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Sample records for catalytic wet air

  1. Progress of catalytic wet air oxidation technology

    Directory of Open Access Journals (Sweden)

    Guolin Jing

    2016-11-01

    Full Text Available Catalytic wet air oxidation (CWAO is one of the most economical and environmental-friendly advanced oxidation process for high strength, toxic, hazardous and non-biodegradable contaminants under milder conditions, which is developed on the basic of wet air oxidation. Various heterogeneous catalysts including noble metals and metal oxides have been extensively studied to enhance the efficiency of CWAO. The advances in the research on wastewater treatment by CWAO process are summarized in aspects of reaction mechanism investigation, reaction kinetics study and catalyst development. It is pointed out that the preparation of active and stable catalysts, the investigation on reaction mechanisms and the study on reaction kinetics models are very important for the promotion of CWAO application.

  2. Catalytic wet Air Oxidation of o-Chlorophenol in Wastewater

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翬

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of catalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removed by wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperature of 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited high catalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCr was removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had better catalytic activity for the degradation of o-chlorophenol in wastewater.

  3. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    Science.gov (United States)

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand).

  4. Wet air and catalytic wet air oxidation of several azodyes from wastewaters: the beneficial role of catalysis.

    Science.gov (United States)

    Rodríguez, A; García, J; Ovejero, G; Mestanza, M

    2009-01-01

    Degradation of several azo dyes, Acid Orange 7 (AO7), Acid Orange 74 (AO74), Direct Blue 71 (DB71), Reactive Black 5 (RB5) and Eriochrome Blue Black B (EBBB), well-known non-biodegradable mono, di and tri azo dyes has been studied using, wet-air oxidation (WAO) and catalytic wet air oxidation (CWAO). The efficiency of substrate decolorization and mineralization in each process has been comparatively discussed by evolution concentration, chemical oxygen demand, total organic carbon content and toxicity of dyes solutions. The most efficient method on decolorization and mineralization (TOC) was observed to be CWAO process. Mineralization efficiency with wet air and catalytic wet air oxidation essays was observed in the order of mono-azo > di-azo > tri-azo dye. Final solutions of CWAO applications after 180 min treatment can be disposed safely to environment.

  5. Homogeneous catalytic wet air oxidation for the treatment oftextile wastewaters

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An extensive series of experiments was carried out in order to identify suitable catalysts to boost the reaction rate of wet air oxidation of real textile wastewaters at relatively mild temperature and pressure. Experimental results indicated that all catalysts tested in this investigation had shown an impressive increase in the initial COD and TOC removal rate as well as the COD and TOC removal levels in two hours reaction. Among all the catalysts tested, copper salts were more effective than the rest. Anions of the salt soluffonsalso played a role in the catalytic process with nitrate ions having better effect than sulfate ions. Hence copper nitrates were more effective than copper sulfates. It was also found that a mixture of salts with different metals performed better than either of the component single salt alone.

  6. Catalytic wet air oxidation for the treatment of emulsifying wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian-fu; CHEN Ling; LU Yi-cheng; TANG Wen-wei

    2005-01-01

    The wet air oxidation (WAO) and catalytic WAO (CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO processes were carried out at the temperature from 433 K to 513 K, with initial oxygen pressure 1.2 MPa. It was found that homogeneous catalyst copper(Cu ( NO3 )2 )had an fairly good catalytic activity for the WAO process, and the oxidation was catalyzed when the temperature was higher than 473 K.Moreover, several heterogeneous catalysts were proved to be effective for the WAO process. At the temperature 473 K, after 2 h reaction,WAO process could achieve about 75% COD removal and 66% TOC removal, while catalysts Cu/Al2O3 and Mn-Ce/Al2O3 elevated the COD removal up to 86%-89% and that of TOC up to 82%. However, complete elimination of COD and TOC was proved to be difficult even the best non-noble catalyst was used. Therefore, the effluent from WAO or CWAO process need to be further disposed. The bioassay proved that the effluent from WAO process was amenable to the biochemical method.

  7. Copper on activated carbon for catalytic wet air oxidation

    Directory of Open Access Journals (Sweden)

    Nora Dolores Martínez

    2009-03-01

    Full Text Available Textile industry is an important source of water contamination. Some of the organic contaminants cannot be eliminated by nature in a reasonable period. Heterogeneous catalytic wet air oxidation is one of the most effective methods to purify wastewater with organic contaminants. In this work, catalysts based on copper supported on activated carbon were synthesized. The activated carbons were obtained from industrial wastes (apricot core and grape stalk of San Juan, Argentina. These were impregnated with a copper salt and thermically treated in an inert atmosphere. Analysis of specific surface, pore volume, p zc, acidity, basicity and XRD patterns were made in order to characterize the catalysts. The catalytic activity was tested in the oxidation of methylene blue (MB and polyvinyl alcohol (PVA in aqueous phase with pure oxygen. Reaction tests were carried out in a Parr batch reactor at different temperatures, with a 0.2 MPa partial pressure of oxygen. The amount of unconverted organics was measured by spectrophotometry. Higher temperatures were necessary for the degradation of PVA compared to those for methylene blue.

  8. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts.

    Science.gov (United States)

    Li, Ning; Descorme, Claude; Besson, Michèle

    2007-07-31

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3wt.% Ru/ZrO(2). 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3wt.% Ru/ZrO(2) is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393K) and lower total pressure (3MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect.

  9. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons.

    Science.gov (United States)

    Quesada-Peñate, I; Julcour-Lebigue, C; Jáuregui-Haza, U J; Wilhelm, A M; Delmas, H

    2012-06-30

    The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  10. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Penate, I. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Julcour-Lebigue, C., E-mail: carine.julcour@ensiacet.fr [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Jauregui-Haza, U.J. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Habana (Cuba); Wilhelm, A.M.; Delmas, H. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Three activated carbons (AC) compared as adsorbents and oxidation catalysts. Black-Right-Pointing-Pointer Similar evolution for catalytic and adsorptive properties of AC over reuses. Black-Right-Pointing-Pointer Acidic and mesoporous AC to be preferred, despite lower initial efficiency. Black-Right-Pointing-Pointer Oxidative degradation of paracetamol improves biodegradability. Black-Right-Pointing-Pointer Convenient hybrid adsorption-regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  11. [Degradation of beta-naphthol by catalytic wet air oxidation].

    Science.gov (United States)

    Liu, Jie; Yu, Chao-Ying; Zhao, Pei-Qing; Chen, Ge-Xin

    2012-11-01

    A series of MnO(x)/nano-TiO2 catalysts were prepared and their application in degradation of beta-naphthol by catalytic wet air oxidation (CWAO) was investigated. The catalysts preparation conditions, reaction conditions and its stability were tested. The catalysts had been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. The results showed that the decrease of the COD removal for the degradation of beta-naphthol at high Mn loading was due to the aggregation of the highly dispersed Mn species and the formation of the correlated crystals. The decline of the COD removal at high calcination temperature was probably attributed to the weak electron transfer between Mn2O3 and MnO2 and the formation of the inactive Mn2O3. The COD removal had been falling slightly when the catalyst was used 6 times, and this was likely related to the decrease of the diffraction peaks. The catalyst had a high activity when the Mn loading (mass fraction) was 4% and the calcination temperature was 450 degrees C. The COD removal was up to 96.4% at 110 degrees C and 0.5 MPa with this catalyst. The COD removal of 92.4% could be obtained with the MnO(x)/nano-TiO2 catalyst was recycled 6 times. The Mn leaching at 50, 80, 110 and 150 degrees C were all less than 9.3 mg x L(-1) by means of Atomic Absorption Spectroscopy (AAS). The probable degradation pathway was proposed according to some publications.

  12. Pretreatment of apramycin wastewater by catalytic wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    YANG Shao-xia; FENG Yu-jie; WAN Jia-feng; LIN Qing-ying; ZHU Wan-peng; JIANG Zhan-peng

    2005-01-01

    The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH4+ concentration, and the ratio of BOD5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO2/Al2 O3 and RuO2-CeO2/Al2 O3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50.2% and 55.0%, COD removals were 40.0% and 46.0%, and the ratio of BOD5/COD was increased to 0.49 and 0.54 with RuO2/Al2 O3 and RuO2-CeO2/Al2 O3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD5/COD was increased to 0.45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were the apramycin wastewater. The addition of CeO2 could promote the activity and stability of RuO2/Al2 O3 in WAO of apramycin wastewater.

  13. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: kinetics and biodegradability enhancement.

    Science.gov (United States)

    Suárez-Ojeda, María Eugenia; Kim, Jungkwon; Carrera, Julián; Metcalfe, Ian S; Font, Josep

    2007-06-18

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15 bar of oxygen partial pressure (P(O2)) and at 180, 200 and 220 degrees C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P(O2) were 140-160 degrees C and 2-9 bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160 degrees C and 2 bar of P(O2), which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD(RB)) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture.

  14. The degradation of Isophorone by catalytic wet air oxidation on Ru/TiZrO4.

    Science.gov (United States)

    Wei, Huangzhao; Yan, Xiaomiao; Li, Xianru; He, Songbo; Sun, Chenglin

    2013-01-15

    The catalyst Ru/TiZrO(4) was applied in the degradation of Isophorone by catalytic wet air oxidation. Mathematical models for the effects of reaction conditions on the Isophorone degradation by catalytic wet air oxidation were developed using a response surface methodology. A model was obtained for each response with multiple regression analysis and then was refined. Analysis of variance revealed that the models developed were adequate. The validity of the models was also verified by experimental data. Analysis of response surface showed that total organic carbon removal and Isophorone conversion were significantly affected (P≤0.01) by reaction time, temperature and their interactions, and affected (P≤0.05) by the square of reaction time. The point of zero charge of Ru/TiZrO(4) catalyst was about 1.72. The total organic carbon removal and Isophorone conversion had a great association with the zeta potential of Ru/TiZrO(4) catalyst. Finally, the degradation pathway of Isophorone in catalytic wet air oxidation was proposed. Within 410 h, the total organic carbon removal remained above 95%, indicating that the Ru/TiZrO(4) catalyst had a good stability.

  15. Application of Catalytic Wet Air Oxidation to Treatment of Landfill Leachate on Co/Bi Catalyst

    Institute of Scientific and Technical Information of China (English)

    LI Hai-sheng; LIU Liang; ZHANG Rong; DONG De-ming; LIU Hong-liang; LI Yu

    2004-01-01

    Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the TOC and CODCr removal rates were studied. The degradation kinetics of landfill leachate was also investigated and an exponential experiential model consisting of four influential factors was established to describe the reduction of the organic compounds in the landfill leachate. Meanwhile, the GC-MS technique was used to detect the components of the organic intermediates for the inference of the decomposition mechanisms of the organic compounds in landfill leachate. The results reveal that the reaction temperature and the catalyst dosage are the most important factors affecting the degradation reaction of the organic compounds and that the principal intermediates confirmed by GC-MS are organic acids at a percentage of more than 88% with no aldehydes or alcohols detected. The decomposition mechanisms of the organic compounds in landfill leachate were inferred based on the GC-MS information as follows: the activated gas phase O2 captured the hydrogen of the organic pollutants to produce free radicals, which then initiated the catalytic reaction. So most of the organic compounds were oxidized into CO2 and H2O ultimately. In general, catalytic wet air oxidation over catalyst Co3O4/Bi2O3 was a very promising technique for the treatment of landfill leachate.

  16. Kinetics study on catalytic wet air oxidation of phenol by several metal oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    WAN Jia-feng; FENG Yu-jie; CAI Wei-min; YANG Shao-xia; SUN Xiao-jun

    2004-01-01

    Four metal oxide catalysts composed of copper (Cu), stannum (Sn), copper-stannum (Cu-Sn) and copper-cerium(Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al2O3) is selected as support. A first-order kinetics model was established to study the catalytic wet air oxidation of phenol at different temperature when these catalysts were used. The model simulations are good agreement with present experimental data. Results showed that the reaction rate constants can be significantly increased when catalysts were used, and the catalyst of 6% Cu-10%Ce/γ-Al2O3 showed the best catalytic activity. This is consistent with the result of catalytic wet air oxidation of phenol and the COD removal can be arrived at 98.2% at temperature 210℃, oxygen partial pressure 3 MPa and reaction time 30 min. The activation energies of each reaction with different catalysts are nearly equal, which is found to be about 42 kJ/mol and the reaction in this study is proved to be kinetics control.

  17. Heterogeneous catalytic wet air oxidation of refractory organic pollutants in industrial wastewaters: a review.

    Science.gov (United States)

    Kim, Kyoung-Hun; Ihm, Son-Ki

    2011-02-15

    Catalytic wet air oxidation (CWAO) is one of the most economical and environmental-friendly advanced oxidation process. It makes a promising technology for the treatment of refractory organic pollutants in industrial wastewaters. Various heterogeneous catalysts including noble metals and metal oxides have been extensively studied to enhance the efficiency of CWAO. The present review is concerned about the literatures published in this regard. Phenolics, carboxylic acids, and nitrogen-containing compounds were taken as model pollutants in most cases, and noble metals such as Ru, Rh, Pd, Ir, and Pt as well as oxides of Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, and Ce were applied as heterogeneous catalysts. Reports on their characterization and catalytic performances for the CWAO of aqueous pollutants are reviewed. Discussions are also made on the reaction mechanisms and kinetics proposed for heterogeneous CWAO and also on the typical catalyst deactivations in heterogeneous CWAO, i.e. carbonaceous deposits and metal leaching.

