High-resolution photoelectron spectroscopy of TiO3H2-: Probing the TiO2- + H2O dissociative adduct

Science.gov (United States)

DeVine, Jessalyn A.; Abou Taka, Ali; Babin, Mark C.; Weichman, Marissa L.; Hratchian, Hrant P.; Neumark, Daniel M.

2018-06-01

Slow electron velocity-map imaging spectroscopy of cryogenically cooled TiO3H2- anions is used to probe the simplest titania/water reaction, TiO20/- + H2O. The resultant spectra show vibrationally resolved structure assigned to detachment from the cis-dihydroxide TiO(OH)2- geometry based on density functional theory calculations, demonstrating that for the reaction of the anionic TiO2- monomer with a single water molecule, the dissociative adduct (where the water is split) is energetically preferred over a molecularly adsorbed geometry. This work represents a significant improvement in resolution over previous measurements, yielding an electron affinity of 1.2529(4) eV as well as several vibrational frequencies for neutral TiO(OH)2. The energy resolution of the current results combined with photoelectron angular distributions reveals Herzberg-Teller coupling-induced transitions to Franck-Condon forbidden vibrational levels of the neutral ground state. A comparison to the previously measured spectrum of bare TiO2- indicates that reaction with water stabilizes neutral TiO2 more than the anion, providing insight into the fundamental chemical interactions between titania and water.

Ab initio studies of O2-(H2O)n and O3-(H2O)n anionic molecular clusters, n≤12

DEFF Research Database (Denmark)

Bork, Nicolai Christian; Kurtén, T.; Enghoff, Martin Andreas Bødker

2011-01-01

that anionic O2−(H2O)n and O3−(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding. Although...... clustering up to 12 H2O, we find that the O2 and O3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O2− and O3− speicies are thus accessible for further reactions. Finally, the thermodynamics of a few relevant cluster reactions are considered....

Syntheses, crystal structures, and properties of the isotypic pair [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O and [In(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Van, Nguyen-Duc; Kleeberg, Fabian M.; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany)

2015-11-15

Single crystals of [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O and [In(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O were obtained by reactions of aqueous solutions of the acid (H{sub 3}O){sub 2}[B{sub 12}H{sub 12}] with chromium(III) hydroxide and indium metal shot, respectively. The title compounds crystallize isotypically in the trigonal system with space group R anti 3c (a = 1157.62(3), c = 6730.48(9) pm for the chromium, a = 1171.71(3), c = 6740.04(9) pm for the indium compound, Z = 6). The arrangement of the quasi-icosahedral [B{sub 12}H{sub 12}]{sup 2-} dianions can be considered as stacking of two times nine layers with the sequence..ABCCABBCA.. and the metal trications arrange in a cubic closest packed..abc.. stacking sequence. The metal trications are octahedrally coordinated by six water molecules of hydration, while another fifteen H{sub 2}O molecules fill up the structures as zeolitic crystal water or second-sphere hydrating species. Between these free and the metal-bonded water molecules, bridging hydrogen bonds are found. Furthermore, there is also evidence of hydrogen bonding between the anionic [B{sub 12}H{sub 12}]{sup 2-} clusters and the free zeolitic water molecules according to B-H{sup δ-}..{sup δ+}H-O interactions. Vibrational spectroscopy studies prove the presence of these hydrogen bonds and also show slight distortions of the dodecahydro-closo-dodecaborate anions from their ideal icosahedral symmetry (I{sub h}). Thermal decomposition studies for the example of [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O gave no hints for just a simple multi-stepwise dehydration process. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

HERSCHEL/HIFI SEARCH FOR H{sub 2}{sup 17}O AND H{sub 2}{sup 18}O IN IRC+10216: CONSTRAINTS ON MODELS FOR THE ORIGIN OF WATER VAPOR

Energy Technology Data Exchange (ETDEWEB)

Neufeld, David A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Tolls, Volker; Melnick, Gary J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Agundez, Marcelino [LAB, Universite de Bordeaux, UMR 5804, F-33270 Floirac (France); Gonzalez-Alfonso, Eduardo [Universidad de Alcala de Henares, Departamento de Fisica y Matematicas, Campus Universitario, E-28871 Alcala de Henares, Madrid (Spain); Decin, Leen [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium); Daniel, Fabien; Cernicharo, Jose [Departamento de Astrofisica, Centro de Astrobiologia, CSIC-INTA, Ctra. de Torrejon a Ajalvir km 4, E-28850 Madrid (Spain); Schmidt, Miroslaw; Szczerba, Ryszard [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Rabianska 8, 87-100 Torun (Poland)

2013-04-10

We report the results of a sensitive search for the minor isotopologues of water, H{sub 2}{sup 17}O and H{sub 2}{sup 18}O, toward the carbon-rich asymptotic giant branch star IRC+10216 (a.k.a. CW Leonis) using the HIFI instrument on the Herschel Space Observatory. This search was motivated by the fact that any detection of isotopic enhancement in the H{sub 2}{sup 17}O and H{sub 2}{sup 18}O abundances would have strongly implicated CO photodissociation as the source of the atomic oxygen needed to produce water in a carbon-rich circumstellar envelope. Our observations place an upper limit of 1/470 on the H{sub 2}{sup 17}O/H{sub 2}{sup 16}O abundance ratio. Given the isotopic {sup 17}O/{sup 16}O ratio of 1/840 inferred previously for the photosphere of IRC+10216, this result places an upper limit of a factor 1.8 on the extent of any isotope-selective enhancement of H{sub 2}{sup 17}O in the circumstellar material, and provides an important constraint on any model that invokes CO photodissociation as the source of O for H{sub 2}O production. In the context of the clumpy photodissociation model proposed previously for the origin of water in IRC+10216, our limit implies that {sup 12}C{sup 16}O (not {sup 13}C{sup 16}O or SiO) must be the dominant source of {sup 16}O for H{sub 2}O production, and that the effects of self-shielding can only have reduced the {sup 12}C{sup 16}O photodissociation rate by at most a factor {approx}2.

Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation.

Science.gov (United States)

Sheng, Hong; Nakamura, Keisuke; Kanno, Taro; Sasaki, Keiichi; Niwano, Yoshimi

2015-01-01

The bactericidal effect of hydroxyl radical (·OH) generated by combination of photolysis of hydrogen peroxide (H2O2) and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2) and ultrasound (power: 30 w, frequency: 1.65 MHz) at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

Simultaneous analysis of 17O/16O, 18O/16O and 2H/1H of gypsum hydration water by cavity ring‐down laser spectroscopy

Science.gov (United States)

Mather, Ian; Rolfe, James; Evans, Nicholas P.; Herwartz, Daniel; Staubwasser, Michael; Hodell, David A.

2015-01-01

Rationale The recent development of cavity ring‐down laser spectroscopy (CRDS) instruments capable of measuring 17O‐excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post‐depositional interaction with other fluids. Methods We developed a semi‐automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (δ17O, δ18O and δ2H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long‐term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of 17O‐excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2. Results The long‐term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for δ17O values, ±0.13‰ for δ18O values and ±0.49‰ for δ2H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium‐excess and 17O‐excess, respectively. Accurate measurement of the 17O‐excess values of GHW, of both synthetic and natural samples, requires the use of a micro‐combustion module (MCM). This accessory removes contaminants (VOCs, H2S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods. Conclusions We

Organic micropollutants (OMPs) in natural waters: Oxidation by UV/H2O2 treatment and toxicity assessment.

Science.gov (United States)

Rozas, Oscar; Vidal, Cristiane; Baeza, Carolina; Jardim, Wilson F; Rossner, Alfred; Mansilla, Héctor D

2016-07-01

Organic micropollutants (OMPs) are ubiquitous in natural waters even in places where the human activity is limited. The presence of OMPs in natural water sources for human consumption encourages the evaluation of different water purification technologies to ensure water quality. In this study, the Biobío river (Chile) was selected since the watershed includes urban settlements and economic activities (i.e. agriculture, forestry) that incorporate a variety of OMPs into the aquatic environment, such as pesticides, pharmaceuticals and personal care products. Atrazine (herbicide), caffeine (psychotropic), diclofenac (anti-inflammatory) and triclosan (antimicrobial) in Biobío river water and in different stages of a drinking and two wastewater treatment plants downstream Biobío river were determined using solid phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) and electrospray ionization (ESI). Quantification of these four compounds showed concentrations in the range of 8 ± 2 to 55 ± 10 ng L(-1) in Biobío river water, 11 ± 2 to 74 ± 21 ng L(-1) in the drinking water treatment plant, and 60 ± 10 to 15,000 ± 1300 ng L(-1) in the wastewater treatment plants. Caffeine was used as an indicator of wastewater discharges. Because conventional water treatment technologies are not designed to eliminate some emerging organic pollutants, alternative treatment processes, UV and UV/H2O2, were employed. The transformation of atrazine, carbamazepine (antiepileptic), diclofenac and triclosan was investigated at laboratory scale. Both processes were tested at different UV doses and the Biobío river water matrix effects were evaluated. Initial H2O2 concentration used was 10 mg L(-1). Results showed that, the transformation profile obtained using UV/H2O2 at UV doses up to 900 mJ cm(-2), followed the trend of diclofenac > triclosan > atrazine > carbamazepine. Furthermore acute toxicity tests with Daphnia magna were carried

Electrochemical, H2O2-Boosted Catalytic Oxidation System

Science.gov (United States)

Akse, James R.; Thompson, John O.; Schussel, Leonard J.

2004-01-01

An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen water-sterilizing systems in the way in which it increases oxidation capabilities, supplies H2O2 when needed, reduces the total organic carbon (TOC) content of treated water to a low level, consumes less energy than prior systems do, reduces the risk of contamination, and costs less to operate. This system was developed as a variant of part of an improved waste-management subsystem of the life-support system of a spacecraft. Going beyond its original intended purpose, it offers the advantage of being able to produce H2O2 on demand for surface sterilization and/or decontamination: this is a major advantage inasmuch as the benign byproducts of this H2O2 system, unlike those of systems that utilize other chemical sterilants, place no additional burden of containment control on other spacecraft air- or water-reclamation systems.

Bactericidal Effect of Photolysis of H2O2 in Combination with Sonolysis of Water via Hydroxyl Radical Generation.

Directory of Open Access Journals (Sweden)

Hong Sheng

Full Text Available The bactericidal effect of hydroxyl radical (·OH generated by combination of photolysis of hydrogen peroxide (H2O2 and sonolysis of water was examined under the condition in which the yield of ·OH increased additively when H2O2 aqueous solution was concomitantly irradiated with laser and ultrasound. The suspension of Staphylococcus aureus mixed with the different concentrations of H2O2 was irradiated simultaneously with a laser light (wavelength: 405 nm, irradiance: 46 and 91 mW/cm2 and ultrasound (power: 30 w, frequency: 1.65 MHz at 20 ± 1°C of the water bulk temperature for 2 min. The combination of laser and ultrasound irradiation significantly reduced the viable bacterial count in comparison with the laser irradiation of H2O2 alone. By contrast, the ultrasound irradiation alone exerted almost no bactericidal effect. These results suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity was synergistic. A multi-way analysis of variance also revealed that the interaction of H2O2 concentration, laser power and ultrasound irradiation significantly affected the bactericidal activity. Since the result of oxidative DNA damage evaluation demonstrated that the combination of laser and ultrasound irradiation significantly induced oxidative damage of bacterial DNA in comparison with the laser irradiation of H2O2 alone, it was suggested that the combination effect of photolysis of H2O2 and sonolysis of water on bactericidal activity would be exerted via oxidative damage of cellular components such as DNA.

Factors affecting ultraviolet irradiation/hydrogen peroxide (UV/H2O2) degradation of mixed N-nitrosamines in water

International Nuclear Information System (INIS)

Zhou, Chao; Gao, Naiyun; Deng, Yang; Chu, Wenhai; Rong, Wenlei; Zhou, Shengdong

2012-01-01

Highlights: ► NAms with three-induced toxicity, as emerging DBPs, has caused a great public attention. ► No paper regards UV/H 2 O 2 oxidation of mixed NAms in an aquatic environment. ► The treatment effect is typically affected by a few factors in water. ► NPIP and NDPhA are the most readily and difficult to be degraded due to unique structure. ► All the NAms degradation exhibited a pseudo-first-order kinetics pattern. - Abstract: Disinfection by-products (DBPs) are a great challenge to our drinking water security. Particularly, nitrosamines (NAms), as emerging DBPs, are potently carcinogenic, mutagenic, and teratogenic, and have increasingly attained public attention. This study was to evaluate the performance of the NAms degradation by the ultraviolet (UV) irradiation (253.7 nm) in the presence of hydrogen peroxide (H 2 O 2 ). In the UV/H 2 O 2 system, hydroxyl radicals (OH·), a type of nonselective and powerful oxidant, was produced to attack the molecules of NAms. Factors affecting the treatment efficiency, including the H 2 O 2 dosage, initial NAms concentration, UV irradiation intensity, initial solution pH, and inorganic anions present in water, were evaluated. All the NAms degradation exhibited a pseudo-first-order kinetics pattern. Within 60 min, 0.1 mg/L of any NAms could be almost decomposed except NDPhA that required 120 min for complete removal, at 25 μmol/L H 2 O 2 and at initial pH 7. Results demonstrate that the UV/H 2 O 2 treatment is a viable option to control NAms in water.

Synthesis and crystal structure of trans-[Ni(pyzdcH)M 2 (H 2 O) 2 ...

African Journals Online (AJOL)

The determined structure of the title compound C24H20Ni2N8O20 consists of the mononuclear trans-[Ni(pyzdc)2(H2O)2], (pyzdc = pyrazine-2,3- dicarboxylate). The Ni(II) atom is hexa-coordinated by two (pyzdcH)- groups and two water molecules. The coordinated water molecules are in trans-diaxial positions and the ...

Effect of Water Content on Properties of Homogeneous [bmim]Fe(IIICl4–H2O Mixtures and Their Application in Oxidative Absorption of H2S

Directory of Open Access Journals (Sweden)

Jianhong Wang

2018-01-01

Full Text Available The potential of 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]Fe(IIICl4 for replacing an iron(III chelate catalytic solution in the catalytic oxidation of H2S is attributed to its no side reaction and no degradation of the chelating agent. The catalytic oxidation product of water in non-aqueous [bmim]Fe(IIICl4 possibly has an influence on the oxidative absorption of H2S. Water and hydrophobic [bmim]Fe(IIICl4 mixtures at water volume percents from 40% to 70% formed separate phases after srirring, without affecting the oxidative absorption of hydrogen sulfide. Then, studies on the properties of homogeneous [bmim]Fe(IIICl4–H2O mixtures at water volume percents in the range of 5.88–30% and above 80% reveal that these mixtures are both Brønsted and Lewis acids at vol % (H2O ≤ 30%, and only Lewis acids at vol % (H2O ≥ 80%. Raman spectra showed that [bmim]Fe(IIICl4 was the dominating species at vol % (H2O ≤ 30%, in contrast, [bmim]Fe(IIICl4 decomposed into FeCl3·2H2O and [bmim]Cl at vol % (H2O ≥ 80%. Further research on oxidative absorption of H2S by homogeneous [bmim]Fe(IIICl4–H2O mixtures demonstrated that [bmim]Fe(IIICl4 was reduced by H2S to [bmim]Fe(IICl4H and FeCl3·2H2O was reduced to FeCl2, at the same time, H2S was oxidized to S8. In addition, the decrease in acidity caused by increasing the water content increased the weight percent of absorbed H2S, and decreased volatile HCl emissions. However, it is difficult to prevent the suspended S8 generated at vol % (H2O ≥ 80% from the formation of sulfur blockage. Therefore, oxidative absorption of H2S by [bmim]Fe(IIICl4–H2O mixtures is feasible at vol % (H2O < 80% without sulfur blockage.

Photoionization-induced water migration in the amide group of trans-acetanilide-(H2O)1 in the gas phase.

Science.gov (United States)

Sakota, Kenji; Harada, Satoshi; Shimazaki, Yuiga; Sekiya, Hiroshi

2011-02-10

IR-dip spectra of trans-acetanilide-water 1:1 cluster, AA-(H(2)O)(1), have been measured for the S(0) and D(0) state in the gas phase. Two structural isomers, where a water molecule binds to the NH group or the CO group of AA, AA(NH)-(H(2)O)(1) and AA(CO)-(H(2)O)(1), are identified in the S(0) state. One-color resonance-enhanced two-photon ionization, (1 + 1) RE2PI, of AA(NH)-(H(2)O)(1) via the S(1)-S(0) origin generates [AA(NH)-(H(2)O)(1)](+) in the D(0) state, however, photoionization of [AA(CO)-(H(2)O)(1)] does not produce [AA(CO)-(H(2)O)(1)](+), leading to [AA(NH)-(H(2)O)(1)](+). This observation explicitly indicates that the water molecule in [AA-(H(2)O)(1)](+) migrates from the CO group to the NH group in the D(0) state. The reorganization of the charge distribution from the neutral to the D(0) state of AA induces the repulsive force between the water molecule and the CO group of AA(+), which is the trigger of the water migration in [AA-(H(2)O)(1)](+).

Low levels of iron enhance UV/H2O2 efficiency at neutral pH.

Science.gov (United States)

Ulliman, Sydney L; McKay, Garrett; Rosario-Ortiz, Fernando L; Linden, Karl G

2018-03-01

While the presence of iron is generally not seen as favorable for UV-based treatment systems due to lamp fouling and decreased UV transmittance, we show that low levels of iron can lead to improvements in the abatement of chemicals in the UV-hydrogen peroxide advanced oxidation process. The oxidation potential of an iron-assisted UV/H 2 O 2 (UV 254  + H 2 O 2  + iron) process was evaluated at neutral pH using iron levels below USEPA secondary drinking water standards (UV/H 2 O 2 systems. The effects of iron species (Fe 2+ and Fe 3+ ), iron concentration (0-0.3 mg/L), H 2 O 2 concentration (0-10 mg/L) and background water matrix (low-carbon tap (LCT) and well water) on HO production and compound removal were examined. Iron-assisted UV/H 2 O 2 efficiency was most influenced by the target chemical and the water matrix. Added iron to UV/H 2 O 2 was shown to increase the steady-state HO concentration by approximately 25% in all well water scenarios. While CBZ removal was unchanged by iron addition, 0.3 mg/L iron improved NDMA removal rates in both LCT and well water matrices by 15.1% and 4.6% respectively. Furthermore, the combination of UV/Fe without H 2 O 2 was also shown to enhance NDMA removal when compared to UV photolysis alone indicating the presence of degradation pathways other than HO oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification and correction of spectral contamination in 2H/1H and 18O/16O measured in leaf, stem, and soil water.

Science.gov (United States)

Schultz, Natalie M; Griffis, Timothy J; Lee, Xuhui; Baker, John M

2011-11-15

Plant water extracts typically contain organic materials that may cause spectral interference when using isotope ratio infrared spectroscopy (IRIS), resulting in errors in the measured isotope ratios. Manufacturers of IRIS instruments have developed post-processing software to identify the degree of contamination in water samples, and potentially correct the isotope ratios of water with known contaminants. Here, the correction method proposed by an IRIS manufacturer, Los Gatos Research, Inc., was employed and the results were compared with those obtained from isotope ratio mass spectrometry (IRMS). Deionized water was spiked with methanol and ethanol to create correction curves for δ(18)O and δ(2)H. The contamination effects of different sample types (leaf, stem, soil) and different species from agricultural fields, grasslands, and forests were compared. The average corrections in leaf samples ranged from 0.35 to 15.73‰ for δ(2)H and 0.28 to 9.27‰ for δ(18)O. The average corrections in stem samples ranged from 1.17 to 13.70‰ for δ(2)H and 0.47 to 7.97‰ for δ(18)O. There was no contamination observed in soil water. Cleaning plant samples with activated charcoal had minimal effects on the degree of spectral contamination, reducing the corrections, by on average, 0.44‰ for δ(2)H and 0.25‰ for δ(18)O. The correction method eliminated the discrepancies between IRMS and IRIS for δ(18)O, and greatly reduced the discrepancies for δ(2)H. The mean differences in isotope ratios between IRMS and the corrected IRIS method were 0.18‰ for δ(18)O, and -3.39‰ for δ(2)H. The inability to create an ethanol correction curve for δ(2)H probably caused the larger discrepancies. We conclude that ethanol and methanol are the primary compounds causing interference in IRIS analyzers, and that each individual analyzer will probably require customized correction curves. Copyright © 2011 John Wiley & Sons, Ltd.

Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

Science.gov (United States)

Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

2013-01-01

We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

Direct Synthesis of H2O2 over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H2O2-ODS of Fuel

International Nuclear Information System (INIS)

Zhang, Han; Song, Haiyan; Chen, Chunxia; Han, Fuqin; Hu, Shaozheng; Liu, Guangliang; Chen, Ping; Zhao, Zhixi

2013-01-01

Direct synthesis of H 2 O 2 and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active Au 0 species for H 2 O 2 synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in H 2 O 2 synthesis as CH 3 OH/H 2 O ratio of solvent changed. H 2 O 2 decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of O 2 /H 2 ratio on H 2 O 2 concentration, H 2 conversion and H 2 O 2 selectivity revealed a relationship between H 2 O 2 generation and H2 consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of O 2 /H 2 ratio and 60 .deg. C. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, H 2 conversion and oxidative desulfurization selectivity of H 2 were presented

Surface tension of H2O and D2O

International Nuclear Information System (INIS)

Vargaftik, N.B.; Voljak, L.D.; Volkov, B.N.

1975-01-01

There is a great number of works on surface tension of clean water (H 2 O) at temperatures up to 100 deg C and very few above the boiling point. Works on surface tension of heavy water (D 2 O) are insufficient. A review of works on surface tension of both kinds of water is given

I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.

Science.gov (United States)

Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F

2016-03-03

The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.

The rates and mechanisms of water exchange of actinide aqua ions: A variable temperature 17O NMR study of U(H2O)104+, UF(H2O)93+, and Th(H2O)104+

International Nuclear Information System (INIS)

Farkas, I.; Grenthe, I.; Banyai, I.

2000-01-01

The rate constants and the activation parameters for the exchange between water solvent and [U(H 2 O) 10 ] 4+ and [UF(H 2 O) 9 ] 3+ , and a lower limit for the rate constant at room temperature for [Th(H 2 O) 10 ] 4+ , were determined by 17 O NMR spectroscopy in the temperature range 255--305 K. The experiments were made at different constant hydrogen ion concentrations, which varied between 0.16 and 0.8 mol kg -1 . The Th(IV) system was investigated using Tb 3+ as a shift reagent. The following kinetic parameters at 25 C were obtained: k ex = (5.4 ± 0.6) 10 6 x -1 , ΔH double dagger = 34 ± 3 kJ mol -1 , ΔS ++ = -16 ± 10 J mol -1 K -1 for U 4+ (aq), k ex = (5.5 ± 0.7) 10 6 x -1 , ΔH d ouble dagger = 34 ± 3 kJ mol -1 , ΔS ++ = 3 ± 15 J mol -1 K -1 for UF 3+ (Iaq), and k ex > 5 10 7 s -1 for Th 4+ (aq), where the uncertainty is given at the 2σ-level. This is the first experimental information on the kinetic parameters for the exchange of water for any M 4+ ion. There is no information on the rates and mechanisms of ligand substitutions involving other mono-dentate ligands, hence the mechanistic interpretation of the data is by necessity provisional. The kinetic data and the known ground-state geometry with a coordination number of 10 ± 1 for the Th(IV) and U(IV) complexes suggest a dissociatively activated interchange mechanism. There is no noticeable effect of coordination of one fluoride or one hydroxide to U(IV) on the water exchange rate. This is unusual, for other metal ions there is a strong labilizing of coordinated water when a second ligand is bonded, e.g., in complexes of aluminum and some d-transition elements. In previous studies of the rates and mechanisms of ligand exchange in uranium (VI) systems the authors found a strong decrease in the lability of coordinated water in some fluoride containing complexes

Adsorption of water on O(2x2)/Ru(0001): thermal stability and inhibition of dissociation by H2O-O bonding

Energy Technology Data Exchange (ETDEWEB)

Mugarza, Aitor; Shimizu, Tomoko; Cabrera-Sanfelix, Pepa; Sanchez-Portal, Daniel; Arnau, Andres; Salmeron, Miquel

2008-08-01

The effect of preadsorbed oxygen on the subsequent adsorption and reactions of water on Ru(0001) has been studied using low temperature scanning tunneling microscopy and DFT calculations. Experiments were carried out for O coverages close to 0.25 ML. It was found that no dissociation of water takes place up to the desorption temperature of {approx}180-230 K. DFT calculations show that intact water on O(2x2)/Ru(0001) is {approx} 0.49 eV more stable than the dissociation products, H and OH, at their preferred fcc and top adsorption sites.

