has been followed by gelelectrophoresis while the concentration of the complex was increased from 0 to 14 mM.The spectroscopic study and electrophoretic experiments support the fact that the complexbinds to DNA by intercalation via p-nitrobenzoate into the base pairs of DNA. Themobility of the bands decreased as the concentration of complex was increased, indicatingthat there was increase in interaction between the metal ion and DNA.
Ash partitioning during the oxy-fuel combustion of lignite and its dependence on the recirculation of flue gas impurities (H{sub 2}O, HCl and SO{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Facun Jiao; Juan Chen; Lian Zhang; Yajuan Wei; Yoshihiko Ninomiya; Sankar Bhattacharya; Hong Yao [Monash University, Clayton, Vic. (Australia). Department of Chemical Engineering

2011-06-15

Oxy-fuel combustion of a brown coal (i.e. lignite) has been carried out at 1000{sup o}C to experimentally examine the vaporisation of organically bound metals and the agglomeration of ash particles as a function of the concentration of gaseous impurities including H{sub 2}O, HCl and SO{sub 2} in about 27% O{sub 2} balanced with CO{sub 2}. The properties of bulk ash and individual metals were investigated intensively. Particularly, attention was paid to Na which is notorious for fouling and to organically bound Al which has been less studied. The results indicate that, the organically bound metals, although possessing a very low content in the raw coal, are vital for the agglomeration of ash particles, which are also highly sensitive to the loading of gas impurities in flue gas. HCl recirculation is the most crucial factor promoting the vaporisation of metals via chlorination. Apart from alkali metals, the organically bound Al and Ti were also vaporised noticeably. Recirculation of SO{sub 2} promoted the sulfation of Na to condense into liquid droplet which increased fine ash yield. Co-existence of bulk HCl and SO{sub 2} played a synergetic role in the sulfation of Na via an initial chlorination of the char-bound Na. In contrast, co-existence of steam with HCl and SO{sub 2} favored the formation of Na alumino-silicates, which are favorable for ash agglomeration. 34 refs., 15 figs., 3 tabs.
Tunable Robust pacs-MOFs: a Platform for Systematic Enhancement of the C2H2 Uptake and C2H2/C2H4 Separation Performance.

Science.gov (United States)

Chen, Di-Ming; Sun, Chun-Xiao; Zhang, Nan-Nan; Si, Huan-Huan; Liu, Chun-Sen; Du, Miao

2018-03-05

As a modulatable class of porous crystalline materials, metal-organic frameworks (MOFs) have gained intensive research attention in the domain of gas storage and separation. In this study, we report on the synthesis and gas adsorption properties of two robust MOFs with the general formula [Co 3 (μ 3 -OH)(cpt) 3 Co 3 (μ 3 -OH)(L) 3 (H 2 O) 9 ](NO 3 ) 4 (guests) n [L = 3-amino-1,2,4-triazole (1) and 3,5-diamino-1,2,4-triazole (2); Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], which show the same pacs topology. Both MOFs are isostructural to each other and show MIL-88-type frameworks whose pore spaces are partitioned by different functionlized trinuclear 1,2,4-triazolate-based clusters. The similar framework components with different amounts of functional groups make them an ideal platform to permit a systematic gas sorption/separation study to evaluate the effects of distinctive parameters on the C 2 H 2 uptake and separation performance. Because of the presence of additional amido groups, the MOF 2 equipped with a datz-based cluster (Hdatz = 3,5-diamino-1,2,4-triazole) shows a much improved C 2 H 2 uptake capacity and separation performance over that of the MOF 1 equipped with atz-based clusters (Hatz = 3-amino-1,2,4-triazole), although the surface area of the MOF 1 is almost twice than that of the MOF 2. Moreover, the high density of open metal sites, abundant free amido groups, and charged framework give the MOF 2 an excellent C 2 H 2 separation performance, with ideal adsorbed solution theory selectivity values reaching up to 11.5 and 13 for C 2 H 2 /C 2 H 4 (1:99) and C 2 H 2 /CO 2 (50:50) at 298 K and 1 bar, showing potential for use in natural gas purification.
Structural analysis of co-evaporated In{sub 2}S{sub 3} and In{sub 2}S{sub 3}:V for solar cell absorber applications

Energy Technology Data Exchange (ETDEWEB)

Waegele, Leonard A.; Rata, Diana; Scheer, Roland [Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale) (Germany); Gurieva, Galina [Department Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

2017-06-15

In this study we use co-evaporation to grow In{sub 2}S{sub 3} thin films on glass substrates and X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to analyse the structural properties of annealed In{sub 2}S{sub 3} and V-doped In{sub 2}S{sub 3} for intermediate band solar cell application. We find co-evaporated In{sub 2}S{sub 3} to be polycrystalline on float glass and with improved crystallinity after annealing in S-atmosphere. We confirm that excessive incorporation of vanadium into the host structure is possible without formation of secondary crystalline phases. The analysis indicates a reduced crystalline quality after V doping. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Co-electrolysis of CO₂ and H₂O in solid oxide cells: Performance and durability

DEFF Research Database (Denmark)

Graves, Christopher R.; Ebbesen, Sune; Mogensen, Mogens Bjerg

2011-01-01

This study examines the initial performance and durability of a solid oxide cell applied for co-electrolysis of CO2 and H2O. Such a cell, when powered by renewable/nuclear energy, could be used to recycle CO2 into sustainable hydrocarbon fuels. Polarization curves and electrochemical impedance...... systematically varied test conditions enabled clear visual identification of five electrode processes that contribute to the cell resistance. The processes could be assigned to each electrode and to gas concentration effects by examining their dependence on gas composition changes and temperature. This study...
FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

Energy Technology Data Exchange (ETDEWEB)

George Rizeq; Janice West; Arnaldo Frydman; Vladimir Zamansky; Linda Denton; Hana Loreth; Tomasz Wiltowski

2001-07-01

It is expected that in the 21st century the Nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It will be necessary to improve both the thermodynamic efficiency and environmental impact performance of fossil fuel utilization. General Electric Energy and Environmental Research Corporation (GE EER) has developed an innovative fuel-flexible Advanced Gasification-Combustion (AGC) concept to produce H{sub 2} and sequestration-ready CO{sub 2} from solid fuels. The AGC module offers potential for reduced cost and increased energy efficiency relative to conventional gasification and combustion systems. GE EER was awarded a Vision-21 program from U.S. DOE NETL to develop the AGC technology. Work on this three-year program started on October 1, 2000. The project team includes GE EER, California Energy Commission, Southern Illinois University at Carbondale, and T. R. Miles, Technical Consultants, Inc. In the AGC technology, coal/opportunity fuels and air are simultaneously converted into separate streams of (1) pure hydrogen that can be utilized in fuel cells, (2) sequestration-ready CO{sub 2}, and (3) high temperature/pressure oxygen-depleted air to produce electricity in a gas turbine. The process produces near-zero emissions and, based on preliminary modeling work in the first quarter of this program, has an estimated process efficiency of approximately 67% based on electrical and H{sub 2} energy outputs relative to the higher heating value of coal. The three-year R&D program will determine the operating conditions that maximize separation of CO{sub 2} and pollutants from the vent gas, while simultaneously maximizing coal conversion efficiency and hydrogen production. The program integrates lab-, bench- and pilot-scale studies to demonstrate the AGC concept. This is the third quarterly technical progress report for the Vision-21 AGC program supported by U.S. DOE NETL (Contract: DE-FC26-00FT40974). This report summarizes program
Electronic structure of shandite Co3Sn2S2

Science.gov (United States)

Dedkov, Y. S.; Holder, M.; Molodtsov, S. L.; Rosner, H.

2008-03-01

The electronic structure of shandite Co3Sn2S2 was determined by photoelectron spectroscopy and compared with ab initio band structure calculations. Presented results give evidence that this compound has half-metallic ferromagnetic properties.

Techno-economic assessment of membrane assisted fluidized bed reactors for pure H_2 production with CO_2 capture

International Nuclear Information System (INIS)

Spallina, V.; Pandolfo, D.; Battistella, A.; Romano, M.C.; Van Sint Annaland, M.; Gallucci, F.