  18. Degradation of phenylamine by catalytic wet air oxidation using metal catalysts with modified supports.

    Science.gov (United States)

    Torrellas, Silvia A; Escudero, Gabriel O; Rodriguez, Araceli R; Rodriguez, Juan G

    2015-01-01

    The effect of acid treatments with HCl and HNO3 on the surface area and surface chemistry of three granular activated carbons was studied. These supports were characterized and the hydrochloric acid treatment leads to the best activated carbon support (AC2-C). The catalytic behavior of Pt, Ru and Fe (1 wt.%) supported on granular activated carbon treated with HCl was tested in the phenylamine continuous catalytic wet air oxidation in a three-phase, high-pressure catalytic reactor over a range of reaction temperatures 130-170ºC and total pressure of 1.0-3.0 MPa at LHSV = 0.4-1 h(-1), whereas the phenylamine concentration range and the catalyst loading were 5-16 mol.m(-3) and 0.5-1.5 g, respectively. Activity as well as conversion varied as a function of the metal, the catalyst preparation method and operation conditions. Higher activities were obtained with Pt incorporated on hydrochloric acid -treated activated carbon by the ion exchange method. In steady state, approximately 98% phenylamine conversion, 77% of TOC and 94% of COD removal, was recorded at 150ºC, 11 mol m(-3) of phenylamine concentration and 1.5 g of catalyst, and the selectivity to non-organic compounds was 78%. Several reaction intermediaries were detected. A Langmuir-Hinshelwood model gave an excellent fit of the kinetic data of phenylamine continuous catalytic wet air oxidation over the catalysts of this work.

  19. Catalytic wet air oxidation of 2-chlorophenol over sewage sludge-derived carbon-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Yuting [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Xiong, Ya; Tian, Shuanghong [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275 (China); Kong, Lingjun [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Descorme, Claude, E-mail: claude.descorme@ircelyon.univ-lyon1.fr [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2014-07-15

    Highlights: • A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared. • FeSC exhibited high catalytic activity in the wet air oxidation of 2-chlorophenol. • A strong correlation was observed between the 2-CP conversion, the iron leaching and the pH. • Using an acetate buffer, the iron leaching was suppressed while keeping some catalytic activity. • A simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst. - Abstract: A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared and used in the Catalytic Wet Air Oxidation (CWAO) of 2-chlorophenol (2-CP). The catalysts were characterized in terms of elemental composition, surface area, pH{sub PZC}, XRD and SEM. The performances of the FeSC catalyst in the CWAO of 2-CP was assessed in a batch reactor operated at 120 °C under 0.9 MPa oxygen partial pressure. Complete decomposition of 2-CP was achieved within 5 h and 90% Total Organic Carbon (TOC) was removed after 24 h of reaction. Quite a straight correlation was observed between the 2-CP conversion, the amount of iron leached in solution and the pH of the reaction mixture at a given reaction time, indicating a strong predominance of the homogeneous catalysis contribution. The iron leaching could be efficiently prevented when the pH of the solution was maintained at values higher than 4.5, while the catalytic activity was only slightly reduced. Upon four successive batch CWAO experiments, using the same FeSC catalyst recovered by filtration after pH adjustment, only a very minor catalyst deactivation was observed. Finally, based on all the identified intermediates, a simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst.

  20. Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts.

    Science.gov (United States)

    Fontanier, Virginie; Zalouk, Sofiane; Barbati, Stéphane

    2011-01-01

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) of slaughtered animal byproducts (ABPs) were investigated. Two step experiment was carried out consisting of a non-catalysed WAO run followed by a CWAO run at 170-275 degrees C, 20 MPa, and reaction time 180 min. The WAO (1st step) of sample (5 g/L total organic carbon (TOC)) yielded (82.0 +/- 4)% TOC removal and (78.4 +/- 13.2)% conversion of the initial organic-N into NH4(+)-N. Four metal catalysts (Pd, Pt, Rh, Ru) supported over alumina have been tested in catalytic WAO (2nd step) at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid. It was found that the catalysts Ru, Pt, and Rh had significant effects on the TOC removal (95.1%, 99.5% and 96.7%, respectively) and on the abatement of ammonia (93.4%, 96.7% and 96.3%, respectively) with high nitrogen selectivity. The catalyst Pd was found to have the less activity while Pt had the best performance. The X-Ray diffraction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution. Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.

  1. Catalytic wet air oxidation of phenol with functionalized carbon materials as catalysts: reaction mechanism and pathway.

    Science.gov (United States)

    Wang, Jianbing; Fu, Wantao; He, Xuwen; Yang, Shaoxia; Zhu, Wanpeng

    2014-08-01

    The development of highly active carbon material catalysts in catalytic wet air oxidation (CWAO) has attracted a great deal of attention. In this study different carbon material catalysts (multi-walled carbon nanotubes, carbon fibers and graphite) were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction, the removal of phenol was nearly 100% over the functionalized multi-walled carbon, while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals, which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions, a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First, maleic acid is transformed directly into malonic acid. Second, acetic acid is oxidized into an unknown intermediate, which is then oxidized into CO2 and H2O. Finally, formic acid and oxalic acid can mutually interconvert when conditions are favorable.

  2. Catalytic wet air oxidation with Ni- and Fe-doped mixed oxides derived from hydrotalcites.

    Science.gov (United States)

    Ovejero, G; Rodríguez, A; Vallet, A; Gómez, P; García, J

    2011-01-01

    Catalytic wet air oxidation of Basic Yellow 11 (BY11), a basic dye, was studied in a batch reactor. Layered double hydroxides with the hydrotalcite-like structure containing nickel or iron cations have been prepared by coprecipitation and subsequently calcined leading to Ni- and Fe-doped mixed oxides, respectively. Compared with the results in the wet air oxidation of BY11, these catalysts showed high activity for total organic carbon (TOC), toxicity and dye removal at 120 degrees C and 50 bars after 120 min. It has been demonstrated that the activity depended strongly on the presence of catalyst. The results show that catalysts containing nickel provide a higher extent of oxidation of the dye whereas the reaction carried out with the iron catalyst is faster. The Ni and Fe dispersion determined from the TPR results was higher for the catalysts with a lower Ni or Fe content and decreased for higher Ni or Fe contents. On the basis of activity and selectivity, the Ni containing catalyst with the medium (3%) Ni content was found to be the best catalyst. Finally, a relationship between metal content of the catalyst and reaction rate has been established.

  3. Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts

    Institute of Scientific and Technical Information of China (English)

    Virginie Fontanier; Sofiane Zalouk; Stéphane Barbati

    2011-01-01

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) of slaughtered animal byproducts (ABPs) were investigated.Two step experiment was carried out consisting ofa non-catalysed WAO run followed by a CWAO run at 170-275℃, 20 MPa, and reaction time 180 min.The WAO (1st step) of sample (5 g/L total organic carbon (TOC)) yielded (82.0 ± 4)% TOC removal and (78.4 ± 13.2)%conversion of the initial organic-N into NH4+-N.Four metal catalysts (Pd, Pt, Rh, Ru) supported over alumina have been tested in catalytic WAO (2nd step) at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid.It was found that the catalysts Ru, Pt, and Rh had significant effects on the TOC removal (95.1%, 99.5% and 96.7%, respectively) and on the abatement of ammonia (93.4%, 96.7% and 96.3%, respectively) with high nitrogen selectivity.The catalyst Pd was found to have the less activity while Pt had the best performance.The X-Ray diffraction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution.Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.

  4. Catalytic wet air oxidation of 2-chlorophenol over sewage sludge-derived carbon-based catalysts.

    Science.gov (United States)

    Tu, Yuting; Xiong, Ya; Tian, Shuanghong; Kong, Lingjun; Descorme, Claude

    2014-07-15

    A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared and used in the Catalytic Wet Air Oxidation (CWAO) of 2-chlorophenol (2-CP). The catalysts were characterized in terms of elemental composition, surface area, pHPZC, XRD and SEM. The performances of the FeSC catalyst in the CWAO of 2-CP was assessed in a batch reactor operated at 120°C under 0.9MPa oxygen partial pressure. Complete decomposition of 2-CP was achieved within 5h and 90% Total Organic Carbon (TOC) was removed after 24h of reaction. Quite a straight correlation was observed between the 2-CP conversion, the amount of iron leached in solution and the pH of the reaction mixture at a given reaction time, indicating a strong predominance of the homogeneous catalysis contribution. The iron leaching could be efficiently prevented when the pH of the solution was maintained at values higher than 4.5, while the catalytic activity was only slightly reduced. Upon four successive batch CWAO experiments, using the same FeSC catalyst recovered by filtration after pH adjustment, only a very minor catalyst deactivation was observed. Finally, based on all the identified intermediates, a simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst.

  5. Preparation of rare-earth metal complex oxide catalysts for catalytic wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    LI Ning; LI Guangming; YAO Zhenya; ZHAO Jianfu

    2007-01-01

    Catalytic wet air oxidation(CWAO)is one of the most promising technologies for pollution abatement.Developing catalysts with high activity and stability is crucial for the application of the CWAO process.The Mn/Ce complex oxide catalyrsts for CWAO of high concentration phenol containing wastewater were prepared by coprecipitation.The catalyst preparation conditions were optimized by using an orthogonal layout method and single-factor experimental analysis.The Mn/Ce serial catalysts were characterized by Brunauer-Emmett-Teller(BET)analysis and the metal cation leaching was measured by inductively coupled plasma torch-atomic emission spectrometry(ICP-AES).The results show that the catalysts have high catalytic activities even at a low temperature(80℃)and low oxygen partial pressure(0.5 MPa)in a batch reactor.The metallic ion leaching is comparatively low(Mn<6.577 mg/L and Ce<0.6910 mg/L,respectively)in the CWAO process.The phenol,CODCD and TOC removal efficiencies in the solution exceed 98.5% using the optimal catalyst(named CSP).The new catalyst would have a promising application in CWAO treatment of high concentration organic wastewater.

  6. Catalytic wet air oxidation of aniline with nanocasted Mn-Ce-oxide catalyst.

    Science.gov (United States)

    Levi, R; Milman, M; Landau, M V; Brenner, A; Herskowitz, M

    2008-07-15

    The catalytic wet air oxidation of aqueous solution containing 1000 ppm aniline was conducted in a trickle-bed reactor packed with a novel nanocasted Mn-Ce-oxide catalyst (surface area of 300 m2/g) prepared using SBA-15 silica as a hard template. A range of liquid hourly space velocities (5-20 h(-1)) and temperatures (110-140 degrees C) at 10 bar of oxygen were tested. The experiments were conducted to provide the intrinsic performance of the catalysts. Complete aniline conversion, 90% TOC conversion, and 80% nitrogen mineralization were achieved at 140 degrees C and 5 h(-1). Blank experiments yielded relatively low homogeneous aniline (<35%) and negligible TOC conversions. Fast deactivation of the catalysts was experienced due to leaching caused by complexation with aniline. Acidification of the solution with HCI (molar HCI to aniline ratio of 1.2) was necessary to avoid colloidization and leaching of the nanoparticulate catalyst components. The catalyst displayed stable performance for over 200 h on stream.

  7. Catalytic Wet Air Oxidation of Oxalic Acid using Platinum Catalysts in Bubble Column Reactor: A Review

    Directory of Open Access Journals (Sweden)

    A. K. Saroha

    2010-01-01

    Full Text Available Wastewater treatment and re-use of industrial process water are critical issue for the development of human activities andenvironment conservation. Catalytic wet air oxidation (CWAO is an attractive and useful technique for treatment of effluentswhere the concentrations of organic pollutants are too low, for the incineration and other pollution control techniquesto be economically feasible and when biological treatments are ineffective, e.g. in the case of toxic effluents. In CWAO,combustion takes place on a Pt/Al2O3 catalysts usually at temperatures several degrees below those required forthermal incineration. In CWAO process, the organic contaminants dissolved in water are either partially degraded by meansof an oxidizing agent into biodegradable intermediates or mineralized into innocuous inorganic compounds such as CO2,H2O and inorganic salts, which remain in the aqueous phase. In contrast to other thermal processes CWAO produces no NOx,SO2, HCl, dioxins, furans, fly ash, etc. This review paper presents the application of platinum catalysts in bubble columnreactor for CWAO of oxalic acid.

  8. Supported noble metal catalysts in the catalytic wet air oxidation of industrial wastewaters and sewage sludges.

    Science.gov (United States)

    Besson, M; Descorme, C; Bernardi, M; Gallezot, P; di Gregorio, F; Grosjean, N; Minh, D Pham; Pintar, A

    2010-12-01

    This paper reviews some catalytic wet air oxidation (CWAO) investigations of industrial wastewaters over platinum and ruthenium catalysts supported on TiO2 and ZrO2 formulated to be active and resistant to leaching, with particular focus on the stability of the catalyst. Catalyst recycling experiments were performed in batch reactors and long-term stability tests were conducted in trickle-bed reactors. The catalyst did not leach upon treatment of Kraft bleaching plant and olive oil mill effluents, and could be either recycled or used for long periods of time in continuous reactors. Conversely, these catalysts were rapidly leached when used to treat effluents from the production of polymeric membranes containing N,N-dimethylformamide. The intermediate formation of amines, such as dimethylamine and methylamine with a high complexing capacity for the metal, was shown to be responsible for the metal leaching. These heterogeneous catalysts also deactivated upon CWAO of sewage sludges due to the adsorption of the solid organic matter. Pre-sonication of the sludge to disintegrate the flocs and improve solubility was inefficient.

  9. Catalytic wet-air oxidation of a chemical plant wastewater over platinum-based catalysts.

    Science.gov (United States)

    Cybulski, Andrzej; Trawczyński, Janusz

    2006-01-01

    Catalytic wet-air oxidation (CWAO) of wastewater (chemical oxygen demand [COD] = 1800 mg O2/dm3) from a fine chemicals plant was investigated in a fixed-bed reactor at T = 393-473 K under total pressure of 5.0 or 8.0 MPa. Catalysts containing 0.3% wt. of platinum deposited on two supports, mixed silica-titania (SM1) and carbon black composites (CBC) were used. The CBC-supported catalyst appeared to be more active than the SM1-supported one. A slow decrease of activity of the platinum on SM1 (Pt-SM1) during the long-term operation is attributed to recrystallization of titania and leaching of a support component, while the Pt-CBC catalyst is deteriorated, owing to combustion of the support component. The power-law-kinetic equations were used to describe the rate of COD removal at CWAO over the catalysts. The kinetic parameters of COD reduction for the wastewater were determined and compared with the kinetic parameters describing phenol oxidation over the same catalysts. Rates of COD removal for the wastewater were found higher than those for phenol oxidation over the same catalysts and under identical operating conditions.