Hydrochemical Characteristics and Formation of the Saline or Salty Springs in Eastern Sichuan Basin of China

Science.gov (United States)

Zhou, X.

2017-12-01

Saline or salty springs provide important information on the hydrogeochemical processes and hydrology within subsurface aquifers. More than 20 saline and salty springs occur in the core of anticlines in the eastern Sichuan Basin in southwestern China where the Lower and Middle Triassic carbonates outcrop. Water samples of 8 saline and salty springs (including one saline hot spring) were collected for analyses of the major and minor constituents, trace elements and stable oxygen and hydrogen isotopes. The TDS of the springs range from 4 to 83 g/L, and they are mainly of Cl-Na type. Sr, Ba and Li are the predominant trace elements. The δ2H and δ18O of the water samples indicate that they are of meteoric origin. The source of salinity of the springs originates from dissolution of minerals in the carbonates, including halite, gypsum, calcite and dolomite. The formation mechanism of the springs is that groundwater receives recharge from infiltration of precipitation, undergoes shallow or deep circulation in the core of the anticline and incongruent dissolution of the salt-bearing carbonates occurs, and emerges in the river valley in the form of springs with relatively high TDS. The 8 springs can be classified into 4 springs of shallow groundwater circulation and 4 springs of deep groundwater circulation according to the depth of groundwater circulation, 7 springs of normal temperature and 1 hot spring according to temperature. There are also 2 up-flow springs: the carbonate aquifers are overlain by relatively impervious sandstone and shale, groundwater may flows up to the ground surface through the local portion of the overlying aquiclude where fractures were relatively well developed, and emerges as an up-flow spring. Knowledge of the hydrochemical characteristics and the geneses of the saline and salty springs are of important significance for the utilization and preservation of the springs.

Biomethanation of salty cheese whey using multichamber anaerobic bioreactor

Energy Technology Data Exchange (ETDEWEB)

Patel, Chirag; Madamwar, Datta [Sardar Patel Univ., Gujarat (India)

1998-07-01

To obtain enriched methane content and improve anaerobic digestion of salty cheese whey after diluting with total dairy waste water, a multichamber anaerobic bioreactor has been developed using different combination of bedding materials in different chambers. Best performance has been obtained at 37''oC under the combination of polystyrene chips, pumice stones and PVC beads as supporting materials, and operating at 2 day hydraulic retention time. Maximum gas production of 3.2 litre/litre of digester/day with methane content of 68% and 83% reduction in COD have been noticed. (Author)

Ethanol oxidation reactions catalyzed by water molecules: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2)

Science.gov (United States)

Takahashi, H.; Hisaoka, S.; Nitta, T.

2002-09-01

Ab initio density functional theory calculations have been performed to investigate the catalytic role of water molecules in the oxidation reaction of ethanol: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2) . The results show that the potential energy barrier for the reaction is 88.0 kcal/mol in case of n=0, while it is reduced by ˜34 kcal/mol when two water molecules are involved ( n=2) in the reaction. As a result, the rate constant increases to 3.31×10 -4 s-1, which shows a significant catalytic role of water molecules in the ethanol oxidation reactions.

Degradation of Organophosphorus Pesticides in Water during UV/H2O2 Treatment: Role of Sulphate and Bicarbonate Ions

Directory of Open Access Journals (Sweden)

Am Fadaei

2012-01-01

Full Text Available The photodegradation of two organophosphorus pesticides, malathian and diazinon, by sulfate radicals and bicarbonate radicals in aqueous solution were studied. The effect of the operational parameters such as pH, salt concentration, water type, H2O2 concentration and initial concentration of pesticides was studied. Gas chromatography mass spectroscopy (GC–MS was used for analyses of pesticides. When salt effect was studied, it was found that sodium bicarbonate was the most powerful inhibitor used, while sodium sulfate was the weakest one. The highest degradation in UV/H2O2 process for malathion was found in alkaline condition and for diazinon in acidic condition. The photodegradation in all waters used in this work exhibited first order kinetics. Photodegradation rate in distilled water was higher than real water. The degradation of pesticides increased with increasing of H2O2 concentration.

Equilibrium water vapor pressures over polyvanadates M2V12O30.7·nH2O

International Nuclear Information System (INIS)

Volkov, V.L.; Zakharova, G.S.; Ivakin, A.A.

1986-01-01

Equilibrium pressures of water vapors over polyvanadates M 2 V 12 O 30.7 xnH 2 O where M=Li, Na, K are determined in the 293-343 K temperature range. Changes in Gibbs free energy and enthalpy of compound dehydration depending on water content in the final product are calculated on the basis of these data. Molar enthalpy of water is shown to reduce from lithium to potassium, while equilibrium pressure of water vapors over the compounds grows from lithium to potassium. Good correlation of thermodynamic properties of crystallization water of polyvanadates with energy characteristics of hydrated M + ions of the solutions confirms the conclusion that they cannot be attributed to ordinary crystallohydrates

H2O2 Synthesis Induced by Irradiation of H2O with Energetic H(+) and Ar(+) Ions at Various Temperatures

Science.gov (United States)

Baragiola, R. A.; Loeffler, M. J.; Raut, U.; Vidal, R. A.; Carlson, R. W.

2004-01-01

The detection of H2O2 on Jupiter's icy satellite Europa by the Galileo NIMS instrument presented a strong evidence for the importance of radiation effects on icy surfaces. A few experiments have investigated whether solar flux of protons incident on Europa ice could cause a significant if any H2O2 production. These published results differ as to whether H2O2 can be formed by ions impacting water at temperatures near 80 K, which are appropriate to Europa. This discrepancy may be a result of the use of different incident ion energies, different vacuum conditions, or different ways of processing the data. The latter possibility comes about from the difficulty of identifying the 3.5 m peroxide OH band on the long wavelength wing of the much stronger water 3.1 m band. The problem is aggravated by using straight line baselines to represent the water OH band with a curvature, in the region of the peroxide band, that increases with temperature. To overcome this problem, we use polynomial baselines that provide good fits to the water band and its derivative.

Zoledronate complexes. III. Two zoledronate complexes with alkaline earth metals: [Mg(C(5)H(9)N(2)O(7)P(2))(2)(H(2)O)(2)] and [Ca(C(5)H(8)N(2)O(7)P(2))(H(2)O)](n).

Science.gov (United States)

Freire, Eleonora; Vega, Daniel R; Baggio, Ricardo

2010-06-01

Diaquabis[dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato-kappa(2)O,O']magnesium(II), [Mg(C(5)H(9)N(2)O(7)P(2))(2)(H(2)O)(2)], consists of isolated dimeric units built up around an inversion centre and tightly interconnected by hydrogen bonding. The Mg(II) cation resides at the symmetry centre, surrounded in a rather regular octahedral geometry by two chelating zwitterionic zoledronate(1-) [or dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonate] anions and two water molecules, in a pattern already found in a few reported isologues where the anion is bound to transition metals (Co, Zn and Ni). catena-Poly[[aquacalcium(II)]-mu(3)-[hydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato]-kappa(5)O:O,O':O',O''], [Ca(C(5)H(8)N(2)O(7)P(2))(H(2)O)](n), consists instead of a Ca(II) cation in a general position, a zwitterionic zoledronate(2-) anion and a coordinated water molecule. The geometry around the Ca(II) atom, provided by six bisphosphonate O atoms and one water ligand, is that of a pentagonal bipyramid with the Ca(II) atom displaced by 0.19 A out of the equatorial plane. These Ca(II) coordination polyhedra are ;threaded' by the 2(1) axis so that successive polyhedra share edges of their pentagonal basal planes. This results in a strongly coupled rhomboidal Ca(2)-O(2) chain which runs along [010]. These chains are in turn linked by an apical O atom from a -PO(3) group in a neighbouring chain. This O-atom, shared between chains, generates strong covalently bonded planar arrays parallel to (100). Finally, these sheets are linked by hydrogen bonds into a three-dimensional structure. Owing to the extreme affinity of zoledronic acid for bone tissue, in general, and with calcium as one of the major constituents of bone, it is expected that this structure will be useful in modelling some of the biologically interesting processes in which the drug takes part.

Structure of LaH(PO3H)2.3H2O

International Nuclear Information System (INIS)

Loukili, M.; Durand, J.; Larbot, A.; Cot, L.; Rafiq, M.

1991-01-01

Lanthanum hydrogen bis(hydrogenphosphite) trihydrate, LaH(Po 3 H) 2 .3H 2 O, M r =353.8, monoclinic, P2 1 /c, a=9.687 (3), b=7.138 (2), c=13.518 A, β=104.48 (3) deg, V=905.0 (5) A 3 , Z=4, D m =2.56 (2), D x =2.598 Mg m -3 , λ(MoKα)=0.71073 A, μ(MoKα)=5.103 mm -1 , F(000)=672, T=300 K, R=0.032 for 1018 independent observed reflections. The structure contains two phosphite anions connected by a hydrogen bond. The La 3+ cation is eight coordinated by seven O atoms from phosphite anions and one O atom of a water molecule. (orig.)

Hyperpolarized H2O MR angiography

DEFF Research Database (Denmark)

Ardenkjær-Larsen, Jan Henrik; Laustsen, Christoffer; Bowen, Sean

2014-01-01

polarization followed by dissolution in D2O. A water 1H signal enhancement of 77 times compared with 4.7 Tesla was obtained. This corresponds to a polarization of 3.5% for the 3.9 mol/L 1H in D2O . Moreover, a T1 in excess of 20 s was achieved. The use of hyperpolarized water as a contrast agent presents a new...

Ground and excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters: Insight into the electronic structure of the [Fe(H2O)6]2+ – [Fe(H2O)6]3+ complex

Energy Technology Data Exchange (ETDEWEB)

Miliordos, Evangelos; Xantheas, Sotiris S.

2015-04-14

We report the ground and low lying electronically excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters using multi-configuration electronic structure theory. In particular, we have constructed the Potential Energy Curves (PECs) with respect to the iron-oxygen distance when removing all water ligands at the same time from the cluster minima and established their correlation to the long range dissociation channels. Due to the fact that both the second and third ionization potentials of iron are larger than the one for water, the ground state products asymptotically correlate with dissociation channels that are repulsive in nature at large separations as they contain at least one H2O+ fragment and a positive metal center. The most stable equilibrium structures emanate – via intersections and/or avoided crossings – from the channels consisting of the lowest electronic states of Fe2+(5D; 3d6) or Fe3+(6S; 3d5) and six neutral water molecules. Upon hydration, the ground state of Fe2+(H2O)6 is a triply (5Tg) degenerate one with the doubly (5Eg) degenerate state lying slightly higher in energy. Similarly, Fe3+(H2O)6 has a ground state of 6Ag symmetry under Th symmetry. We furthermore examine a multitude of electronically excited states of many possible spin multiplicities, and report the optimized geometries for several selected states. The PECs for those cases are characterized by a high density of states. Focusing on the ground and the first few excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters, we studied their mutual interaction in the gas phase. We obtained the optimal geometries of the Fe2+(H2O)6 – Fe3+(H2O)6 gas phase complex for different Fe–Fe distances. For distances shorter than 6.0 Å, the water molecules in the respective first solvation shells located between the two metal centers were found to interact via weak hydrogen bonds. We examined a total of ten electronic states for this complex, including those corresponding to the

Application of UV/TiO2/H2O2 Advanced Oxidation to Remove Naphthalene from Water

Directory of Open Access Journals (Sweden)

Behroz Karimi

2016-11-01

Full Text Available Naphthalene is released into the environment by burning such organic materials as fossil fuels and wood and in industrial and vehicle exhaust emissions. Naphthalene is used in the manufacture of plastics, resins, fuels, and dyes. The aim of this study was to evaluate the performance of UV/TiO2/H2O2 process to decompose naphthalene in aqueous solutions. For this purpose, the photocatalytic degradation of naphthalene was investigated under UV light irradiation in the presence of TiO2 and H2O2 under a variety of conditions. Photodegradation efficiencies of H2O2/UV, TiO2/UV, and H2O2/TiO2/UV processes were compared in a batch reactor using the low pressure mercury lamp irradiation. The effects of operating parameters such as reaction time (min; solution pH; and initial naphthalene, TiO2, and H2O2 concentrations on photodegradation were examined. In the UV/TiO2/H2O2 system with a naphthalene concentration of 15 mg/L, naphthalene removal efficiencies of 63, 75, 80, 88, 92, 95, 96.5, and 98% were achieved, respectively, for reaction times of 5, 10, 20, 30, 40, 50, 60, 100 and 120 min. This is while removal efficienciesof 50, 59.5, 69, 80, 85, 88, 91, and 95% were obtained in the UV/TiO2 system under the same conditions. For initial pH values of 3, 4, 5, 6, 7,9, 10, and 12, naphthalene removal efficiencies of approximately 96.8, 85.5, 86, 75.5, 68.8, 57.8, and 52.5% were acheived, respectively, with the UV/TiO2/H2O2 system. Thus, it may be claiomed that, compared to either H2O2/UV or TiO2/UV process, the H2O2/TiO2/UV process yielded a far more efficient photodegradation.

Synthesis and structure of heptaaqua(nitrilotris(methylenephosphonato))(dibarium)sodium monohydrate [Na(H{sub 2}O){sub 3}(μ{sup 6}-NH(CH{sub 2}PO{sub 3}){sub 3})(μ-H{sub 2}O){sub 3}Ba{sub 2}(H{sub 2}O)] · H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Somov, N. V., E-mail: somov@phys.unn.ru [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Chausov, F. F., E-mail: xps@ftiudm.ru [Russian Academy of Sciences, Physical–Technical Institute, Ural Branch (Russian Federation); Zakirova, R. M., E-mail: ftt@udsu.ru [Udmurt State University (Russian Federation)

2017-03-15

Crystals of the monohydrate form of heptaaqua(nitrilotris(methylenephosphonato))(dibarium) sodium [Na(H{sub 2}O{sub )3}(µ{sup 6}-NH(CH{sub 2}PO{sub 3}){sub 3})(µ-H{sub 2}O){sub 3}Ba{sub 2}(H{sub 2}O)] · H{sub 2}O are obtained; space group P2{sub 1}/c, Z = 4; a = 13.9117(10) Å, b = 11.54030(10) Å, and c = 24.1784(17) Å, ß = 148.785(18)°. The Na atom is coordinated octahedrally by one oxygen atom of a phosphonate group and five water molecules, including two bridging molecules. Ba atoms occupy two inequivalent crystallographic positions with coordination number eight and nine. The coordination spheres of both Ba atoms include two water molecules. Each ligand is bound to one Na atom and five Ba atoms forming three Ba–O–P–O and five Ba–O–P–C–N–C–P–O chelate cycles. In addition to the coordination bonds, molecules, including the solvate water molecule, are involved in hydrogen bonds in the crystal packing.

The fate of H2O2 during managed aquifer recharge: A residual from advanced oxidation processes for drinking water production.

Science.gov (United States)

Wang, F; van Halem, D; van der Hoek, J P

2016-04-01

The fate of H2O2 residual from advanced oxidation process (AOP) preceding managed aquifer recharge (MAR) is of concern because H2O2 could lead to undesired effects on organisms in the MAR aquatic and soil ecosystem. The objective of this study was to distinguish between factors affecting H2O2 decomposition in MAR systems, simulated in batch reactors with synthetic MAR water and slow sand filter sand. The results showed that pure sand and soil organic matter had no considerable effect on H2O2 decomposition, whereas naturally occurring inorganic substances on the surface of sand grains and microbial biomass are the two main factors accelerating H2O2 decomposition in MAR systems. Additionally, the results showed that the H2O2 decompositions with different initial concentrations fitted first-order kinetics in 2-6 h in a mixture of slow sand filter sand (as a substitute for sand from a MAR system) and synthetic MAR water with high bacterial population. An estimation indicated that low concentrations of H2O2 (<3 mg/L) could decompose to the provisional standard of 0.25 mg/L in the first centimeters of MAR systems with the influent water containing high microbial biomass 38 ng ATP/mL. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water as a solute in aprotic dipolar solvents. 2. D2O-H2O solute isotope effects on the enthalpy of water dissolution in nitromethane, acetonitrile and propylene carbonate at 298.15 K

International Nuclear Information System (INIS)

Ivanov, Evgeniy V.; Smirnov, Valeriy I.

2010-01-01

The enthalpies of solution of ordinary (H 2 O) and heavy (D 2 O) water in nitromethane (NM), acetonitrile (ACN) and propylene carbonate (PC) were measured calorimetrically at 298.15 K. Standard (at the infinite dilution) enthalpies of solution and solvation, along with D 2 O-H 2 O solute isotope effects on the quantities in question, were calculated. The enthalpies of solution of water H/D isotopologues were found to be positive by sign and substantially increasing in magnitude on going from ACN and PC to NM, whereas the corresponding positive solute H/D isotope effect changes in a consequence: NM > ACN > PC. The qualitative interrelations between the enthalpy-isotopic effect of dissolution (solvation) of water and the electron-accepting/donating ability of aprotic dipolar solvent (within a series considered) were found.

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

New metal-organic frameworks of [M(C6H5O7)(C6H6O7)(C6H7O7)(H2O)] . H2O (M=La, Ce) and [Ce2(C2O4)(C6H6O7)2] . 4H2O

International Nuclear Information System (INIS)

Weng Shengfeng; Wang, Yun-Hsin; Lee, Chi-Shen

2012-01-01

Two novel materials, [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2), with a metal-organic framework (MOF) were prepared with hydrothermal reactions and characterized with photoluminescence, magnetic susceptibility, thermogravimetric analysis and X-ray powder diffraction in situ. The crystal structures were determined by single-crystal X-ray diffraction. Compound 1 crystallized in triclinic space group P1-bar (No. 2); compound 2 crystallized in monoclinic space group P2 1 /c (No. 14). The structure of 1 is built from a 1D MOF, composed of deprotonated citric ligands of three kinds. Compound 2 contains a 2D MOF structure consisting of citrate and oxalate ligands; the oxalate ligand arose from the decomposition in situ of citric acid in the presence of Cu II ions. Photoluminescence spectra of compounds 1b and 2 revealed transitions between the 5d 1 excited state and two levels of the 4f 1 ground state ( 2 F 5/2 and 2 F 7/2 ). Compounds 1b and 2 containing Ce III ion exhibit a paramagnetic property with weak antiferromagnetic interactions between the two adjacent magnetic centers. - Graphical Abstract: [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2)—with 1D and 2D structures were synthesized and characterized. Highlights: ► Two MOF – [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2) – with 1D and 2D structures. ► The adjacent chains of the 1D framework were correlated with each other through an oxalate ligand to form a 2D layer structure. ► The source of the oxalate ligand was the decomposition in situ of citric acid oxidized in the presence of Cu II ions.

Relative transport of water (H2O) and tritiated water (HTO) across cellulose acetate (CA) membranes

International Nuclear Information System (INIS)

Prabhakar, S.; Misra, B.M.; Ramani, M.P.S.

1986-01-01

The relative transport characteristics of water (H 2 O) and tritiated water (HTO) were evaluated through cellulose acetate membranes under osmosis, reverse osmosis and pervaporation. The results indicate that the relative transport is independent of the process. The anamolous observations under osmotic conditions are explained. (orig.)

D/H fractionation in the H2-H2O system at supercritical water conditions: Compositional and hydrogen bonding effects

Science.gov (United States)

Foustoukos, Dionysis I.; Mysen, Bjorn O.

2012-06-01

A series of experiments has been conducted in the H2-D2-D2O-H2O-Ti-TiO2 system at temperatures ranging from 300 to 800 °C and pressures between ∼0.3 and 1.3 GPa in a hydrothermal diamond anvil cell, utilizing Raman spectroscopy as a quantitative tool to explore the relative distribution of hydrogen and deuterium isotopologues of the H2 and H2O in supercritical fluids. In detail, H2O-D2O solutions (1:1) were reacted with Ti metal (3-9 h) in the diamond cell, leading to formation of H2, D2, HD, and HDO species through Ti oxidation and H-D isotope exchange reactions. Experimental results obtained in situ and at ambient conditions on quenched samples indicate significant differences from the theoretical estimates of the equilibrium thermodynamic properties of the H-D exchange reactions. In fact, the estimated enthalpy for the H2(aq)-D2(aq) disproportionation reaction (ΔHrxn) is about -3.4 kcal/mol, which differs greatly from the +0.16 kcal/mol predicted for the exchange reaction in the gas phase by statistical mechanics models. The exothermic behavior of the exchange reaction implies enhanced stability of H2 and D2 relative to HD. Accordingly, the significant energy difference of the internal H2(aq)-D2(aq)-HD(aq) equilibrium translates to strong differences of the fractionation effects between the H2O-H2 and D2O-D2 isotope exchange relationships. The D/H fractionation factors between H2O-H2(aq) and D2O-D2(aq) differ by 365‰ in the 600-800 °C temperature range, and are indicative of the greater effect of D2O contribution to the δD isotopic composition of supercritical fluids. The negative ΔHrxn values for the H2(aq)-D2(aq)-HD(aq) equilibrium and the apparent decrease of the equilibrium constant with increasing temperature might be because of differences of the Henry’s law constant between the H- and D-bearing species dissolved in supercritical aqueous solutions. Such effects may be attributed to the stronger hydrogen bonding in the O-H⋯O relative to the

Synthesis, structural characterization, and dehydration analysis of uranyl zinc mellitate, (UO{sub 2})Zn(H{sub 2}O){sub 4}(H{sub 2}mel).2H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Olchowka, Jakub; Volkringer, Christophe; Henry, Natacha; Loiseau, Thierry [Unite de Catalyse et Chimie du Solide (UCCS) - UMR CNRS 8181, Universite de Lille Nord de France, USTL-ENSCL, Villeneuve d' Ascq (France)

2013-04-15

A new heterometallic uranyl zinc carboxylate, (UO{sub 2})Zn(H{sub 2}O){sub 4}(H{sub 2}mel).2H{sub 2}O, has been hydrothermally prepared (150 C, 24 h) by using 1,2,3,4,5,6-benzenehexacarboxylic acid (mellitic acid) as organic linker in order to form a three-dimensional network. Four of the six carboxylate groups of the mellitate ligand interact with mononuclear uranyl or zinc cations, which are eightfold (hexagonal bipyramid, UO{sub 8}) or sixfold [octahedron, ZnO{sub 2}(H{sub 2}O){sub 4}] coordinated, respectively. The remaining free carboxylate arms of the mellitate species preferentially interact through hydrogen bonds with water molecules trapped within the framework. Thermogravimetric and X-ray thermodiffraction (up to 800 C) analyses and in situ infrared spectroscopy (up to 210 C) indicated that both free and bound water species are evacuated from the structure in one step between 80 and 170 C, followed by its transformation into an unknown, anhydrous, poorly crystalline phase [UO{sub 2}Zn(mel)] up to 320 C. After the formation of an amorphous phase, the re-crystallization of oxides α-ZnU{sub 3}O{sub 10} and ZnO was observed from 460 C. The fluorescence spectrum of the as-synthesized uranyl zinc mellitate shows the six bands that are typical for vibronic couplings of the [O=U=O]{sup 2+} moiety. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Crystal structures of hydrates of simple inorganic salts. III. Water-rich aluminium halide hydrates: AlCl3 · 15H2O, AlBr3 · 15H2O, AlI3 · 15H2O, AlI3 · 17H2O and AlBr3 · 9H2O.