2016-01-01

Highlights: • Membrane reactors improve the overall efficiency of H_2 production up to 20%. • Respect to conventional reforming, the H_2 yield increases from 12% to 20%. • The COH is reduced of at least 220% using membrane reactors. • FBMR capture 72% of CO_2 with a specific cost of 8 eur/tonn_C_O_2_. • MA-CLR can reach 90% of CO_2 avoided with same cost of FTR. - Abstract: This paper addresses the techno-economic assessment of two membrane-based technologies for H_2 production from natural gas, fully integrated with CO_2 capture. In the first configuration, a fluidized bed membrane reactor (FBMR) is integrated in the H_2 plant: the natural gas reacts with steam in the catalytic bed and H_2 is simultaneously separated using Pd-based membranes, and the heat of reaction is provided to the system by feeding air as reactive sweep gas in part of the membranes and by burning part of the permeated H_2 (in order to avoid CO_2 emissions for heat supply). In the second system, named membrane assisted chemical looping reforming (MA-CLR), natural gas is converted in the fuel rector by reaction with steam and an oxygen carrier (chemical looping reforming), and the produced H_2 permeates through the membranes. The oxygen carrier is re-oxidized in a separate air reactor with air, which also provides the heat required for the endothermic reactions in the fuel reactor. The plants are optimized by varying the operating conditions of the reactors such as temperature, pressures (both at feed and permeate side), steam-to-carbon ratio and the heat recovery configuration. The plant design is carried out using Aspen Simulation, while the novel reactor concepts have been designed and their performance have been studied with a dedicated phenomenological model in Matlab. Both configurations have been designed and compared with reference technologies for H_2 production based on conventional fired tubular reforming (FTR) with and without CO_2 capture. The results of the analysis show
FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

International Nuclear Information System (INIS)

George Rizeq; Ravi Kumar; Janice West; Vitali Lissianski; Neil Widmer; Vladimir Zamansky

2001-01-01

It is expected that in the 21st century the Nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It will be necessary to improve both the thermodynamic efficiency and environmental impact performance of fossil fuel utilization. General Electric Energy and Environmental Research Corporation (GE-EER) has developed an innovative fuel-flexible Advanced Gasification-Combustion (AGC) concept to produce H(sub 2) and sequestration-ready CO(sub 2) from solid fuels. The AGC module offers potential for reduced cost and increased energy efficiency relative to conventional gasification and combustion systems. GE-EER was awarded a Vision-21 program from U.S. DOE NETL to develop the AGC technology. Work on this three-year program started on October 1, 2000. The project team includes GE-EER, California Energy Commission, Southern Illinois University at Carbondale, and T. R. Miles, Technical Consultants, Inc. In the AGC technology, coal/opportunity fuels and air are simultaneously converted into separate streams of (1) pure hydrogen that can be utilized in fuel cells, (2) sequestration-ready CO(sub 2), and (3) high temperature/pressure oxygen depleted air to produce electricity in a gas turbine. The process produces near-zero emissions and, based on preliminary modeling work in the first quarter of this program, has an estimated process efficiency of approximately 67% based on electrical and H(sub 2) energy outputs relative to the higher heating value of coal. The three-year R and D program will determine the operating conditions that maximize separation of CO(sub 2) and pollutants from the vent gas, while simultaneously maximizing coal conversion efficiency and hydrogen production. The program integrates lab-, bench- and pilot-scale studies to demonstrate the AGC concept. This is the 1st quarterly progress report for the Vision-21 AGC program supported by U.S. DOE NETL (Contract: DE-FC26-00FT40974). This report summarizes program
Methanol absorption characteristics for the removal of H2S (hydrogen sulfide), COS (carbonyl sulfide) and CO2 (carbon dioxide) in a pilot-scale biomass-to-liquid process

International Nuclear Information System (INIS)

Seo, Myung Won; Yun, Young Min; Cho, Won Chul; Ra, Ho Won; Yoon, Sang Jun; Lee, Jae Goo; Kim, Yong Ku; Kim, Jae Ho; Lee, See Hoon; Eom, Won Hyun; Lee, Uen Do; Lee, Sang Bong

2014-01-01

The BTL (biomass-to-liquid) process is an attractive process that produces liquid biofuels from biomass. The FT (Fisher–Tropsch) process is used to produce synfuels such as diesel and gasoline from gasified biomass. However, the H 2 S (hydrogen sulfide), COS (carbonyl sulfide) and CO 2 (carbon dioxide) in the syngas that are produced from the biomass gasifiers cause a decrease of the conversion efficiency and deactivates the catalyst that is used in the FT process. To remove the acid gases, a pilot-scale methanol absorption tower producing diesel at a rate of 1 BPD (barrel per day) was developed, and the removal characteristics of the acid gases were determined. A total operation time of 500 h was achieved after several campaigns. The average syngas flow rate at the inlet of methanol absorption tower ranged from 300 to 800 L/min. The methanol absorption tower efficiently removed H 2 S from 30 ppmV to less than 1 ppmV and COS from 2 ppmV to less than 1 ppmV with a removal of CO 2 from 20% to 5%. The outlet gas composition adhered to the guidelines for FT reactors. No remaining sulfurous components were found, and the tar component was analyzed in the spent methanol after long-term operations. - Highlights: • The gas cleaning system in a pilot-scale BTL (biomass-to-liquid) process is reported. • Although methanol absorption tower is conventional process, its application to BTL process is attempted. • The methanol absorption tower efficiently removed H 2 S, COS and CO 2 in the syngas. • The sulfurous and tar components in the methanol are analyzed
Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

Science.gov (United States)

Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

2010-12-01

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenated hydrocarbons, halocarbons and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Carbon dioxide, CH4, CO, NO, NO2, NOy, SO2 and 53 VOCs (e.g., non-methane hydrocarbons, halocarbons, sulphur species) showed clear statistical enhancements (1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were greater over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (industry fell into two groups: (1) evaporative emissions from the oil sands and its products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort, such as upgraders (i.e., CO2, CO, CH4, NO, NO2, NOy
Evaluation of plasma H2S levels and H2S synthesis in streptozotocin induced Type-2 diabetes-an experimental study based on Swietenia macrophylla seeds

Directory of Open Access Journals (Sweden)

Moumita Dutta

2014-05-01

Conclusions: Although considering a small sample size, it can conclude that the fasting blood glucose levels are inversely related to plasma H2S levels as well as H2S synthesis activity in plasma and the extract of S. macrophylla is associated with increased plasma H2S levels with effective lowering of blood glucose in streptozotocin induced diabetic rats.
Oxidation of SO{sub 2} and formation of water droplets under irradiation of 20 MeV protons in N{sub 2}/H{sub 2}O/SO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Tomita, Shigeo [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Nakai, Yoichi, E-mail: nakaiy@riken.jp [Radioactive Isotope Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Funada, Shuhei; Tanikawa, Hideomi; Harayama, Isao [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Kobara, Hitomi [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8569 (Japan); Sasa, Kimikazu [Tandem Accelerator Complex, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Pedersen, Jens Olaf Pepke [National Space Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Hvelplund, Preben [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2015-12-15

We have performed an experiment on charged droplet formation in a humidified N{sub 2} gas with trace SO{sub 2} concentration and induced by 20 MeV proton irradiation. It is thought that SO{sub 2} reacts with the chemical species, such as OH radicals, generated through the reactions triggered by N{sub 2}{sup +} production. Both droplet number and droplet size increased with SO{sub 2} consumption for the proton irradiation. The total charged droplet numbers entering the differential mobility analyzer per unit time were proportional to the 0.68 power of the SO{sub 2} consumption. These two findings suggest that coagulation among the small droplets contributes to the formation of the droplets. The charged droplet volume detected per unit time is proportional to the SO{sub 2} consumption, which indicates that a constant amount of sulfur atoms is contained in a unit volume of droplet, regardless of different droplet-size distributions depending on the SO{sub 2} consumption.
Computational study on the mechanisms and energetics of trimethylindium reactions with H2O and H2S.