  10. Development of a Catalytic Wet Air Oxidation Method to Produce Feedstock Gases from Waste Polymers

    Science.gov (United States)

    Kulis, Michael J.; Guerrero-Medina, Karen J.; Hepp, Aloysius F.

    2012-01-01

    Given the high cost of space launch, the repurposing of biological and plastic wastes to reduce the need for logistical support during long distance and long duration space missions has long been recognized as a high priority. Described in this paper are the preliminary efforts to develop a wet air oxidation system in order to produce fuels from waste polymers. Preliminary results of partial oxidation in near supercritical water conditions are presented. Inherent corrosion and salt precipitation are discussed as system design issues for a thorough assessment of a second generation wet air oxidation system. This work is currently being supported by the In-Situ Resource Utilization Project.

  11. Effect of Composition and Mass Ratio on the Catalytic Wet Air Oxidation Catalyst Cu–Fe–La/FSC

    Directory of Open Access Journals (Sweden)

    Wu Chao

    2016-01-01

    Full Text Available The catalytic wet air oxidation (CWAO technology is used for the treatment of the simulated printing and dyeing wastewater and also for investigating the catalyst performance indicators such as catalyst activity and stability. The catalyst activity is mainly reflected from the water decolorization and CODCr removal rates, and the stability of the catalyst is mainly reflected by the quantity of metal dissolution. The experimental results showed that the prepared Cu–Fe–La/FSC catalyst with a 1:1:2 ratio of Cu–Fe–La by the impregnation method exhibited good activity for the treatment of the simulated printing and dyeing wastewater by the CWAO method, and the decolorization and CODCr removal rates using this catalyst were 98.7% and 78.6%, respectively, with a higher catalytic activity, lower concentration of metal dissolution, and good stability.

  12. Catalytic wet air oxidation of coke-plant wastewater on ruthenium-based eggshell catalysts in a bubbling bed reactor.

    Science.gov (United States)

    Yang, M; Sun, Y; Xu, A H; Lu, X Y; Du, H Z; Sun, C L; Li, C

    2007-07-01

    Catalytic wet air of coke-plant wastewater was studied in a bubbling bed reactor. Two types of supported Ru-based catalysts, eggshell and uniform catalysts, were employed. Compared with the results in the wet air oxidation of coke-plant wastewater, supported Ru uniform catalysts showed high activity for chemical oxygen demand (COD) and ammonia/ammonium compounds (NH3-N) removal at temperature of 250 degrees C and pressure of 4.8 MPa, and it has been demonstrated that the catalytic activity of uniform catalyst depended strongly on the distribution of active sites of Ru on catalyst. Compared to the corresponding uniform catalysts with the same Ru loading (0.25 wt.% and 0.1 wt.%, respectively), the eggshell catalysts showed higher activities for CODcr removal and much higher activities for NH3-N degradation. The high activity of eggshell catalyst for treatment of coke-plant wastewater can be attributed to the higher density of active Ru sites in the shell layer than that of the corresponding uniform catalyst with the same Ru loading. It has been also evidenced that the active Ru sites in the internal core of uniform catalyst have very little or no contribution to CODcr and NH3-N removal in the total oxidation of coke-plant wastewater.

  13. Catalytic wet oxidation of black liquor

    OpenAIRE

    Viader Riera, Gerard

    2012-01-01

    The major aspects of wet air oxidation and catalytic wet air oxidation have been reviewed in this work paying special attention to the reaction mechanisms, kinetics and the industrial process. In the experimental section a set of heterogeneous catalysts have been tested in the wet oxidation of non-wood black liquor. The oxidation runs were performed batchwise in a laboratory-scale mechanically stirred slurry reactor for 1 h at a temperature of 170°C and total pressure of 12 bar. Pure oxygen w...

  14. Catalytic wet-air oxidation of lignin in a three-phase reactor with aromatic aldehyde production

    Directory of Open Access Journals (Sweden)

    Sales F.G.

    2004-01-01

    Full Text Available In the present work a process of catalytic wet air oxidation of lignin obtained from sugar-cane bagasse is developed with the objective of producing vanillin, syringaldehyde and p-hydroxybenzaldehyde in a continuous regime. Palladium supported on g-alumina was used as the catalyst. The reactions in the lignin degradation and aldehyde production were described by a kinetic model as a system of complex parallel and series reactions, in which pseudo-first-order steps are found. For the purpose of producing aromatic aldehydes in continuous regime, a three-phase fluidized reactor was built, and it was operated using atmospheric air as the oxidizer. The best yield in aromatic aldehydes was of 12%. The experimental results were compatible with those values obtained by the pseudo-heterogeneous axial dispersion model (PHADM applied to the liquid phase.

  15. Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process.

    Science.gov (United States)

    Lefèvre, Sébastien; Boutin, Olivier; Ferrasse, Jean-Henry; Malleret, Laure; Faucherand, Rémy; Viand, Alain

    2011-08-01

    This work is dedicated to an accurate evaluation of thermodynamic and kinetics aspects of phenol degradation using wet air oxidation process. Phenol is a well known polluting molecule and therefore it is important having data of its behaviour during this process. A view cell is used for the experimental study, with an internal volume of 150 mL, able to reach pressures up to 30 MPa and temperatures up to 350°C. Concerning the thermodynamic phase equilibria, experimental and modelling results are obtained for different binary systems (water/nitrogen, water/air) and ternary system (water/nitrogen/phenol). The best model is the Predictive Soave Redlich Kwong one. This information is necessary to predict the composition of the gas phase during the process. It is also important for an implementation in a process simulation. The second part is dedicated to kinetics evaluation of the degradation of phenol. Different compounds have been detected using GC coupled with a MS. A kinetic scheme is deduced, taking into account the evolution of phenol, hydroquinones, catechol, resorcinol and acetic acid. The kinetic parameters are calculated for this scheme. These data are important to evaluate the evolution of the concentration of the different polluting molecules during the process. A simplified kinetic scheme, which can be easily implemented in a process simulation, is also determined for the direct degradation of phenol into H(2)O and CO(2). The Arrhenius law data obtained for the phenol disappearance are the following: k=1.8×10(6)±3.9×10(5)M(-1)s(-1) (pre-exponential factor) and E(a)=77±8 kJ mol(-1) (activation energy).

  16. Active carbon-ceramic sphere as support of ruthenium catalysts for catalytic wet air oxidation (CWAO) of resin effluent.

    Science.gov (United States)

    Liu, Wei-Min; Hu, Yi-Qiang; Tu, Shan-Tung

    2010-07-15

    Active carbon-ceramic sphere as support of ruthenium catalysts were evaluated through the catalytic wet air oxidation (CWAO) of resin effluent in a packed-bed reactor. Active carbon-ceramic sphere and ruthenium catalysts were characterized by N(2) adsorption and chemisorption measurements. BET surface area and total pore volume of active carbon (AC) in the active carbon-ceramic sphere increase with increasing KOH-to-carbon ratio, and AC in the sample KC-120 possesses values as high as 1100 m(2) g(-1) and 0.69 cm(3) g(-1) (carbon percentage: 4.73 wt.%), especially. Active carbon-ceramic sphere supported ruthenium catalysts were prepared using the RuCl(3) solution impregnation onto these supports, the ruthenium loading was fixed at 1-5 wt.% of AC in the support. The catalytic activity varies according to the following order: Ru/KC-120>Ru/KC-80>Ru/KC-60>KC-120>without catalysts. It is found that the 3 wt.% Ru/KC-120 catalyst displays highest stability in the CWAO of resin effluent during 30 days. Chemical oxygen demand (COD) and phenol removal were about 92% and 96%, respectively at the reaction temperature of 200 degrees C, oxygen pressure of 1.5 MPa, the water flow rate of 0.75 L h(-1) and the oxygen flow rate of 13.5 L h(-1).

  17. Catalytic wet air oxidation of phenol over Co-doped Fe3O4 nanoparticles

    Science.gov (United States)

    Song, Xu Chun; Zheng, Yi Fan; Yin, Hao Yong

    2013-08-01

    The Fe3O4 nanoparticles doped with cobalt ions have been successfully synthesized by the co-precipitation process. The X-ray diffraction, inductively coupled plasma, scanning electron microscopy, and transmission electron microscopy were used to characterize the as-prepared nanoparticles. The results show that the phase structure of the nanoparticles is spinel structure of pure Fe3O4 with the particle size ranging from 40 to 50 nm. The Co-doping concentration can be controlled by changing the atomic ratio of the stock materials. The catalytic activity of the Co-doped Fe3O4 was further investigated by decomposing the phenol in liquid phase. The results show that cobalt ions doping can improve the catalytic efficiency of Fe3O4 nanoparticles in phenol degradation with catalytic reaction fitting the first-order kinetics. According to the estimated reaction rate of Co-doped Fe3O4 nanoparticles at different temperatures, the activation energy was calculated to be 45.63 kJ/mol.

  18. Al 2O 3 supported Ru catalysts prepared by thermolysis of Ru 3(CO) 12 for catalytic wet air oxidation

    Science.gov (United States)

    Yu, Chaoying; Zhao, Peiqing; Chen, Gexin; Hu, Bin

    2011-06-01

    Low loading catalysts Ru/γ-Al 2O 3 and Ru-Ce/γ-Al 2O 3 were prepared by thermolysis of Ru 3(CO) 12 on γ-Al 2O 3. The catalysts were characterized by XPS, XRD and SEM. Two new Ru species (Ru A and Ru B) were detected during the Ru 3(CO) 12 decomposition process due to chemical interaction with the active OH groups on the surface of Al 2O 3 support, and the reduction of them can lead to more dispersed metallic phases. The sample was completely decomposed at 673 K in H 2, and RuO 2 was formed with minor amounts of Ru 0. When the temperature was increased to 773 K to heat the sample, the ratio of Ru 0 to RuO 2 increased. However, after the addition of CeO 2, only RuO 2 was detected on surface. The catalysts exhibited high activities in Catalytic Wet Air Oxidation (CWAO) of different organic compounds at high concentration such as isopropyl alcohol, phenol, acetic acids and N,N-dimethylformamide, which is attributed to the better dispersion of Ru particles and the addition of CeO 2 further enhanced number of effectively active sites on the cluster-derived catalyst surface.

  19. Low-pressure catalytic wet-air oxidation of a high-strength industrial wastewater using Fenton's reagent.

    Science.gov (United States)

    Biçaksiz, Zeliha; Aytimur, Gülin; Atalay, Süheyda

    2008-06-01

    Wastewater from the Afyon Alkaloids Factory (Afyon, Turkey) was subjected to low-pressure catalytic wet-air oxidation (CWAO) using Fenton's reagent, and the optimal reaction conditions were investigated. The CWAO using Fenton's reagent was applied to the factory effluent, diluted factory effluent, and aerobically pretreated wastewater. To find the optimum quantities of reagents, ferrous iron (Fe(+2))-to-substrate ratios of 1:10, 1:25, and 1:50 and hydrogen peroxide (H2O2)-to-Fe(+2) ratios of 1, 5, and 10 were investigated, and the treatment was carried out at different temperatures. High chemical oxygen demand (COD) removals were obtained at 50 degrees C, with the Fe(+2)-to-substrate ratio range between 1:10 and 1:25. The change in H2O2-to-Fe(+2) ratios did not cause any considerable effect. Also, the percentages of COD removals were nearly the same, so the ratio H2O2:Fe(+2):1 is recommended. Aerobic pretreatment seems to be effective. On the other hand, no enhancement was observed in the case of the diluted wastewater.

  20. Conversion and Estrogenicity of 17β-estradiol During Photolytic/Photocatalytic Oxidation and Catalytic Wet-air Oxidation.

    Science.gov (United States)

    Bistan, Mirjana; Tišler, Tatjana; Pintar, Albin

    2012-06-01

    Estrogen 17β-estradiol (E2), produced by human body and excreted into municipal wastewaters, belongs to the group of endocrine disrupting compounds that are resistant to biological degradation. The aim of this study was to assess the efficiency of E2 removal from aqueous solutions by means of catalytic wet-air oxidation (CWAO) and photolytic/photocatalytic oxidation. CWAO experiments were conducted in a trickle-bed reactor at temperatures up to 230 °C and oxygen partial pressure of 10 bar over TiO2 and Ru/TiO2 solids. Photolytic/photocatalytic oxidation was carried out in a batch slurry reactor employing a TiO2 P-25 (Degussa) catalyst under visible or UV light. HPLC analysis and yeast estrogen screen assay were used to evaluate the removal of E2 and estrogenicity of treated samples. The latter was completely removed during photolytic/photocatalytic oxidation under UV (365 nm) light and photocatalytic oxidation under visible light. In CWAO experiments, complete removal of both E2 and estrogenicity from the feed solution were noticed in the presence of TiO2 and Ru/TiO2 catalysts.

  1. Catalytic Wet Air Oxidation of o-Chlorophenol in Wastewater%邻氯苯酚废水的催化湿式氧化处理

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翚

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatmentof o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence ofcatalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removedby wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperatureof 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited highcatalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCrwas removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had bettercatalytic activity for the degradation of o-chlorophenol in wastewater.

  2. Investigation on preparation of CuO-SnO2-CeO2/γ-Al2O3 catalysts for catalytic wet air oxidation process and their catalytic activity for degradation of phenol

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-jun; ZHANG Mi-lin; WAN Jia-feng; XIA Zhi; LIU Xiao-hui; LIU hui

    2008-01-01

    Catalytic Wet Air Oxidation process is an efficient measure for treatment of wastewater with great strength which is not biodegradable. Heterocatalysts now become the key investigation subject of catalytic wet air oxidation process due to their good stability and easy separation. In the paper, CuO-SnOE-CeO2/γ-Al2O3 catalysts are prepared by impregnation method, with SnO2 as a doping component, CuO as an active component, CeO2 as a structure stabilizer, γ-Al2O3 as a substrate. XPS test is carried out to investigate the effect of Sn on the chemical surrounding of Cu and O element on the catalyst surface and their catalytic activity. It is shown that the right do-ping of Sn can increase Cu+ content on the catalyst surface, as a result the quantity of adsorption oxygen is also increased. It is found that Cu + content on the catalyst surface is one of the primary factors that determin catalytic activity of catalyst through analyzing the catalytic wet air oxidation process of phenol.