Science.gov (United States)

Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang

2014-09-01

Water-rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low-temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI(3) · 15H2O, half of the Al(3+) cations are surrounded by two complete hydration spheres, with six H2O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al(3+).

A simulation study of homogeneous ice nucleation in supercooled salty water

Science.gov (United States)

Soria, Guiomar D.; Espinosa, Jorge R.; Ramirez, Jorge; Valeriani, Chantal; Vega, Carlos; Sanz, Eduardo

2018-06-01

We use computer simulations to investigate the effect of salt on homogeneous ice nucleation. The melting point of the employed solution model was obtained both by direct coexistence simulations and by thermodynamic integration from previous calculations of the water chemical potential. Using a seeding approach, in which we simulate ice seeds embedded in a supercooled aqueous solution, we compute the nucleation rate as a function of temperature for a 1.85 NaCl mol per water kilogram solution at 1 bar. To improve the accuracy and reliability of our calculations, we combine seeding with the direct computation of the ice-solution interfacial free energy at coexistence using the Mold Integration method. We compare the results with previous simulation work on pure water to understand the effect caused by the solute. The model captures the experimental trend that the nucleation rate at a given supercooling decreases when adding salt. Despite the fact that the thermodynamic driving force for ice nucleation is higher for salty water for a given supercooling, the nucleation rate slows down with salt due to a significant increase of the ice-fluid interfacial free energy. The salty water model predicts an ice nucleation rate that is in good agreement with experimental measurements, bringing confidence in the predictive ability of the model. We expect that the combination of state-of-the-art simulation methods here employed to study ice nucleation from solution will be of much use in forthcoming numerical investigations of crystallization in mixtures.

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

Synergistic effects for the TiO2/RuO2/Pt photodissociation of water

Energy Technology Data Exchange (ETDEWEB)

Blondel, G; Harriman, A; Williams, D

1983-07-01

Compressed discs of naked TiO2 or TiO2 coated with a thin film of a noble metal (e.g. Pt) do not photodissociate water upon illumination with UV light, but small amounts of H2 are generated if the TiO2 has been reduced in a stream of H2 at 600 C. Discs prepared from mixtures of TiO2/RuO2 facilitate the UV photodissociation of water into H2 and O2 although the yields are very low. When a thin (about 9 nm) film of Pt is applied to the TiO2/RuO2 discs, the yields of H2 and O2 observed upon irradiation with UV light are improved drastically. 25 references.

Super-Maxwellian helium evaporation from pure and salty water

International Nuclear Information System (INIS)

Hahn, Christine; Kann, Zachary R.; Faust, Jennifer A.; Skinner, J. L.; Nathanson, Gilbert M.

2016-01-01

Helium atoms evaporate from pure water and salty solutions in super-Maxwellian speed distributions, as observed experimentally and modeled theoretically. The experiments are performed by monitoring the velocities of dissolved He atoms that evaporate from microjets of pure water at 252 K and 4–8.5 molal LiCl and LiBr at 232–252 K. The average He atom energies exceed the flux-weighted Maxwell-Boltzmann average of 2RT by 30% for pure water and 70% for 8.5m LiBr. Classical molecular dynamics simulations closely reproduce the observed speed distributions and provide microscopic insight into the forces that eject the He atoms from solution. Comparisons of the density profile and He kinetic energies across the water-vacuum interface indicate that the He atoms are accelerated by He–water collisions within the top 1-2 layers of the liquid. We also find that the average He atom kinetic energy scales with the free energy of solvation of this sparingly soluble gas. This free-energy difference reflects the steeply decreasing potential of mean force on the He atoms in the interfacial region, whose gradient is the repulsive force that tends to expel the atoms. The accompanying sharp decrease in water density suppresses the He–water collisions that would otherwise maintain a Maxwell-Boltzmann distribution, allowing the He atom to escape at high energies. Helium is especially affected by this reduction in collisions because its weak interactions make energy transfer inefficient

Super-Maxwellian helium evaporation from pure and salty water

Energy Technology Data Exchange (ETDEWEB)

Hahn, Christine; Kann, Zachary R.; Faust, Jennifer A.; Skinner, J. L., E-mail: skinner@chem.wisc.edu, E-mail: nathanson@chem.wisc.edu; Nathanson, Gilbert M., E-mail: skinner@chem.wisc.edu, E-mail: nathanson@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706 (United States)

2016-01-28

Helium atoms evaporate from pure water and salty solutions in super-Maxwellian speed distributions, as observed experimentally and modeled theoretically. The experiments are performed by monitoring the velocities of dissolved He atoms that evaporate from microjets of pure water at 252 K and 4–8.5 molal LiCl and LiBr at 232–252 K. The average He atom energies exceed the flux-weighted Maxwell-Boltzmann average of 2RT by 30% for pure water and 70% for 8.5m LiBr. Classical molecular dynamics simulations closely reproduce the observed speed distributions and provide microscopic insight into the forces that eject the He atoms from solution. Comparisons of the density profile and He kinetic energies across the water-vacuum interface indicate that the He atoms are accelerated by He–water collisions within the top 1-2 layers of the liquid. We also find that the average He atom kinetic energy scales with the free energy of solvation of this sparingly soluble gas. This free-energy difference reflects the steeply decreasing potential of mean force on the He atoms in the interfacial region, whose gradient is the repulsive force that tends to expel the atoms. The accompanying sharp decrease in water density suppresses the He–water collisions that would otherwise maintain a Maxwell-Boltzmann distribution, allowing the He atom to escape at high energies. Helium is especially affected by this reduction in collisions because its weak interactions make energy transfer inefficient.

Direct Synthesis of H{sub 2}O{sub 2} over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H{sub 2}O{sub 2}-ODS of Fuel

Energy Technology Data Exchange (ETDEWEB)

Zhang, Han; Song, Haiyan; Chen, Chunxia; Han, Fuqin; Hu, Shaozheng [Northeast Forestry Univ., Harbin (China); Liu, Guangliang [Univ. of Connecticut, Storrs (United States); Chen, Ping; Zhao, Zhixi [Xinjiang Normal Univ., Urumqi (China)

2013-10-15

Direct synthesis of H{sub 2}O{sub 2} and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active Au{sup 0} species for H{sub 2}O{sub 2} synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in H{sub 2}O{sub 2} synthesis as CH{sub 3}OH/H{sub 2}O ratio of solvent changed. H{sub 2}O{sub 2} decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of O{sub 2}/H{sub 2} ratio on H{sub 2}O{sub 2} concentration, H{sub 2} conversion and H{sub 2}O{sub 2} selectivity revealed a relationship between H{sub 2}O{sub 2} generation and H2 consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of O{sub 2}/H{sub 2} ratio and 60 .deg. C. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, H{sub 2} conversion and oxidative desulfurization selectivity of H{sub 2} were presented.

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

Observations of different core water cluster ions Y-(H2O)n (Y = O2, HOx, NOx, COx) and magic number in atmospheric pressure negative corona discharge mass spectrometry.

Science.gov (United States)

Sekimoto, Kanako; Takayama, Mitsuo

2011-01-01

Reliable mass spectrometry data from large water clusters Y(-)(H(2)O)(n) with various negative core ions Y(-) such as O(2)(-), HO(-), HO(2)(-), NO(2)(-), NO(3)(-), NO(3)(-)(HNO(3))(2), CO(3)(-) and HCO(4)(-) have been obtained using atmospheric pressure negative corona discharge mass spectrometry. All the core Y(-) ions observed were ionic species that play a central role in tropospheric ion chemistry. These mass spectra exhibited discontinuities in ion peak intensity at certain size clusters Y(-)(H(2)O)(m) indicating specific thermochemical stability. Thus, Y(-)(H(2)O)(m) may correspond to the magic number or first hydrated shell in the cluster series Y(-)(H(2)O)(n). The high intensity discontinuity at HO(-)(H(2)O)(3) observed was the first mass spectrometric evidence for the specific stability of HO(-)(H(2)O)(3) as the first hydrated shell which Eigen postulated in 1964. The negative ion water clusters Y(-)(H(2)O)(n) observed in the mass spectra are most likely to be formed via core ion formation in the ambient discharge area (760 torr) and the growth of water clusters by adiabatic expansion in the vacuum region of the mass spectrometers (≈1 torr). The detailed mechanism of the formation of the different core water cluster ions Y(-)(H(2)O)(n) is described. Copyright © 2010 John Wiley & Sons, Ltd.

Degradation of process water containing polymers UV/H{sub 2}O{sub 2} system; Degradacao de agua de processo contendo polimeros via sistema UV/H{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Will, Isabela B.S.; Telemaco, Emmanuelle P.; Chiavone-Filho, Osvaldo; Guardani, Roberto; Nascimento, Claudio A.O. do

2004-07-01

The water rationalization has been one of the goals of the petrochemical industry. Such goals in such a way demand technological innovations for new productive processes how much for new techniques of treatment and reuse of water in the production chain. The high industrial water costs in Brazil, particularly in the regions metropolitans, have stimulated the national industries to evaluate the possibilities of reuse. The objective of this work is the application of the process water treatment containing polypropylene using ultraviolet radiation and hydrogen peroxide, that is system UV/H{sub 2}O{sub 2}, aiming at to adjust them for reuses in the proper process, reducing the water capitation daily pay-treated and improving the water exploitation. Photochemical annular reactor with medium pressure mercury vapor lamp was used and the following parameters of process had been evaluated: radiation, temperature of reaction and hydrogen peroxide concentration. The monitoring of the experiments was based on the measurement of contents of dissolved organic carbon, total carbon and inorganic carbon. Additionally, experiments using solar radiation had been evaluated. The experimental results had indicated the viability of application of system UV/H{sub 2}O{sub 2} having used artificial and solar light sources. The quality of the water obtained in the treatment was adequate to reuse it. (author)

The H2O/D2O exchange across vesicular lipid bilayers

International Nuclear Information System (INIS)

Engelbert, H.P.; Lawaczek, R.

1985-01-01

A new method to measure the water (D 2 O/H 2 O) permeation across vesicular lipid bilayers is described. The method is based on the solvent isotope effect of the light scattering which is a consequence of the different indices of refraction of D 2 O and H 2 O. Unilamellar lipid vesicles in excess of H 2 O are rapidly mixed with D 2 O or vice versa. As result of the H 2 O/D 2 O exchange across the vesicular bilayer the light scattering signal has a time dependent, almost single exponential component allowing the deduction of the exchange relaxation rate and, at known size, of the permeability coefficient. The experimental results are in accord with calculations from the Mie theory of light scattering for coated spheres. The method is applicable for large vesicles where the permeation is the rate-limiting step. Size separations are performed by a flow dialysis through a sequence of pore-membrane-filters. For dimyristoyl-lecithin bilayers the water permeability-coefficient is 1.9 . 10 -5 cm/s in the crystalline phase and increases by a factor of 10-100 in the liquid-crystalline state. The temperature dependence of the permeation exhibits a sharp change at the phase transition. For binary mixtures of lecithins this sharp change follows the solidus curve of the non-ideal phase diagram determined by spectroscopic techniques. (orig.)

Revisit the landscape of protonated water clusters H+(H2O)n with n = 10-17: An ab initio global search

Science.gov (United States)

Shi, Ruili; Li, Keyao; Su, Yan; Tang, Lingli; Huang, Xiaoming; Sai, Linwei; Zhao, Jijun

2018-05-01

Using a genetic algorithm incorporated with density functional theory, we explore the ground state structures of protonated water clusters H+(H2O)n with n = 10-17. Then we re-optimize the isomers at B97-D/aug-cc-pVDZ level of theory. The extra proton connects with a H2O molecule to form a H3O+ ion in all H+(H2O)10-17 clusters. The lowest-energy structures adopt a monocage form at n = 10-16 and core-shell structure at n = 17 based on the MP2/aug-cc-pVTZ//B97-D/aug-cc-pVDZ+ZPE single-point-energy calculation. Using second-order vibrational perturbation theory, we further calculate the infrared spectra with anharmonic correction for the ground state structures of H+(H2O)10-17 clusters at the PBE0/aug-cc-pVDZ level. The anharmonic correction to the spectra is crucial since it reproduces the experimental results quite well. The extra proton weakens the O-H bond strength in the H3O+ ion since the Wiberg bond order of the O-H bond in the H3O+ ion is smaller than that in H2O molecules, which causes a red shift of the O-H stretching mode in the H3O+ ion.

Methanol reformer with water vapor and oxygen in catalysts of Cu/CeO2-ZrO2 to generate H2

International Nuclear Information System (INIS)

Aguila M, M.M.

2007-01-01

The environmental pollution is one of the problems more important to solve in the present time because its affect the quality of the alive beings' life. For such a reason alternatives have been looked for to diminish the percentage of air pollution (NO x , CO x , SO x , etc.), for they have been developed it the well-known catalytic converters. Another possibility is the energy use through fuel cells in vehicles using H 2 as fuel free of CO (smaller concentration to 10 ppm). Processes exist for the production of H 2 starting from the methanol and in this work the one was used reformed of methanol with water vapor and oxygen (OSRM) as the main reaction of this work. The primordial objective of this work consists on studying the catalytic properties of the copper (Cu) supported in mixed oxides (ZrO 2 -CeO 2 ) in the reaction of having reformed of methanol with water vapor and oxygen for the production of H 2 . Zirconia is synthesized (ZrO 2 ) and mixed oxides ZrO 2 -CeO 2 (with different relationship Zr/Ce) for the sol-gel method and the one cerium oxide (CeO 2 ) by direct combustion of the cerium nitrate. The oxides were stabilized thermally at 600 C by 5h. The catalysts were prepared by classic impregnation using copper acetate, the nominal concentration was of 3% in weight. The catalysts were roasted at 350 C and later on reduced in flow from H 2 to 350 C for 1h. The characterization of the catalytic materials is carried out through different techniques as: adsorption-desorption of nitrogen to determine the surface area BET, scanning electron microscopy (SEM) to determine the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials and reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were studied in the reaction CH 3 OH + H 2 O + O 2 , to determine the activity and selectivity. The surface area of the mixed oxides was

Physical limit of stability in supercooled D2O and D2O+H2O mixtures

Science.gov (United States)

Kiselev, S. B.; Ely, J. F.

2003-01-01

The fluctuation theory of homogeneous nucleation was applied for calculating the physical boundary of metastable states, the kinetic spinodal, in supercooled D2O and D2O+H2O mixtures. The kinetic spinodal in our approach is completely determined by the surface tension and equation of state of the supercooled liquid. We developed a crossover equation of state for supercooled D2O, which predicts a second critical point of low density water-high density water equilibrium, CP2, and represents all available experimental data in supercooled D2O within experimental accuracy. Using Turnbull's expression for the surface tension we calculated with the crossover equation of state for supercooled D2O the kinetic spinodal, TKS, which lies below the homogeneous nucleation temperature, TH. We show that CP2 always lies inside in the so-called "nonthermodynamic habitat" and physically does not exist. However, the concept of a second "virtual" critical point is physical and very useful. Using this concept we have extended this approach to supercooled D2O+H2O mixtures. As an example, we consider here an equimolar D2O+H2O mixture in normal and supercooled states at atmospheric pressure, P=0.1 MPa.

Photochemical degradation of diethyl phthalate with UV/H2O2

International Nuclear Information System (INIS)

Xu Bin; Gao Naiyun; Sun Xiaofeng; Xia Shengji; Rui Min; Simonnot, Marie-Odile; Causserand, Christel; Zhao Jianfu

2007-01-01

The decomposition of diethyl phthalate (DEP) in water using UV-H 2 O 2 process was investigated in this paper. DEP cannot be effectively removed by UV radiation and H 2 O 2 oxidation alone, while UV-H 2 O 2 combination process proved to be effective and could degrade this compound completely. With initial concentration about 1.0 mg/L, more than 98.6% of DEP can be removed at time of 60 min under intensity of UV radiation of 133.9 μW/cm 2 and H 2 O 2 dosage of 20 mg/L. The effects of applied H 2 O 2 dose, UV radiation intensity, water temperature and initial concentration of DEP on the degradation of DEP have been examined in this study. Degradation mechanisms of DEP with hydroxyl radicals oxidation also have been discussed. Removal rate of DEP was sensitive to the operational parameters. A simple kinetic model is proposed which confirms to pseudo-first order reaction. There is a linear relationship between rate constant k and UV intensity and H 2 O 2 concentration

SPADE H2O measurements and the seasonal cycle of statospheric water vapor

Science.gov (United States)

Hintsa, Eric J.; Weinstock, Elliot M.; Dessler, Andrew E.; Anderson, James G.; Loewenstein, Max; Podolske, James R.

1994-01-01

We present measurements of lower statospheric water vapor obtained during the Stratospheric Phototchemistry, Aerosols and Dynamics Expedition (SPADE) mission with a new high precision, fast response, Lyman-alpha hygrometer. The H2O data show a distinct seasonal cycle. For air that recently entered the statosphere, data collected during the fall show much more water vapor than data from the spring. Fast quasi-horizontal mixing causes compact relationships between water and N2O to be established on relatively short time scales. The measurements are consistent with horizontal mixing times of a few months or less. Vertical mixing appears to cause the seasonal variations in water vapor to propagate up to levels corresponding to air that has been in the stratosphere approximately one year.

Laser spectrometry applied to the simultaneous determination of the δ2H, δ17O, and δ18O isotope abundances in water

International Nuclear Information System (INIS)

Kerstel, E.R.T.; Trigt, R. van; Dam, N.; Reuss, J.; Meijer, H.A.J.

2001-01-01

We demonstrate the first successful application of infrared laser spectrometry to the accurate, simultaneous determination of the relative 2 H/ 1 H, 17 O/ 16 O, and 18 O/ 16 O isotope abundance ratios in natural water. The method uses a narrow line width color center laser to record the direct absorption spectrum of low-pressure gas-phase water samples (presently 10 μl liquid) in the 3μm spectral region. The precision of the spectroscopic technique is shown to be 0.7 per mille for δ 2 H and 0.5 per mille for δ 17 O and δ 18 O, while the calibrated accuracy for natural waters amounts to about 3 per mille and 1 per mille, respectively. (author)

DETAILED ANALYSIS OF NEAR-IR WATER (H2O) EMISSION IN COMET C/2014 Q2 (LOVEJOY) WITH THE GIANO/TNG SPECTROGRAPH

International Nuclear Information System (INIS)

Faggi, S.; Brucato, J. R.; Tozzi, G. P.; Oliva, E.; Massi, F.; Sanna, N.; Tozzi, A.; Villanueva, G. L.; Mumma, M. J.

2016-01-01

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1–2.5 μ m region. Spectral lines from eight ro-vibrational bands of H 2 O were detected, six of them for the first time. We quantified the water production rate [ Q (H 2 O), (3.11 ± 0.14) × 10 29 s −1 ] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H 2 O. The production rates of ortho-water [ Q (H 2 O) ORTHO , (2.33 ± 0.11) × 10 29 s −1 ] and para-water [ Q (H 2 O) PARA , (0.87 ± 0.21) × 1029 s −1 ] provide a measure of the ortho-to-para ratio (2.70 ± 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature.

Detailed Analysis of Near-IR Water (H2O) Emission in Comet C/2014 Q2 (LOVEJOY) with the GIANO/TNG Spectrograph

Science.gov (United States)

Faggi, S.; Villanueva, G. L.; Mumma, M. J.; Brucato, J.R.; Tozzi, G. P.; Oliva, E.; Massi, F.; Sanna, N.; Tozzi, A.

2016-01-01

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1-2.5 micron region. Spectral lines from eight ro-vibrational bands of H2O were detected, six of them for the first time. We quantified the water production rate [Q(H2O), (3.11+/- 0.14) x 10(exp 29)/s] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H2O. The production rates of ortho-water [Q(H2O)ORTHO, (2.33+/- 0.11) x 10(exp 29)/s] and para-water [Q(H2O)PARA, (0.87+/-0.21) x 10(exp 29)/s] provide a measure of the ortho-to-para ratio (2.70+/- 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature.

Water oxidation by photosystem II: H(2)O-D(2)O exchange and the influence of pH support formation of an intermediate by removal of a proton before dioxygen creation.

Science.gov (United States)

Gerencsér, László; Dau, Holger

2010-11-30

Understanding the chemistry of photosynthetic water oxidation requires deeper insight into the interrelation between electron transfer (ET) and proton relocations. In photosystem II membrane particles, the redox transitions of the water-oxidizing Mn complex were initiated by nanosecond laser flashes and monitored by absorption spectroscopy at 360 nm (A(360)). In the oxygen evolution transition (S(3) + hν → S(0) + O(2)), an exponential decrease in A(360) (τ(O(2)) = 1.6 ms) can be assigned to Mn reduction and O(2) formation. The corresponding rate-determining step is the ET from the Mn complex to a tyrosine radical (Y(Z)(ox)). We find that this A(360) decrease is preceded by a lag phase with a duration of 170 ± 40 μs (τ(lag) at pH 6.2), indicating formation of an intermediate before ET and O-O bond formation and corroborating results obtained by time-resolved X-ray spectroscopy. Whereas τ(O(2)) exhibits a minor kinetic isotope effect and negligible pH dependence, formation of the intermediate is slowed significantly both in D(2)O (τ(lag) increase of ∼140% in D(2)O) and at low pH (τ(lag) of 30 ± 20 μs at pH 7.0 vs τ(lag) of 470 ± 80 μs at pH 5.5). These findings support the fact that in the oxygen evolution transition an intermediate is created by deprotonation and removal of a proton from the Mn complex, after Y(Z)(ox) formation but before the onset of electron transfer and O-O bond formation.

The crystal structure of Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Winkler, Verena; Schlosser, Marc; Pfitzner, Arno [Regensburg Univ. (Germany). Inst. fuer Anorganische Chemie

2016-08-01

A reinvestigation of the alkali metal thiosulfates has led to the new phase Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O. At first cesium thiosulfate monohydrate was obtained as a byproduct of the synthesis of Cs{sub 4}In{sub 2}S{sub 5}. Further investigations were carried out using the traditional synthesis reported by J. Meyer and H. Eggeling. Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O crystallizes in transparent, colorless needles. The crystal structure of the title compound was determined by single crystal X-ray diffraction at room temperature: space group C2/m (No. 12), unit cell dimensions: a = 11.229(4), b = 5.851(2), c = 11.260(5) Aa, β = 95.89(2) , with Z = 4 and a cell volume of V = 735.9(5) Aa{sup 3}. The positions of all atoms including the hydrogen atoms were located in the structure refinement. Cs{sub 2}S{sub 2}O{sub 3}.H{sub 2}O is isotypic with Rb{sub 2}S{sub 2}O{sub 3}.H{sub 2}O. Isolated tetrahedra [S{sub 2}O{sub 3}]{sup 2-} are coordinated by the alkali metal cations, and in addition they serve as acceptors for hydrogen bonding. For both Cs atoms the shortest distances are observed to oxygen atoms of the S{sub 2}O{sub 3}{sup 2-} anions whereas the terminating sulfur atom has its shortest contacts to the water hydrogen atoms. Thus, an extended hydrogen bonding network is formed. The title compound has also been characterized by IR spectroscopy. IR spectroscopy reveals the vibrational bands of the water molecules at 3385 cm{sup -1}. They show a red shift in the OH stretching and bending modes as compared to free water. This is due both to the S..H hydrogen bonding and to the coordination of H{sub 2}O molecules to the cesium atoms.