Science.gov (United States)

Raghunath, P; Lin, M C

2007-07-19

The reactions of trimethylindium (TMIn) with H2O and H2S are relevant to the chemical vapor deposition of indium oxide and indium sulfide thin films. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional theory and ab initio calculations using the CCSD(T)/[6-31G(d,p)+Lanl2dz]//B3LYP/[6-31G(d,p)+Lanl2dz] and CCSD(T)/[6-31G(d,p)+Lanl2dz] //MP2/[6-31G(d,p)+Lanl2dz] methods. The results of both methods are in good agreement for the optimized geometries and relative energies. When TMIn reacts with H2O and H2S, initial molecular complexes [(CH3)3In:OH2 (R1)] and [(CH3)3In:SH2 (R2)] are formed with 12.6 and 3.9 kcal/mol binding energies. Elimination of a CH4 molecule from each complex occurs with a similar energy barrier at TS1 (19.9 kcal/mol) and at TS3 (22.1 kcal/mol), respectively, giving stable intermediates (CH3)2InOH and (CH3)2InSH. The elimination of the second CH4 molecule from these intermediate products, however, has to overcome very high and much different barriers of 66.1 and 53.2 kcal/mol, respectively. In the case of DMIn with H2O and H2S reactions, formation of both InO and InS is exothermic by 3.1 and 30.8 kcal/mol respectively. On the basis of the predicted heats of formation of R1 and R2 at 0 K and -20.1 and 43.6 kcal/mol, the heats of formation of (CH3)2InOH, (CH3)2InSH, CH3InO, CH3InS, InO, and InS are estimated to be -20.6, 31.8, and 29.0 and 48.4, 35.5, and 58.5 kcal/mol, respectively. The values for InO and InS are in good agreement with available experimental data. A similar study on the reactions of (CH3)2In with H2O and H2S has been carried out; in these reactions CH3InOH and CH3InSH were found to be the key intermediate products.
Corrosion processes and coalification of ferrtic-martensitic steels in H{sub 2}O-CO{sub 2} atmospheres; Korrosionsprozesse und Aufkohlung von ferritisch-martensitischen Staehlen in H{sub 2}O-CO{sub 2} Atmosphaeren

Energy Technology Data Exchange (ETDEWEB)

Huenert, Daniela

2010-09-20

The dissertation desribes the corrosion of steels with chromium concentrations of 1-12 percent in H{sub 2}O-CO{sub 2} atmospheres at variable pressure in the temperature range of 500-650 C and shows the corresponding degree of coalification. The investigations were carried out in a specially constructed corrosion unit which enables simulations of the power plant conditions temperature, pressure, gas composition, and gas flow rate. Above 575 C, the experimentally measured corrosion rates decrease, similar to those in hydrogen. Below 575 C, higher corrosion rates are observed in H{sub 2}O-CO{sub 2} atmospheres than in hydrogen, which is assumed to be the result of chromium fixation by the carbon formed in the corrosion process and of the existence of wuestite below this temperature. Below 600 C, temperature and pressure act independently of each other. Investigations between 600 and 625 C showed that pressure and temperature are not independent parameters with regard to oxide layer growth. The combined effect of these parameters results in higher corrosion rates and coalification depths. The dissertation describes this higher corrosion rate and coalification depth by an enhanced transport model. (orig.) [German] In der vorliegenden Arbeit wurde das Korrosionsverhalten an Stahlqualitaeten mit Chromgehalten zwischen 1 und 12 % in H{sub 2}O-CO-2-Atmosphaeren bei unterschiedlichem Druck im Temperaturbereich von 500 bis 650 C dargestellt und die parallel erfolgende Aufkohlung gezeigt. Fuer die Untersuchungen wurde eine Korrosionsanlage aufgebaut, welche die Simulation der Kraftwerksbedingungen Temperatur, Druck und Gaszusammensetzung und -geschwindigkeit erlaubt. Die experimentell bestimmten Korrosionsraten sind oberhalb von 575 C vergleichbar mit denen in Wasserdampf. Unterhalb von 575 C werden hoehere Korrosionsraten in H2O-CO2- Atmosphaeren beobachtet als in Wasserdampf, was als Folge der Fixierung des Chroms durch den waehrend des Korrosionsprozesses gebildeten
Chemistry of fluids from a natural analogue for a geological CO{sub 2} storage site (Montmiral, France): Lessons for CO{sub 2}-water-rock interaction assessment and monitoring

Energy Technology Data Exchange (ETDEWEB)

Pauwels, Helene [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)], E-mail: h.pauwels@brgm.fr; Gaus, Irina; Le Nindre, Yves Michel [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France); Pearce, Jonathan [British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG125GG (United Kingdom); Czernichowski-Lauriol, Isabelle [BRGM - Water Division, 3, av Claude Guillemin, 45060 Orleans Cedex (France)

2007-12-15

Chemical and isotope studies of natural CO{sub 2} accumulations aid in assessing the chemical effects of CO{sub 2} on rock and thus provide a potential for understanding the long-term geochemical processes involved in CO{sub 2} geological storage. Several natural CO{sub 2} accumulations were discovered during gas and oil exploration in France's carbogaseous peri-Alpine province (south-eastern France) in the 1960s. One of these, the Montmiral accumulation at a depth of more than 2400 m, is currently being exploited. The chemical composition of the water collected at the wellhead has changed in time and the final salinity exceeds 75 g/L. These changes in time can be explained by assuming that the fraction of the reservoir brine in the recovered brine-CO{sub 2}-H{sub 2}O mixture varies, resulting in variable proportions of H{sub 2}O and brine in the sampled water. The proportions can be estimated in selected samples due to the availability of gas and water flowrate data. These data enabled the reconstruction of the chemical and isotope composition of the brine. The proportions of H{sub 2}O and brine can also be estimated from isotope ({delta}{sup 2}H, {delta}{sup 18}O) composition of collected water and {delta}{sup 18}O of the sulfates or CO{sub 2}. The reconstituted brine has a salinity of more than 85 g/L and, according to its Br{sup -} content and isotope ({delta}{sup 2}H, {delta}{sup 18}O, {delta}{sup 34}S) composition, originates from an evaporated Triassic seawater that underwent dilution by meteoric water. The reconstitution of the brine's chemical composition enabled an evaluation of the CO{sub 2}-water-rock interactions based on: (1) mineral saturation indices; and (2) comparison with initial evaporated Triassic seawater. Dissolution of K- and SO{sub 4}-containing minerals such as K-feldspar and anhydrite, and precipitation of Ca and Mg containing minerals that are able to trap CO{sub 2} (carbonates) are highlighted. The changes in concentration of
Efficient degradation of H2S over transition metal modified TiO2 under VUV irradiation: Performance and mechanism

Science.gov (United States)

Liu, Gaoyuan; Ji, Jian; Hu, Peng; Lin, Sixin; Huang, Haibao

2018-03-01

Odor pollution causes great harm to the atmospheric environment and human health. H2S, as an odor gas, is highly toxic and corrosive and thus requires removal efficiently. In this study, TiO2 catalysts modified by transition metals including Mn, Cu, Ni and Co, were prepared using a modified sol-gelatin method and tested under UV-PCO or VUV-PCO process. H2S degradation was great enhanced in VUV-PCO compared with conventional UV-PCO. Among the catalysts, 1 wt% Mn-TiO2 showed the highest removal efficiency of 89.9%, which is 30 times higher than that under 254 nm UV irradiation. Residual ozone in the outlet can be completely eliminated by Mn-TiO2. Photocatalytic oxidation, photolysis and ozone-assisted catalytic oxidation all involved in the VUV-PCO process and their contribution were determined by H2S removal efficiency.
Using H2O2 as oxidant in leaching of uranium ores. The new research on the reaction of H2O2 with Fe2+

International Nuclear Information System (INIS)

Gao Xizhen

1997-05-01

The new research on the reaction of H 2 O 2 with Fe 2+ has been studied. Through determining the electric potential, pH and O 2 release during the mutual titration between H 2 O 2 solution and FeSO 4 solution, deduced the chemical equations of H 2 O 2 (without free hydroxyl) oxidizing FeSO 4 and Fe 2 (SO 4 ) 3 oxidizing H 2 O 2 . The research results show that acid is a catalytic agent for decomposing H 2 O 2 to be O 2 and H 2 O besides iron ions. The maximum oxidizing potential is up to about 640 mV. While using H 2 O 2 as an oxidant in uranium heap leaching and in-situ leaching, controlling electric potential can be regarded as a method for adjusting the feeding speed of H 2 O 2 to keep the electric potential below 500 mV, thus the H 2 O 2 decomposition can be reduced. (13 refs., 3 tabs., 1 fig.)
Crown Ether Complexes of Alkali-Metal Chlorides from SO2.