  3. Chemical and toxicological evaluation of an emerging pollutant (enrofloxacin) by catalytic wet air oxidation and ozonation in aqueous solution.

    Science.gov (United States)

    Li, Yan; Zhang, Feifang; Liang, Xinmiao; Yediler, Ayfer

    2013-01-01

    This study evaluates the degradation efficiency of enrofloxacin (ENR) by catalytic wet air oxidation (CWAO) and ozonation. Results obtained by CWAO experiments show that 99.5% degradation, 37.0% chemical oxidation demand (COD) removal and 51.0% total organic carbon (TOC) conversion were obtained when 100 mol% FeCl(3) and 25 mol% NaNO(2) at 150 °C under 0.5 MPa oxygen pressure after 120 min are used. The degradation products are identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), gas chromatography-mass spectrometry (GC-MS) and ion chromatography (IC). The oxidation end products, F(-), NO(3)(-) and NH(4)(+) were determined by IC. The BOD(5)/COD ratio as a measure of the biodegradability of the parent compound increased from 0.01 to 0.12 after 120 min of reaction time, indicating an improved biodegradability of the parent compound. The inhibition of bioluminescence of the marine bacteria V. fischeri decreased from 43% to 12% demonstrating a loss in toxicity of ENR during CWAO. Ozonation of 0.2 mM ENR was carried out with an ozone concentration of 7.3 g m(-3) at pH 7. ENR decomposition with a degradation rate of 87% was obtained corresponding to the reaction time. Moderate changes in COD (18%) and TOC (17%) removal has been observed. The bioluminescence inhibition increased from 8% to 50%, due to the generation of toxic degradation products during ozonation. In comparison to the widely use of well developed method of ozonation CWAO exhibits better performance in terms of COD, TOC removals and generates less toxic products.

  4. Treatment of municipal landfill leachate by catalytic wet air oxidation: Assessment of the role of operating parameters by factorial design.

    Science.gov (United States)

    Anglada, Angela; Urtiaga, Ane; Ortiz, Inmaculada; Mantzavinos, Dionissios; Diamadopoulos, Evan

    2011-08-01

    The wet air oxidation (WAO) of municipal landfill leachate catalyzed by cupric ions and promoted by hydrogen peroxide was investigated. The effect of operating conditions such as WAO treatment time (15-30min), temperature (160-200°C), Cu(2+) concentration (250-750mgL(-1)) and H(2)O(2) concentration (0-1500mgL(-1)) on chemical oxygen demand (COD) removal was investigated by factorial design considering a two-stage, sequential process comprising the heating-up of the reactor and the actual WAO. The leachate, at an initial COD of 4920mgL(-1), was acidified to pH 3 leading to 31% COD decrease presumably due to the coagulation/precipitation of colloidal and other organic matter. During the 45min long heating-up period of the WAO reactor under an inert atmosphere, COD removal values up to 35% (based on the initial COD value) were recorded as a result of the catalytic decomposition of H(2)O(2) to reactive hydroxyl radicals. WAO at 2.5MPa oxygen partial pressure advanced treatment further; for example, 22min of oxidation at 200°C, 250mgL(-1) Cu(2+) and 0-1500mgL(-1) H(2)O(2) resulted in an overall (i.e. including acidification and heating-up) COD reduction of 78%. Amongst the operating variables in question, temperature had the strongest influence on both the heating-up and WAO stages, while H(2)O(2) concentration strongly affected the former and reaction time the latter. Nonetheless, the effects of temperature and H(2)O(2) concentration were found to depend on the concentration levels of catalyst as suggested by the significance of their 3rd order interaction term.

  5. [Catalytic stability in wet air oxidation of carboxylic acids over ZnFe0.25Al1.75 O4 catalyst].

    Science.gov (United States)

    Xu, Ai-hua; Yang, Min; Du, Hong-zhang; Peng, Fu-yong; Sun, Cheng-lin

    2007-07-01

    Oxalic, formic and acetic acid are main intermediate products in catalytic wet air oxidation process (CWAO). The catalytic activity and stability in CWAO of the three short-chain organic acids over ZnFe0.25Al1.75O4 catalyst were studied. Oxalic acid is the only oxidizable intermediate and the largest amount of Fe leaching is 9.5 mg L(-1) at 160 degrees C during CWAO process. Formic and acetic acid have little influence on Fe leaching. Due to the strong reducible ability of oxalic acid, the amount of Fe leaching is larger in nitrogen atmosphere than that in oxygen atmosphere. Salicylic acid can be also degraded by ZnFe0.25Al1.75O4 catalyst with a high catalytic activity and stability.

  6. Treatment of aniline by catalytic wet air oxidation: comparative study over CuO/CeO2 and NiO/Al2O3.

    Science.gov (United States)

    Ersöz, Gülin; Atalay, Süheyda

    2012-12-30

    The treatment of aniline by catalytic wet air oxidation (CWAO) was studied in a bubble reactor. The experiments were performed to investigate the effects of catalyst loading, temperature, reaction time, air flow rate, and pressure on aniline removal. The catalytic effects of the prepared nanostructured catalysts, CuO/CeO(2) (10% wt) and NiO/Al(2)O(3) (10% wt), on the CWAO treatment efficiency were also examined and compared. The prepared catalysts seem to be active having an aniline removal of 45.7% with CuO/CeO(2) and 41.9% with NiO/Al(2)O(3). The amount of N(2) formed was approximately the same for both of the catalysts.

  7. Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction

    Energy Technology Data Exchange (ETDEWEB)

    Vallet, Ana [Grupo de Catálisis y Procesos de Separación (CyPS), Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Ovejero, Gabriel, E-mail: govejero@quim.ucm.es [Grupo de Catálisis y Procesos de Separación (CyPS), Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Rodríguez, Araceli [Grupo de Catálisis y Procesos de Separación (CyPS), Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Peres, José A. [Centro de Química de Vila Real, Universidade de Trás-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real (Portugal); García, Juan, E-mail: juangcia@quim.ucm.es [Grupo de Catálisis y Procesos de Separación (CyPS), Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

    2013-01-15

    Highlights: ► Ni supported over hydrotalcite calcined precursors as catalyst. ► Catalytic wet air oxidation in trickle bed reactor for Chromotrope 2R removal. ► Dye removal depends on temperature, initial dye concentration and flow rate. ► The catalyst proved to bare-usable after in situ regeneration. -- Abstract: Active nickel catalysts (7 wt%) supported over Mg–Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min{sup −1} and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min{sup −1}, respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T{sub r} = 0.098 g{sub Ni} min mL{sup −1}. After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T{sub r} = 0.098 g{sub Ni} min mL{sup −1}, attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity.

  8. Influence of the different oxidation treatment on the performance of multi-walled carbon nanotubes in the catalytic wet air oxidation of phenol.

    Science.gov (United States)

    Yang, Shaoxia; Wang, Xingang; Yang, Hongwei; Sun, Yu; Liu, Yunxia

    2012-09-30

    Multi-walled carbon nanotubes (MWCNTs) functionalized by different oxidants (HNO(3)/H(2)SO(4), H(2)O(2), O(3) and air) have been used as catalysts for the wet air oxidation of phenol. To investigate the effect of the oxidation conditions on the structure of the functionalized MWCNTs, various characterization techniques, e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) have been used. The MWCNTs treated with O(3) and H(2)O(2) show higher amounts of oxygen-containing functional groups and carboxylic acid groups, and a weaker acidic nature, in comparison with those treated with other oxidizing agents. All the functionalized MWCNTs exhibit good activity in the catalytic wet air oxidation (CWAO) of phenol. However, the MWCNTs treated with O(3) show the highest activity with desirable stability in comparison with other functionalized MWCNTs, indicating that the functionalization of carbon nanotubes with O(3) is a very promising strategy in synthesizing efficient catalysts for CWAO.

  9. Ni/MgAlO regeneration for catalytic wet air oxidation of an azo-dye in trickle-bed reaction.

    Science.gov (United States)

    Vallet, Ana; Ovejero, Gabriel; Rodríguez, Araceli; Peres, José A; García, Juan

    2013-01-15

    Active nickel catalysts (7 wt%) supported over Mg-Al mixed oxides have been recently developed and it has also been demonstrated that they are also highly selective in Catalytic Wet air Oxidation (CWAO) of dyes. CWAO of Chromotrope 2R (C2R) has been studied using a trickle bed reactor employing temperatures from 100 to 180 °C, liquid flow rates from 0.1 to 0.7 mL min(-1) and initial dye concentration from 10 to 50 ppm. Total pressure and air flow were 25 bar and 300 mL min(-1), respectively. The catalyst showed a very stable activity up to 24 h on stream with an average TOC conversion of 82% at 150 °C and T(r)=0.098 g(Ni) min mL(-1). After the reaction, a 1.1 wt% C of carbonaceous deposit is formed onto the catalyst and a diminution of 30% of the surface area with respect of the fresh catalyst was observed. An increase in the space time gave higher TOC conversions up to T(r)=0.098 g(Ni) min mL(-1), attaining values of 80% at 180 °C. The performance of TOC and dye removal does not decrease after two regeneration cycles. In total, a 57 h effective reaction has been carried out with no loss of catalytic activity.

  10. Carbon and nitrogen removal from glucose-glycine melanoidins solution as a model of distillery wastewater by catalytic wet air oxidation.

    Science.gov (United States)

    Phuong Thu, Le; Michèle, Besson

    2016-06-05

    Sugarcane molasses distillery wastewater contains melanoidins, which are dark brown recalcitrant nitrogenous polymer compounds. Studies were carried out in batch mode to evaluate Pt and Ru supported catalysts in the Catalytic Wet Air Oxidation (CWAO) process of a synthetic melanoidins solution, prepared by stoichiometric reaction of glucose with glycine. The addition of a catalyst slightly improved TOC removal compared with the non-catalytic reaction, and especially promoted the conversion of ammonium produced from organically-bound nitrogen in melanoidins to molecular nitrogen and nitrate. The selectivity to N2 attained 89% in the presence of the Pt catalysts in the reaction conditions used (TOC=2200mgL(-1), TN=280mgL(-1), 0.5g catalyst loaded with 3% metal, 210°C, 70bar total air pressure). To avoid leaching of the active metal by organically-bound nitrogen, the reaction was very efficiently performed in a two-step reaction consisting in WAO to convert nitrogen into ammonium, before the introduction of a catalyst.

  11. Catalytic wet air oxidation of bisphenol A solution in a batch-recycle trickle-bed reactor over titanate nanotube-based catalysts.

    Science.gov (United States)

    Kaplan, Renata; Erjavec, Boštjan; Senila, Marin; Pintar, Albin

    2014-10-01

    Catalytic wet air oxidation (CWAO) is classified as an advanced oxidation process, which proved to be highly efficient for the removal of emerging organic pollutant bisphenol A (BPA) from water. In this study, BPA was successfully removed in a batch-recycle trickle-bed reactor over bare titanate nanotube-based catalysts at very short space time of 0.6 min gCAT g(-1). The as-prepared titanate nanotubes, which underwent heat treatment at 600 °C, showed high activity for the removal of aqueous BPA. Liquid-phase recycling (5- or 10-fold recycle) enabled complete BPA conversion already at 200 °C, together with high conversion of total organic carbon (TOC), i.e., 73 and 98 %, respectively. The catalyst was chemically stable in the given range of operating conditions for 189 h on stream.

  12. [Catalytic wet air oxidation of phenol with Ru/ZrO2-CeO2 catalyst].

    Science.gov (United States)

    Wang, Jian-bing; Zhu, Wan-peng; Wang, Wei; Yang, Shao-xia

    2007-07-01

    Wet air oxidation of phenol with Ru/ZrO2-CeO2 was systematically investigated and results showed that Ru/ZrO2-CeO2 could significantly increase the removal of COD and phenol. At the reaction temperature of 170 degrees C and pressure of 3MPa, about 99% COD and 100% phenol was removed respectively after 120 min. The optimal conditions were: reaction temperature, 170 degrees C; reaction pressure, 3 MPa; catalyst dosage, 5 g/L; agitator speed, 500 r/min. By analyzing intermediates, a simplified scheme of phenol oxidation was brought out. It includes two main steps. The first step is the production of organic acids, which is fast. The second step is the oxidation of organic acid, in which the oxidation of acetic acid is slow. Complete oxidation of acetic acid needs high temperature at which the radicals assault the C-H bond of a carbon and acetic acid is oxidized into carbon dioxide and water through formic acid.

  13. Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

    Science.gov (United States)

    Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

    2010-12-01

    This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.

  14. Degradation process analysis of the azo dyes by catalytic wet air oxidation with catalyst CuO/γ-Al2O3.

    Science.gov (United States)

    Hua, Li; Ma, Hongrui; Zhang, Lei

    2013-01-01

    Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide.

  15. Degradation of cationic red GTL by catalytic wet air oxidation over Mo-Zn-Al-O catalyst under room temperature and atmospheric pressure.

    Science.gov (United States)

    Xu, Yin; Li, Xiaoyi; Cheng, Xiang; Sun, Dezhi; Wang, Xueye

    2012-03-06

    To overcome the drawback of catalytic wet air oxidation (CWAO) with high temperature and high pressure, the catalytic activity of Mo-Zn-Al-O catalyst for degradation of cationic red GTL under room temperature and atmospheric pressure was investigated. Mo-Zn-Al-O catalyst was prepared by coprecipitation and impregnation. XRD, TG-DTG, and XPS were used to characterize the resulting sample. Central composition design using response surface methodology was employed to optimize correlation of factors on the decolorization of cationic red GTL. The results show that the optimal conditions of pH value, initial concentration of dye and catalyst dosage were found to be 4.0, 85 mg/L and 2.72 g/L, respectively, for maximum decolorization of 80.1% and TOC removal of 50.9%. Furthermore, the reaction on the Mo-Zn-Al-O catalyst and degradation mechanism of cationic red GTL was studied by Electron spin resonance (ESR) and GC-MS technique. The possible reaction mechanism was that the Mo-Zn-Al-O catalyst can efficiently react with adsorbed oxygen/H(2)O to produce ·OH and (1)O(2) and finally induce the degradation of cationic red GTL. GC-MS analysis of the degradation products indicates that cationic red GTL was initiated by the cleavage of -N ═ N- and the intermediates were further oxidized by ·OH or (1)O(2).