U3Si2 behavior in H2O environments: Part II, pressurized water with controlled redox chemistry

Science.gov (United States)

Nelson, A. T.; Migdisov, A.; Wood, E. Sooby; Grote, C. J.

2018-03-01

Recent interest in U3Si2 as an advanced light water reactor fuel has driven assessment of numerous properties, but characterization of its response to H2O environments is sparse in available literature. The behavior of U3Si2 in H2O containing atmospheres is investigated and presented in a two-part series of articles. This work examines the behavior of U3Si2 following exposure to pressurized H2O at temperatures from 300 to 350 °C. Testing was performed using two autoclave configurations and multiple redox conditions. Use of solid state buffers to attain a controlled water chemistry is also presented as a means to test actinide-bearing systems. Buffers were used to vary the hydrogen concentration between 1 and 30 parts per million H2. Testing included UN, U3Si5, and UO2. Both UN and U3Si5 were found to rapidly pulverize in less than 50 h at 300 °C. Uranium dioxide was included as a control for the autoclave system, and was found to be minimally impacted by exposure to pressurized water at the conditions tested for extended time periods. Testing of U3Si2 at 300 °C found reasonable stability through 30 days in 1-5 ppm H2. However, pulverization was observed following 35 days. The redox condition of testing strongly affected pulverization. Characterization of the resulting microstructures suggests that the mechanism responsible for pulverization under more strongly reducing conditions differs from that previously identified. Hydride formation is hypothesized to drive this transition. Testing performed at 350 °C resulted in rapid pulverization of U3Si2 in under 50 h.

Removal of pharmaceutically active compounds from synthetic and real aqueous mixtures and simultaneous disinfection by supported TiO2/UV-A, H2O2/UV-A, and TiO2/H2O2/UV-A processes.

Science.gov (United States)

Bosio, Morgana; Satyro, Suéllen; Bassin, João Paulo; Saggioro, Enrico; Dezotti, Márcia

2018-05-01

Pharmaceutically active compounds are carried into aquatic bodies along with domestic sewage, industrial and agricultural wastewater discharges. Psychotropic drugs, which can be toxic to the biota, have been detected in natural waters in different parts of the world. Conventional water treatments, such as activated sludge, do not properly remove these recalcitrant substances, so the development of processes able to eliminate these compounds becomes very important. Advanced oxidation processes are considered clean technologies, capable of achieving high rates of organic compounds degradation, and can be an efficient alternative to conventional treatments. In this study, the degradation of alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine was evaluated through TiO 2 /UV-A, H 2 O 2 /UV-A, and TiO 2 /H 2 O 2 /UV-A, using sunlight and artificial irradiation. While using TiO 2 in suspension, best results were found at [TiO 2 ] = 0.1 g L -1 . H 2 O 2 /UV-A displayed better results under acidic conditions, achieving from 60 to 80% of removal. When WWTP was used, degradation decreased around 50% for both processes, TiO 2 /UV-A and H 2 O 2 /UV-A, indicating a strong matrix effect. The combination of both processes was shown to be an adequate approach, since removal increased up to 90%. H 2 O 2 /UV-A was used for disinfecting the aqueous matrices, while mineralization was obtained by TiO 2 -photocatalysis.

Experimental Study of Effects of pH, Temperature and H2O2 on Gasoline Removal from Contaminated Water Using Granular Activated Carbon

Directory of Open Access Journals (Sweden)

Hasti Hasheminejad

2010-01-01

Full Text Available Contamination of water with petroleum compounds is a serious environmental problem in Iran. Old fuel storage tanks, gasoline stations, and oil refineries are the main sources of gasoline leakage into water resources. In this study, the batch adsorption technique was used to investigate adsorption of petroleum compounds (gasoline on granular activated carbon. Experiments showed that the adsorption capacity of activated carbon is a function of pH, temperature, and H2O2 concentration in solution. Maximum adsorption of petroleum compounds was obtained at pH of 8. Adsorption of petroleum compounds was increased by decreasing temperature (due to decreasing van der Waals forces between the adsorbent and the adsorbate and H2O2 concentration in solution (due to the decrease in the initial concentration of the adsorbate by oxidation . In this experiment, the maximum equilibrium capacity of granular activated carbon was 129.05 mg COD/g GAC at pH 8 and at an ambient temperature of 10˚C. The experimental adsorption data were fitted to the Freundlich and Langmuir adsorption model. The correlation coefficients calculated indicate that the Freundlich model was best fitted. Also, the regression analysis was used with a correlation coefficient of 0.981 to develop a model for describing the relationship between absorption variation in equilibrium state, pH, temperature, and H2O2. On the whole, the correlation coefficient calculated by the proposed model was found to be higher than Freundlich’s.

Chemical kinetics in H2O and D2O under hydrothermal conditions

International Nuclear Information System (INIS)

Ghandi, K.; Alcorn, C.D.; Legate, G.; Percival, P.W.; Brodovitch, J.-C.

2010-01-01

Muonium (Mu = μ + e - ) is a light analogue of the H-atom. Studies of Mu chemical kinetics have been extended to supercritical water, a medium in some designs of future generation nuclear reactors. The Supercritical-Water-Cooled Reactor (SCWR) would operate at higher temperatures than current pressurized water-cooled reactors, and the lack of knowledge of water radiolysis under supercritical conditions constitutes a technology gap for SCWR development. Accurate modeling of chemistry in a SCWR requires data on kinetics of reactions involved in the radiolysis of water. In this paper, we first review our measurements of kinetics in H 2 O and then describe new data for D 2 O under sub- and supercritical conditions. (author)

A Cadmium Anionic 1-D Coordination Polymer {[Cd(H2O6][Cd2(atr2(μ2-btc2(H2O4] 2H2O}n within a 3-D Supramolecular Charge-Assisted Hydrogen-Bonded and π-Stacking Network

Directory of Open Access Journals (Sweden)

Anas Tahli

2016-03-01

Full Text Available The hydrothermal reaction of 4,4′-bis(1,2,4-triazol-4-yl (btr and benzene-1,3,5-tricarboxylic acid (H3btc with Cd(OAc2·2H2O at 125 °C in situ forms 4-amino-1,2,4-triazole (atr from btr, which crystallizes to a mixed-ligand, poly-anionic chain of [Cd2(atr2(µ2-btc2(H2O4]2–. Together with a hexaaquacadmium(II cation and water molecules the anionic coordination-polymeric forms a 3-D supramolecular network of hexaaquacadmium(II-catena-[bis(4-amino-1,2,4-triazoletetraaquabis(benzene-1,3,5-tricarboxylatodicadmate(II] dihydrate, 1-D-{[Cd(H2O6][Cd2(atr2(µ2-btc2(H2O4] 2H2O}n which is based on hydrogen bonds (in part charge-assisted and π–π interactions.

Synthesis and complex study of the crystal hydrate Zn{sub 2}ZrF{sub 8}.12H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Voit, Elena; Didenko, Nina; Gayvoronskaya, Kseniya; Slobodyuk, Arseniy; Gerasimenko, Andrey [Institute of Chemistry, Far-Eastern Branch, Russian Academy of Sciences, 159 Prosp. 100-Letiya Vladivostoka, 690022 Vladivostok (Russian Federation)

2016-05-15

The synthesis and study of structure and properties of a crystal hydrate of the composition Zn{sub 2}ZrF{sub 8}.12H{sub 2}O were performed by XRD, DTA analysis as well as IR, Raman, and {sup 1}H, and {sup 19}F NMR, including {sup 19}F MAS NMR spectroscopy. The compound crystallizes in the monoclinic syngony with the following unit cell parameters: a = 20.9649 (12), b = 9.6851 (6), c = 24.0209 (14) Aa, β = 103.742 (2) , space group C2/c, Z = 12. The structure is built from monomeric complex [ZrF{sub 8}]{sup 4-} and [Zn(H{sub 2}O){sub 6}]{sup 2+} linked through hydrogen bonds of different lengths (O-H..F and O-H..O). The peculiarity of the structure consists in the presence of short hydrogen bonds (interatomic O..F distances 2.5-2.6 Aa). Analysis of the IR and Raman spectra allowed interpretation of bands corresponding to vibrations of the [ZrF{sub 8}]{sup 4-} anion and to describe hydrogen bonds in the structure of Zn{sub 2}ZrF{sub 8}.12H{sub 2}O. Phase transformations in the process of thermal dehydration were studied on the basis of changes in vibrational and NMR spectra. It has been established that the interligand exchange in the complex anion takes place as early as at -103 C, whereas no reorientation of hexaaquacations was observed up to 47 C. At 58 C, the compound undergoes an incongruent melting accompanied with formation of much more stable ZnZrF{sub 6}.6H{sub 2}O and an aqueous salty liquid phase characterized with high mobility of fluorine atoms and protons, in accordance with the NMR spectroscopic data. (Copyright copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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.

Chemisorption of H2O and CO2 on hydrotalcites for sorptionenhanced water-gas-shift processes

NARCIS (Netherlands)

Coenen, K.T.; Gallucci, F.; Cobden, P.; van Dijk, E; Hensen, E.J.M.; van Sint Annaland, M.

2017-01-01

Thermogravimetric analysis and breakthrough experiments in a packed bed reactor were used to validate a developed adsorption model to describe the cyclic working capacity of CO2 and H2O on a potassium-promoted hydrotalcite, a very promising adsorbent for sorption-enhanced water-gas-shift

Chemisorption of H2O and CO2 on hydrotalcites for sorptionenhanced water-gas-shift processes

NARCIS (Netherlands)

Coenen, K.T.; Gallucci, F.; Cobden, P.; van Dijk, E.; Hensen, E.J.M.; van Sint Annaland, M.

2016-01-01

Thermogravimetric analysis and breakthrough experiments in a packed bed reactor were used to validate a developed adsorption model to describe the cyclic working capacity of CO¬2 and H2O on a potassium-promoted hydrotalcite, a very promising adsorbent for sorption-enhanced water-gas-shift

Estimated Critical Conditions for UO(Sub 2)F(Sub 2)-H(Sub 2)O Systems in Fully Water-Reflected Spherical Geometry

Energy Technology Data Exchange (ETDEWEB)

Jordan, W.C.

1992-01-01

The purpose of this report is to document reference calculations performed using the SCALE-4.0 code system to determine the critical parameters of UO{sub 2}F{sub 2}-H{sub 2}O spheres. The calculations are an extension of those documented in ORNL/CSD/TM-284. Specifically, the data for low-enriched UO{sub 2}F{sub 2}-H{sub 2}O spheres have been extended to highly enriched uranium. These calculations, together with those reported in ORNL/CSD/TM-284, provide a consistent set of critical parameters (k{sub {infinity}}, volume, mass, mass of water) for UO{sub 2}F{sub 2} and water over the full range of enrichment and moderation ratio.

Estimated critical conditions for UO{sub 2}F{sub 2}--H{sub 2}O systems in fully water-reflected spherical geometry

Energy Technology Data Exchange (ETDEWEB)

Jordan, W.C.; Turner, J.C.

1992-12-01

The purpose of this report is to document reference calculations performed using the SCALE-4.0 code system to determine the critical parameters of UO{sub 2}F{sub 2}-H{sub 2}O spheres. The calculations are an extension of those documented in ORNL/CSD/TM-284. Specifically, the data for low-enriched UO{sub 2}F{sub 2}-H{sub 2}O spheres have been extended to highly enriched uranium. These calculations, together with those reported in ORNL/CSD/TM-284, provide a consistent set of critical parameters (k{sub {infinity}}, volume, mass, mass of water) for UO{sub 2}F{sub 2} and water over the full range of enrichment and moderation ratio.

Study of the solubility, viscosity and density in Na+, Zn2+/Cl− − H2O, Na+ − Zn2+ − (H2PO2)− − H2O, Na+, Cl−/(H2PO2)− − H2O, and Zn2+, Cl−/(H2PO2)− − H2O ternary systems, and in Na+, Zn2+/Cl−, (H2PO2)−//H2O reciprocal quaternary system at 273.15 K

International Nuclear Information System (INIS)

Adiguzel, Vedat; Erge, Hasan; Alisoglu, Vahit; Necefoglu, Hacali

2014-01-01

Highlights: • The physicochemical properties of ternary and one quaternary have been studied. • Reciprocal quaternary systems’ solubility and phase equilibrium have been studied. • In all systems the solid phases have been found. • It was found that Zn(H 2 PO 2 ) 2 salt contains 70% of the general crystallization field. - Abstract: The solubility and the physicochemical properties (density, viscosity) in the Na-Zn- Cl-H 2 O), (Na + Zn + H 2 PO 2 + H 2 O), (Na + Cl + H 2 PO 2 + H 2 O), and (Zn + Cl + H 2 PO 2 + H 2 O) ternaries, and in Na + , Zn 2+ /Cl − , (H 2 PO 2 ) − //H 2 O reciprocal quaternary systems at T = 273.15 K were investigated by using the isothermal method. The diagrams of ternary salts systems, (NaCl + ZnCl 2 + H 2 O), (NaCl + NaH 2 PO 2 + H 2 O), (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), are plotted in figures 1–4. However, whole ions of reciprocal quaternary salt systems are plotted in figure 5. Additionally, the density and viscosity values of ternary systems vs. their corresponding composition values in weight per cent are plotted in figures 6–10. At the (i) (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ii) (NaCl + ZnCl 2 + H 2 O), (iii) (NaCl + NaH 2 PO 2 + H 2 O), (iv) (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O) ternary systems the solid phase compositions have been determined as: (i) Zn(H 2 PO 2 ) 2 ⋅ H 2 O, Zn(H 2 PO 2 ) 2 , ZnCl 2 ⋅ 2H 2 O, (ii) NaCl, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, and ZnCl 2 ⋅ 2H 2 O, (iii) NaCl and NaH 2 PO 2 ⋅ H 2 O, (iv) Zn(H 2 PO 2 ) 2 ⋅ H 2 O and NaH 2 PO 2 ⋅ H 2 O, respectively. On the other hand reciprocal quaternary system was observed as: ZnCl 2 ⋅ 2H 2 O, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, Zn(H 2 PO 2 ) 2 ⋅ H 2 O, NaH 2 PO 2 ⋅ H 2 O, NaCl. According to results, the least soluble salt was Zn(H 2 PO 2 ) 2 . The crystallization field of this salt, being the largest in comparison with those of other salts, occupied 70% of the general crystallization field

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).

Structure of Sr3V10O28.22H2O

International Nuclear Information System (INIS)

Nieto, J.M.; Salagre, P.; Medina, F.; Sueiras, J.E.; Solans, X.

1993-01-01

The crystal structure of hydrated strontium decavanadate, Sr 3 V 10 O 28 .22H 2 O, has been determined. It contains two types of strontium ions: the first is coordinated to seven water molecules which define a pentagonal bipyramid; the second bonds to five molecules of water and three O atoms of different decavanadate ions, thereby bridging between decavanadate ions to produce layers of formula [Sr 2 V 10 O 38 H 20 ] n on the crystallographic plane (100). The heptacoordinated Sr and the five molecules of water associated with it are located between the different layers. (orig.)

UV and VUV photolysis vs. UV/H2O2 and VUV/H2O2, treatment for removal of clofibric acid from aqueous solution.

Science.gov (United States)

Li, Wenzhen; Lu, Shuguang; Qiu, Zhaofu; Lin, Kuangfei

2011-07-01

Clofibric acid (CA), a metabolite of lipid regulators, was investigated in ultra-pure water and sewage treatment plant (STP) effluent at 10 degrees C under UV, vacuum UV (VUV), UV/H2O2 and VUV/H2O2 processes. The influences of NO3-, HCO3- and humic acid (HA) on CA photolysis in all processes were examined. The results showed that all the experimental data well fitted the pseudo-first-order kinetic model, and the apparent rate constant (k(ap)) and half-life time (t(1/2)) were calculated accordingly. Direct photolysis of CA through UV irradiation was the main process, compared with the indirect oxidation of CA due to the slight generation of hydroxyl radicals dissociated from water molecules under UV irradiation below 200 nm monochromatic wavelength emission. In contrast, indirect oxidation was the main CA degradation mechanism in UV/H2O2 and VUV/H2O2, and VUV/H2O2 was the most effective process for CA degradation. The addition of 20 mg L(-1) HA could significantly inhibit CA degradation, whereas, except for UV irradiation, the inhibitive effects of NO3- and HCO3- (1.0 x 10(-3) and 0.1 mol L(-1), respectively) on CA degradation were observed in all processes, and their adverse effects were more significant in UV/H2O2 and VUV/H2O2 processes, particularly at the high NO3- and HCO3- concentrations. The degradation rate decreased 1.8-4.9-fold when these processes were applied to a real STP effluent owing to the presence of complex constituents. Of the four processes, VUV/H2O2 was the most effective, and the CA removal efficiency reached over 99% after 40 min in contrast to 80 min in both the UV/H2O2 and VUV processes and 240 min in the UV process.

The MgSeO4-UO2SeO4-H2O system at 25 deg C

International Nuclear Information System (INIS)

Serezhkina, L.B.; Serezhkin, V.N.

1984-01-01

The method of isothermal solubility at 25 deg C has been used to study MgSeO 4 -UO 2 SeO 4 -H 2 O system. Formation of the new compound Mg 2 (UO 2 ) 3 (SeO 4 ) 5 X32H 2 O, congruently soluble in water is stated. Thermographic and X-ray diffraction investigations of the prepared magnesium selenato-uranylate and products of its dehydration are conducted

Thermodynamic analysis of behaviour of boiling water reactor coolant on the basis of solubility in Fe3O4-H2O-O2 system

International Nuclear Information System (INIS)

Zarembo, V.I.; Slobodov, A.A.; Kritskij, V.G.; Puchkov, L.V.; Sedov, V.M.

1986-01-01

The thermodynamic analysis of the behaviour of boiling water reactor coolant on the basis of solubility in Fe 3 O 4 -H 2 O-O 2 system is performed for the purpose of establishing the iron existence forms in non-sedimentated suspended corrosion product particles as well as iron concentration of corrosion origin in power plants. It is shown that the iron solubility in the considered system with temperature variation occurs through the maximum at 423 K. Below this temperature the crystal Fe(OH) 3 is responsible for its value, at higher temperatures - magnetite. The growth of equilibrium oxygen concentration from 0.1 to 1000 μg/kg H 2 O only slightly increases the magnetite solubility

Topology-energy relationships and lowest energy configurations for pentagonal dodecahedral (H2O)20X clusters, X=empty, H2O, NH3, H3O+: The importance of O-topology

Science.gov (United States)

Anick, David J.

2010-04-01

For (H2O)20X water clusters consisting of X enclosed by the 512 dodecahedral cage, X=empty, H2O, NH3, and H3O+, databases are made consisting of 55-82 isomers optimized via B3LYP/6-311++G∗∗. Correlations are explored between ground state electronic energy (Ee) or electronic energy plus zero point energy (Ee+ZPE) and the clusters' topology, defined as the set of directed H-bonds. Linear regression is done to identify topological features that correlate with cluster energy. For each X, variables are found that account for 99% of the variance in Ee and predict it with a rms error under 0.2 kcal/mol. The method of analysis emphasizes the importance of an intermediate level of structure, the "O-topology," consisting of O-types and a list of O pairs that are bonded but omitting H-bond directions, as a device to organize the databases and reduce the number of structures one needs to consider. Relevant variables include three parameters, which count the number of H-bonds having particular donor and acceptor types; |M|2, where M is the cluster's vector dipole moment; and the projection of M onto the symmetry axis of X. Scatter diagrams for Ee or Ee+ZPE versus |M| show that clusters fall naturally into "families" defined by the values of certain discrete parameters, the "major parameters," for each X. Combining "family" analysis and O-topologies, a small group of clusters is identified for each X that are candidates to be the global minimum, and the minimum is determined. For X=H3O+, one cluster with central hydronium lies just 2.08 kcal/mol above the lowest isomer with surface hydronium. Implications of the methodology for dodecahedral (H2O)20(NH4+) and (H2O)20(NH4+)(OH-) are discussed, and new lower energy isomers are found. For MP2/TZVP, the lowest-energy (H2O)20(NH4+) isomer features a trifurcated H-bond. The results suggest a much more efficient and comprehensive way of seeking low-energy water cluster geometries that may have wide applicability.

Water-Induced Degradation of Polymer Solar Cells Studied by (H2O)-O-18 Labeling

DEFF Research Database (Denmark)

Norrman, Kion; Gevorgyan, Suren; Krebs, Frederik C

2009-01-01

Water-induced degradation of polymer photovoltaics based on the active materials poly(3-hexylthiophene) (P3HT) or poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) was studied. The solar cell devices comprised a bulk heterojunction formed by the active material and [6,6]-phenyl......-C61-butyric acid methyl ester (PCBM) in a standard device geometry. The use of H218O in conjunction with time-of-flight secondary ion mass spectrometry enabled mapping of the parts of the device that were induced by water. A comparison was made between the two active materials and between devices...

Simulation of the inhibition of water α-radiolysis via H2 addition

International Nuclear Information System (INIS)

Lertnaisat, Phantira; Katsumura, Yosuke; Mukai, Satoru; Umehara, Ryuji; Shimizu, Yuichi; Suzuki, Masashi

2014-01-01

The continuous formation of H 2 , O 2 , and H 2 O 2 observed in water during α-radiolysis may be suppressed by the addition of H 2 above the threshold hydrogen concentration (THC). Using the FACSIMILE simulation code, water radiolysis was reproduced in order to determine the THC and clarify the mechanism at room temperature. Using the reaction set and rate constants reported by Ershov and Gordeev together with the primary yields for water decomposition products generated using 12 MeV α-particles, the THC was found to be 165 μM. Further simulation results clearly showed that the value of THC is strongly dependent on the reaction set and rate constants. In addition, a possible mechanism involving a chain reaction governed by the two reactions OH + H 2 → H + H 2 O and H + H 2 O 2 → OH + H 2 O was proposed. Furthermore, the same inhibition effect was found when a high-temperature simulation (300degC) was performed, but the concentration range and THC were much smaller than the values obtained at room temperature. The importance of the reverse reaction OH + H 2 → H + H 2 O was also investigated. (author)

Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region.

Science.gov (United States)

Ndounla, J; Pulgarin, C

2015-11-01

The photo-disinfection of natural alkaline surface water (pH 8.6 ± 0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10(4) CFU/ml) and Salmonella spp. (10(4) CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H2O2). The addition of H2O2 (10 mg/L) to the sample water was sufficient to enhance the photo-disinfection and ensure an irreversible lethal action on the wild enteric bacteria contents of the sample. The inactivation kinetic of the system was significantly enhanced compared to the one carried out without H2O2 addition. The effect of the solar radiation parameters on the efficiency of the photo-disinfection were assessed. The pH has increased during the treatment in all the photo-disinfection processes (hv and H2O2/hv). The Salmonella spp strain has shown the best effective inactivate time in alkaline water than the one recorded under acidic or near-neutral conditions. The evolution of some physico-chemical parameters of the water (turbidity, NO2(-), NO3(-), NH4(+), HPO4(2-), and bicarbonate (HCO3(-))) was monitored during the treatment. Finally, the possible mechanistic process involved during the enteric bacteria inactivation was suggested.

Effects of H2O and H2O2 on thermal desorption of tritium from stainless steel

International Nuclear Information System (INIS)

Quinlan, M. J.; Shmayda, W. T.; Lim, S.; Salnikov, S.; Chambers, Z.; Pollock, E.; Schroeder, W. U.