Science.gov (United States)

Reuter, Kirsten; Rudel, Stefan S; Buchner, Magnus R; Kraus, Florian; von Hänisch, Carsten

2017-07-18

The structures of alkali-metal chloride SO 2 solvates (Li-Cs) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 show strong discrepancies, despite the structural similarity of the ligands. Both types of crown ethers form 1:1 complexes with LiCl to give [Li(1,2-disila-12-crown-4)(SO 2 Cl)] (1) and [Li(12-crown-4)Cl]⋅4 SO 2 (2). However, 1,2-disila-12-crown-4 proved unable to coordinate cations too large for the cavity diameter, for example, by the formation of sandwich-type complexes. As a result, 12-crown-4 reacts exclusively with the heavier alkali-metal chlorides NaCl, KCl and RbCl. Compounds [Na(12-crown-4) 2 ]Cl⋅4 SO 2 (3) and [M(12-crown-4) 2 (SO 2 )]Cl⋅4 SO 2 (4: M=K; 5: M=Rb) all showed S-coordination to the chloride ions through four SO 2 molecules. Compounds 4 and 5 additionally exhibit the first crystallographically confirmed non-bridging O,O'-coordination mode of SO 2 . Unexpectedly, the disila-crown ether supports the dissolution of RbCl and CsCl in the solvent and gives the homoleptic SO 2 -solvated alkali-metal chlorides [MCl⋅3 SO 2 ] (6: M=Rb; 7: M=Cs), which incorporate bridging μ-O,O'-coordinating moieties and the unprecedented side-on O,O'-coordination mode. All compounds were characterised by single-crystal X-ray diffraction. The crown ether complexes were additionally studied by using NMR spectroscopy, and the presence of SO 2 at ambient temperature was revealed by IR spectroscopy of the neat compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Electronic structure of the alkyne-bridged dicobalt hexacarbonyl complex Co(2) micro-C(2)H(2) (CO)(6): evidence for singlet diradical character and implications for metal-metal bonding.

Science.gov (United States)

Platts, James A; Evans, Gareth J S; Coogan, Michael P; Overgaard, Jacob

2007-08-06

A series of ab initio calculations are presented on the alkyne-bridged dicobalt hexacarbonyl cluster Co2 micro-C2H2 (CO)6, indicating that this compound has substantial multireference character, which we interpret as evidence of singlet diradical behavior. As a result, standard theoretical methods such as restricted Hartree-Fock (RHF) or Kohn-Sham (RKS) density functional theory cannot properly describe this compound. We have therefore used complete active space (CAS) methods to explore the bonding in and spectroscopic properties of Co2 micro-C2H2 (CO)6. CAS methods identify significant population of a Co-Co antibonding orbital, along with Co-pi* back-bonding, and a relatively large singlet-triplet energy splitting. Analysis of the electron density and related quantities, such as energy densities and atomic overlaps, indicates a small but significant amount of covalent bonding between cobalt centers.
Kinetics of the reaction of iron blast furnace slag/hydrated lime sorbents with SO{sub 2} at low temperatures: effects of the presence of CO{sub 2}, O{sub 2}, and NOx

Energy Technology Data Exchange (ETDEWEB)

Liu, C.F.; Shih, S.M. [Industrial Technological Research Institute, Hsinchu (Taiwan)

2009-09-15

The effects of the presence of CO{sub 2}, O{sub 2}, and NOx in the flue gas on the kinetics of the sulfation of blast furnace slag/hydrated lime sorbents at low temperatures were studied using a differential fixed-bed reactor. When O{sub 2} and NOx were not present simultaneously, the reaction kinetics was about the same as that under the gas mixtures containing SO{sub 2}, H{sub 2}O, and N{sub 2} only, being affected mainly by the relative humidity. The sulfation of sorbents can be described by the surface coverage model and the model equations derived for the latter case. When both O{sub 2} and NOx, were present, the sulfation of sorbents was greatly enhanced, forming a great amount of sulfate in addition to sulfite. The surface coverage model is still valid in this case, but the model equations obtained show a more marked effect of relative humidity and negligible effects of SO{sub 2} concentration and temperature on the reaction. The effect of sorbent composition on the reaction kinetics was entirely represented by the effects of the initial specific surface area (S{sub g0}) and the Ca molar content (M{sup -1}) of sorbent. The initial conversion rate of sorbent increased linearly with increasing S{sub g0}, and the ultimate conversion increased linearly with increasing S{sub g0}M{sup -1}. The model equations obtained in this work are applicable to describe the kinetics of the sulfation of the sorbents in the low-temperature dry and semidry fine gas desulfurization processes either with an upstream NOx, removal unit or without.111
How light-harvesting semiconductors can alter the bias of reversible electrocatalysts in favor of H2 production and CO2 reduction.

Science.gov (United States)

Bachmeier, Andreas; Wang, Vincent C C; Woolerton, Thomas W; Bell, Sophie; Fontecilla-Camps, Juan C; Can, Mehmet; Ragsdale, Stephen W; Chaudhary, Yatendra S; Armstrong, Fraser A

2013-10-09

The most efficient catalysts for solar fuel production should operate close to reversible potentials, yet possess a bias for the fuel-forming direction. Protein film electrochemical studies of Ni-containing carbon monoxide dehydrogenase and [NiFeSe]-hydrogenase, each a reversible electrocatalyst, show that the electronic state of the electrode strongly biases the direction of electrocatalysis of CO2/CO and H(+)/H2 interconversions. Attached to graphite electrodes, these enzymes show high activities for both oxidation and reduction, but there is a marked shift in bias, in favor of CO2 or H(+) reduction, when the respective enzymes are attached instead to n-type semiconductor electrodes constructed from CdS and TiO2 nanoparticles. This catalytic rectification effect can arise for a reversible electrocatalyst attached to a semiconductor electrode if the electrode transforms between semiconductor- and metallic-like behavior across the same narrow potential range (<0.25 V) that the electrocatalytic current switches between oxidation and reduction.
Implications of the (H2O)n + CO ↔ trans-HCOOH + (H2O)n-1 (n = 1, 2, and 3) reactions for primordial atmospheres of Venus and Earth

Science.gov (United States)

Vichietti, R. M.; Spada, R. F. K.; da Silva, A. B. F.; Machado, F. B. C.; Haiduke, R. L. A.

2018-04-01

The forward and backward (H2O)n + CO ↔ HCOOH + (H2O)n-1 (n = 1, 2, and 3) reactions were studied in order to furnish trustworthy thermochemical and kinetic data. Stationary point structures involved in these chemical processes were achieved at the B2PLYP/cc-pVTZ level so that the corresponding vibrational frequencies, zero-point energies, and thermal corrections were scaled to consider anharmonicity effects. A complete basis set extrapolation was also employed with the CCSD(T) method in order to improve electronic energy descriptions and providing therefore more accurate results for enthalpies, Gibbs energies, and rate constants. Forward and backward rate constants were encountered at the high-pressure limit between 200 and 4000 K. In turn, modified Arrhenius' equations were fitted from these rate constants (between 700 and 4000 K). Next, considering physical and chemical conditions that have supposedly prevailed on primitive atmospheres of Venus and Earth, our main results indicate that 85-88 per cent of all water forms on these atmospheres were monomers, whereas (H2O)2 and (H2O)3 complexes would represent 12-15 and ˜0 per cent, respectively. Besides, we estimate that Earth's and Venus' primitive atmospheres could have been composed by ˜0.001-0.003 per cent of HCOOH when their temperatures were around 1000-2000 K. Finally, the water loss process on Venus may have occurred by a mechanism that includes the formic acid as intermediate species.
Treatment for GaSb surfaces using a sulphur blended (NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4} solution