  16. 陶瓷-活性炭球为载体的CWAO催化剂%Ceramic-activated carbon sphere supported catalyst for catalytic wet air oxidation(CWAO)

    Institute of Scientific and Technical Information of China (English)

    刘卫民

    2012-01-01

    Ceramic-activated carbon sphere as support of ruthenium catalysts were evaluated through the catalytic wet air oxidation(CWAO) of resin effluent.The effects of the preparation conditions,such as ceramic-activated carbon sphere support,Ru loading,macro-pore diameter of ceramic sphere,etc.on the catalytic activity and stability were investigated.The results show that the catalytic activity varies according to the following order: Ru/KC-120 Ru/KC-80 Ru/KC-60 KC-120 without catalysts.It is found that the 3% Ru/KC-120 catalyst displayed highest stability in the CWAO of resin effluent during 120 min.Chemical oxygen demand(COD) and phenol removal were about 91% and 96%,respectively,at the reaction temperature of 200℃,oxygen pressure of 1.5 MPa.%以陶瓷-活性炭球为载体制备载Ru催化剂,用于催化湿式氧化(CWAO)法处理酚醛树脂废水,考察了陶瓷-活性炭球载体、Ru负载量和陶瓷球宏孔孔径等对催化剂的催化活性和稳定性的影响。实验结果表明,催化剂催化活性的顺序为:Ru/KC-120〉Ru/KC-80〉Ru/KC-60〉KC-120〉无催化剂。在200℃,氧气分压为1.5 MPa等条件下,催化湿式氧化酚醛树脂废水,3%Ru/KC-120催化剂表现良好的催化活性与稳定性,在120 min内,COD和苯酚去除率分别达到91%和96%。

  17. Catalytic wet air oxidation of phenol over CeO2-TiO2 catalyst in the batch reactor and the packed-bed reactor.

    Science.gov (United States)

    Yang, Shaoxia; Zhu, Wanpeng; Wang, Jianbing; Chen, Zhengxiong

    2008-05-30

    CeO2-TiO2 catalysts are prepared by coprecipitation method, and the activity and stability in the catalytic wet air oxidation (CWAO) of phenol are investigated in a batch reactor and packed-bed reactor. CeO2-TiO2 mixed oxides show the higher activity than pure CeO2 and TiO2, and CeO2-TiO2 1/1 catalyst displays the highest activity in the CWAO of phenol. In a batch reactor, COD and TOC removals are about 100% and 77% after 120 min in the CWAO of phenol over CeO2-TiO2 1/1 catalyst at reaction temperature of 150 degrees C, the total pressure of 3 MPa, phenol concentration of 1000 mg/L, and catalyst dosage of 4 g/L. In a packed-bed reactor using CeO2-TiO2 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 degrees C, the air total pressure of 3.5 MPa, the phenol concentration of 1000 mg/L for 100 h continue reaction. Leaching of metal ions of CeO2-TiO2 1/1 particle catalyst is very low during the continuous reaction. CeO2-TiO2 1/1 catalyst exhibits the excellent activity and stability in the CWAO of phenol.

  18. Microwave assisted catalytic wet air oxidation of H-acid in aqueous solution under the atmospheric pressure using activated carbon as catalyst.

    Science.gov (United States)

    Zhang, Yaobin; Quan, Xie; Chen, Shuo; Zhao, Yazhi; Yang, Fenglin

    2006-09-01

    Catalytic wet air oxidation (CWAO) is a promising method for the treatment of heavily contaminated wastewater. However, its application is restricted due to severe operation conditions (high pressure and high temperature). A microwave (MW) assisted oxidation method was investigated aiming to treat heavily contaminated wastewater under milder conditions. H-acid (1-amino-8-naphthol-3, 6-disulfonic acid) was selected as target compound to evaluate the performance of this novel process. The removal of H-acid and TOC (total organic carbon) for H-acid solution of 3000 mg/L reached as high as 92.6% in 20 min and 84.2% in 60 min, respectively under optimal conditions. The existence of activated carbon and oxygen proved to be critical for effective treatment. The activated carbon acted not only as a catalyst for H-acid decomposition, but also as a special material for the absorption of MW energy. Air was supplied to the reactor as an oxygen source at constant flows. The amino group in H-acid was converted ultimately into nitrate, and sulfonic group into sulfate. This observation gave an evidence of H-acid mineralization although other organic intermediates were unable to be determined. The value of BOD(5)/COD (ratio of 5d biochemical oxygen demand to chemical oxygen demand) increased from 0.008 to 0.467 indicating a significant improvement of biodegradability for the solution, which is beneficial for the further biological treatment of the wastewater.

  19. Catalytic behaviour and copper leaching of Cu0.10Zn0.90Al1.90Fe0.10O4 spinel for catalytic wet air oxidation of phenol.

    Science.gov (United States)

    Xu, Aihua; Sun, Chenglin

    2012-06-01

    A Cu0.10Zn0.90Al1.90Fe0.10O4 spinel catalyst prepared by the sol-gel method was tested for catalytic wet air oxidation (CWAO) of phenol. The catalyst showed high activity for phenol degradation. During successive test at 170 degrees C, 100% phenol conversion and 95% chemical oxygen demand (COD) removal were observed. Results from scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) indicated that the catalyst structure remained unchanged during reaction. From the analysis of temperature programmed reduction (TPR), diffuse reflectance UV-Vis spectra (DR UV-Vis) and activity assay at basic solution pH, it can be suggested that the highly dispersed copper ions on the catalyst surface were almost completely dissolved into the reaction solution, whereas the tetra-coordinated copper ions were not only stable against leaching but also active towards phenol degradation.

  20. Removal of salicylic acid on perovskite-type oxide LaFeO3 catalyst in catalytic wet air oxidation process.

    Science.gov (United States)

    Yang, Min; Xu, Aihua; Du, Hongzhang; Sun, Chenglin; Li, Can

    2007-01-02

    It has been found that salicylic acid can be removal effectively at the lower temperature of 140 degrees C on perovskite-type oxide LaFeO3 catalyst in the catalytic wet air oxidation (CWAO) process. Under the same condition, the activities for the CWAO of phenol, benzoic acid and sulfonic salicylic acid have been also investigated. The results indicated that, with compared to the very poor activities for phenol and benzoic acid, the activities for salicylic acid and sulfonic salicylic acid were very high, which are attributed to their same intramolecular H-bonding structures. With the role of hard acidity of intramolecular H-bonding, salicylic acid and sulfonic salicylic acid can be adsorbed effectively on the basic center of LaFeO3 catalyst and are easy to take place the total oxidation reaction. However, at temperatures higher than 140 degrees C, the intramolecular H-bonding structure of salicylic acid was destroyed and the activities at 160 and 180 degrees C decreased greatly, which confirms further the key role of intramolecular H-bonding in the CWAO. Moreover, the LaFeO3 catalyst also indicated a superior stability of activity and structure in CWAO of salicylic acid.

  1. Catalytic wet air oxidation of phenol over RuO2/γ-Al2O3 catalyst

    Institute of Scientific and Technical Information of China (English)

    YANG Shaoxia; FENG Yujie; CAI Weimin; ZHU Wanpeng; JIANG Zhanpeng; WAN Jiafeng

    2004-01-01

    A kind of CWAO catalyst, RuO2/γ-Al2O3, was prepared by dipping Al2O3 into the aqueous solution of RuCl3.3H2O. XRD, SEM and TEM were used to determine the catalytic structure. Influences of the calcination temperature,the initial pH of the feed solution and degradation temperature on the activity of the RuO2/γ-Al2O3 catalyst were investigated and the reaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO2 crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher at calcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO2 crystallites were abundant at high calcination temperature of 500℃. The activity of the catalyst was better in the acid solution than in the alkaline solution. Increasing degradation temperature and using the catalyst could shorten the induction periods so that the phenol and COD removal were increased. For RuO2/γ-Al2O3 catalyst, the phenol and COD removal were respectively 98% and 80% in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated that Ru/γ-Al2O3 catalyst had good activity.

  2. Catalytic properties of carbon materials for wet oxidation of aniline.

    Science.gov (United States)

    Gomes, Helder T; Machado, Bruno F; Ribeiro, Andreia; Moreira, Ivo; Rosário, Márcio; Silva, Adrián M T; Figueiredo, José L; Faria, Joaquim L

    2008-11-30

    A mesoporous carbon xerogel with a significant amount of oxygen functional groups and a commercial activated carbon, were tested in the catalytic wet air oxidation of aniline at 200 degrees C and 6.9 bar of oxygen partial pressure. Both carbon materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-catalytic wet air oxidation being observed. The best results in terms of aniline removal were obtained with carbon xerogel, an almost complete aniline conversion after 1h oxidation with high selectivity to non-organic compounds being achieved. The materials were characterized by thermogravimetric analysis, temperature programmed desorption, N(2) adsorption and scanning electron microscopy, in order to relate their performances to the chemical and textural characteristics. It was concluded that the removal efficiency, attributed to both adsorption and catalytic activity, is related to the mesoporous character of the materials and to the presence of specific oxygen containing functional groups at their surface. The effect of catalytic activity was found to be more important in the removal of aniline than the effect of adsorption at the materials surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.

  3. Catalytic properties of carbon materials for wet oxidation of aniline

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Helder T. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Departamento de Tecnologia Quimica e Biologica, Escola Superior de Tecnologia e de Gestao, Instituto Politecnico de Braganca, Campus de Santa Apolonia, 5300-857 Braganca (Portugal); Machado, Bruno F.; Ribeiro, Andreia; Moreira, Ivo; Rosario, Marcio; Silva, Adrian M.T.; Figueiredo, Jose L. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Faria, Joaquim L. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: jlfaria@fe.up.pt

    2008-11-30

    A mesoporous carbon xerogel with a significant amount of oxygen functional groups and a commercial activated carbon, were tested in the catalytic wet air oxidation of aniline at 200 deg. C and 6.9 bar of oxygen partial pressure. Both carbon materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-catalytic wet air oxidation being observed. The best results in terms of aniline removal were obtained with carbon xerogel, an almost complete aniline conversion after 1 h oxidation with high selectivity to non-organic compounds being achieved. The materials were characterized by thermogravimetric analysis, temperature programmed desorption, N{sub 2} adsorption and scanning electron microscopy, in order to relate their performances to the chemical and textural characteristics. It was concluded that the removal efficiency, attributed to both adsorption and catalytic activity, is related to the mesoporous character of the materials and to the presence of specific oxygen containing functional groups at their surface. The effect of catalytic activity was found to be more important in the removal of aniline than the effect of adsorption at the materials surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.

  4. Comparative study of supported CuOx and MnOx catalysts for the catalytic wet air oxidation of β-naphthol

    Science.gov (United States)

    Liu, Jie; Yu, Chaoying; Zhao, Peiqing; Chen, Gexin

    2012-09-01

    MnOx/nano-TiO2, MnOx/Al2O3-TiO2 (Al-Ti), CuOx/nano-TiO2 and CuOx/Al-Ti were prepared and their application in catalytic wet air oxidation (CWAO) of β-naphthol were investigated. The catalysts had been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. Phases of CuO, Cu2O, CuAl2O4, MnO2 and Mn2O3 could be found on the surface of the aforementioned catalysts. Significant differences in activities were observed among the prepared catalysts. Compared to CuOx/nano-TiO2, the combined action of highly dispersed CuO as well as CuAl2O4 of CuOx/Al-Ti helped to achieve higher activity for the CWAO of β-naphthol, while the Cu2O component lead to lower efficiency of CuOx/nano-TiO2. On the surface of MnOx/nano-TiO2, both the larger amount of highly dispersed MnO2 and the stronger electron transfer between MnO2 and Mn2O3 were helpful to promote the activity for the degradation of β-naphthol. However, the higher amount of bulk MnO2 and the weaker electron transfer for MnOx/Al-Ti were unfavorable to increase its efficiency. Among the four catalysts as-prepared, MnOx/nano-TiO2 was identified the highest activity with 93.7% COD removal.

  5. Integrated catalytic wet air oxidation and aerobic biological treatment in a municipal WWTP of a high-strength o-cresol wastewater.

    Science.gov (United States)

    Suarez-Ojeda, María Eugenia; Guisasola, Albert; Baeza, Juan A; Fabregat, Azael; Stüber, Frank; Fortuny, Agustí; Font, Josep; Carrera, Julián

    2007-02-01

    This study examines the feasibility of coupling a Catalytic Wet Air Oxidation (CWAO), with activated carbon (AC) as catalyst, and an aerobic biological treatment to treat a high-strength o-cresol wastewater. Two goals are pursued: (a) To determine the effect of the main AC/CWAO intermediates on the activated sludge of a municipal WasteWater Treatment Plant (WWTP) and (b) To demonstrate the feasibility of coupling the AC/CWAO effluent as a part of the influent of a municipal WWTP. In a previous study, a high-strength o-cresol wastewater was treated by AC/CWAO aiming to establish the distribution of intermediates and the biodegradability enhancement. In this work, the biodegradability, toxicity and inhibition of the most relevant intermediates detected in the AC/CWAO effluent were determined by respirometry. Also, the results of a pilot scale municipal WWTP study for an integrated AC/CWAO-aerobic biological treatment of this effluent are presented. The biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) of main AC/CWAO intermediates allowed the classification of the intermediates into readily biodegradable, inert or toxic/inhibitory compounds. This detailed study, allowed to understand the biodegradability enhancement exhibited by an AC/CWAO effluent and to achieve a successful strategy for coupling the AC/CWAO step with an aerobic biological treatment for a high-strength o-cresol wastewater. Using 30%, as COD, of AC/CWAO effluent in the inlet to the pilot scale WWTP, the integrated AC/CWAO-biological treatment achieved a 98% of total COD removal and, particularly, a 91% of AC/CWAO effluent COD removal without any undesirable effect on the biomass.