2008-01-01

Tritiated stainless steel was subjected to thermal desorption at various temperatures, different temperature profiles, and in the presence of different helium carrier gas additives. In all cases the identities of the desorbing tritiated species were characterized as either water-soluble or insoluble. The samples were found to contain 1.1 mCi±0.4 mCi. Approximately ninety-five percent of this activity was released in molecular water-soluble form. Additives of H 2 O or H 2 O 2 to dry helium carrier gas increase the desorption rate and lower the maximum temperature to which the sample must be heated, in order to remove the bulk of the tritium. The measurements validate a method of decontamination of tritiated steel and suggest a technique that can be used to further explore the mechanisms of desorption from tritiated metals. (authors)

The δ2H and δ18O of tap water from 349 sites in the United States and selected territories

Science.gov (United States)

Coplen, Tyler B.; Landwehr, Jurate M.; Qi, Haiping; Lorenz, Jennifer M.

2013-01-01

Because the stable isotopic compositions of hydrogen (δ2H) and oxygen (δ18O) of animal (including human) tissues, such as hair, nail, and urine, reflect the δ2H and δ18O of water and food ingested by an animal or a human and because the δ2H and δ18O of environmental waters vary geographically, δ2H and δ18O values of tap water samples collected in 2007-2008 from 349 sites in the United States and three selected U.S. territories have been measured in support of forensic science applications, creating one of the largest databases of tap water δ2H and δ18O values to date. The results of replicate isotopic measurements for these tap water samples confirm that the expanded uncertainties (U = 2μc) obtained over a period of years by the Reston Stable Isotope Laboratory from δ2H and δ18O dual-inlet mass spectrometric measurements are conservative, at ±2‰ and ±0.2 ‰, respectively. These uncertainties are important because U.S. Geological Survey data may be needed for forensic science applications, including providing evidence in court cases. Half way through the investigation, an isotope-laser spectrometer was acquired, enabling comparison of dual-inlet isotope-ratio mass spectrometric results with isotope-laser spectrometric results. The uncertainty of the laser-based δ2H measurement results for these tap water samples is comparable to the uncertainty of the mass spectrometric method, with the laser-based method having a slightly lower uncertainty. However, the δ18O uncertainty of the laser-based method is more than a factor of ten higher than that of the dual-inlet isotoperatio mass spectrometric method.

DETAILED ANALYSIS OF NEAR-IR WATER (H{sub 2}O) EMISSION IN COMET C/2014 Q2 (LOVEJOY) WITH THE GIANO/TNG SPECTROGRAPH

Energy Technology Data Exchange (ETDEWEB)

Faggi, S.; Brucato, J. R.; Tozzi, G. P.; Oliva, E.; Massi, F.; Sanna, N.; Tozzi, A. [Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Villanueva, G. L.; Mumma, M. J., E-mail: sfaggi@arcetri.astro.it [NASA Goddard Space Flight Centre, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)

2016-10-20

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1–2.5 μ m region. Spectral lines from eight ro-vibrational bands of H{sub 2}O were detected, six of them for the first time. We quantified the water production rate [ Q (H{sub 2}O), (3.11 ± 0.14) × 10{sup 29} s{sup −1}] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H{sub 2}O. The production rates of ortho-water [ Q (H{sub 2}O){sup ORTHO}, (2.33 ± 0.11) × 10{sup 29} s{sup −1}] and para-water [ Q (H{sub 2}O){sup PARA}, (0.87 ± 0.21) × 1029 s{sup −1}] provide a measure of the ortho-to-para ratio (2.70 ± 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature.

Are UV photolysis and UV/H2O2 process efficient to treat estrogens in waters? Chemical and biological assessment at pilot scale.

Science.gov (United States)

Cédat, Bruno; de Brauer, Christine; Métivier, Hélène; Dumont, Nathalie; Tutundjan, Renaud

2016-09-01

In this study, UV based treatments were implemented at pilot scale to assess their ability to remove hormones from treated wastewater, especially with the view to equip small and medium size Wastewater Treatment Plants (WTPs). To this end, the degradation of a mixture of estrogenic hormones (Estrone (E1), β-Estradiol (E2), and 17α-Ethinyl Estradiol (EE2)) in waters by UV photolysis and UV/H2O2 process was investigated in real conditions. A particular attention was paid at designing a well validated laboratory scale pilot in order to optimise oxidant concentrations and UV fluence. A Low pressure lamp (254 nm) was used in a flow through commercial reactor. The effects of water matrices (drinking water and treated wastewater) and H2O2 concentrations (10, 40, and 90 mg/L) on the pilot efficiency were first determined. Only E1 could be partially degraded by UV photolysis whereas hormones were all well removed by UV/H2O2 process in both matrices. The second part of the study focused on a chemical and biological assessment of UV photolysis and UV/H2O2 process (30 and 50 mg/L). Degradation rate constants of hormones as well as changes in estrogenic activity (YES bioassay) and toxicity (Vibrio fischeri) were followed at the same time. UV photolysis could not remove neither estrogens nor estrogenic activity at relevant UV fluence in waters. However 80% of initial estrogenic compounds and estrogenic activity could be removed from treated wastewater by combining UV fluence of 423 and 520 mJ/cm(2) with 50 and 30 mg/L of H2O2, respectively. No high estrogenic or toxic by-products were detected by the two bioassays following UV photolysis or UV/H2O2 process. Operating costs were estimated for a full scale pilot. H2O2 was the major cost. By combining the appropriate concentration of H2O2 and UV fluence, it could be possible to design a cost effective treatment for treating estrogens in small and medium size WTPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Proton conducting system (ImH2)2SeO4·2H2O investigated with vibrational spectroscopy

Science.gov (United States)

Zięba, Sylwia; Mizera, Adam; Pogorzelec-Glaser, Katarzyna; Łapiński, Andrzej

2017-06-01

Imidazolium selenate dihydrate (ImH2)2SeO4·2H2O crystals have been investigated using Raman and IR spectroscopy. Experimental data were supported by the quantum-chemical calculations (DFT), Hirshfield surfaces and fingerprint plots analysis, and Bader theory calculations. The imidazolium selenate dihydrate crystal exhibits high proton conductivity of the order of 10- 1 S/m at T = 333 K. The spectra of this compound are dominated by bands related to the lattice modes, the internal vibrations of the protonated imidazole cation, selenate anion, water molecules, and hydrogen bonds network. For the imidazolium selenate dihydrate crystal, the formal classification of the fundamental modes has been carried out.

On the basic substances used in the separation process by isotope exchange H2S - H2O, at two temperatures, in view of producing heavy water

International Nuclear Information System (INIS)

Popescu, V.

1977-01-01

In view of producing heavy water, the influence of the deuterium proportion in the basic substances, on the efficiency of the isotope exchange process H 2 S - H 2 O for two temperatures was studied. Heavy water is extracted from ordinary water and concentrated from 0.014 per cent to 5-15 per cent D 2 O by isotope bithermal exchange with the hydrogen sulphite. Theoretical and experimental research was carried out in laboratories and then applied on a pilot plant by designing and testing a drying equipment for hydrogen sulphite. The maximum H 2 S concentration rose to 99.84 per cent. The purity of the hydrogen sulphite resulting from the pilot plant, as well as the optimization of the installation for producing H 2 S depending on the deuterium distribution, make sure that the two methods for the preparation of sodium sulphite and hydrogen sulphite can be applied in industry. (author)

Mesospheric H2O and H2O2 densities inferred from in situ positive ion composition measurement

Science.gov (United States)

Kopp, E.

1984-01-01

A model for production and loss of oxonium ions in the high-latitude D-region is developed, based on the observed excess of 34(+) which has been interpreted as H2O2(+). The loss mechanism suggested in the study is the attachment of N2 and/or CO2 in three-body reactions. Furthermore, mesospheric water vapor and H2O2 densities are inferred from measurements of four high-latitude ion compositions, based on the oxonium model. Mixing ratios of hydrogen peroxide of up to two orders of magnitude higher than previous values were obtained. A number of reactions, reaction constants, and a block diagram of the oxonium ion chemistry in the D-region are given.

Cross sections for Scattering and Mobility of OH- and H3 O+ ions in H2 O

Science.gov (United States)

Petrovic, Zoran; Stojanovic, Vladimir; Maric, Dragana; Jovanovic, Jasmina

2016-05-01

Modelling of plasmas in liquids and in biological and medical applications requires data for scattering of all charged and energetic particles in water vapour. We present swarm parameters for OH- and H3 O+, as representatives of principal negative and positive ions at low pressures in an attempt to provide the data that are not yet available. We applied Denpoh-Nanbu procedure to calculate cross section sets for collisions of OH- and H3 O+ ions with H2 O molecule. Swarm parameters for OH- and H3 O+ ions in H2 O are calculated by using a well tested Monte Carlo code for a range of E / N(E -electric field, N-gas density) at temperature T = 295 K, in the low pressure limit. Non-conservative processes were shown to strongly influence the transport properties even for OH- ions above the average energy of 0.2 eV(E / N >200 Td). The data are valid for low pressure water vapour or small amounts in mixtures. They will provide a basis for calculating properties of ion-water molecule clusters that are most commonly found at higher pressures and for modelling of discharges in liquids. Acknowledgment to Ministry of Education, Science and Technology of Serbia.

Hydrothermal synthesis and structure of nickel(II) metavanadate monohydrate, NiV2O6.H2O

International Nuclear Information System (INIS)

Marcos, M.D.; Amoros, P.; Beltran-Porter, A.; Ramirez de Arellano, M.C.

1995-01-01

The structure of NiV 2 O 6 .H 2 O consists of infinite chains of [VO 4 ] tetrahedra running along the [100] direction connected by isolated [Ni 2 O 8 (H 2 O) 2 ] dimeric entities to build up a three-dimensional network. A valence-bond analysis allows the identification of the O atoms of the water molecules. (orig.)

Influence of γ-radiation on the reactivity of montmorillonite towards H2O2

International Nuclear Information System (INIS)

Holmboe, Michael; Jonsson, Mats; Wold, Susanna

2012-01-01

Compacted and water saturated bentonite will be used as an engineered barrier in deep geological repositories for radioactive waste in many countries. Due to the high dose rate of ionizing radiation outside the canisters holding the nuclear waste, radiolysis of the interlayer and pore water in the compacted bentonite is unavoidable. Upon reaction with the oxidizing and reducing species formed by water radiolysis (OH • , e − (aq) , H • , H 2 O 2 , H 2 , HO 2 • , H 3 O + ), the overall redox properties in the bentonite barrier may change. In this study the influence of γ-radiation on the structural Fe(II)/Fe Tot ratio in montmorillonite and its reactivity towards hydrogen peroxide (H 2 O 2 ) was investigated in parallel experiments. The results show that under anoxic conditions the structural Fe(II)/Fe Tot ratio of dispersed Montmorillonite increased from ≤3 to 25–30% after γ-doses comparable to repository conditions. Furthermore, a strong correlation between the structural Fe(II)/Fe Tot ratio and the H 2 O 2 decomposition rate in montmorillonite dispersions was found. This correlation was further verified in experiments with consecutive H 2 O 2 additions, since the structural Fe(II)/Fe Tot ratio was seen to decrease concordantly. This work shows that the structural iron in montmorillonite could be a sink for one of the major oxidants formed upon water radiolysis in the bentonite barrier, H 2 O 2 .

Hydrothermal synthesis and crystal structure of a new molybdenum oxide compound with manganese-o-phen subunit: [Mn(o-phen)(H2O)MoO4]·H2O (o-phen=o-phenanthroline)

International Nuclear Information System (INIS)

Zhang Quanzheng; Lu Canzhong; Yang Wenbin; Chen Shumei; Yu Yaqin; He Xiang; Yan Ying; Liu Jiuhui; Xu Xinjiang; Xia Changkun; Wu Xiaoyuan; Chen Lijuan

2004-01-01

A new one-dimensional molybdenum oxide compound with manganese-o-phen subunit: [Mn(o-phen)(H 2 O)MoO 4 ]·H 2 O (1) (o-phen=o-phenanthroline) was synthesized by the hydrothermal reaction of Na 2 MoO 4 ·2H 2 O, MnSO 4 ·H 2 O, oxalic acid, o-phenanthroline (o-phen) and water. Its structure was determined by elemental analyses, ESR spectrum, TG analysis, IR spectrum and single-crystal X-ray diffraction. Compound 1 crystallizes in triclinic system, space group P-1 with a=7.0401(2) A, b=10.4498(2) A, c=10.5720(2) A, α=73.26(7) deg., β=83.34(8) deg., γ=77.33(9) deg., V=725.5089(0) A 3 , Z=2, and R 1 =0.0322 for 2337 observed reflections. Compound 1 exhibits one-dimensional chain structure. The chains are linked up via hydrogen bonding to 2D layers, which are further assembled through π-π stacking interactions to a 3D supermolecular structure

Vibrational Dynamics of Interfacial Water by Free Induction Decay Sum Frequency Generation (FID-SFG) at the Al2O3(1120)/H2O Interface.

Science.gov (United States)

Boulesbaa, Abdelaziz; Borguet, Eric

2014-02-06

The dephasing dynamics of a vibrational coherence may reveal the interactions of chemical functional groups with their environment. To investigate this process at a surface, we employ free induction decay sum frequency generation (FID-SFG) to measure the time that it takes for free OH stretch oscillators at the charged (pH ≈ 13, KOH) interface of alumina/water (Al2O3/H2O) to lose their collective coherence. By employing noncollinear optical parametric amplification (NOPA) technology and nonlinear vibrational spectroscopy, we showed that the single free OH peak actually corresponds to two distinct oscillators oriented opposite to each other and measured the total dephasing time, T2, of the free OH stretch modes at the Al2O3/H2O interface with a sub-40 fs temporal resolution. Our results suggested that the free OH oscillators associated with interfacial water dephase on the time scale of 89.4 ± 6.9 fs, whereas the homogeneous dephasing of interfacial alumina hydroxyls is an order of magnitude slower.

Synthesis, crystal structure and magnetic properties of [Cu(mal(abpt(H2O].3/2H2O and [Cu2(sq(abpt 2].2H2O (mal = malonate, sq = squarate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole

Directory of Open Access Journals (Sweden)

Eno A. Ededet

2011-04-01

Full Text Available Two new mixed-ligand complexes of formula [Cu(mal(abpt(H2O].3/2H2O (1 and [Cu2(sq(abpt2].2H2O (2 [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex 1 crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2 Å, b = 10.0980(2 Å, c = 25.630(4 Å; β = 97.5900(10 o, and Z = 8. Complex 2 crystallizes in the triclinic system, space group P-1 with a = 7.5696(15 Å, b = 8.4697(17 Å, c = 11.049(2 Å; β = 93.00(3o, α = 96.98(3, γ = 90.111(3 and Z = 1. Complex 1 consist of a neutral mononuclear [Cu(mal(abpt(H2O] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex 2 is viewed as being made up of [Cu(sq(abpt2] units with the squarato ligand bridging the two copper(II cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex 1 and weak ferromagnetic intrachain interaction for complex 2.

Synthesis of CuO nanoflower and its application as a H2O2 sensor

Indian Academy of Sciences (India)

Administrator

CuO; nanoflowers; electrochemical; H2O2. 1. Introduction. Cupric oxide (CuO) is an important transition metal oxide ... several high temperature superconductors and giant mag- ... precipitate was washed with ethanol and distilled water.

H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane

International Nuclear Information System (INIS)

Pandiangan, Tumpal

2002-01-01

It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H 2 , and N 2 was measured at 300-600 o C. Hydrogen permeance of the modified membrane at a permeation temperature of 600 o C was about 5.22 x 10 -08 mol/Pa m 2 s, and 3.2 x 10 -09 of using gas mixture of H 2 -H 2 O-HI, where as HI permeances was below 1 x 10 -10 mol/Pa m 2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H 2 -H 2 O-HI gas at the temperature of 450 o C. (author)

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.

Decolorization of Mordant red 73 azo dye in water using H2O2/UV and photo-Fenton treatment.

Science.gov (United States)

Elmorsi, Taha M; Riyad, Yasser M; Mohamed, Zeinhom H; Abd El Bary, Hassan M H

2010-02-15

Decolorization of the Mordant red 73 (MR73) azo dye in water was investigated in laboratory-scale experiments using UV/H(2)O(2) and photo-Fenton treatments. Photodegradation experiments were carried out in a stirred batch photoreactor equipped with a low-pressure mercury lamp as UV source at 254 nm. The effect of operating parameters such as pH, [H(2)O(2)](,) [dye] and the presence of inorganic salts (NaNO(3), NaCl and Na(2)CO(3)) were also investigated. The results indicated that complete dye decolorization was obtained in less than 60 min under optimum conditions. Furthermore, results showed that dye degradation was dependent upon pH, [H(2)O(2)] and initial dye concentration. The presence of chloride ion led to large decreases in the photodegradation rate of MR73 while both nitrate and carbonate ions have a slight effect. The photo-Fenton treatment, in the presence of Fe powder as a source of Fe(2+) ions, was highly efficient and resulted in 99% decolorization of the dye in 15 min. Mineralization of MR73 dye was investigated by determining chemical oxygen demand (COD). In a 3h photoperiod "65%" of the dye was mineralized by the H(2)O(2)/UV process, while the photo-Fenton treatment was more efficient producing 85% mineralization over the same 3-h period.

Photochemical degradation of diethyl phthalate with UV/H{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xu Bin [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Gao Naiyun [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)]. E-mail: gaonaiyun@mail.tongji.edu.cn; Sun Xiaofeng [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Xia Shengji [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Rui Min [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Simonnot, Marie-Odile [Laboratory of Chemical Engineering Science, CNRS-INPL, 1 rue Grandville, BP451, F-54001 Nancy Cedex (France); Causserand, Christel [Laboratory of Chemical Engineering, UMR 5503 CNRS INP, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Zhao Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

2007-01-02

The decomposition of diethyl phthalate (DEP) in water using UV-H{sub 2}O{sub 2} process was investigated in this paper. DEP cannot be effectively removed by UV radiation and H{sub 2}O{sub 2} oxidation alone, while UV-H{sub 2}O{sub 2} combination process proved to be effective and could degrade this compound completely. With initial concentration about 1.0 mg/L, more than 98.6% of DEP can be removed at time of 60 min under intensity of UV radiation of 133.9 {mu}W/cm{sup 2} and H{sub 2}O{sub 2} dosage of 20 mg/L. The effects of applied H{sub 2}O{sub 2} dose, UV radiation intensity, water temperature and initial concentration of DEP on the degradation of DEP have been examined in this study. Degradation mechanisms of DEP with hydroxyl radicals oxidation also have been discussed. Removal rate of DEP was sensitive to the operational parameters. A simple kinetic model is proposed which confirms to pseudo-first order reaction. There is a linear relationship between rate constant k and UV intensity and H{sub 2}O{sub 2} concentration.

A comparative study of the disinfection efficacy of H2O2/ferrate and UV/H2O2/ferrate processes on inactivation of Bacillus subtilis spores by response surface methodology for modeling and optimization.

Science.gov (United States)

Matin, Atiyeh Rajabi; Yousefzadeh, Samira; Ahmadi, Ehsan; Mahvi, Amirhossein; Alimohammadi, Mahmood; Aslani, Hassan; Nabizadeh, Ramin

2018-04-03

Although chlorination can inactivate most of the microorganisms in water but protozoan parasites like C. parvum oocysts and Giardia cysts can resist against it. Therefore, many researches have been conducted to find a novel method for water disinfection. Present study evaluated the synergistic effect of H2O2 and ferrate followed by UV radiation to inactivate Bacillus subtilis spores as surrogate microorganisms. Response surface methodology(RSM) was employed for the optimization for UV/H2O2/ferrate and H2O2/ferrate processes. By using central composite design(CCD), the effect of three main parameters including time, hydrogen peroxide, and ferrate concentrations was examined on process performance. The results showed that the combination of UV, H2O2 and ferrate was the most effective disinfection process in compare with when H2O2 and ferrate were used. This study indicated that by UV/H2O2/ferrate, about 5.2 log reductions of B. subtilis spores was inactivated at 9299 mg/l of H2O2 and 0.4 mg/l of ferrate concentrations after 57 min of contact time which was the optimum condition, but H2O2/ferrate can inactivate B. subtilis spores about 4.7 logs compare to the other process. Therefore, the results of this research demonstrated that UV/H2O2 /ferrate process is a promising process for spore inactivation and water disinfection. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Application of UV/H2O2 system to treatment of wastewater arising from thermal treatment of oil-water emulsions

Directory of Open Access Journals (Sweden)

Ivanildo Hespanhol

2009-12-01

Full Text Available In this work it is presented the results of bench scale tests using Advanced Oxidation Process (AOP in a UV/H2O2 system, for the treatment of an industrial effluent with a high concentration of dissolved organic matter, resulted from thermal treatment of oil-water emulsions. Treatability tests were carried out in a batch photochemical system with recycle, and the raw effluent was characterized by the analysis of pH, turbidity, color, COD and TOC. Results from these assays shown that UV/H2O2 process is technically feasible resulting in TOC removal above 90%. However, for one log TOC removal from this effluent the energy required was about 455.5 kw.h.m-3, for an alpha relation of 10 mg H2O2/mg COT, resulting in a higher operational cost, considering the evaluated conditions.

Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge

DEFF Research Database (Denmark)

Imanaka, M.; Tomita, S.; Kanda, S.

2010-01-01

To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using...

Pd-catalytic in situ generation of H2O2 from H2 and O2 produced by water electrolysis for the efficient electro-fenton degradation of rhodamine B.

Science.gov (United States)

Yuan, Songhu; Fan, Ye; Zhang, Yucheng; Tong, Man; Liao, Peng

2011-10-01

A novel electro-Fenton process was developed for wastewater treatment using a modified divided electrolytic system in which H2O2 was generated in situ from electro-generated H2 and O2 in the presence of Pd/C catalyst. Appropriate pH conditions were obtained by the excessive H+ produced at the anode. The performance of the novel process was assessed by Rhodamine B (RhB) degradation in an aqueous solution. Experimental results showed that the accumulation of H2O2 occurred when the pH decreased and time elapsed. The maximum concentration of H2O2 reached 53.1 mg/L within 120 min at pH 2 and a current of 100 mA. Upon the formation of the Fenton reagent by the addition of Fe2+, RhB degraded completely within 30 min at pH 2 with a pseudo first order rate constant of 0.109 ± 0.009 min(-1). An insignificant decline in H2O2 generation and RhB degradation was found after six repetitions. RhB degradation was achieved by the chemisorption of H2O2 on the Pd/C surface, which subsequently decomposed into •OH upon catalysis by Pd0 and Fe2+. The catalytic decomposition of H2O2 to •OH by Fe2+ was more powerful than that by Pd0, which was responsible for the high efficiency of this novel electro-Fenton process.

Kinetic model describing the UV/H2O2 photodegradation of phenol from water

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Rubio-Clemente Ainhoa

2017-01-01

Full Text Available A kinetic model for phenol transformation through the UV/H2O2 system was developed and validated. The model includes the pollutant decomposition by direct photolysis and HO•, HO2• and O2 •- oxidation. HO• scavenging effects of CO3 2-, HCO3 -, SO4 2- and Cl- were also considered, as well as the pH changes as the process proceeds. Additionally, the detrimental action of the organic matter and reaction intermediates in shielding UV and quenching HO• was incorporated. It was observed that the model can accurately predict phenol abatement using different H2O2/phenol mass ratios (495, 228 and 125, obtaining an optimal H2O2/phenol ratio of 125, leading to a phenol removal higher than 95% after 40 min of treatment, where the main oxidation species was HO•. The developed model could be relevant for calculating the optimal level of H2O2 efficiently degrading the pollutant of interest, allowing saving in costs and time.