Energy Technology Data Exchange (ETDEWEB)

Murape, D.M., E-mail: Davison.Murape@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Eassa, N.; Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Betz, R. [Department of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa); Coetsee, E.; Swart, H.C. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031 (South Africa)

2012-07-01

A sulphur based chemical, [(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na{sub 2}S{center_dot}9H{sub 2}O and (NH{sub 4}){sub 2}S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) than with (NH{sub 4}){sub 2}S or Na{sub 2}S{center_dot}9H{sub 2}O, as evidenced by the ratio of the O{sub 506eV} to Sb{sub 457eV} AES peaks. XPS results reveal that Sb{sub 2}S{sub 3}/Sb{sub 2}S{sub 5} 'replaces' Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5}, suggesting that sulphur atoms substitute oxygen atoms in Sb{sub 2}O{sub 3}/Sb{sub 2}O{sub 5} to form Sb-S. It seems sulphurization only partially removes Ga{sub 2}O{sub 3}. Treatment with ([(NH{sub 4}){sub 2}S/(NH{sub 4}){sub 2}SO{sub 4}] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.
Application of banana peels waste as adsorbents for the removal of CO2, NO, NOx, and SO2 gases from motorcycle emissions

Science.gov (United States)

Viena, V.; Elvitriana; Wardani, S.

2018-03-01

The aims of the study were to investigate the application of banana peels as adsorbent for the removal of CO, NO, NOx and SO2 gases from motorcycles emissions. The effect of differents thermal activation on the characteristics of banana peels adsorbent (BPA) such as moisture content, ash content, volatile matter and fixed carbon has been studied using proximate analysis. The study of Iodine adsorption capacity of BPA was obtained at 952 mg/g adsorbent. Structure and morphology of BPA were characterized by Fourier transform infrared (FTIR) and field emission scanning electron microscopy (SEM). The results showed that BPA could significantly adsorbed the CO and SO2 gases emissions from motorcycles, but not applicable for NO, NOx gases. After 10 minutes of flue gas analysis at idle mode using BPA adsorption tube, CO gas could be totally removed, from initial 19618 ppm to 0 ppm, while SO2 gas could also be totally removed from 24523 ppm to 0 ppm. SEM test showed that temperature of activation had significant effect on the size of pores of BPA formed. BPA was suitable for application in removing CO and SO2 gases emissions from motorcycles and it helps to reduce the green house gas effects of fossil fuel to the environment.
Topological surface Fermi arcs in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$

OpenAIRE

Xu, Qiunan; Liu, Enke; Shi, Wujun; Muechler, Lukas; Felser, Claudia; Sun, Yan

2017-01-01

Very recently, the half-metallic compound Co$_3$Sn$_2$S$_2$ was predicted to be a magnetic WSM with Weyl points only 60 meV above the Fermi level ($E_F$). Owing to the low charge carrier density and large Berry curvature induced, Co$_3$Sn$_2$S$_2$ possesses both a large anomalous Hall conductivity (AHC) and a large anomalous Hall angle (AHA), which provide strong evidence for the existence of Weyl points in Co$_3$Sn$_2$S$_2$. In this work, we theoretically studied the surface topological feat...
NMR Study of the S=1/2 Quantum Kagome Lattice Antiferromagnet [Cu_3(titmb)_2(CH_3CO_2)_6]・H_2O(Frustrated Systems, Field-Induced Phase Transitions and Dynamics in Quantum Spin Systems)

OpenAIRE

Satoru, MAEGAWA; Kenji, YOSHIOKA; Shinichi, KAWAHARA; Akira, OYAMADA; Kenichi, FUJITA; Ryohei, YAMAGUCHI; Graduate School of Human and Environmental Studies, Kyoto University; Graduate School of Human and Environmental Studies, Kyoto University; Graduate School of Human and Environmental Studies, Kyoto University; Graduate School of Human and Environmental Studies, Kyoto University; Graduate School of Human and Environmental Studies, Kyoto University; Graduate School of Human and Environmental Studies, Kyoto University

2005-01-01

A quantum kagome lattice magnet, [Cu_3(titmb)_2(CH_3CO_2)_6]・H_2O with s=1/2 has been studied by magnetization and NMR experiments. No magnetic phase transition was observed down to 180mK. The spin-lattice relaxation rate T^_1 above 20K is almost temperature independent, while below 10K the rates decrease sharply as the temperature is decreased, and can be described as T^_1=B exp(-△/κ_BT). The field dependence on the energy gap △ has been obtained and is found to show plateaus between 3.2 and...

Optimization of a cascade refrigeration system using refrigerant C_3H_8 in high temperature circuits (HTC) and a mixture of C_2H_6/CO_2 in low temperature circuits (LTC)

International Nuclear Information System (INIS)

Nasruddin; Sholahudin, S.; Giannetti, N.; Arnas

2016-01-01

Highlights: • Multi-objective optimization is conducted in the cascade refrigeration system. • Combination of operating temperature and refrigerant performance has been studied. • Characteristic of C_3H_8 and a mixture of C_2H_6/CO_2 have been investigated. • Determining of CO_2 fraction to optimize refrigeration system has been done. - Abstract: This paper discusses the multi-objectives optimization of a cascade refrigeration system using refrigerant C_3H_8 in high temperature circuits (HTC) and a mixture of C_2H_6/CO_2 in low temperature circuits (LTC). The evaporator temperature, condenser temperature, C_2H_6/CO_2 mixture condensation temperature, cascade temperature differences, and the CO_2 mass fraction are chosen as the decision variables. Whereas cooling capacity, cold space temperature, and ambient temperature are taken as the constraints. The purpose of this research is to design a cascade refrigeration system whose optimum performance are defined in terms of economics and thermodynamics. Accordingly, there are two objective functions that should be simultaneously optimized including the total annual cost which consists of the capital and operational cost and the total exergy destruction of the system. To this aim, the optimum operating temperature of the system and CO_2 fraction should be determined so that the system has minimum exergy destruction and annual cost. Results show that, the optimum value of the decision variables for this system can be determined by trade-off between annual cost and exergy destruction.
Solar Cycle Variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere Region

Science.gov (United States)

Salinas, C. C. J.; Chang, L. C.; Liang, M. C.; Qian, L.; Yue, J.; Russell, J. M., III; Mlynczak, M. G.

2017-12-01

This work aims to present the solar cycle variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere region. These observations are then compared to SD-WACCM outputs of CO2 and H2O in order to understand their physical mechanisms. After which, we attempt to model their solar cycle variations using the default TIME-GCM and the TIME-GCM with MERRA reanalysis as lower-boundary conditions. Comparing the outputs of the default TIME-GCM and TIME-GCM with MERRA will give us insight into the importance of solar forcing and lower atmospheric forcing on the solar cycle variations of CO2 and H2O. The solar cycle influence in the parameters are calculated by doing a multiple linear regression with the F10.7 index. The solar cycle of SABER CO2 is reliable above 1e-2 mb and below 1e-3 mb. Preliminary results from the observations show that SABER CO2 has a stronger negative anomaly due to the solar cycle over the winter hemisphere. MLS H2O is reliable until 1e-2. Preliminary results from the observations show that MLS H2O also has a stronger negative anomaly due to the solar cycle over the winter hemisphere. Both SD-WACCM and the default TIME-GCM reproduce these stronger anomalies over the winter hemisphere. An analysis of the tendency equations in SD-WACCM and default TIME-GCM then reveal that for CO2, the stronger winter anomaly may be attributed to stronger downward transport over the winter hemisphere. For H2O, an analysis of the tendency equations in SD-WACCM reveal that the stronger winter anomaly may be attributed to both stronger downward transport and stronger photochemical loss. On the other hand, in the default TIME-GCM, the stronger winter anomaly in H2O may only be attributed to stronger downward transport. For both models, the stronger downward transport is attributed to enhanced stratospheric polar winter jet during solar maximum. Future work will determine whether setting the lower boundary conditions of TIME-GCM with MERRA will improve the match
Radiative transition probabilities for the main diatomic electronic systems of N2, N2+, NO, O2, CO, CO+, CN, C2 and H2 produced in plasma of atmospheric entry

Science.gov (United States)

Qin, Z.; Zhao, J. M.; Liu, L. H.