  6. Cu/TiO2催化湿式氧化甲醛废水%CATALYTIC WET AIR OXIDATION OF FORMALDEHYDE BY Cu/TiO2

    Institute of Scientific and Technical Information of China (English)

    李艳; 张科军; 杜青; 章飞芳; 顾江萍; 梁鑫淼

    2012-01-01

    Formaldehyde wastewater would destroy ecological system and influence human health when discharging the wastewater into the water body. This study mainly focused on the degradation of formaldehyde wastewater by catalytic wet air oxidation (CWAO) with the self-prepared Cu/TiO2 as catalyst. After optimizing the reaction conditions, Total Organic Carbon (TOC) removal reached 85% and the toss of Cu2+ and Ti4+ was very low under 180X?, pH=5, 0.5MPa with 6 g/L catalyst after 2 h reaction. Finally, mcthanol in formaldehyde solution and the degradation products formic acid were detected Results demonstrated that CWAO with Cu/TiO] as catalyst could remove formaldehyde in wastewater efficiently.%甲醛废水排放入水体后,破坏生态系统,影响人们的身体健康.考察了以自制的Cu/TiO2为催化剂,用催化湿式氧化的方法降解甲醛废水的情况.通过优化反应条件,在180℃、pH=5、0.5 MPa、催化剂量为6g/L时反应2h,TOC的去除率高达85%且Cu2+和TP4+基本没有流失.此外还检测了甲醛溶液中甲醇变化情况和经处理后甲醛废水的降解产物甲酸.结果表明,以Cu/TiO2为催化剂的催化湿式氧化能有效地降解甲醛废水.

  7. 湿式催化氧化催化剂及其活性组分流失控制的研究%Research on Catalyst and Control of Active Catalyst Components Lossing in Catalytic Wet Air Oxidation

    Institute of Scientific and Technical Information of China (English)

    王锐; 尹华强; 李建军; 郭家秀; 任吉萍

    2011-01-01

    Catalytic Wet Air Oxidation is an efficient and feasible technology for high concentration and refractory organic wastewater treatment. But the lossing of the active components of catalyst induced decreased catalytic activity, shorter life, higher investment costs, etc. in industrial operation In the paper, the catalytic wet oxidation technology and catalyst applications were described. What's more, the loss mechanism of the catalyst, affecting factors and methods to improve catalyst stability were emphatically illustrated, at the same time, related experiments and the results obtained are introduced.%湿式催化氧化技术是一种处理高浓度、难降解有机废水的高效、可行的技术,但是在使用过程中,活性组分易流失,在工业化应用中带来催化活性降低、使用寿命变短、投资成本增高等问题。文中介绍了湿式催化氧化技术及催化剂研究,着重讲述催化剂流失机理、影响因素以及提高催化剂稳定的方法,同时对相关实验和成果也做了介绍。

  8. Pretreatment of Cartap Wastewater by Catalytic Wet Air Oxidation%湿式催化氧化预处理杀螟丹农药废水的研究

    Institute of Scientific and Technical Information of China (English)

    袁美和; 舒和英; 王学文; 陈征宇; 袁聪

    2015-01-01

    Inhomogeneous catalytic wet air oxidation was applied to pretreat wastewater of cartap using Mn/Ce mixed oxide cata-lysts. The influence of reaction temperature, reaction pressure, water distribution pH value, catalytic agent dose on the treatment ef-fect of cartap wastewater was observed and studied, the better technologic conditions were obtained based on our study. The result showed that the removal rate of COD would up to 92.5% when the reaction temperature was 180℃, reaction pressure was 1.3MPa, solution pH value was 9, catalytic agent dose was 7g/L.%以Mn/Ce复合氧化物催化剂的非均相的湿式催化氧化处理杀螟丹生产废水.考察了反应温度、反应压力、配水pH值、催化剂用量等因素对杀螟丹农药废水处理效果的影响,并依此确定较佳的工艺条件.结果表明,当反应温度为180℃,反应压力为1.3MPa,溶液pH值为9,催化剂用量为7g·L-1,在此条件下,COD的去除率达到92.5%以上.

  9. Research Progress on Catalytic Wet Air Oxidation for Treating Highly Concentrated Wastewater%催化湿式氧化处理高浓度有机废水的研究进展

    Institute of Scientific and Technical Information of China (English)

    李云; 袁志文

    2013-01-01

    The reaction principle,technical flow and catalyst research progress of catalytic wet air oxidation technology were introduced.Its application in wastewater treatment was analyzed and summarized.The problems existing in current application were reviewed,and some pieces of advice about the research were proposed.%介绍了催化湿式氧化技术的反应原理、工艺流程以及近些年来不同种催化剂的研究进展,分析和归纳了催化湿式氧化技术在污水处理中的应用现状,对实际应用中出现的问题进行了总结,并提出了一些建议.

  10. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  11. Research Progress on Catalyst of Catalytic Wet Air Oxidation for Phenol Wastewater%催化湿式氧化含酚废水催化剂的研究进展

    Institute of Scientific and Technical Information of China (English)

    李荣; 段大勇

    2015-01-01

    Catalytic wet air oxidation ( CWAO ) technology is an effective technology for phenol wastewater, developing and selecting suitable catalyst is a key factor of CWAO. Active components were briefly introduced and CWAO catalyst for phenol wastewater treatment was carried out. It was specified that selecting the best combination of suitable active component and carrier of CWAO catalyst can improve the efficiency of phenol degradation, developing the catalyst with high activity, stability and cheap characteristics was the development direction of CWAO for phenol wastewater treatment.%催化湿式氧化技术是处理含酚废水的有效技术,此技术的关键是合适催化剂的研制和选用。本文对催化湿式氧化含酚废水催化剂的活性组分、载体等情况进行了综述,并指出选用最佳活性组分和载体的组合能够提高催化剂对苯酚的降解效率,研发高活性、高稳定性及廉价的催化剂是催化湿式氧化含酚废水的发展方向。

  12. 湿式氧化法处理工业废水的实验教学设计%Experimental teaching design of treating industrial wastewater by catalytic wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    李道圣; 王小聪; 占伟; 康建雄; 刘冬啟

    2012-01-01

    To combine the experimental teaching with scientific research tightly, an experiment was designed to treat industrial wastewater by catalytic wet air oxidation. The impacts on the oxidation efficiencies of the type of the catalysts, reaction temperature, and catalyst contents were studied, and the bioability of the wastewater after treatment was also investigated. This proposal provided the students with a better understanding and mastering of the detection principle, the operation procedure and the analysis method.%为实现实验教学与科研工作的紧密结合,该教学设计采用催化湿式氧化技术对工业废水进行处理.通过研究催化剂种类、反应温度和催化剂的投加量对处理效果的影响、考察处理后废水的可生化性变化,使学生更好地理解和掌握催化湿式氧化技术处理工业废水的基本原理、操作步骤及结果分析方法.

  13. [Research on synergy of combining electrochemical oxidation and catalytic wet oxidation].

    Science.gov (United States)

    Wang, Hua; Li, Guang-Ming; Zhang, Fang; Huang, Ju-Wen

    2009-07-15

    A new catalytic wet oxidation fixed-bed reactor combined with three-dimensional electric-field was developed to investigate catalytic wet oxidation, electrochemical oxidation and electroassisted catalytic wet oxidation of the solution containing phenol in the presence of a catalyst Mn-Sn-Sb-3/gamma-Al2O3. Good electroassisted catalytic wet oxidation efficiency was obtained in the setup for the combination system even at mild conditions (T = 130 degrees C, po2 = 1.0 MPa) that the phenol conversion and TOC reduction were up to 94.0% and 88.4% after 27 min treatment, respectively. The result also shows that the rate constants of electroassisted catalytic wet oxidation are much higher than that of not only both catalytic wet oxidation and electrochemical oxidation process alone but also additive efficiencies of catalytic wet oxidation and electrochemical oxidation processes, which indicates an apparent synergetic effect between CWO and ECO processes.

  14. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  15. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  16. Thermal and sonochemical synthesis of porous (Ce,Zr)O2 mixed oxides from metal β-diketonate precursors and their catalytic activity in wet air oxidation process of formic acid.

    Science.gov (United States)

    Cau, Camille; Guari, Yannick; Chave, Tony; Larionova, Joulia; Nikitenko, Sergey I

    2014-07-01

    Porous (Ce0.5Zr0.5)O2 solid solutions were prepared by thermolysis (T=285 °C) or sonolysis (20 kHz, I=32 W cm(-2), Pac=0.46 W mL(-1), T=200 °C) of Ce(III) and Zr(IV) acetylacetonates in oleylamine or hexadecylamine under argon followed by heat treatment of the precipitates obtained in air at 450 °C. Transmission Electron Microscopy images of the samples show nanoparticles of ca. 4-6 nm for the two synthetic approaches. The powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and μ-Raman spectroscopy of solids obtained after heat treatment indicate the formation of (Ce0.5Zr0.5)O2 solid solutions with a metastable tetragonal crystal structure for the two synthetic routes. The specific surface area of the samples varies between 78 and 149 m(2) g(-1) depending on synthesis conditions. The use of Barrett-Joyner-Halenda and t-plot methods reveal the formation of mixed oxides with a hybrid morphology that combines mesoporosity and microporosity regardless of the method of preparation. Platinum nanoparticles were deposited on the surface of the mixed oxides by sonochemical reduction of Pt(IV). It was found that the materials prepared by sonochemistry exhibit better resistance to dissolution during the deposition process of platinum. X-ray photoelectron spectroscopy analysis shows the presence of Pt(0) and Pt(II) on the surface of mixed oxides. Porous (Ce0.5Zr0.5)O2 mixed oxides loaded with 1.5%wt. platinum exhibit high activity in catalytic wet air oxidation of formic acid at 40 °C.

  17. Catalytic wet hydrogen peroxide oxidation of a petrochemical wastewater.

    Science.gov (United States)

    Pariente, M I; Melero, J A; Martínez, F; Botas, J A; Gallego, A I

    2010-01-01

    Continuous Catalytic Wet Hydrogen Peroxide Oxidation (CWHPO) for the treatment of a petrochemical industry wastewater has been studied on a pilot plant scale process. The installation, based on a catalytic fixed bed reactor (FBR) coupled with a stirred tank reactor (STR), shows an interesting alternative for the intensification of a continuous CWHPO treatment. Agglomerated SBA-15 silica-supported iron oxide (Fe(2)O(3)/SBA-15) was used as Fenton-like catalyst. Several variables such as the temperature and hydrogen peroxide concentration, as well as the capacity of the pilot plant for the treatment of inlet polluted streams with different dilution degrees were studied. Remarkable results in terms of TOC reduction and increased biodegradability were achieved using 160 degrees C and moderate hydrogen peroxide initial concentration. Additionally, a good stability of the catalyst was evidenced for 8 hours of treatment with low iron leaching (less than 1 mg/L) under the best operating conditions.

  18. Process of forming catalytic surfaces for wet oxidation reactions

    Science.gov (United States)

    Jagow, R. B. (Inventor)

    1977-01-01

    A wet oxidation process was developed for oxidizing waste materials, comprising dissolved ruthenium salt in a reactant feed stream containing the waste materials. The feed stream is introduced into a reactor, and the reactor contents are then raised to an elevated temperature to effect deposition of a catalytic surface of ruthenium black on the interior walls of the reactor. The feed stream is then maintained in the reactor for a period of time sufficient to effect at least partial oxidation of the waste materials.

  19. Degradation of phenol via wet-air oxidation over CuO/CeO2-ZrO2 nanocatalyst synthesized employing ultrasound energy: physicochemical characterization and catalytic performance.

    Science.gov (United States)

    Parvas, Mohsen; Haghighi, Mohammad; Allahyari, Somaiyeh

    2014-01-01

    Catalytic wet air oxidation (CWAO) of phenol was carried out under atmospheric pressure of oxygen at 160 degrees C in a stirred batch reactor over copper catalysts supported by CeO2-ZrO2. The copper with different loadings were impregnated over the composite support by a sonication process. The catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) specific surface area and Fourier-transformed infrared analyses. Characteristic peaks attributed to copper were not found in XRD patterns even at high loadings, but based on EDX results, the existence of copper particles was confirmed. It means that sonochemical synthesis method even at high loadings produced small copper particles with low crystallinity and excellent dispersion over the CeO2-ZrO2 composite. FESEM micrographs indicated just slight enhancement in particle size at high loadings of Cu. Blank CWAO experiments illustrated low conversion of phenol using bare CeO2-ZrO2 support. Although some agglomeration of particles was found at high loadings of copper but owning to the fact that almost all ZrO2 particles incorporated into the CeO2 lattice at high contents of Cu, catalyst activity not only did not decrease but also the phenol conversion reached to the higher values. The optimal catalyst loading for phenol degradation was found to be 9 g/l. Complete conversion of phenol was achieved using CuO/CeO2-ZrO2 in 9 g/l catalyst loading with initial phenol concentration of 1000 ppm after 3 h of reaction.

  20. Evolution of toxicity upon wet catalytic oxidation of phenol.

    Science.gov (United States)

    Santos, A; Yustos, P; Quintanilla, A; García-Ochoa, F; Casas, J A; Rodríguez, J J

    2004-01-01

    This work reports on the evolution of the toxicity of phenol-containing simulated wastewater upon catalytic wet oxidation with a commercial copper-based catalyst (Engelhard Cu-0203T). The results of the study show that this catalyst enhances detoxification, in addition to its effect on the oxidation rate. The EC50 values of the intermediates identified throughout the oxidation route of phenol have been determined and used to predict the evolution of toxicity upon oxidation. The predicted values have been compared with the ones measured directly from the aqueous solution during the oxidation process. To learn about the evolution of toxicity through out the routes of phenol oxidation, experiments have been performed with simulated wastewaters containing separately phenol, catechol, and hydroquinone as original pollutants. The significant increase of toxicity observed during the early stages of phenol oxidation is not directly related to the development of the brown color that derives mainly from catechol oxidation. This increase of toxicity is caused by the formation of hydroquinone and p-benzoquinone as intermediates, the former showing the highest toxicity. Furthermore, synergistic effects, giving rise to a significant increase of toxicity, have been observed. These effects derive from the interactions among copper leached from the catalyst and catechol, hydroquinone, and p-benzoquinone and demand that close attention be paid to this potential problem in catalytic wet oxidation.