Improved water vapour spectroscopy in the 4174–4300 cm−1 region and its impact on SCIAMACHY HDO/H2O measurements

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R. A. Scheepmaker

2013-04-01

Full Text Available The relative abundance of the heavy water isotopologue HDO provides a deeper insight into the atmospheric hydrological cycle. The SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY allows for global retrievals of the ratio HDO/H2O in the 2.3 micron wavelength range. However, the spectroscopy of water lines in this region remains a large source of uncertainty for these retrievals. We therefore evaluate and improve the water spectroscopy in the range 4174–4300 cm−1 and test if this reduces systematic uncertainties in the SCIAMACHY retrievals of HDO/H2O. We use a laboratory spectrum of water vapour to fit line intensity, air broadening and wavelength shift parameters. The improved spectroscopy is tested on a series of ground-based high resolution FTS spectra as well as on SCIAMACHY retrievals of H2O and the ratio HDO/H2O. We find that the improved spectroscopy leads to lower residuals in the FTS spectra compared to HITRAN 2008 and Jenouvrier et al. (2007 spectroscopy, and the retrievals become more robust against changes in the retrieval window. For both the FTS and SCIAMACHY measurements, the retrieved total H2O columns decrease by 2–4% and we find a negative shift of the HDO/H2O ratio, which for SCIAMACHY is partly compensated by changes in the retrieval setup and calibration software. The updated SCIAMACHY HDO/H2O product shows somewhat steeper latitudinal and temporal gradients and a steeper Rayleigh distillation curve, strengthening previous conclusions that current isotope-enabled general circulation models underestimate the variability in the near-surface HDO/H2O ratio.

Hydrazinium lanthanide oxalates: synthesis, structure and thermal reactivity of N_2H_5[Ln_2(C_2O_4)_4(N_2H_5)].4H_2O, Ln = Ce, Nd

International Nuclear Information System (INIS)

De Almeida, Lucie; Grandjean, Stephane; Abraham, Francis; Rivenet, Murielle; Patisson, Fabrice

2014-01-01

New hydrazinium lanthanide oxalates N_2H_5[Ln_2(C_2O_4)_4(N_2H_5)].4H_2O, Ln = Ce (Ce-H_yO_x) and Nd (Nd- H_yO_x), were synthesized by hydrothermal reaction at 150 C between lanthanide nitrate, oxalic acid and hydrazine solutions. The structure of the Nd compound was determined from single-crystal X-ray diffraction data, space group P2_1/c with a = 16.315(4), b = 12.127(3), c = 11.430(2) Angstroms, β = 116.638(4) degrees, V = 2021.4(7) Angstroems"3, Z = 4, and R1 = 0.0313 for 4231 independent reflections. Two distinct neodymium polyhedra are formed, NdO_9 and NdO_8N, an oxygen of one monodentate oxalate in the former being replaced by a nitrogen atom of a coordinated hydrazinium ion in the latter. The infrared absorption band at 1005 cm"-"1 confirms the coordination of N_2H_5"+ to the metal. These polyhedra are connected through μ"2 and μ"3 oxalate ions to form an anionic three-dimensional neodymium-oxalate arrangement. A non-coordinated charge-compensating hydrazinium ion occupies, with water molecules, the resulting tunnels. The N-N stretching frequencies of the infrared spectra demonstrate the existence of the two types of hydrazine ions. Thermal reactivity of these hydrazinium oxalates and of the mixed isotypic Ce/Nd (CeNd-H_yO_x) oxalate were studied by using thermogravimetric and differential thermal analyses coupled with gas analyzers, and high temperature X-ray diffraction. Under air, fine particles of CeO_2 and Ce_0_._5Nd_0_._5O_1_._7_5 are formed at low temperature from Ce-H_yO_x and CeNd-H_yO_x, respectively, thanks to a decomposition/oxidation process. Under argon flow, dioxy-mono-cyanamides Ln_2O_2CN_2 are formed. (authors)

Development of a method for the study of H{sub 2} gas emission in sealed compartments containing canister copper immersed in O{sub 2}-free water

Energy Technology Data Exchange (ETDEWEB)

Bengtsson, Andreas; Chukharkina, Alexandra; Eriksson, Lena; Hallbeck, Bjoern; Hallbeck, Lotta; Johansson, Jessica; Johansson, Linda; Pedersen, Karsten [Microbial Analytics Sweden AB, Moelnlycke (Sweden)

2013-06-15

Current models of copper corrosion indicate that copper is not subject to corrosion by water in itself, but that additional components, such as O{sub 2}, chloride or sulphide are needed to initiate a corrosive process. Of late however, a number of reports have suggested that copper may be susceptible to water-induced corrosion in the absence of external constituents affecting the process. The process has been proposed to rely the auto-ionization driven presence of the hydroxide ions in pure water, and to result in the development of atomic hydrogen (H), with subsequent release of H{sub 2} gas. A suggested equilibrium is reached at a partial pressure of H{sub 2} of about 1 mbar (0.1 kPa) in 73 deg C, and the corrosion reaction is proposed to be rate-limited by the supply of hydroxide ions from the water, a process being slower than proposed formation of water from a H{sub 2}-O{sub 2} reaction. In consequence, the presence of O{sub 2} in the system would result in no detectable release of H{sub 2} until all O{sub 2} was consumed, while the absence of O{sub 2} would lead to water-driven corrosion of copper proceeding until the H{sub 2} equilibrium is reached, at a partial H{sub 2} pressure of about 1 mbar. The proposed mechanism presents a novel aspect on copper corrosion processes. By extension, the suggested corrosion process may have implications for proposed strategies for long-term storage of spent nuclear fuel waste (SNF), which in part rely on the long-term (>105 years) integrity of copper canisters stored in anoxic water inundated environments (SKB 2010)

(Solid + liquid) phase equilibria of (Ca(H2PO2)2 + CaCl2 + H2O) and (Ca(H2PO2)2 + NaH2PO2 + H2O) ternary systems at T = 323.15 K

International Nuclear Information System (INIS)

Cao, Hong-yu; Zhou, Huan; Bai, Xiao-qin; Ma, Ruo-xin; Tan, Li-na; Wang, Jun-min

2016-01-01

Graphical abstract: Solubility diagram of the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system at T = (323.15 and 298.15) K. - Highlights: • Phase diagrams of Ca 2+ -H 2 PO 2 − -Cl − -H 2 O, Ca 2+ -Na + -H 2 PO 2 − -H 2 O at 323.15 K were obtained. • Incompatible double salt of NaCa(H 2 PO 2 ) 3 in Ca 2+ -Na + -H 2 PO 2 − -H 2 O system was determined. • Density diagram of the corresponding liquid were simultaneously measured. - Abstract: Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) and (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) ternary systems at T = 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl 2 ·2H 2 O and Ca(H 2 PO 2 ) 2 exist in the (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) system, and three salts of Ca(H 2 PO 2 ) 2 , NaH 2 PO 2 ·H 2 O and one incompatible double salt, NaCa(H 2 PO 2 ) 3 occur in the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system.

H2O masers in star-forming regions

International Nuclear Information System (INIS)

Downes, D.

1985-01-01

Water vapour near star forming regions was first detected by Cheung et al. (1969) and shortly thereafter was recognised to be maser emission. In spite of this 15 year history of H 2 O observations, the problem of interpreting such strong H 2 O masers as W49 and Orion is still very acute. Not one of the models now available can explain in an unconstrained fashion why a very large maser flux can emanate from clouds of such small size. Whereas some models proposed to explain OH masers have retained their plausibility under the pressure of new observations, H 2 O models have not. The author outlines the background of the H 2 O problem, stating that the strongest of the masers discovered are still not satisfactorily explained today. (Auth.)

Chemical kinetics in H{sub 2}O and D{sub 2}O under hydrothermal conditions

Energy Technology Data Exchange (ETDEWEB)

Ghandi, K.; Alcorn, C.D.; Legate, G. [Mount Allison Univ., Sackville, New Brunswick (Canada); Percival, P.W.; Brodovitch, J.-C. [Simon Fraser Univ., Burnaby, British Columbia (Canada)

2010-07-01

Muonium (Mu = μ{sup +}e{sup -}) is a light analogue of the H-atom. Studies of Mu chemical kinetics have been extended to supercritical water, a medium in some designs of future generation nuclear reactors. The Supercritical-Water-Cooled Reactor (SCWR) would operate at higher temperatures than current pressurized water-cooled reactors, and the lack of knowledge of water radiolysis under supercritical conditions constitutes a technology gap for SCWR development. Accurate modeling of chemistry in a SCWR requires data on kinetics of reactions involved in the radiolysis of water. In this paper, we first review our measurements of kinetics in H{sub 2}O and then describe new data for D{sub 2}O under sub- and supercritical conditions. (author)

Determination of the δ2H and δ18O of soil water and water in plant matter; RSIL lab code 1700

Science.gov (United States)

Revesz, Kinga M.; Buck, Bryan; Coplen, Tyler B.

2012-01-01

The purpose of the Reston Stable Isotope Laboratory lab code 1700 is to determine the δ2H/1H), abbreviated as δ2H, and the δ18O/16O), abbreviated as δ18O, of soil water and water in plant matter. This method is based on the observation that water and toluene form an azeotropic mixture at 84.1 °C. This temperature is substantially lower than the boiling points of water (100 °C) and toluene (110 °C), but water and toluene are immiscible at ambient temperature. The water content of a soil or plant is determined by weighing, drying, and reweighing a small amount of sample. Sufficient sample to collect 3 to 5 milliliters of water after distillation is loaded into a distillation flask. Sufficient toluene is added so that the sample is immersed throughout the entire distillation to minimize evaporation of water, which would affect the δ2H and δ18O values. The mixture of sample and toluene is heated in a flask to its boiling point (84.1 °C) so that water from the sample and toluene can distill together into a specially designed collection funnel. The temperature of 84.1 °C is maintained until the water has been quantitatively transferred to the collection funnel, at which time the temperature is raised to the boiling point of the remaining component (toluene, 110 °C). The collection funnel is maintained at ambient temperature so that the sample water and toluene can be separated physically. After separation, the sample water is purified by addition of paraffin wax to the container with the sample water, capping the container, and heating to approximately 60 °C to melt the wax. Trace amounts of toluene will dissolve in the wax, purifying the sample water for isotopic analysis. The isotopic composition of the purified water is then determined by equilibration with gaseous hydrogen or carbon dioxide, followed by dual-inlet isotope-ratio mass spectrometry. Because laser-absorption spectrometry is sensitive to organic compounds, such as trace toluene remaining in

Reduction in soil N2O emissions by pH manipulation and enhanced nosZ gene transcription under different water regimes.

Science.gov (United States)

Shaaban, Muhammad; Wu, Yupeng; Khalid, Muhammad Salman; Peng, Qi-An; Xu, Xiangyu; Wu, Lei; Younas, Aneela; Bashir, Saqib; Mo, Yongliang; Lin, Shan; Zafar-Ul-Hye, Muhammad; Abid, Muhammad; Hu, Ronggui

2018-04-01

Several studies have been carried out to examine nitrous oxide (N 2 O) emissions from agricultural soils in the past. However, the emissions of N 2 O particularly during amelioration of acidic soils have been rarely studied. We carried out the present study using a rice-rapeseed rotation soil (pH 5.44) that was amended with dolomite (0, 1 and 2 g kg -1 soil) under 60% water filled pore space (WFPS) and flooding. N 2 O emissions and several soil properties (pH, NH 4 + N, NO 3 - -N, and nosZ gene transcripts) were measured throughout the study. The increase in soil pH with dolomite application triggered soil N transformation and transcripts of nosZ gene controlling N 2 O emissions under both water regimes (60% WFPS and flooding). The 60% WFPS produced higher soil N 2 O emissions than that of flooding, and dolomite largely reduced N 2 O emissions at higher pH under both water regimes through enhanced transcription of nosZ gene. The results suggest that ameliorating soil acidity with dolomite can substantially mitigate N 2 O emissions through promoting nosZ gene transcription. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of Nitrate by Zero Valent Iron in the Presence of H2O2

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M.R. Samarghandi

2014-01-01

Full Text Available Background & Aims: Nitrate is the oxidation state of nitrogen compounds, which is founded in water resources that contaminated by municipal, industrial and agricultural waste water. If nitrate leek in to ground water resources, it can cause health problems. Material and Methods: Removal of nitrate from ground water by iron powder in the presence of H2O2 was investigated. Experiments have been done by use of 250 ml of water samples containing 100 mg/L nitrate in various condition. Various parameters such as pH (3, 5, 7, 9, iron dosage (10, 15, 20, 30 g/L, initial H2O2 concentration (5, 10, 15, 20 ml/L and contact time (10-120 min. Results: Obtained results shows the removal of nitrate was increased by pH reduction, increment of iron mass and contact time. In addition, nitrate reduction was increased by increment of initial H2O2 concentration up to 15 ml/L. High removal was observed at pH=3, iron mass=30 g/L, contact time equal 120 min and H2O2 concentration=15 ml/L. At above condition, upon 98% of nitrate was removed. Conclusion: In summary, this method is simple, low cost and effective for removal of nitrate from ground water and industrial activity.

Characterization of a real time H2O2 monitor for use in studies on H2O2 production by antibodies and cells.

Science.gov (United States)

Sharma, Harish A; Balcavage, Walter X; Waite, Lee R; Johnson, Mary T; Nindl, Gabi

2003-01-01

It was recently shown that antibodies catalyze a reaction between water and ultraviolet light (UV) creating singlet oxygen and ultimately H2O2. Although the in vivo relevance of these antibody reactions is unclear, it is interesting that among a wide variety of non-antibody proteins tested, the T cell receptor is the only protein with similar capabilities. In clinical settings UV is believed to exert therapeutic effects by eliminating inflammatory epidermal T cells and we hypothesized that UV-triggered H2O2 production is involved in this process. To test the hypothesis we developed tools to study production of H2O2 by T cell receptors with the long-term goal of understanding, and improving, UV phototherapy. Here, we report the development of an inexpensive, real time H2O2 monitoring system having broad applicability. The detector is a Clark oxygen electrode (Pt, Ag/AgCl) modified to detect UV-driven H2O2 production. Modifications include painting the electrode black to minimize UV effects on the Ag/AgCl electrode and the use of hydrophilic, large pore Gelnots electrode membranes. Electrode current was converted to voltage and then amplified and recorded using a digital multimeter coupled to a PC. A reaction vessel with a quartz window was developed to maintain constant temperature while permitting UV irradiation of the samples. The sensitivity and specificity of the system and its use in cell-free and cell-based assays will be presented. In a cellfree system, production of H2O2 by CD3 antibodies was confirmed using our real time H2O2 monitoring method. Additionally we report the finding that splenocytes and Jurkat T cells also produce H2O2 when exposed to UV light.

Removal of arsenic from water by Friedel's salt (FS: 3CaO·Al2O3·CaCl2·10H2O).

Science.gov (United States)

Zhang, Danni; Jia, Yongfeng; Ma, Jiayu; Li, Zhibao

2011-11-15

Low levels of arsenic can be effectively removed from water by adsorption onto various materials and searching for low-cost, high-efficiency new adsorbents has been a hot topic in recent years. In the present study, the performance of Friedel's salt (FS: 3CaO·Al(2)O(3)·CaCl(2)·10H(2)O), a layered double hydroxide (LDHs), as an adsorbent for arsenic removal from aqueous solution was investigated. Friedel's salt was synthesized at lower temperature (50°C) compared to traditional autoclave methods by reaction of calcium chloride with sodium aluminate. Kinetic study revealed that adsorption of arsenate by Friedel's salt was fast in the first 12h and equilibrium was achieved within 48 h. The adsorption kinetics are well described by second-order Lageren equation. The adsorption capacity of the synthesized sorbent for arsenate at pH 4 and 7 calculated from Langmuir adsorption isotherms was 11.85 and 7.80 mg/g, respectively. Phosphate and silicate markedly decreased the removal of arsenate, especially at higher pH, but sulfate was found to suppress arsenate adsorption at lower pH and the adverse effect was disappeared at pH ≥ 6. Common metal cations (Ca(2+), Mg(2+)) enhanced arsenate adsorption. The results suggest that Friedel's salt is a potential cost-effective adsorbent for arsenate removal in water treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

Relationship between interlayer hydration and photocatalytic water splitting of A'1-xNaxCa2Ta3O10.nH2O (A'=K and Li)

International Nuclear Information System (INIS)

Mitsuyama, Tomohiro; Tsutsumi, Akiko; Sato, Sakiko; Ikeue, Keita; Machida, Masato

2008-01-01

Partial replacement of alkaline metals in anhydrous KCa 2 Ta 3 O 10 and LiCa 2 Ta 3 O 10 was studied to control interlayer hydration and photocatalytic activity for water splitting under UV irradiation. A' 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O (A'=K and Li) samples were synthesized by ion exchange of CsCa 2 Ta 3 O 10 in mixed molten nitrates at 400 deg. C. In K 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O, two phases with the orthorhombic (C222) and tetragonal (I4/mmm) structures were formed at x≤0.7 and x≥0.5, respectively. Upon replacement by Na + having a larger enthalpy of hydration (ΔH h 0 ), the interlayer hydration occurred at x≥0.3 and the hydration number (n) was increased monotonically with an increase of x. Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O showed a similar hydration behavior, but the phase was changed from I4/mmm (x 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity increasing in consistent with n, whereas Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity maximum at x=0.77, where the rates of H 2 /O 2 evolution were nearly doubled compared with those for end-member compositions (x=0 and 1). - Graphical abstract: The partial substitution of Na in the interlayer of anhydrous-layered perovskite has been found as useful structural modification toward highly active hydrated photocatalysts

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

Removal of Organic Dyes from Industrial Wastewaters Using UV/H2O2, UV/H2O2/Fe (II, UV/H2O2/Fe (III Processes

Directory of Open Access Journals (Sweden)

Nezamaddin Daneshvar

2007-03-01

Full Text Available UV/H2O2, UV/H2O2/Fe (II and UV/H2O2/Fe (III processes are very effective in removing pollutants from wastewater and can be used for treatment of dyestuff units wastewaters. In this study, Rhodamine B was used as a typical organic dye. Rhodamine B has found wide applications in wax, leather, and paper industries. The results from this study showed that this dye was degradable in the presence of hydrogen peroxide under UV-C irradiation (30W mercury light and Photo-Fenton process. The dye was resistant to UV irradiation. In the absence of UV irradiation, the decolorization efficiency was very negligible in the presence of hydrogen. The effects of different system variables such as initial dye concentration, duration of UV irradiation, and initial hydrogen peroxide concentration were investigated in the UV/H2O2 process. Investigation of the kinetics of the UV/H2O2 process showed that the semi-log plot of the dye concentration versus time was linear, suggesting a first order reaction. It was found that Rhodamine B decolorization efficiencies in the UV/H2O2/Fe (II and UV/H2O2/Fe (III processes were higher than that in the UV/H2O2 process. Furthermore, a solution containing 20 ppm of Rhodamine B was decolorized in the presence 18 mM of H2O2 under UV irradiation for 15 minutes. It was also found that addition of 0.1 mM Fe(II or Fe(III to the solution containing  20  ppm of the dye and 5 mM H2O2 under UV light  illumination decreased removal time to 10 min.

Vibrational spectroscopy of NO + (H2O)n: Evidence for the intracluster reaction NO + (H2O)n --> H3O + (H2O)n - 2 (HONO) at n => 4

Science.gov (United States)

Choi, Jong-Ho; Kuwata, Keith T.; Haas, Bernd-Michael; Cao, Yibin; Johnson, Matthew S.; Okumura, Mitchio

1994-05-01

Infrared spectra of mass-selected clusters NO+(H2O)n for n=1 to 5 were recorded from 2700 to 3800 cm-1 by vibrational predissociation spectroscopy. Vibrational frequencies and intensities were also calculated for n=1 and 2 at the second-order Møller-Plesset (MP2) level, to aid in the interpretation of the spectra, and at the singles and doubles coupled cluster (CCSD) level energies of n=1 isomers were computed at the MP2 geometries. The smaller clusters (n=1 to 3) were complexes of H2O ligands bound to a nitrosonium ion NO+ core. They possessed perturbed H2O stretch bands and dissociated by loss of H2O. The H2O antisymmetric stretch was absent in n=1 and gradually increased in intensity with n. In the n=4 clusters, we found evidence for the beginning of a second solvation shell as well as the onset of an intracluster reaction that formed HONO. These clusters exhibited additional weak, broad bands between 3200 and 3400 cm-1 and two new minor photodissociation channels, loss of HONO and loss of two H2O molecules. The reaction appeared to go to completion within the n=5 clusters. The primary dissociation channel was loss of HONO, and seven vibrational bands were observed. From an analysis of the spectrum, we concluded that the n=5 cluster rearranged to form H3O+(H2O)3(HONO), i.e., an adduct of the reaction products.

Validation of the doubly-labeled water (H3H18O) method for measuring water flux and energy metabolism in tenebrionid beetles

International Nuclear Information System (INIS)

Cooper, P.D.

1981-01-01

Doubly-labeled water (H 3 H 18 O) has been used to determine water flux and energy metabolism in a variety of vertebrates. This study examines the applicability of this technique to arthropods. The theory of the technique depends upon the assumption that doubly-labeled water introduced into the animal's body water equilibrates with water and carbon dioxide by the action of carbonic anhydrase. Tritium ( 3 H) is lost from the animal only with water while oxygen-18 is lost with both water and carbon dioxide. The difference bwtween the rates of loss of the two isotopes is proportional to CO 2 loss rate. Validation of the use of tritiated water for measuring water flux was accomplished by comparing gravimetric measurements of water gain with flux rates determined by loss of tritiated water. At room humidity, an overestimate for influx calculated from labeled water calculations was found, averaging 12 mg H 2 O (g.d) -1 . Comparison of CO 2 loss rate determined isotopically with rates of CO 2 loss determined by standard metabolic rates also yielded overestimates for the isotopic technique, overestimates ranging between 20 and 30%. The relevance of this for studies using labeled water for studying water fluxes and free metabolism of free-ranging arthropods is discussed

Photodegradation and toxicity changes of antibiotics in UV and UV/H2O2 process

International Nuclear Information System (INIS)

Yuan Fang; Hu Chun; Hu Xuexiang; Wei Dongbin; Chen Yong; Qu Jiuhui

2011-01-01

The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H 2 O 2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H 2 O 2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV , defined as the experimentally determined ·OH radical exposure per UV fluence. The R OH,UV values represent the background ·OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H 2 O 2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H 2 O 2 process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H 2 O 2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of ·OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H 2 O 2 process would be determined by parent compound degradation and toxicity changes.

Effects of variation in background mixing ratios of N2, O2, and Ar on the measurement of δ18O-H2O and δ2H-H2O values by cavity ring-down spectroscopy

Science.gov (United States)

Johnson, Jennifer E.; Rella, Chris W.

2017-08-01

Cavity ring-down spectrometers have generally been designed to operate under conditions in which the background gas has a constant composition. However, there are a number of observational and experimental situations of interest in which the background gas has a variable composition. In this study, we examine the effect of background gas composition on a cavity ring-down spectrometer that measures δ18O-H2O and δ2H-H2O values based on the amplitude of water isotopologue absorption features around 7184 cm-1 (L2120-i, Picarro, Inc.). For background mixtures balanced with N2, the apparent δ18O values deviate from true values by -0.50 ± 0.001 ‰ O2 %-1 and -0.57 ± 0.001 ‰ Ar %-1, and apparent δ2H values deviate from true values by 0.26 ± 0.004 ‰ O2 %-1 and 0.42 ± 0.004 ‰ Ar %-1. The artifacts are the result of broadening, narrowing, and shifting of both the target absorption lines and strong neighboring lines. While the background-induced isotopic artifacts can largely be corrected with simple empirical or semi-mechanistic models, neither type of model is capable of completely correcting the isotopic artifacts to within the inherent instrument precision. The development of strategies for dynamically detecting and accommodating background variation in N2, O2, and/or Ar would facilitate the application of cavity ring-down spectrometers to a new class of observations and experiments.