2017-11-01

Accurate radiative transition probabilities of diatomic electronic systems are required to calculate the discrete radiation of plasmas. However, most of the published transition probabilities are obtained using older spectroscopic constants and electronic transition moment functions (ETMFs), some of which deviates greatly from experimental data. Fortunately, a lot of new spectroscopic constants that include more anharmonic correction terms than the earlier ones have been published over the past few years. In this work, the Einstein coefficients, Franck-Condon factors and absorption band oscillator strengths are calculated for important diatomic radiative transition processes of N2-O2, CO2-N2 and H2 plasmas produced in entering into the atmosphere of Earth, Mars and Jupiter. The most up-to-date spectroscopic constants are selected to reconstruct the potential energy curves by the Rydberg-Klein-Rees (RKR) method. Then the vibrational wave functions are calculated through the resolution of the radial Schrödinger equation for such potential energy curves. These results, together with the latest "ab-initio" ETMFs derived from the literature are used to compute the square of electronic-vibrational transition moments, Einstein coefficients and absorption band oscillator strengths. Moreover, the Franck-Condon factors are determined with the obtained vibrational wave functions. In the supplementary material we present tables of the radiative transition probabilities for 40 band systems of N2, N2+, NO, O2, CO, CO+, CN, C2 and H2 molecules. In addition, the calculated radiative lifetimes are systematically validated by available experimental results.
Measurement of OCS, CO2, CO and H2O aboard NASA's WB-57 High Altitude Platform Using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS)

Science.gov (United States)

Leen, J. B.; Owano, T. G.; Du, X.; Gardner, A.; Gupta, M.

2014-12-01

Carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere and has been implicated in controlling the sulfur budget and aerosol loading of the stratosphere. In the troposphere, OCS is irreversibly consumed during photosynthesis and may serve as a tracer for gross primary production (GPP). Its primary sources are ocean outgassing, industrial processes, and biomass burning. Its primary sinks are vegetation and soils. Despite the importance of OCS in atmospheric processes, the OCS atmospheric budget is poorly determined and has high uncertainty. OCS is typically monitored using either canisters analyzed by gas chromatography or integrated atmospheric column measurements. Improved in-situ terrestrial flux and airborne measurements are required to constrain the OCS budget and further elucidate its role in stratospheric aerosol formation and as a tracer for biogenic volatile organics and photosynthesis. Los Gatos Research has developed a flight capable mid-infrared Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) analyzer to simultaneously quantify OCS, CO2, CO, and H2O in ambient air at up to 2 Hz. The prototype was tested on diluted, certified samples and found to be precise (OCS, CO2, CO, and H2O to better than ±4 ppt, ±0.2 ppm, ±0.31 ppb, and ±3.7 ppm respectively, 1s in 1 sec) and linear (R2 > 0.9997 for all gases) over a wide dynamic range (OCS, CO2, CO, and H2O ranging from 0.2 - 70 ppb, 500 - 3000 ppm, 150 - 480 ppb, and 7000 - 21000 ppm respectively). Cross-interference measurements showed no appreciable change in measured OCS concentration with variations in CO2 (500 - 3500 ppm) or CO. We report on high altitude measurements made aboard NASA's WB-57 research aircraft. Two research flights were conducted from Houston, TX. The concentration of OCS, CO2, CO, and H2O were continuously recorded from sea level to approximately 60,000 feet. The concentration of OCS was observed to increase with altitude through the troposphere due to the
Multicomponent Biginelli's synthesis of 3,4-dihydropyrimidin-2(1H-ones promoted by SnCl2.2H2O

Directory of Open Access Journals (Sweden)

Russowsky Dennis

2004-01-01

Full Text Available The ability of SnCl2.2H2O as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, ethyl acetoacetate and urea or thiourea is described. The reaction was carried out in acetonitrile or ethanol as solvents in neutral media and represents an improvement of the classical Biginelli protocol and an advantage in comparison with FeCl3.6H2O, NiCl2.6H2O and CoCl2.6H2O which were used with HCl as co-catalyst. The synthesis of 3,4-dihydropyrimidinones was achieved in good to excelent yields.
Three-dimensional hierarchical NiCo2O4 nanowire@Ni3S2 nanosheet core/shell arrays for flexible asymmetric supercapacitors

Science.gov (United States)

Liu, Bo; Kong, Dezhi; Huang, Zhi Xiang; Mo, Runwei; Wang, Ye; Han, Zhaojun; Cheng, Chuanwei; Yang, Hui Ying

2016-05-01

Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power density of 56.33 W cm-3 at 0.94 mW h cm-3. As a result, the hybrid nanoarchitecture opens a new way to design high performance electrodes for electrochemical energy storage applications.Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power
Electron capture into the n = 3 states of hydrogen by proton impact on CO, CO2, and N2O

International Nuclear Information System (INIS)

Loyd, D.H.; Dawson, H.R.

1979-01-01

Absolute cross sections for electron capture into the 3s, 3p, and 3d states of hydrogen have been measured for 2.2--8.2-keV proton impact on CO, CO 2 , and N 2 O. The relative magnitudes of the 3s, 3p, and 3d cross sections for CO are very similar to cross sections previously measured for elemental gases. The CO 2 and N 2 O cross sections have a very different relative distribution among the 3s, 3p, and 3d states compared to all other gases studied in this laboratory, with the 3p cross section being so small that only an estimate of the upper limit to the cross section was possible
Interactions of methylamine and ammonia with atmospheric nucleation precursor H{sub 2}SO{sub 4} and common organic acids: Thermodynamics and atmospheric implications

Energy Technology Data Exchange (ETDEWEB)

Xu, Y.; Jiang, L.; Bai, Z. [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012 (China); Nadykto, A. B., E-mail: anadykto@gmail.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012 (China); Department of Applied Mathematics, Moscow State University of Technology “STANKIN”, Vadkovsky per. 1, Moscow 127055 (Russian Federation); Atmospheric Science Research Center, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203 (United States)

2016-06-08

Interactions of the two common atmospheric bases, ammonia (NH{sub 3}) and methylamine MA (CH{sub 3}NH{sub 2}), which are considered to be important stabilizers of binary clusters in the Earth’s atmosphere, with H{sub 2}SO{sub 4}, the key atmospheric precursor, and 14 common atmospheric organic acids (COA) (formic (CH{sub 2}O{sub 2}), acetic (C{sub 2}H{sub 4}O{sub 2}), oxalic (C{sub 2}H{sub 2}O{sub 4}), malonic (C{sub 3}H{sub 4}O{sub 4}), succinic (C{sub 4}H{sub 6}O{sub 4}), glutaric acid (C{sub 5}H{sub 8}O{sub 4}), adipic (C{sub 6}H{sub 10}O{sub 4}), benzoic (C{sub 6}H{sub 5}COOH), phenylacetic (C{sub 6}H{sub 5}CH{sub 2}COOH), pyruvic (C{sub 3}H{sub 4}O{sub 3}), maleic acid (C{sub 4}H{sub 4}O{sub 4}), malic (C{sub 4}H{sub 6}O{sub 5}), tartaric (C{sub 4}H{sub 6}O{sub 6}) and pinonic acid (C{sub 10}H{sub 16}O{sub 3})) have been studied using the composite high-accuracy G3MP2 method. The thermodynamic stability of mixed (COA) (H{sub 2}SO{sub 4}), (COA)(B1) and (COA)(B2) dimers and (COA) (H{sub 2}SO{sub 4}) (B1) and (COA) (H{sub 2}SO{sub 4}) (B1) trimers, where B1 and B2 represent methylamine (CH{sub 3}NH{sub 2}) and ammonia (NH{sub 3}), respectively, have been investigated and their impacts on the thermodynamic stability of clusters containing H{sub 2}SO{sub 4} have been analyzed. It has been shown that in many cases the interactions of H{sub 2}SO{sub 4} with COA, ammonia and methylamine lead to the formation of heteromolecular dimers and trimers, which are certainly more stable than (H{sub 2}SO{sub 4}){sub 2} and (H{sub 2}SO{sub 4}){sub 3}. It has also been found that free energies of (COA) (H{sub 2}SO{sub 4})+ CH{sub 3}NH{sub 2}⇔(COA) (H{sub 2}SO{sub 4})(CH{sub 3}NH{sub 2}) reactions exceed 10-15 kcal mol{sup −1}. This is a clear indication that mixed trimers composed of COA, H{sub 2}SO{sub 4} and methylamine are very stable and can thus serve as possible nucleation sites. The present study leads us to conclude that the interactions of COA coexisting with H
SYSTEMATIC VARIATIONS IN CO2/H2O ICE ABUNDANCE RATIOS IN NEARBY GALAXIES FOUND WITH AKARI NEAR-INFRARED SPECTROSCOPY

International Nuclear Information System (INIS)

Yamagishi, M.; Kaneda, H.; Ishihara, D.; Oyabu, S.; Onaka, T.; Shimonishi, T.; Suzuki, T.