  1. Wet peroxide oxidation and catalytic wet oxidation of stripped sour water produced during oil shale refining.

    Science.gov (United States)

    Prasad, Jaidev; Tardio, James; Jani, Harit; Bhargava, Suresh K; Akolekar, Deepak B; Grocott, Stephen C

    2007-07-31

    Catalytic wet oxidation (CWO) and wet peroxide oxidation (WPO) of stripped sour water (SSW) from an oil shale refinery was investigated. Greater than 70% total organic carbon (TOC) removal from SSW was achieved using Cu(NO(3))(2) catalysed WO under the following conditions using a glass lined reaction vessel: 200 degrees C, pO(2)=0.5MPa, 3h, [Cu(NO(3))(2)]=67mmol/L. Significant TOC removal ( approximately 31%) also occurred in the system without added oxygen. It is proposed that this is predominantly due to copper catalysed oxidative decarboxylation of organics in SSW based on observed changes in copper oxidation state. Greater than 80% TOC removal was achieved using WPO under the following conditions: 150 degrees C, t=1.5h, [H(2)O(2)]=64g/L. Significantly more TOC could be removed from SSW by adding H(2)O(2) in small doses as opposed to adding the same total amount in one single dose. It was concluded that WPO was a far more effective process for removing odorous compounds from SSW.

  2. Wet air oxidation of epoxy acrylate monomer industrial wastewater.

    Science.gov (United States)

    Yang, Shaoxia; Liu, Zhengqian; Huang, Xiaohui; Zhang, Beiping

    2010-06-15

    Epoxy acrylate monomer industrial wastewater contained highly concentrated and toxic organic compounds. The wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were used to eliminate pollutants in order to examine the feasibility of the WAO/CWAO as a pre-treatment method for the industrial wastewater. The results showed that in the WAO 63% chemical oxygen demand (COD) and 41% total organic carbon (TOC) removals were achieved and biological oxygen demand (BOD(5))/COD ratio increased from 0.13 to 0.72 after 3h reaction at 250 degrees C, 3.5MPa and the initial concentration of 100g(COD)/L. Among homogenous catalysts (Cu(2+), Fe(2+), Fe(3+) and Mn(2+) salts), Cu(2+) salt exhibited better performance. CuO catalyst was used in the CWAO of the wastewater, COD and TOC conversion were 77 and 54%, and good biodegradability was achieved. The results proved that the CWAO was an effective pre-treatment method for the epoxy acrylate monomer industrial wastewater.

  3. Catalytic wet oxidation of aqueous methylamine: comparative study on the catalytic performance of platinum-ruthenium, platinum, and ruthenium catalysts supported on titania.

    Science.gov (United States)

    Song, Aiying; Lu, Gongxuan

    2015-01-01

    Promotion of the dispersion of Ru species supported on TiO2 was achieved by introduction of Pt component and the role of Pt in enhancing the catalytic performances of Pt-Ru was investigated with catalytic wet air oxidation of methylamine used as a probing reaction. It was found that Pt-Ru/TiO2 displayed a much better catalytic performance compared with Pt/TiO2 and Ru/TiO2 catalysts due to having the highest dispersion of active species. Both high total organic carbon conversion and nitrogen selectivity (∼100%) over Pt-Ru/TiO2 catalyst were achieved at low temperature (200 °C). X-ray photoelectron spectroscopy characterization indicated that there were strong interactions between metal particles and the support, which may increase the catalytic performance of catalysts.

  4. Study on mechanism of wet air oxidation of emulsification wastewater.

    Science.gov (United States)

    Tang, Wen W; Zeng, Xin P; Xiao, Yao M; Gu, Guo W

    2009-04-01

    Wet air oxidation (WAO) can effectively be used to treat high-concentration, non-biodegradable emulsification wastewater that contains nonionic matters. Gas chromatograph analysis of emulsification wastewater after oxidation indicated that a catalyst increased production of fatty acids but could not promote its oxidation between 160 and 180 degrees C. When the temperature was greater than or equal to 220 degrees C, the catalyst not only increased production of fatty acids initially but effectively promoted its oxidation in later stages and significantly reduced the concentration of residual surfactants. Experiments proved that fatty acids (especially acetic acid) were the primary intermediate products and that oxidation of these acids was the rate-limiting step. During the process of catalytic WAO of emulsification wastewater, active oxygen molecules attacked organic matters resulting in production of fatty acids, ketone, alcohol, hydrocarbon, and oligo-polyether through radical chain reactions.

  5. Study on Catalytic Wet Oxidation of H2S into Sulfur on Fe/Cu Catalyst

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A wet catalytic oxidation at room temperature was investigated with solution containing ferric, ferrous and cupric ions for H2S removal. The experiments were carried out in a two step process,and the results obtained show that the removal efficiency of H2S can always reach 100% in a 300 mm scrubbing column with four sieve plates, and the regeneration of ferric ions in 200 mm bubble column can match the consumed ferric species in absorption. Removal of H2S, production of elemental sulfur and regeneration of ferric, cupric ions can all be accomplished at the same time. No raw material is consumed except O2 in flue gas or air, the process has no secondary pollution and no problem of catalyst degradation and congestion.

  6. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)

    1993-12-31

    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  7. The applicability of the catalytic wet-oxidation to CELSS

    Science.gov (United States)

    Takahashi, Y.; Nitta, K.; Ohya, H.; Oguchi, M.

    1987-01-01

    The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

  8. Wet-air oxidation cleans up black wastewater

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    Sterling Organics produces the analgesic paracetamol (acetaminophen) at its Dudley, England, plant. The wastewater from the batch process contains intermediates such as para-aminophenol (PAP) and byproducts such as thiosulfates, sulfites and sulfides. To stay ahead of increasingly strict environmental legislation, Sterling Organics installed a wet-air oxidation system at the Dudley facility in August 1992. The system is made by Zimpro Environmental Inc. (Rothschild, Wis.). Zimpro's wet-air oxidation system finds a way around the limitations of purely chemical or physical processes. In the process, compressed air at elevated temperature and pressure oxidizes the process intermediates and byproducts and removes the color from the wastewater.

  9. CuO impregnated activated carbon for catalytic wet peroxide oxidation of phenol.

    Science.gov (United States)

    Liou, Rey-May; Chen, Shih-Hsiung

    2009-12-15

    This paper presents an original approach to the removal of phenol in synthetic wastewater by catalytic wet peroxide oxidation with copper binding activated carbon (CuAC) catalysts. The characteristics and oxidation performance of CuAC in the wet hydrogen peroxide catalytic oxidation of phenol were studied in a batch reactor at 80 degrees C. Complete conversion of the oxidant, hydrogen peroxide, was observed with CuAC catalyst in 20 min oxidation, and a highly efficient phenol removal and chemical oxygen demand (COD) abatement were achieved in the first 30 min. The good oxidation performance of CuAC catalyst was contributed to the activity enhancement of copper oxide, which was binding in the carbon matrix. It can be concluded that the efficiency of oxidation dominated by the residual H2O2 in this study. An over 90% COD removal was achieved by using the multiple-step addition in this catalytic oxidation.

  10. [Copper leaching in catalytic wet oxidation of phenol with Cu-containing spinel].

    Science.gov (United States)

    Xu, Ai-hua; He, Song-bo; Yang, Min; Du, Hong-zhang; Sun, Cheng-lin

    2008-09-01

    The Cu0.10, Zn0.90 Al1.90 Fe0.10 O4 spinel type catalyst prepared by sol-gel method was tested for catalytic wet air oxidation of phenol. The performances of Cu0.10 Zn0.90 Al1.90 Fe0.10 O4 catalyst in TPR experiment, the influence of phenol as reducer, reaction temperature and phenol-to-catalyst mass ratio on copper leaching were checked respectively. According to the experimental results, it is suggested that the reduced active species can not be easily re-oxidized under low reaction temperature and high phenol-to-catalyst mass ratio are the main reasons for copper leaching. Under high enough reaction temperature and low phenol-to-catalyst mass ratio, the copper leaching reduces remarkably. At 190 degrees C in the presence of 100 mL aqueous solution of 4.29 g x L(-1) of phenol and 2.5 g catalyst, the copper leaching was only 0.96 mg x L(-1) after 2 h of reaction.

  11. Low-temperature catalytic gasification of wet industrial wastes

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D C; Neuenschwander, G G; Baker, E G; Sealock, Jr, L J; Butner, R S

    1991-04-01

    Bench-scale reactor tests are in progress at Pacific Northwest Laboratory to develop a low-temperature, catalytic gasification system. The system, licensed under the trade name Thermochemical Environmental Energy System (TEES{reg sign}), is designed for treating a wide variety of feedstocks ranging from dilute organics in water to waste sludges from food processing. This report describes a test program which used a continuous-feed tubular reactor. This test program is an intermediate stage in the process development. The reactor is a laboratory-scale version of the commercial concept as currently envisioned by the process developers. An energy benefit and economic analysis was also completed on the process. Four conceptual commercial installations of the TEES process were evaluated for three food processing applications and one organic chemical manufacturing application. Net energy production (medium-Btu gas) was achieved in all four cases. The organic chemical application was found to be economically attractive in the present situation. Based on sensitivity studies included in the analysis, the three food processing cases will likely become attractive in the near future as waste disposal regulations tighten and disposal costs increase. 21 refs., 2 figs., 9 tabs.

  12. Ultrasound assisted catalytic wet peroxide oxidation of phenol: kinetics and intraparticle diffusion effects.

    Science.gov (United States)

    Nikolopoulos, Apostolos N; Igglessi-Markopoulou, Olga; Papayannakos, Nikolaos

    2006-01-01

    The combination of ultrasound irradiation and catalytic wet peroxide oxidation was used as a means to degrade phenol. Direct and indirect irradiation were employed, while experiments in the absence of ultrasound were used as reference. A mixed (Al-Fe) pillared clay named FAZA, was used as a catalyst in the form of powder, extrudates and crushed extrudates. Ultrasound was found to clearly enhance the extrudates performance, increasing the conversion at 4h by more than 6 times under direct and almost 11 times under indirect irradiation. This observation is attributed to the reduction of diffusion resistance within the catalyst pores. The overall sonication-catalytic wet peroxide oxidation process appears very promising for environmental purposes.

  13. Magnetic carbon xerogels for the catalytic wet peroxide oxidation of 4-nitrophenol solutions

    OpenAIRE

    Ribeiro, R.; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2015-01-01

    Catalytic wet peroxide oxidation (CWPO) is a well-known advanced oxidation process for the removal of organic pollutants from industrial process waters and wastewater. Specifically, CWPO employs hydrogen peroxide (H2O2) as oxidation source and a suitable catalyst to promote its decomposition via formation of hydroxyl radicals (HO•), which exhibit high oxidizing potential and serve as effective species in the destruction of a huge range of organic pollutants

  14. Glycerol-based carbon materials for the catalytic wet peroxide oxidation process

    OpenAIRE

    Ribeiro, Rui S.; Silva, Adrián; Pinho, Maria; Figueiredo,José; Faria, Joaquim; Gomes, Helder

    2013-01-01

    It is known that metal-free carbon materials can act as catalysts for the catalytic wet peroxide oxidation (CWPO) process to treat organic pollutants in aqueous solutions [I]. On the other hand, crude glycerol, such as resulting from biodiesel production, is being offered as an abundant and low cost feedstock [2]. In the present work, glycerol-based carbon materials (OBCMs) with distinct properties were produced and tested as catalysts for CWPO, using 2-nitrophenol (2-NP) as a ...

  15. Catalytic wet-oxidation of a mixed liquid waste: COD and AOX abatement.

    Science.gov (United States)

    Goi, D; de Leitenburg, C; Trovarelli, A; Dolcetti, G

    2004-12-01

    A series of catalytic wet oxidation (CWO) reactions, at temperatures of 430-500 K and in a batch bench-top pressure vessel were carried out utilizing a strong wastewater composed of landfill leachate and heavily organic halogen polluted industrial wastewater. A CeO2-SiO2 mixed oxide catalyst with large surface area to assure optimal oxidation performance was prepared. The catalytic process was examined during batch reactions controlling Chemical Oxygen Demand (COD) and Adsorbable Organic Halogen (AOX) parameters, resulting AOX abatement to achieve better effect. Color and pH were also controlled during batch tests. A simple first order-two stage reaction behavior was supposed and verified with the considered parameters. Finally an OUR test was carried out to evaluate biodegradability changes of wastewater as a result of the catalytic reaction.

  16. Oxidation and mineralisation of substituted phenols by Fenton's reagent and catalytic wet oxidation.

    Science.gov (United States)

    Santos, A; Rodriguez, S; Garcia-Ochoa, F; Yustos, P

    2007-01-01

    Catalytic abatement of solutions of 1,000 mg/L in phenol, ortho and para nitrophenol and ortho and para cresols was acomplished by using two catalytic systems. Fenton's reagent was used at 50 degrees C by adding 10 mg/L of ferrous cation and different dosages of H2O2. The mixture was reacting isothermically in a batch way during 3 hours. Catalytic wet oxidation (CWO) was carried out by using a commercial Activated Carbon, Industrial React FE01606A, CWO runs were carried out in a fixed bed reactor (FBR) with concurrent upflow. Temperature and oxygen pressure of the reactor were set to 160 degrees C and 16 bar, respectively. While phenols are quicky oxidised by the Fenton reagent higher mineralisation was obtained in the CWO process.

  17. Graphene oxide as an effective catalyst for wet air oxidation of phenol.

    Science.gov (United States)

    Yang, Shaoxia; Cui, Yuhong; Sun, Yu; Yang, Hongwei

    2014-09-15

    The graphene oxide (GO) and chemically reduced graphene oxides, used as catalysts in absence of any metals, were investigated in the catalytic wet air oxidation (CWAO) of phenol in a batch reactor. The characterization of the materials was measured with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman, fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The carbon materials exhibited good phenol and total organic compounds (TOC) removals in the CWAO of phenol. The GO had the highest catalytic activity, total phenol removal was achieved after 40 min, and ca. 84% TOC removal was obtained after 120 min at reaction temperature of 155°C, total pressure of 2.5 MPa and catalyst loading of 0.2 gL(-1).