An i.r. investigation on some calcium aluminate hydrates, Ca2Al(OH)6+X-.yH2O (= 3CaO.Al2O3.CaX2.nH2O, X- = univalent anion)

NARCIS (Netherlands)

Houtepen, C.J.M.; Stein, H.N.

1976-01-01

The i.r. spectra of some hydrated and dehydrated calcium aluminate hydrates of the type Ca2Al(OH)6+X-·yH2O with X- = Cl-, Br-, J-, ClO3-, NO3-, ClO4- (y = 2) and X- = BrO3-, JO3- (2 water with the anions

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

Perspective: A controversial benchmark system for water-oxide interfaces: H2O/TiO2(110)

Science.gov (United States)

Diebold, Ulrike

2017-07-01

The interaction of water with the single-crystalline rutile TiO2(110) surface has been the object of intense investigations with both experimental and computational methods. Not only is TiO2(110) widely considered the prototypical oxide surface, its interaction with water is also important in many applications where this material is used. At first, experimental measurements were hampered by the fact that preparation recipes for well-controlled surfaces had yet to be developed, but clear experimental evidence that water dissociation at defects including oxygen vacancies and steps emerged. For a perfect TiO2(110) surface, however, an intense debate has evolved whether or not water adsorbs as an intact molecule or if it dissociates by donating a proton to a so-called bridge-bonded surface oxygen atom. Computational studies agree that the energy difference between these two states is very small and thus depends sensitively on the computational setup and on the approximations used in density functional theory (DFT). While a recent molecular beam/STM experiment [Z.-T. Wang et al., Proc. Natl. Acad. Sci. U. S. A. 114(8), 1801-1805 (2017)] gives conclusive evidence for a slight preference (0.035 eV) for molecular water and a small activation energy of (0.36 eV) for dissociation, understanding the interface between liquid water and TiO2(110) arises as the next controversial frontier.

Inhibitory Effect of Dissolved Silica on the H2O2 Decomposition by Iron(III) and Manganese(IV) Oxides: Implications for H2O2-based In Situ Chemical Oxidation

Science.gov (United States)

Pham, Anh Le-Tuan; Doyle, Fiona M.; Sedlak, David L.

2011-01-01

The decomposition of H2O2 on iron minerals can generate •OH, a strong oxidant that can transform a wide range of contaminants. This reaction is critical to In Situ Chemical Oxidation (ISCO) processes used for soil and groundwater remediation, as well as advanced oxidation processes employed in waste treatment systems. The presence of dissolved silica at concentrations comparable to those encountered in natural waters decreases the reactivity of iron minerals toward H2O2, because silica adsorbs onto the surface of iron minerals and alters catalytic sites. At circumneutral pH values, goethite, amorphous iron oxide, hematite, iron-coated sand and montmorillonite that were pre-equilibrated with 0.05 – 1.5 mM SiO2 were significantly less reactive toward H2O2 decomposition than their original counterparts, with the H2O2 loss rates inversely proportional to the SiO2 concentration. In the goethite/H2O2 system, the overall •OH yield, defined as the percentage of decomposed H2O2 producing •OH, was almost halved in the presence of 1.5 mM SiO2. Dissolved SiO2 also slows the H2O2 decomposition on manganese(IV) oxide. The presence of dissolved SiO2 results in greater persistence of H2O2 in groundwater, lower H2O2 utilization efficiency and should be considered in the design of H2O2-based treatment systems. PMID:22129132

Composite photocatalyst containing Eosin Y and multiwalled carbon nanotubes loaded with CuO/NiO: Mixed metal oxide as an active center of H2 evolution from water

International Nuclear Information System (INIS)

Kang Shizhao; Chen Lili; Li Xiangqing; Mu Jin

2012-01-01

A composite photocatalyst containing Eosin Y as a sensitizer, multiwalled carbon nanotubes as a supporter material or electron transfer channel, and CuO/NiO as an active center of H 2 evolution from water was fabricated and characterized with X-ray photoelectron spectroscopy and transmission electron microscope. Meanwhile, photocatalytic hydrogen evolution from water over this catalyst was explored using triethanolamine as a sacrificial reagent under visible irradiation. A rate of H 2 evolution of approximately 1.0 mmol g -1 h -1 was achieved under optimal conditions. Furthermore, for practical purposes, the photocatalytic hydrogen evolution was studied as a function of content of CuO/NiO, mass ratio of CuO to NiO, pH of solution, concentration of triethanolamine and dosage of Eosin Y, respectively. The results show that mixed metal oxides are a kind of promising active centers of H 2 evolution from water in the photocatalytic system studied.

Composite photocatalyst containing Eosin Y and multiwalled carbon nanotubes loaded with CuO/NiO: Mixed metal oxide as an active center of H2 evolution from water

Science.gov (United States)

Kang, Shi-Zhao; Chen, Lili; Li, Xiangqing; Mu, Jin

2012-06-01

A composite photocatalyst containing Eosin Y as a sensitizer, multiwalled carbon nanotubes as a supporter material or electron transfer channel, and CuO/NiO as an active center of H2 evolution from water was fabricated and characterized with X-ray photoelectron spectroscopy and transmission electron microscope. Meanwhile, photocatalytic hydrogen evolution from water over this catalyst was explored using triethanolamine as a sacrificial reagent under visible irradiation. A rate of H2 evolution of approximately 1.0 mmol g-1 h-1 was achieved under optimal conditions. Furthermore, for practical purposes, the photocatalytic hydrogen evolution was studied as a function of content of CuO/NiO, mass ratio of CuO to NiO, pH of solution, concentration of triethanolamine and dosage of Eosin Y, respectively. The results show that mixed metal oxides are a kind of promising active centers of H2 evolution from water in the photocatalytic system studied.

Treatment of hospital laundry wastewater by UV/H2O2 process.

Science.gov (United States)

Zotesso, Jaqueline Pirão; Cossich, Eneida Sala; Janeiro, Vanderly; Tavares, Célia Regina Granhen

2017-03-01

Hospitals consume a large volume of water to carry out their activities and, hence, generate a large volume of effluent that is commonly discharged into the local sewage system without any treatment. Among the various sectors of healthcare facilities, the laundry is responsible for the majority of water consumption and generates a highly complex effluent. Although several advanced oxidation processes (AOPs) are currently under investigation on the degradation of a variety of contaminants, few of them are based on real wastewater samples. In this paper, the UV/H 2 O 2 AOP was evaluated on the treatment of a hospital laundry wastewater, after the application of a physicochemical pretreatment composed of coagulation-flocculation and anthracite filtration. For the UV/H 2 O 2 process, a photoreactor equipped with a low-pressure UV-C lamp was used and the effects of initial pH and [H 2 O 2 ]/chemical oxygen demand (COD) ratio on COD removal were investigated through a randomized factorial block design that considered the batches of effluent as blocks. The results indicated that the initial pH had no significant effect on the COD removal, and the process was favored by the increase in [H 2 O 2 ]/COD ratio. Color and turbidity were satisfactorily reduced after the application of the physicochemical pretreatment, and COD was completely removed by the UV/H 2 O 2 process under suitable conditions. The results of this study show that the UV/H 2 O 2 AOP is a promising candidate for hospital laundry wastewater treatment and should be explored to enable wastewater reuse in the washing process.

The Enhancement of H2O2/UV AOPs for the Removal of Selected Organic Pollutants from Drinking Water with Hydrodynamic Cavitation.

Science.gov (United States)

Čehovin, Matej; Medic, Alojz; Kompare, Boris; Žgajnar Gotvajn, Andreja

2016-12-01

Drinking water contains organic matter that occasionally needs to be treated to assure its sufficient quality and safety for the consumers. H2O2 and UV advanced oxidation processes (H2O2/UV AOPs) were combined with hydrodynamic cavitation (HC) to assess the effects on the removal of selected organic pollutants. Water samples containing humic acid, methylene blue dye and micropollutants (metaldehyde, diatrizoic acid, iohexol) were treated first by H2O2 (dosages from 1 to 12 mg L-1) and UV (dosages from 300 to 2800 mJ cm-2) AOPs alone and later in combination with HC, generated by nozzles and orifice plates (4, 8, 18 orifices). Using HC, the removal of humic acid was enhanced by 5-15%, methylene blue by 5-20% and metaldehyde by approx. 10%. Under favouring conditions, i.e. high UV absorbance of the matrix (more than 0.050 cm-1 at a wavelength of 254 nm) and a high pollutant to oxidants ratio, HC was found to improve the hydrodynamic conditions in the photolytic reactor, to improve the subjection of the H2O2 to the UV fluence rate distribution and to enhance the removal of the tested organic pollutants, thus showing promising potential of further research in this field.

Study of the reversible water vapour sorption process of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub 2}O under the conditions of seasonal solar heat storage

Energy Technology Data Exchange (ETDEWEB)

Ferchaud, C.J.; De Boer, R. [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands); Zondag, H.A.; Veldhuis, J.B.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2012-08-15

The characterization of the structural, compositional and thermodynamic properties of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub O} has been done for seasonal heat storage using in-situ X-ray Diffraction and thermal analyses (TG/DSC) under practical conditions for seasonal heat storage (T{sub max} = 150C, p(H{sub 2}O)=13 mbar). This study showed that these two materials release heat after a dehydration/hydration cycle with energy densities of 0.38 GJ/m{sup 3} for MgSO{sub 4}.7H{sub 2}O and 0.71 GJ/m{sup 3} MgCl{sub 2}.6H{sub 2}O. The low heat release found for MgSO{sub 4}.7H2O is mainly attributed to the amorphization of the material during the dehydration performed at 13 mbar which reduces its sorption capacity during the rehydration. MgCl{sub 2}.6H{sub 2}O presents a high energy density which makes this material interesting for the seasonal heat storage in domestic applications. This material would be able to fulfil the winter heat demand of a passive house estimated at 6 GJ with a packed bed reactor of 8.5 m{sup 3}. However, a seasonal heat storage system based on the water vapour sorption process in MgCl{sub 2}.6H{sub 2}O should be carefully set with a restricted temperature of 40C for the hydration reaction to avoid the liquefaction of the material at ambient temperature which limits its performances for long term storage.

Synthetic, spectroscopic and structural studies on 4-aminobenzoate complexes of divalent alkaline earth metals: x-ray crystal structures of [[Mg(H2O)6] (4-aba)2].2H2O and [Ca(H2O)2(4-aba)2] (4-aba=4-aminobenzoate)

International Nuclear Information System (INIS)

Murugavel, Ramaswamy; Karambelkar, Vivek V.; Anantharaman, Ganapathi

2000-01-01

Reactions between MCl 2 .nH 2 O (M = Mg, Ca, Sr, and Ba) and 4-aminobenzoic acid (4-abaH) result in the formation of complexes [(Mg(H 2 O) 6 )(4-aba) 2 ) .2H 2 O (I), [Ca(4-aba) 2 (H2 O ) 2 ] (2), [Sr(4-aba) 2 (H2 O ) 2 ] (3), and [Ba(4-aba) 2 Cl] (4), respectively. The new compounds 1 and 2, as well as the previously reported 3 and 4 form an extended intra- and intermolecular hydrogen bonded network in the solid-state. The compounds have been characterized by elemental analysis, pH measurements, thermogravimetric studies, and IR, NMR, and UV-Vis spectroscopy. The solid state structures of the molecules 1 and 2 have been determined by single crystal x-ray diffraction studies. In the case of magnesium complex 1, the dipositively charged Mg cation is surrounded by six water molecules and the two 4-aminobenzoate ligands show no direct bonding to the metal ion. The calcium ion in 2 is octa-coordinated with direct coordination of the 4-aminobenzoate ligands to the metal ion. The Ca-Ca separation in the polymeric chain of 2 is 3.9047(5) A. (author)

Synthesis of Nanoscale CaO-Al2O3-SiO2-H2O and Na2O-Al2O3-SiO2-H2O Using the Hydrothermal Method and Their Characterization

Directory of Open Access Journals (Sweden)

Jingbin Yang

2017-06-01

Full Text Available C-A-S-H (CaO-Al2O3-SiO2-H2O and N-A-S-H (Na2O-Al2O3-SiO2-H2O have a wide range of chemical compositions and structures and are difficult to separate from alkali-activated materials. Therefore, it is difficult to analyze their microscopic properties directly. This paper reports research on the synthesis of C-A-S-H and N-A-S-H particles with an average particle size smaller than 300 nm by applying the hydrothermal method. The composition and microstructure of the products with different CaO(Na2O/SiO2 ratios and curing conditions were characterized using XRD, the RIR method, FTIR, SEM, TEM, and laser particle size analysis. The results showed that the C-A-S-H system products with a low CaO/SiO2 ratio were mainly amorphous C-A-S-H gels. With an increase in the CaO/SiO2 ratio, an excess of Ca(OH2 was observed at room temperature, while in a high-temperature reaction system, katoite, C4AcH11, and other crystallized products were observed. The katoite content was related to the curing temperature and the content of Ca(OH2 and it tended to form at a high-temperature and high-calcium environment, and an increase in the temperature renders the C-A-S-H gels more compact. The main products of the N-A-S-H system at room temperature were amorphous N-A-S-H gels and a small amount of sodalite. An increase in the curing temperature promoted the formation of the crystalline products faujasite and zeolite-P. The crystallization products consisted of only zeolite-P in the high-temperature N-A-S-H system and its content were stable above 70%. An increase in the Na2O/SiO2 ratio resulted in more non-bridging oxygen and the TO4 was more isolated in the N-A-S-H structure. The composition and microstructure of the C-A-S-H and N-A-S-H system products synthesized by the hydrothermal method were closely related to the ratio of the raw materials and the curing conditions. The results of this study increase our understanding of the hydration products of alkali

Thermal decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O: Influence on structure, microstructure and hydrofluorination

Energy Technology Data Exchange (ETDEWEB)

Thomas, R. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Rivenet, M., E-mail: murielle.rivenet@ensc-lille.fr [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Berrier, E. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Waele, I. de [Université de Lille, CNRS, UMR 8516 – LASIR - Laboratoire de Spectrochimie Infrarouge et Raman, F-59000 Lille (France); Arab, M.; Amaraggi, D.; Morel, B. [Hall de Recherche de Pierrelatte, AREVA NC, BP 16, 26701 Pierrelatte (France); Abraham, F. [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille (France)

2017-01-15

The thermal decomposition of uranyl peroxide tetrahydrate, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}.2H{sub 2}O, was studied by combining high temperature powder X-ray diffraction, scanning electron microscopy, thermal analyses and spectroscopic techniques (Raman, IR and {sup 1}H NMR). In situ analyses reveal that intermediates and final uranium oxides obtained upon heating are different from that obtained after cooling at room temperature and that the uranyl precursor used to synthesize (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O, sulfate or nitrate, has a strong influence on the peroxide thermal behavior and morphology. The decomposition of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O ex sulfate is pseudomorphic and leads to needle-like shaped particles of metastudtite, (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}, and UO{sub 3-x}(OH){sub 2x}·zH{sub 2}O, an amorphous phase found in air in the following of (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2} dehydration. (UO{sub 2})O{sub 2}(H{sub 2}O){sub 2}·2H{sub 2}O and the compounds resulting from its thermal decomposition are very reactive towards hydrofluorination as long as their needle-like morphology is kept.

Systems Li2B4O7 (Na2B4O7, K2B4O7)-N2H3H4OH-H2O at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Sadetdinov, Sh.V.; Akimov, V.M.; Mitrasov, Yu.N.; Petrova, O.V.; Klopov, Yu.N.

1994-01-01

Phase equilibriums in the Li 2 B 4 O 7 (Na 2 B 4 O 7 , K 2 B 4 O 7 )-N 2 H 3 H 4 OH-H 2 O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM 2 B 4 O 7 ·nN 2 H 3 C 2 H 4 OH·XH 2 O, where M=Li, Na with hydrazine ethanol. K 2 B 4 O 7 ·4H 2 O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods

H2O sources in regions of star formation

International Nuclear Information System (INIS)

Lo, K.Y.; Burke, B.F.; Haschick, A.D.

1975-01-01

Regions and objects believed to be in early stages of stellar formation have been searched for H 2 O 22-GHz line emission with the Haystack 120-foot (37 m) telescope. The objects include radio condensations, infrared objects in H ii regions, and Herbig-Haro objects. Nine new H 2 O sources were detected in the vicinity of such objects, including the Sharpless H ii regions S152, S235, S255, S269, G45.1+0.1, G45.5+0.1, AFCRL infrared object No. 809--2992, and Herbig-Haro objects 1 and 9. The new H 2 O sources detected in H ii regions are associated, but not coincident, with the the radio condensations. Water vapor line emission was detected in approx.25 percent of the regions searched. The association of H 2 O sources with regions of star formation is taken to be real. The spatial relationship of H 2 O sources to infrared objects, radio condensations, class I OH sources, and molecular clouds are discussed. The suggestion is made that an H 2 O source may be excited by a highly obscured star of extreme youth

Tracing groundwater recharge sources in the northwestern Indian alluvial aquifer using water isotopes (δ18O, δ2H and 3H)

Science.gov (United States)

Joshi, Suneel Kumar; Rai, Shive Prakash; Sinha, Rajiv; Gupta, Sanjeev; Densmore, Alexander Logan; Rawat, Yadhvir Singh; Shekhar, Shashank

2018-04-01

Rapid groundwater depletion from the northwestern Indian aquifer system in the western Indo-Gangetic basin has raised serious concerns over the sustainability of groundwater and the livelihoods that depend on it. Sustainable management of this aquifer system requires that we understand the sources and rates of groundwater recharge, however, both these parameters are poorly constrained in this region. Here we analyse the isotopic (δ18O, δ2H and tritium) compositions of groundwater, precipitation, river and canal water to identify the recharge sources, zones of recharge, and groundwater flow in the Ghaggar River basin, which lies between the Himalayan-fed Yamuna and Sutlej River systems in northwestern India. Our results reveal that local precipitation is the main source of groundwater recharge. However, depleted δ18O and δ2H signatures at some sites indicate recharge from canal seepage and irrigation return flow. The spatial variability of δ18O, δ2H, d-excess, and tritium reflects limited lateral connectivity due to the heterogeneous and anisotropic nature of the aquifer system in the study area. The variation of tritium concentration with depth suggests that groundwater above c. 80 mbgl is generally modern water. In contrast, water from below c. 80 mbgl is a mixture of modern and old waters, and indicates longer residence time in comparison to groundwater above c. 80 mbgl. Isotopic signatures of δ18O, δ2H and tritium suggest significant vertical recharge down to a depth of 320 mbgl. The spatial and vertical variations of isotopic signature of groundwater reveal two distinct flow patterns in the aquifer system: (i) local flow (above c. 80 mbgl) throughout the study area, and (ii) intermediate and regional flow (below c. 80 mbgl), where water recharges aquifers through large-scale lateral flow as well as vertical infiltration. The understanding of spatial and vertical recharge processes of groundwater in the study area provides important base-line knowledge

Binding water to a PEG-linked flexible bichromophore: IR spectra of diphenoxyethane-(H{sub 2}O){sub n} clusters, n = 2-4

Energy Technology Data Exchange (ETDEWEB)

Walsh, Patrick S.; Buchanan, Evan G.; Gord, Joseph R.; Zwier, Timothy S., E-mail: zwier@purdue.edu [Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084 (United States)

2015-04-21

The single-conformation infrared (IR) and ultraviolet (UV) spectroscopies of neutral 1,2-diphenoxyethane-(H{sub 2}O){sub n} clusters with n = 2-4 (labeled henceforth as 1:n) have been studied in a molecular beam using a combination of resonant two-photon ionization, IR-UV holeburning, and resonant ion-dip infrared (RIDIR) spectroscopies. Ground state RIDIR spectra in the OH and CH stretch regions were used to provide firm assignments for the structures of the clusters by comparing the experimental spectra with the predictions of calculations carried out at the density functional M05-2X/6-31+G(d) level of theory. At all sizes in this range, the water molecules form water clusters in which all water molecules engage in a single H-bonded network. Selective binding to the tgt monomer conformer of 1,2-diphenoxyethane (C{sub 6}H{sub 5}-O-CH{sub 2}-CH{sub 2}-O-C{sub 6}H{sub 5}, DPOE) occurs, since this conformer provides a binding pocket in which the two ether oxygens and two phenyl ring π clouds can be involved in stabilizing the water cluster. The 1:2 cluster incorporates a water dimer “chain” bound to DPOE much as it is in the 1:1 complex [E. G. Buchanan et al., J. Phys. Chem. Lett. 4, 1644 (2013)], with primary attachment via a double-donor water that bridges the ether oxygen of one phenoxy group and the π cloud of the other. Two conformers of the 1:3 cluster are observed and characterized, one that extends the water chain to a third molecule (1:3 chain) and the other incorporating a water trimer cycle (1:3 cycle). A cyclic water structure is also observed for the 1:4 cluster. These structural characterizations provide a necessary foundation for studies of the perturbations imposed on the two close-lying S{sub 1}/S{sub 2} excited states of DPOE considered in the adjoining paper [P. S. Walsh et al., J. Chem. Phys. 142, 154304 (2015)].

Exploring H2O Prominence in Reflection Spectra of Cool Giant Planets

Science.gov (United States)

MacDonald, Ryan J.; Marley, Mark S.; Fortney, Jonathan J.; Lewis, Nikole K.

2018-05-01

The H2O abundance of a planetary atmosphere is a powerful indicator of formation conditions. Inferring H2O in the solar system giant planets is challenging, due to condensation depleting the upper atmosphere of water vapor. Substantially warmer hot Jupiter exoplanets readily allow detections of H2O via transmission spectroscopy, but such signatures are often diminished by the presence of clouds composed of other species. In contrast, highly scattering water clouds can brighten planets in reflected light, enhancing molecular signatures. Here, we present an extensive parameter space survey of the prominence of H2O absorption features in reflection spectra of cool (T eff clouds brighten the planet: T eff ∼ 150 K, g ≳ 20 ms‑2, f sed ≳ 3, m ≲ 10× solar. In contrast, planets with g ≲ 20 ms‑2 and T eff ≳ 180 K display substantially prominent H2O features embedded in the Rayleigh scattering slope from 0.4 to 0.73 μm over a wide parameter space. High f sed enhances H2O features around 0.94 μm, and enables these features to be detected at lower temperatures. High m results in dampened H2O absorption features, due to water vapor condensing to form bright, optically thick clouds that dominate the continuum. We verify these trends via self-consistent modeling of the low-gravity exoplanet HD 192310c, revealing that its reflection spectrum is expected to be dominated by H2O absorption from 0.4 to 0.73 μm for m ≲ 10× solar. Our results demonstrate that H2O is manifestly detectable in reflected light spectra of cool giant planets only marginally warmer than Jupiter, providing an avenue to directly constrain the C/O and O/H ratios of a hitherto unexplored population of exoplanetary atmospheres.