2015-01-01

We report CO 2 /H 2 O ice abundance ratios in seven nearby star-forming galaxies based on the AKARI near-infrared (2.5–5.0 μm) spectra. The CO 2 /H 2 O ice abundance ratios show clear variations between 0.05 and 0.2 with the averaged value of 0.14 ± 0.01. The previous study on M82 revealed that the CO 2 /H 2 O ice abundance ratios strongly correlate with the intensity ratios of the hydrogen recombination Brα line to the polycyclic aromatic hydrocarbon (PAH) 3.3 μm feature. In the present study, however, we find no correlation for the seven galaxies as a whole due to systematic differences in the relation between CO 2 /H 2 O ice abundance and Brα/PAH 3.3 μm intensity ratios from galaxy to galaxy. This result suggests that there is another parameter that determines the CO 2 /H 2 O ice abundance ratios in a galaxy in addition to the Brα/PAH 3.3 μm ratios. We find that the CO 2 /H 2 O ice abundance ratios positively correlate with the specific star formation rates of the galaxies. From these results, we conclude that CO 2 /H 2 O ice abundance ratios tend to be high in young star-forming galaxies
Two-component, ab initio potential energy surface for CO2—H2O, extension to the hydrate clathrate, CO2@(H2O)20, and VSCF/VCI vibrational analyses of both

Science.gov (United States)

Wang, Qingfeng Kee; Bowman, Joel M.

2017-10-01

We report an ab initio, full-dimensional, potential energy surface (PES) for CO2—H2O, in which two-body interaction energies are fit using a basis of permutationally invariant polynomials and combined with accurate potentials for the non-interacting monomers. This approach which we have termed "plug and play" is extended here to improve the precision of the 2-body fit in the long range. This is done by combining two separate fits. One is a fit to 47 593 2-body energies in the region of strong interaction and approaching the long range, and the second one is a fit to 6244 2-body energies in the long range. The two fits have a region of overlap which permits a smooth switch from one to the other. All energies are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory. Properties of the full PES, i.e., stationary points, harmonic frequencies of the global minimum, etc., are shown to be in excellent agreement with direct CCSD(T)-F12b/aug-cc-pVTZ results. Diffusion Monte Carlo calculations of the dimer zero-point energy (ZPE) are performed, and a dissociation energy, D0, of 787 cm-1 is obtained using that ZPE, De, and the rigorous ZPEs of the monomers. Using a benchmark De, D0 is 758 cm-1. Vibrational self-consistent field (VSCF)/virtual state configuration interaction (VCI) MULTIMODE calculations of intramolecular fundamentals are reported and are in good agreement with available experimental results. Finally, the full dimer PES is combined with an existing ab initio water potential to develop a potential for the CO2 hydrate clathrate CO2(H2O)20(512 water cage). A full normal-mode analysis of this hydrate clathrate is reported as are local-monomer VSCF/VCI calculations of the fundamentals of CO2.
A review on the effects of TiO2 surface point defects on CO2 photoreduction with H2O

Directory of Open Access Journals (Sweden)

Huilei Zhao

2017-03-01

Full Text Available Photocatalytic reduction of CO2 with water by photocatalysts such as TiO2 to produce solar fuels is an attractive approach to alleviate the environmental influences of greenhouse gases and in the meantime produce valuable carbon-neutral fuels. Among the materials properties that affect catalytic activity of CO2 photoreduction, the point defect on TiO2 is one of the most important but not frequently addressed and well understood in the literature. In this review, we have examined the major influences of TiO2 point defects on CO2 photoreduction with H2O, by changing the catalysts' gas adsorption capabilities, optical properties, and electronic structures. In addition, the performances of various defective TiO2 toward CO2 photoreduction are summarized and compared in terms of productivity, selectivity, and stability. We hope this review can contribute to understanding the mechanism of CO2 photoreduction on defective TiO2 and provide insights to the design of highly efficient defect-rich TiO2 to boost the CO2 utilization.
Alkali/TX[sub 2] catalysts for CO/H[sub 2] conversion to C[sub 1]-C[sub 4] alcohols

Energy Technology Data Exchange (ETDEWEB)

Klier, K.; Herman, R.G.; Bastian, R.D.; Flanagan, K.L.

1989-01-01

Ruthenium disulfide catalysts have been synthesized, tested, and characterized during this period of research. It was observed that both the undoped and Cs-doped RuS[sub 2] catalysts produced alcohols and lower amounts of hydrocarbons from H[sub 2]/CO = 1.0 synthesis gas at temperatures above 300[degree]C. Calcination and catalytic testing resulted in partial reduction of the RuS[sub 2] to Ru[sup o]. Calcination under H[sub 2]S prevented the partial reduction of the RuS[sub 2] catalyst, but subsequent catalytic testing again resulted in the formation of a quantity of Ru[sup o]. A Cs-doped RuS[sub 2] catalyst was prepared, but it might have had too high of a loading of Cs. Upon testing, a lower activity was observed for the doped catalyst compared with the undoped catalyst, but the alcohol selectivity was the same for the two catalysts.
High-Temperature Corrosion of T92 Steel in N{sub 2}/H{sub 2}O/H{sub 2}S-Mixed Gas

Energy Technology Data Exchange (ETDEWEB)

Shi, Yuke; Kim, Min Jung; Park, Soon Yong; Abro, M. Ali; Yadav, Poonam; Lee, Dong Bok [Sungkyunkwan University, Suwon (Korea, Republic of)

2016-06-15

The ASTM T92 steel was corroded at 600 ℃ and 800 ℃ at 1 atm of N{sub 2}/3.1%H{sub 2}O/2.42%H{sub 2}S-mixed gas. The formed scales were thick and fragile. They consisted primarily of the outer FeS scale and the inner (FeS, FeCr{sub 2}S{sub 4})-mixed scale containing a small amount of the Cr{sub 2}O{sub 3} scale. This indicated that corrosion occurred mainly via sulfidation rather than oxidation due to the H{sub 2}S gas. Since FeS was present throughout the whole scale, T92 steel was non-protective, displaying high corrosion rates.
Carbon Dioxide and Water Vapor Concentrations, Co-spectra and Fluxes from Latest Standardized Automated CO2/H2O Flux Systems versus Established Analyzer Models

Science.gov (United States)

Burba, G. G.; Kathilankal, J. C.; Begashaw, I.; Franzen, D.; Welles, J.; McDermitt, D. K.