Supramolecular assemblies in [Cu(L-Arg){sub 2}(H{sub 2}O)]C{sub 2}O{sub 4}·6H{sub 2}O complex – Structural, spectroscopic, magnetic and thermal behavior

Energy Technology Data Exchange (ETDEWEB)

Wojciechowska, Agnieszka, E-mail: agnieszka.wojciechowska@pwr.edu.pl [Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, 50-370, Wrocław (Poland); Kochel, Andrzej [Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383, Wrocław (Poland); Duczmal, Marek [Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, 50-370, Wrocław (Poland)

2016-10-01

The reaction of L-arginine and oxalate ions with copper(II) salts yields a new complex with formula of [Cu(L-Arg){sub 2}(H{sub 2}O)]·C{sub 2}O{sub 4}·6H{sub 2}O (1) (where L-Arg = L-arginine). Single crystals of 1 were synthesized by crystallization from aqueous solution. The complex properties were characterized by X-ray diffraction, spectroscopy (FT-IR, FT-Raman, NIR-Vis-UV and EPR) as well as thermal and magnetic methods. The square pyramidal (SP) geometry around Cu(II) ions in [Cu(L-Arg){sub 2}(H{sub 2}O)]{sup 2+} cation complex is formed by two cis-chelated L-arginine zwitterions and a water molecule coordinated in the apex of square pyramid. The trigonality distortion of SP geometry is relatively small, τ = 0.0087. The solid state EPR spectrum showed broad hyperfine splitting with g{sub ⊥} = 2.061 at 77 K. The copper centres distanced at 7.558(5) Å are joined in a single zig-zag structure via a chain based on the combination of Cu−O(5)−H(29)⋯O(2)−C1−O1−Cu hydrogen bonds along the b axis (d (O2⋯O5) = 2.812 Å). Taking into account the structural features, the magnetic susceptibility data were best-fitted, giving the exchange parameter J = −0.16 cm{sup −1}. Complex 1 is thermally stable up to 66 °C, where it was observed to lose the crystallization water molecules with an 11.7% mass loss (calc. 11.5%). - Highlights: • Crystal and molecular structure of [Cu(L-Arg){sub 2}(H{sub 2}O)]C{sub 2}O{sub 4}·6H{sub 2}O crystals have been studied. • The magnetic interactions of Cu(II) centres are assisted by the formation of single zig-zag chain. • Role of oxalate ions in completed relatively small square pyramid distortion is described. • The cis-fashioned L-arginine created the stronger ligand field than trans-configuration.

Theoretical study of [Li(H2O)n]+ and [K(H2O)n]+ (n = 1-4) complexes

International Nuclear Information System (INIS)

Wojcik, M.J.; Mains, G.J.; Devlin, J.P.

1995-01-01

The geometries, successive binding energies, vibrational frequencies, and infrared intensities are calculated for the [Li(H 2 O) n ] + and [K(H 2 O) n ] + (n = 1-4) complexes. The basis sets used are 6-31G * and LANL1DZ (Los Alamos ECP+DZ) at the SCF and MP2 levels. There is an agreement for calculated structures and frequencies between the MP2/6-31G * and MP2/LANL1DZ basis sets, which indicates that the latter can be used for calculations of water complexes with heavier ions. Our results are in a reasonable agreement with available experimental data and facilitate experimental study of these complexes. 19 refs., 4 figs., 6 tabs

Oxyhydroxide of metallic nanowires in a molecular H2O and H2O2 environment and their effects on mechanical properties.

Science.gov (United States)

Aral, Gurcan; Islam, Md Mahbubul; Wang, Yun-Jiang; Ogata, Shigenobu; Duin, Adri C T van

2018-06-14

To avoid unexpected environmental mechanical failure, there is a strong need to fully understand the details of the oxidation process and intrinsic mechanical properties of reactive metallic iron (Fe) nanowires (NWs) under various aqueous reactive environmental conditions. Herein, we employed ReaxFF reactive molecular dynamics (MD) simulations to elucidate the oxidation of Fe NWs exposed to molecular water (H2O) and hydrogen peroxide (H2O2) environment, and the influence of the oxide shell layer on the tensile mechanical deformation properties of Fe NWs. Our structural analysis shows that oxidation of Fe NWs occurs with the formation of different iron oxide and hydroxide phases in the aqueous molecular H2O and H2O2 oxidizing environments. We observe that the resulting microstructure due to pre-oxide shell layer formation reduces the mechanical stress via increasing the initial defect sites in the vicinity of the oxide region to facilitate the onset of plastic deformation during tensile loading. Specifically, the oxide layer of Fe NWs formed in the H2O2 environment has a relatively significant effect on the deterioration of the mechanical properties of Fe NWs. The weakening of the yield stress and Young modulus of H2O2 oxidized Fe NWs indicates the important role of local oxide microstructures on mechanical deformation properties of individual Fe NWs. Notably, deformation twinning is found as the primary mechanical plastic deformation mechanism of all Fe NWs, but it is initially observed at low strain and stress level for the oxidized Fe NWs.

H2O2: A Dynamic Neuromodulator

Science.gov (United States)

Rice, Margaret E.

2012-01-01

Increasing evidence implicates hydrogen peroxide (H2O2) as an intra- and intercellular signaling molecule that can influence processes from embryonic development to cell death. Most research has focused on relatively slow signaling, on the order of minutes to days, via second messenger cascades. However, H2O2 can also mediate subsecond signaling via ion channel activation. This rapid signaling has been examined most thoroughly in the nigrostriatal dopamine (DA) pathway, which plays a key role in facilitating movement mediated by the basal ganglia. In DA neurons of the substantia nigra, endogenously generated H2O2 activates ATP-sensitive K+ (KATP) channels that inhibit DA neuron firing. In the striatum, H2O2 generated downstream from glutamatergic AMPA receptor activation in medium spiny neurons acts as a diffusible messenger that inhibits axonal DA release, also via KATP channels. The source of dynamically generated H2O2 is mitochondrial respiration; thus, H2O2 provides a novel link between activity and metabolism via KATP channels. Additional targets of H2O2 include transient receptor potential (TRP) channels. In contrast to the inhibitory effect of H2O2 acting via KATP channels, TRP channel activation is excitatory. This review describes emerging roles of H2O2 as a signaling agent in the nigrostriatal pathway and other basal ganglia neurons. PMID:21666063

Tropospheric water vapour isotopologue data (H216O, H218O, and HD16O) as obtained from NDACC/FTIR solar absorption spectra

Science.gov (United States)

Barthlott, Sabine; Schneider, Matthias; Hase, Frank; Blumenstock, Thomas; Kiel, Matthäus; Dubravica, Darko; García, Omaira E.; Sepúlveda, Eliezer; Mengistu Tsidu, Gizaw; Takele Kenea, Samuel; Grutter, Michel; Plaza-Medina, Eddy F.; Stremme, Wolfgang; Strong, Kim; Weaver, Dan; Palm, Mathias; Warneke, Thorsten; Notholt, Justus; Mahieu, Emmanuel; Servais, Christian; Jones, Nicholas; Griffith, David W. T.; Smale, Dan; Robinson, John

2017-01-01

We report on the ground-based FTIR (Fourier transform infrared) tropospheric water vapour isotopologue remote sensing data that have been recently made available via the database of NDACC (Network for the Detection of Atmospheric Composition Change; MUSICA/" target="_blank">ftp://ftp.cpc.ncep.noaa.gov/ndacc/MUSICA/) and via doi:10.5281/zenodo.48902. Currently, data are available for 12 globally distributed stations. They have been centrally retrieved and quality-filtered in the framework of the MUSICA project (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). We explain particularities of retrieving the water vapour isotopologue state (vertical distribution of H216O, H218O, and HD16O) and reveal the need for a new metadata template for archiving FTIR isotopologue data. We describe the format of different data components and give recommendations for correct data usage. Data are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies disregarding different isotopologues (comparison with radiosonde data, analyses of water vapour variability and trends, etc.). The second type is needed for analysing moisture pathways by means of H2O, δD-pair distributions.

Hydrothermal synthesis and crystal structures of new uranyl oxalate hydroxides: α- and β-[(UO2)2(C2O4)(OH)2(H2O)2] and [(UO2)2(C2O4)(OH)2(H2O)2].H2O

International Nuclear Information System (INIS)

Duvieubourg, Laurence; Nowogrocki, Guy; Abraham, Francis; Grandjean, Stephane

2005-01-01

Two modifications of the new uranyl oxalate hydroxide dihydrate [UO 2 ) 2 (C 2 O 4 )(OH) 2 (H 2 O) 2 ] (1 and 2) and one form of the new uranyl oxalate hydroxide trihydrate [(UO 2 ) 2 (C 2 O 4 )(OH) 2 (H 2 O) 2 ].H 2 O (3) were synthesized by hydrothermal methods and their structures determined from single-crystal X-ray diffraction data. The crystal structures were refined by full-matrix least-squares methods to agreement indices R(wR)=0.0372(0.0842) and 0.0267(0.0671) calculated for 1096 and 1167 unique observed reflections (I>2σ(I)), for α (1) and β (2) forms, respectively and to R(wR)=0.0301(0.0737) calculated for 2471 unique observed reflections (I>2σ(I)), for 3. The α-form of the dihydrate is triclinic, space group P1-bar , Z=1, a=6.097(2), b=5.548(2), c=7.806(3)A, α=89.353(5), β=94.387(5), γ=97.646(5) o , V=260.88(15)A 3 , β-form is monoclinic, space group C2/c, Z=4, a=12.180(3), b=8.223(2), c=10.777(3)A, β=95.817(4), V=1073.8(5)A 3 . The trihydrate is monoclinic, space group P2 1 /c, Z=4, a=5.5095(12), b=15.195(3), c=13.398(3)A, β=93.927(3), V=1119.0(4)A 3 . In the three structures, the coordination of uranium atom is a pentagonal bipyramid composed of dioxo UO 2 2+ cation perpendicular to five equatorial oxygen atoms belonging to one bidentate oxalate ion, one water molecule and two hydroxyl ions in trans configuration in 2 and in cis configuration in 1 and 3. The UO 7 polyhedra are linked through hydroxyl oxygen atoms to form different structural building units, dimers [U 2 O 10 ] obtained by edge-sharing in 1, chains [UO 6 ] ∼ and tetramers [U 4 O 26 ] built by corner-sharing in 2 and 3, respectively. These units are further connected by oxalate entities that act as bis-bidentate to form one-dimensional chains in 1 and bi-dimensional network in 2 and 3. These chains or layers are connected in frameworks by hydrogen-bond arrays

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

Composite photocatalyst containing Eosin Y and multiwalled carbon nanotubes loaded with CuO/NiO: Mixed metal oxide as an active center of H{sub 2} evolution from water

Energy Technology Data Exchange (ETDEWEB)

Kang Shizhao [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Chen Lili [Key Laboratory for Ultrafine Materials of the Ministry of Education, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Li Xiangqing [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Mu Jin, E-mail: mujin@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

2012-06-01

A composite photocatalyst containing Eosin Y as a sensitizer, multiwalled carbon nanotubes as a supporter material or electron transfer channel, and CuO/NiO as an active center of H{sub 2} evolution from water was fabricated and characterized with X-ray photoelectron spectroscopy and transmission electron microscope. Meanwhile, photocatalytic hydrogen evolution from water over this catalyst was explored using triethanolamine as a sacrificial reagent under visible irradiation. A rate of H{sub 2} evolution of approximately 1.0 mmol g{sup -1} h{sup -1} was achieved under optimal conditions. Furthermore, for practical purposes, the photocatalytic hydrogen evolution was studied as a function of content of CuO/NiO, mass ratio of CuO to NiO, pH of solution, concentration of triethanolamine and dosage of Eosin Y, respectively. The results show that mixed metal oxides are a kind of promising active centers of H{sub 2} evolution from water in the photocatalytic system studied.

Hydration of DNA by tritiated water and isotope distribution: a study by 1H, 2H, and 3H NMR spectroscopy

International Nuclear Information System (INIS)

Mathur-De Vre, R.; Grimee-Declerck, R.; Lejeune, P.; Bertinchamps, A.J.

1982-01-01

The hydration layer of DNA (0.75%) in tritiated water represents 3.5% of solvent 3 HHO. The combined effects of temperature (-6 to -40 0 C) and H 2 O/ 2 H 2 O solvent composition on the spin-lattice relaxation times of water protons and deuterons suggest selective distribution of isotopes in the hydration layer. The ''hydration isotope'' effect and the localization of tritiated water molecules in the hydration layer of DNA have important implications in describing the radiobiological effects of tritiated water because the initial molecular damage caused by 3 HHO (internal radiation source) localizes close to 3 H due to the short range and low energy of 3 H β rays

[Pr2(pdc3(Hpdc(H2O4]n·n(H3hp·8n(H2O, a One-Dimensional Coordination Polymer Containing PrO6N3 Tri-Capped Trigonal Prisms and PrO8N Mono-Capped Square Anti-Prisms (H2pdc = Pyridine 2,6-Dicarboxylic Acid, C7H5NO4; 3hp = 3-Hydroxy Pyridine, C5H5NO

Directory of Open Access Journals (Sweden)

Shahzad Sharif

2012-08-01

Full Text Available The synthesis, structure and some properties of the one-dimensional coordination polymer, [Pr2(pdc3(Hpdc]n·n(H3hp·8n(H2O, (H2pdc = pyridine 2,6-dicarboxylic acid, C7H5NO4; 3hp = 3-hydroxypyridine, C5H5NO are described. One of the Pr3+ ions is coordinated by two O,N,O-tridentate pdc2− ligands and one tridentate Hpdc− anion to generate a fairly regular PrO6N3 tri-capped trigonal prism, with the N atoms acting as the caps. The second Pr3+ ion is coordinated by one tridentate pdc2− dianion, four water molecules and two monodentate bridging pdc2− ligands to result in a PrO8N coordination polyhedron that approximates to a mono-capped square-anti-prism. The ligands bridge the metal-atom nodes into a chain, which extends in the [100] direction. The H3hp+ cation and uncoordinated water molecules occupy the inter-chain regions and an N–HLO and numerous O–HLO hydrogen bonds consolidate the structure. The H3hp+ species appears to intercalate between pendant pdc rings to consolidate the polymeric structure. Crystal data: 1 (C33H43N5O29Pr2, Mr = 1255.54, triclinic,  (No. 2, Z = 2, a = 13.2567(1 Å, b = 13.6304(2 Å, c = 13.6409(2 Å, α = 89.695(1°, β = 63.049(1°, γ = 86.105(1°, V = 2191.16(5 Å3, R(F = 0.033, wR(F2 = 0.084.

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.

Glass transition behaviour of the quaternary ammonium type ionic liquid, {[DEME][I] + H2O} mixtures

International Nuclear Information System (INIS)

Imai, Yusuke; Abe, Hiroshi; Matsumoto, Hitoshi; Shimada, Osamu; Hanasaki, Tomonori; Yoshimura, Yukihiro

2011-01-01

By a simple DTA system, the glass transition temperatures of the quaternary ammonium type ionic liquid, {N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium iodide, [DEME][I] + H 2 O} mixtures after quick pre-cooling were measured as a function of water concentration (x mol% H 2 O). Results were compared with the previous results of {[DEME][BF 4 ] + H 2 O} mixtures in which double glass transitions were observed in the water concentration region of (16.5 to 30.0) mol% H 2 O. Remarkably, we observed the double glass transition phenomenon in {[DEME][I] + H 2 O} mixtures too, but the two-T g s regions lie towards the water-rich side of (77.5 to 85.0) mol% H 2 O. These clearly reflect the difference in the anionic effect between BF 4 - and I - on the water structure. The end of the glass-formation region of {[DEME][I] + H 2 O} mixtures is around x = 95.0 mol% H 2 O, and this is comparable to that of {[DEME][BF 4 ] + H 2 O} mixtures (x = 96.0 mol% H 2 O).

Mass transfer of H2O between petroleum and water: implications for oil field water sample quality

International Nuclear Information System (INIS)

McCartney, R.A.; Ostvold, T.

2005-01-01

Water mass transfer can occur between water and petroleum during changes in pressure and temperature. This process can result in the dilution or concentration of dissolved ions in the water phase of oil field petroleum-water samples. In this study, PVT simulations were undertaken for 4 petroleum-water systems covering a range of reservoir conditions (80-185 o C; 300-1000 bar) and a range of water-petroleum mixtures (volume ratios of 1:1000-300:1000) to quantify the extent of H 2 O mass transfer as a result of pressure and temperature changes. Conditions were selected to be relevant to different types of oil field water sample (i.e. surface, downhole and core samples). The main variables determining the extent of dilution and concentration were found to be: (a) reservoir pressure and temperature, (b) pressure and temperature of separation of water and petroleum, (c) petroleum composition, and (d) petroleum:water ratio (PWR). The results showed that significant dilution and concentration of water samples could occur, particularly at high PWR. It was not possible to establish simple guidelines for identifying good and poor quality samples due to the interplay of the above variables. Sample quality is best investigated using PVT software of the type used in this study. (author)

Kinetic removal of haloacetonitrile precursors by photo-based advanced oxidation processes (UV/H2O2, UV/O3, and UV/H2O2/O3).

Science.gov (United States)

Srithep, Sirinthip; Phattarapattamawong, Songkeart

2017-06-01

The objective of the study is to evaluate the performance of conventional treatment process (i.e., coagulation, flocculation, sedimentation and sand filtration) on the removals of haloacetonitrile (HAN) precursors. In addition, the removals of HAN precursors by photo-based advanced oxidation processes (Photo-AOPs) (i.e., UV/H 2 O 2 , UV/O 3 , and UV/H 2 O 2 /O 3 ) are investigated. The conventional treatment process was ineffective to remove HAN precursors. Among Photo-AOPs, the UV/H 2 O 2 /O 3 was the most effective process for removing HAN precursors, followed by UV/H 2 O 2 , and UV/O 3 , respectively. For 20min contact time, the UV/H 2 O 2 /O 3 , UV/H 2 O 2 , and UV/O 3 suppressed the HAN formations by 54, 42, and 27% reduction. Increasing ozone doses from 1 to 5 mgL -1 in UV/O 3 systems slightly improved the removals of HAN precursors. Changes in pH (6-8) were unaffected most of processes (i.e., UV, UV/H 2 O 2 , and UV/H 2 O 2 /O 3 ), except for the UV/O 3 system that its efficiency was low in the weak acid condition. The pseudo first-order kinetic constant for removals of dichloroacetonitrile precursors (k' DCANFP ) by the UV/H 2 O 2 /O 3 , UV/H 2 O 2 and standalone UV systems were 1.4-2.8 orders magnitude higher than the UV/O 3 process. The kinetic degradation of dissolved organic nitrogen (DON) tended to be higher than the k' DCANFP value. This study firstly differentiates the kinetic degradation between DON and HAN precursors. Copyright © 2017 Elsevier Ltd. All rights reserved.

CANDIDATE WATER VAPOR LINES TO LOCATE THE H{sub 2}O SNOWLINE THROUGH HIGH-DISPERSION SPECTROSCOPIC OBSERVATIONS. I. THE CASE OF A T TAURI STAR

Energy Technology Data Exchange (ETDEWEB)

Notsu, Shota; Ishimoto, Daiki [Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nomura, Hideko [Department of Earth and Planetary Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Walsh, Catherine [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Honda, Mitsuhiko [Department of Physics, School of Medicine, Kurume University, 67 Asahi-machi, Kurume, Fukuoka 830-0011 (Japan); Hirota, Tomoya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Millar, T. J., E-mail: snotsu@kusastro.kyoto-u.ac.jp [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, University Road, Belfast, BT7 1NN (United Kingdom)

2016-08-20

Inside the H{sub 2}O snowline of protoplanetary disks, water evaporates from the dust-grain surface into the gas phase, whereas it is frozen out onto the dust in the cold region beyond the snowline. H{sub 2}O ice enhances the solid material in the cold outer part of a disk, which promotes the formation of gas-giant planet cores. We can regard the H{sub 2}O snowline as the surface that divides the regions between rocky and gaseous giant planet formation. Thus observationally measuring the location of the H{sub 2}O snowline is crucial for understanding the planetesimal and planet formation processes, and the origin of water on Earth. In this paper, we find candidate water lines to locate the H{sub 2}O snowline through future high-dispersion spectroscopic observations. First, we calculate the chemical composition of the disk and investigate the abundance distributions of H{sub 2}O gas and ice, and the position of the H{sub 2}O snowline. We confirm that the abundance of H{sub 2}O gas is high not only in the hot midplane region inside the H{sub 2}O snowline but also in the hot surface layer of the outer disk. Second, we calculate the H{sub 2}O line profiles and identify those H{sub 2}O lines that are promising for locating the H{sub 2}O snowline: the identified lines are those that have small Einstein A coefficients and high upper state energies. The wavelengths of the candidate H{sub 2}O lines range from mid-infrared to sub-millimeter, and they overlap with the regions accessible to the Atacama Large Millimeter/sub-millimeter Array and future mid-infrared high-dispersion spectrographs (e.g., TMT/MICHI, SPICA).

Genotoxicity testing of samples generated during UV/H2O2 treatment of surface water for the production of drinking water using the Ames test in vitro and the Comet assay and the SCE test in vivo

NARCIS (Netherlands)

Penders, E.J.M.; Martijn, A.J.; Spenkelink, A.; Alink, G.M.; Rietjens, I.; Hoogenboezem, W.

2012-01-01

UV/H2O2 treatment can be part of the process converting surface water to drinking water, but would pose a potential problem when resulting in genotoxicity. This study investigates the genotoxicity of samples collected from the water treatment plant Andijk, applying UV/H2O2 treatment with an

USGS48 Puerto Rico precipitation - A new isotopic reference material for δ2H and δ18O measurements of water

Science.gov (United States)

Qi, Haiping; Coplen, Tyler B.; Tarbox, Lauren V.; Lorenz, Jennifer M.; Scholl, Martha A.

2014-01-01

A new secondary isotopic reference material has been prepared from Puerto Rico precipitation, which was filtered, homogenised, loaded into glass ampoules, sealed with a torch, autoclaved to eliminate biological activity, and calibrated by dual-inlet isotope-ratio mass spectrometry. This isotopic reference material, designated as USGS48, is intended to be one of two isotopic reference waters for daily normalisation of stable hydrogen (δ2H) and stable oxygen (δ18O) isotopic analysis of water with a mass spectrometer or a laser absorption spectrometer. The δ2H and δ18O values of this reference water are−2.0±0.4 and−2.224±0.012 ‰, respectively, relative to Vienna Standard Mean Ocean Water on scales normalised such that the δ2H and δ18O values of Standard Light Antarctic Precipitation reference water are−428 and−55.5 ‰, respectively. Each uncertainty is an estimated expanded uncertainty (U=2uc) about the reference value that provides an interval that has about a 95 % probability of encompassing the true value. This isotopic reference water is available by the case of 144 glass ampoules containing 5 mL of water in each ampoule.

[KDy(Hptc3(H3ptc]n·2n(Hbipy·5n(H2O, a Layered Coordination Polymer Containing DyO6N3 Tri-Capped Trigonal Prisms (H3ptc = Pyridine 2,4,6-Tricarboxylic Acid, C8H5NO6; Bipy = 2,2'-Bipyridine, C10H8N2

Directory of Open Access Journals (Sweden)

Shoaib Anwar

2012-08-01

Full Text Available The synthesis, structure and properties of the bimetallic layered coordination polymer, [KDy(C8H3NO63(C8H5NO6]n·2n(C10H9N2·5n(H2O = [KDy(Hptc3(H3ptc]n·2n(Hbipy·5n(H2O, are described. The Dy3+ ion is coordinated by three O,N,O-tridentate doubly-deprotonated pyridine tri-carboxylate (Hptc ligands to generate a fairly regular DyO6N3 tri-capped trigonal prism, with the N atoms acting as the caps. The potassium ion is coordinated by an O,N,O-tridentate H3ptc molecule as well as monodentate and bidentate Hptc ligands to result in an irregular KNO9 coordination geometry. The ligands bridge the metal-atom nodes into a bimetallic, layered, coordination polymer, which extends as corrugated layers in the (010 plane, with the mono-protonated bipyridine cations and water molecules occupying the inter-layer regions: Unlike related structures, there are no dysprosium–water bonds. Many O–HLO and N–HLO hydrogen bonds consolidate the structure. Characterization and bioactivity data are described. Crystal data: C52H42DyKN8O29, Mr = 1444.54, triclinic,  (No. 2, Z = 2, a = 9.188(2 Å, b = 15.7332(17 Å, c = 19.1664(19 Å, α = 92.797(6°, β = 92.319(7°, γ = 91.273(9°, V = 2764.3(7 Å3, R(F = 0.029, wR(F2 = 0.084.

Effect of operational and water quality parameters on conventional ozonation and the advanced oxidation process O3/H2O2: Kinetics of micropollutant abatement, transformation product and bromate formation in a surface water.