2017-12-01

Spatial and temporal flux data coverage have improved significantly in recent years, due to standardization, automation and management of data collection, and better handling of the generated data. With more stations and networks, larger data streams from each station, and smaller operating budgets, modern tools are required to effectively and efficiently handle the entire process.These tools should produce standardized verifiable datasets, and provide a way to cross-share the standardized data with external collaborators to leverage available funding, and promote data analyses and publications. In 2015, new open-path and enclosed flux measurement systems1 were developed, based on established gas analyzer models2,3, with the goal of improving stability in the presence of contamination, refining temperature control and compensation, and providing more accurate gas concentration measurements. In 2017, the new open-path system was further refined to simplify hardware configuration, and to reduce power consumption and cost. Additionally, all new systems incorporate complete automated on-site flux calculations using EddyPro® Software4 run by a weatherized remotely-accessible microcomputer to provide standardized traceable data sets for fluxes and supporting variables. This presentation will describe details and results from the field tests of the new flux systems, in comparison to older models and reference instruments. References:1 Burba G., W. Miller, I. Begashaw, G. Fratini, F. Griessbaum, J. Kathilankal, L. Xu, D. Franz, E. Joseph, E. Larmanou, S. Miller, D. Papale, S. Sabbatini, T. Sachs, R. Sakai, D. McDermitt, 2017. Comparison of CO2 Concentrations, Co-spectra and Flux Measurements between Latest Standardized Automated CO2/H2O Flux Systems and Older Gas Analysers. 10th ICDC Conference, Switzerland: 21-25/08 2 Metzger, S., G. Burba, S. Burns, P. Blanken, J. Li, H. Luo, R. Zulueta, 2016. Optimization of an enclosed gas analyzer sampling system for measuring eddy
Vibrational modes and Structure of Niobium(V) Oxosulfato Complexes in the Molten Nb2O5-K2S2O7-K2SO4 System Studied by Raman Spectroscopy

DEFF Research Database (Denmark)

Paulsen, Andreas L.; Borup, Flemming; Berg, Rolf W.

2010-01-01

The structural and vibrational properties of NbV oxosulfato complexes formed in Nb2O5-K2S2O7 and Nb2O5-K2S2O7-K2SO4 molten mixtures with 0 ... for the binary Nb2O5-K2S2O7 molten system indicate that the dissolution of Nb2O5 proceeds with consumption of S2O7 leading to the formation of a NbV oxosulfato complex according to Nb2O5 + nS2O7 --> C2n-; a simple formalism exploiting the relative Raman band intensities is used for determining the stoichiometric...... coefficient, n, pointing to n = 3 and to the following reaction: Nb2O5 + 3S2O7 --> 2NbO(SO4)3, which is consistent with the Raman spectra of the molten mixtures. Nb2O5 could be dissolved much easier when K2SO4 was present in an equimolar (1:1) SO4/Nb ratio; the incremental presence of K2SO4 in Nb2O5-K2S2O7...
A second polymorph with composition Co3(PO4)2·H2O

Science.gov (United States)

Lee, Young Hoon; Clegg, Jack K.; Lindoy, Leonard F.; Lu, G. Q. Max; Park, Yu-Chul; Kim, Yang

2008-01-01

Single crystals of Co3(PO4)2·H2O, tricobalt(II) bis[orthophosphate(V)] monohydrate, were obtained under hydrothermal conditions. The compound is the second polymorph of this composition and is isotypic with its zinc analogue, Zn3(PO4)2·H2O. Three independent Co2+ cations are bridged by two independent orthophosphate anions. Two of the metal cations exhibit a distorted tetrahedral coordination while the third exhibits a considerably distorted [5 + 1] octahedral coordination environment with one very long Co—O distance of 2.416 (3) Å. The former cations are bonded to four different phosphate anions, and the latter cation is bonded to four anions (one of which is bidentate) and one water molecule, leading to a framework structure. Additional hydrogen bonds of the type O—H⋯O stabilize this arrangement. PMID:21200979
Modeling CO, CO2, and H2O Ice Abundances in the Envelopes of Young Stellar Objects in the Magellanic Clouds

Science.gov (United States)

Pauly, Tyler; Garrod, Robin T.

2018-02-01

Massive young stellar objects (MYSOs) in the Magellanic Clouds show infrared absorption features corresponding to significant abundances of CO, CO2, and H2O ice along the line of sight, with the relative abundances of these ices differing between the Magellanic Clouds and the Milky Way. CO ice is not detected toward sources in the Small Magellanic Cloud, and upper limits put its relative abundance well below sources in the Large Magellanic Cloud and the Milky Way. We use our gas-grain chemical code MAGICKAL, with multiple grain sizes and grain temperatures, and further expand it with a treatment for increased interstellar radiation field intensity to model the elevated dust temperatures observed in the MCs. We also adjust the elemental abundances used in the chemical models, guided by observations of H II regions in these metal-poor satellite galaxies. With a grid of models, we are able to reproduce the relative ice fractions observed in MC MYSOs, indicating that metal depletion and elevated grain temperature are important drivers of the MYSO envelope ice composition. Magellanic Cloud elemental abundances have a subgalactic C/O ratio, increasing H2O ice abundances relative to the other ices; elevated grain temperatures favor CO2 production over H2O and CO. The observed shortfall in CO in the Small Magellanic Cloud can be explained by a combination of reduced carbon abundance and increased grain temperatures. The models indicate that a large variation in radiation field strength is required to match the range of observed LMC abundances. CH3OH abundance is found to be enhanced in low-metallicity models, providing seed material for complex organic molecule formation in the Magellanic Clouds.
Investigation of H2S separation from H2S/CH4 mixtures using functionalized and non-functionalized vertically aligned carbon nanotube membranes

Science.gov (United States)

Gilani, Neda; Towfighi, Jafar; Rashidi, Alimorad; Mohammadi, Toraj; Omidkhah, Mohammad Reza; Sadeghian, Ahmad

2013-04-01

Separation of H2S from binary mixtures of H2S/CH4 using vertically aligned carbon nanotube membranes fabricated in anodic aluminum oxide (AAO) template was studied experimentally. Carbon nanotubes (CNTs) were grown in five AAO templates with different pore diameters using chemical vapor deposition, and CNT/AAO membranes with tubular carbon nanotube structure and open caps were selected for separation of H2S. For this, two tubular CNT/AAO membranes were fabricated with the CNT inner diameters of 23 and 8 nm. It was found that permeability and selectivity of the membrane with inner diameter of 23 nm for CNT were independent of upstream feed pressure and H2S feed concentration unlike that of CNT having an inner diameter of 8 nm. Selectivity of these membranes for separation of H2S was obtained in the ranges of 1.36-1.58 and 2.11-2.86, for CNTs with internal diameters of 23 and 8 nm, respectively. In order to enhance the separation of H2S from H2S/CH4 mixtures, dodecylamine was used to functionalize the CNT/AAO membrane with higher selectivity. The results showed that for amido-functionalized membrane, both upstream feed pressure and H2S partial pressure in the feed significantly increased H2S permeability, and selectivity for H2S being in the range of 3.0-5.57 respectively.
Importance of collisional rates for anomalous absorption in H2CO molecule

International Nuclear Information System (INIS)

Sharma, Monika; Sharma, M.K.; Chandra, Suresh

2012-01-01

Formaldehyde (H 2 CO) is the first organic molecule identified in a number of galactic and extragalactic radio sources through its transition 1 10 –1 11 at 4.830 GHz in absorption. Later on, this transition was found in anomalous absorption. In some cosmic objects, this transition however was found in emission and even as a maser radiation. Since the transition 1 10 –1 11 of ortho-H 2 CO is considered as a unique probe of high density gas at low temperature, the study of H 2 CO has always been of great importance for astrophysicists as well as for spectroscopists. In view of the availability of better input data required for such investigation, it is worth while to investigate again about the radiations from ortho-H 2 CO. In the present study, we have investigated anomalous absorption of 1 10 –1 11 , 2 11 –2 12 and 3 12 –3 13 transitions of ortho-H 2 CO. The present results are more reliable as compared to those obtained earlier. -- Highlights: ► Accurate rotational levels and A-coefficients for H 2 CO are calculated. ► Transitions 1 10 –1 11 , 2 11 –2 12 and 3 12 –3 13 show anomalous absorption. ► Anomalous absorption is found to increase with kinetic temperature. ► Anomalous absorption may be found for n H 2 ≈10 4 cm −3 . ► Colliding partner para-H 2 may be approximated as He atom.
Anomalous absorption in H2CN and CH2CN molecules

Indian Academy of Sciences (India)

Abstract. Structures of H2CN and CH2CN molecules are similar to that of H2CO mole- cule. The H2CO has shown anomalous absorption for its transition 111 − 110 at 4.8 GHz in a number of cool molecular clouds. Though the molecules H2CN and CH2CN have been identified in TMC-1 and Sgr B2 through some ...

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