  18. Catalytic wet oxidation of o-chlorophenol at mild temperatures under alkaline conditions.

    Science.gov (United States)

    Kojima, Yoshihiro; Fukuta, Tadashi; Yamada, Takehisa; Onyango, Maurice S; Bernardo, Eileen C; Matsuda, Hitoki; Yagishita, Kohichi

    2005-01-01

    Wet oxidation of a 100 ppm aqueous solution of o-chlorophenol (o-CP) was performed in a lab-scale batch reactor using 3% Ru/TiO(2) catalyst at 373 and 413 K, and a partial oxygen pressure of 0.1 MPa. The experiments were conducted by varying the initial pH values of o-CP solution from pH 6.3 to 9.8 and 11.8. From the results, it was revealed that the catalytic decomposition of o-CP occurred most effectively at 413 K and at the initial pH of 9.8. Complete decomposition and dechlorination of o-CP were almost achieved within 1h, and about 85% of TOC was removed in 3.0 h. On the other hand, the catalytic wet oxidation of o-CP at a higher pH value of 11.8 was not effective in the removal of TOC. The incomplete removal of TOC at the initial pH of 11.8 is likely attributed to a low pK(a) of carboxylic acids formed during the wet oxidation of o-CP.

  19. Catalytic wet peroxide oxidation of phenol solutions over CuO/CeO2 systems.

    Science.gov (United States)

    Massa, Paola; Ivorra, Fernando; Haure, Patricia; Fenoglio, Rosa

    2011-06-15

    Three 5% CuO/CeO(2) catalysts were synthesized by sol-gel, precipitation and combustion methods, followed by incipient wetness impregnation with copper nitrate. The samples were characterized by XRD, TPR, BET and tested for the catalytic wet peroxide oxidation of a phenol solution (5 g/L). The reaction took place in a batch reactor at atmospheric pressure, in a temperature range of 60-80°C, during 4h. Phenol conversion, H(2)O(2) consumption, pH and chemical oxygen demand were determined. The reaction temperature and the catalyst loading did improve the phenol and the H(2)O(2) conversions. The effect on the selectivity towards complete mineralization was less marked, with levels among 60-70%. Stepwise addition of H(2)O(2) was also tested.

  20. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst.

    Science.gov (United States)

    Collado, Sergio; Laca, Adriana; Díaz, Mario

    2010-05-15

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 10(3) and 1.0 x 10(4)kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu(2+) to Cu(+) that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation.

  1. Catalytic wet peroxide oxidation of phenol solutions over CuO/CeO{sub 2} systems

    Energy Technology Data Exchange (ETDEWEB)

    Massa, Paola, E-mail: pamassa@fi.mdp.edu.ar [Division Catalizadores y Superficies, INTEMA, Universidad Nacional de Mar del Plata/CONICET, Juan B. Justo 4302, 7600 Mar del Plata, Buenos Aires (Argentina); Ivorra, Fernando; Haure, Patricia; Fenoglio, Rosa [Division Catalizadores y Superficies, INTEMA, Universidad Nacional de Mar del Plata/CONICET, Juan B. Justo 4302, 7600 Mar del Plata, Buenos Aires (Argentina)

    2011-06-15

    Three 5% CuO/CeO{sub 2} catalysts were synthesized by sol-gel, precipitation and combustion methods, followed by incipient wetness impregnation with copper nitrate. The samples were characterized by XRD, TPR, BET and tested for the catalytic wet peroxide oxidation of a phenol solution (5 g/L). The reaction took place in a batch reactor at atmospheric pressure, in a temperature range of 60-80{sup Degree-Sign }C , during 4 h. Phenol conversion, H{sub 2}O{sub 2} consumption, pH and chemical oxygen demand were determined. The reaction temperature and the catalyst loading did improve the phenol and the H{sub 2}O{sub 2} conversions. The effect on the selectivity towards complete mineralization was less marked, with levels among 60-70%. Stepwise addition of H{sub 2}O{sub 2} was also tested.

  2. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Sergio; Laca, Adriana [Department of Chemical Engineering and Environmental Technology, University of Oviedo, c/ Julian Claveria s/n, E-33071, Oviedo (Spain); Diaz, Mario, E-mail: mariodiaz@uniovi.es [Department of Chemical Engineering and Environmental Technology, University of Oviedo, c/ Julian Claveria s/n, E-33071, Oviedo (Spain)

    2010-05-15

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 10{sup 3} and 1.0 x 10{sup 4} kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu{sup 2+} to Cu{sup +} that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation.

  3. Physical effects of negative air ions in a wet sauna

    Science.gov (United States)

    Watanabe, I.; Noro, Hiroshi; Ohtsuka, Yoshinori; Mano, Yukio; Agishi, Yuko

    The physical effects of negative air ions on humans were determined in an experimental sauna room equipped with an ionizer. Thirteen healthy persons took a wet sauna bath (dry bulb temperature 42° C, relative humidity 100%, 10 min exposure) with or without negative air ions. The subjects were not told when they were being exposed to negative air ions. There were no differences in the moods of these persons or changes in their blood pressures between the two saunas. The surface temperatures of the foreheads, hands, and legs in the sauna with negative ions were significantly higher than those in the sauna without ions. The pulse rates and sweat produced in the sauna with ions were singificantly higher than those in the sauna without ions. The results suggest that negative ions may amplify the effects on humans of the sauna.

  4. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop advanced catalysts for a volatile removal assembly used to purify spacecraft water. The innovation of the proposed...

  5. Catalytic wet oxidation of phenol: the role of promoter and ceramic support.

    Science.gov (United States)

    Hussain, S Tajammul; Jamil, Sadaf; Mazhar, Muhammad

    2009-04-14

    Complete mineralization of phenol has been achieved over a cerium-manganese catalyst, doped with potassium, supported on a modified zeolite with a high surface area, under very mild conditions (110 degrees C, P(O2) = 0.5 MPa). This newly developed supported catalyst restricts the formation of bulk polymeric species on the surface, thus increasing the lifetime of the catalyst. It demonstrates superior textural, structural and surface oxygen properties compared with the reference cerium-manganese oxide catalyst. The supported catalyst maintains not only the high surface area but also the nanoparticle size during the catalytic run, thereby providing the full availability of the surface for reacting molecules. The geometry of the catalyst is modified electronically by the addition of potassium, and the zeolite addition restricts the conversion of Ce, Mn and K to higher oxidation states, thereby maintaining the geometry of catalytic active sites. The performance measured with this novel catalyst indicates a major improvement in the efficient application of the catalytic wet oxidation process for complete purification ofa complex waste stream.

  6. Tough and catalytically active hybrid biofibers wet-spun from nanochitin hydrogels.

    Science.gov (United States)

    Das, Paramita; Heuser, Thomas; Wolf, Andrea; Zhu, Baolei; Demco, Dan Eugen; Ifuku, Shinsuke; Walther, Andreas

    2012-12-10

    Sustainable alternatives for high-performance and functional materials based on renewable resources are intensely needed as future alternatives for present-day, fossil-based materials. Nanochitin represents an emerging class of highly crystalline bionanoparticles with high intrinsic mechanical properties and the ability for conjugation into functional materials owing to reactive amine and hydroxyl groups. Herein we demonstrate that hydrogels containing surface-deacetylated chitin nanofibrils of micrometer length and average diameters of 9 nm, as imaged by cryogenic transmission electron microscopy, can be wet-spun into macrofibers via extrusion in a coagulation bath, a simple low energy and large-scale processing route. The resulting biofibers display attractive mechanical properties with a large plastic region of about 12% in strain, in which frictional sliding of nanofibrils allows dissipation of fracture energy and enables a high work-of-fracture of near 10 MJ/m3. We further show how to add functionality to these macrofibers by exploiting the amine functions of the surface chitosan groups to host catalytically active noble metal nanoparticles, furnishing biobased, renewable catalytic hybrids. These inorganic/organic macrofibers can be used repeatedly for fast catalytic reductions of model compounds without loss of activity, rendering the concept of hybridized chitin materials interesting as novel bioderived supports for nanoparticle catalysts.

  7. Wet air oxidation of seedcorn wastes containing pesticides and insecticides

    Energy Technology Data Exchange (ETDEWEB)

    Sievers, M.; Schlaefer, O.; Onyeche, T.I.; Schroeder, C.; Bormann, H.; Schaefer, S. [CUTEC-Inst. GmbH (Clausthal Environment Technology Inst.), Clausthal-Zellerfeld (Germany)

    2003-07-01

    Wet air oxidation as an alternative treatment process to pyrolysis and combustion of seedcorn wastes was investigated in lab-scale experiments. Due to solid condition of the seed corn waste, the process has been adapted by repeated spraying of water on the seed corn bulk to avoid the production of sludge and its subsequent dewatering. Original seed corns from industrial production plants were used for a degradation kinetic study under smooth wet air oxidation conditions. The temperatures were between 80 and 150 C, the pressure from 1 to 4.5 bar and the pH at different values from 3 to 13. Degradation rates for five different compounds of pesticides and insecticides, namely Imidacloprid, Thiram, Hymexazol, Carbofuran and Tefluthrin were conducted. These compounds represent the recently used in agricultural seedcorn applications. The degradation rate depends linearly on temperature between 80 and 150 C. At 120 C the lowest degradation rate was found for Tefluthrin by 25 mg/h per L reaction volume while the highest degradation rate to be conducted was for Imidacloprid at 363 mg/h L. (orig.)

  8. Kinetics of Wet Air Oxidation of Wastewater from Natural Fiber Web Desizing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work described the application of wet air oxidation (WAO) to the treatment of desizing wastewater from natural fiber processing. A two-liter autoclave batch reactor was used for the experiments. The range of operating temperature examined was between 150 and 290℃, and partial pressure of oxygen ranged from 0.375 to 2.25 MPa standardized at 25℃. Variations in Chemical Oxygen Demand(COD) and Total Organic Carbon(TOC) were monitored during each experiment and used to assess the performance of the process. Experimental results showed that WAO can be an efficient method for the treatment of desizing wnstewater. Furthermore, Catalytic Wet Air Oxidation (CWAO) was applied to reduce the reaction temperature and pressure in WAO process. A higher COD removal ratio was achieved under more mild reaction condition with the aid of CWAO. A mathematical model was also proposed to simulate the WAO process of desizing wastewater, in which three distinct kinetics steps were considered to describe the degradation of starch. The model simulations were in well agreement with the experimental data.

  9. Air Entrainment in Dynamic Wetting: Knudsen Effects and the Influence of Ambient Air Pressure

    CERN Document Server

    Sprittles, James E

    2015-01-01

    Recent experiments on coating flows and liquid drop impact both demonstrate that wetting failures caused by air entrainment can be suppressed by reducing the ambient gas pressure. Here, it is shown that non-equilibrium effects in the gas can account for this behaviour, with ambient pressure reductions increasing the gas' mean free path and hence the Knudsen number $Kn$. These effects first manifest themselves through Maxwell slip at the gas' boundaries so that for sufficiently small $Kn$ they can be incorporated into a continuum model for dynamic wetting flows. The resulting mathematical model contains flow structures on the nano-, micro- and milli-metre scales and is implemented into a computational platform developed specifically for such multiscale phenomena. The coating flow geometry is used to show that for a fixed gas-liquid-solid system (a) the increased Maxwell slip at reduced pressures can substantially delay air entrainment, i.e. increase the `maximum speed of wetting', (b) unbounded maximum speeds ...

  10. Kinetics of wet air oxidation (WAO) of alcaloide factory wastewater.

    Science.gov (United States)

    Kunukcu, Y Kaçar

    2005-01-01

    Wet air oxidation (WAO) of Afyon alcaloide factory wastewater, a typical high strength industrial wastewater, was carried out. The process was performed in a specifically designed titanium bubble reactor at temperatures in the range of 140-160 degrees C. The kinetics of WAO of alcaloide factory wastewater was modeled by assuming two distinct steps. The rates of destruction were measured with respect to reduction in COD. The oxidation reaction was found to be first order with respect to COD concentration and also second order with respect to oxygen concentration in both steps. The values of activation energies were found to be in the range of 4.93 x 10(4)-7.85 x 10(4) kJ/kmol.

  11. P-chlorophenol wastewater treatment by microwave-enhanced catalytic wet peroxide oxidation.

    Science.gov (United States)

    Zhao, Guohua; Lv, Baoying; Jin, Yan; Li, Dongming

    2010-02-01

    A microwave-enhanced catalytic wet peroxide oxidation (MW-CWPO) technology was investigated to treat a high concentration of p-chlorophenol wastewater under a mild condition. The MW-CWPO experiments were carried out in a microwave autoclave using copper(II) oxide (CuO)-loaded active carbon as a catalyst. The p-chlorophenol was directly ring-opened within 5 minutes at 343 K and 0.3 MPa and then mineralized to carbon dioxide and water. More than 90% of the total organic carbon was removed within 15 minutes. The reaction activation energy (Ea) of hydrogen peroxide (H2O2) decomposition was decreased from 47.7 to 43.1 kJ/mol under microwave irradiation. The H2O2 catalytic decomposition was fitted to a second-order reaction under microwave irradiation, while it followed a first-order reaction without microwave irradiation. The experimental results indicate that the MW-CWPO method has significant potential applications for a high concentration of p-chlorophenol wastewater.

  12. Catalytic wet peroxide oxidation of p-nitrophenol by Fe (III) supported on resin.

    Science.gov (United States)

    Liou, Rey-May; Chen, Shih-Hsiung; Huang, Cheng-Hsien; Lai, Cheng-Lee; Shih, C Y; Chang, Jing-Song; Hung, Mu-Ya

    2010-01-01

    Fe(III) supported on resin (Fe(III)-resin) as an effective catalyst for peroxide oxidation was prepared and applied for the degradation of p-nitrophenol (PNP). Catalytic wet peroxide oxidation (CWPO) experiments with hydrogen peroxide as oxidant were performed in a batch rector with p-nitrophenol as the model pollutant. Under given conditions (PNP concentration 500 mg/L, H(2)O(2) 0.1 M, 80°C, resin dosage 0.6% g/mL), p-nitrophenol was almost completely removed, corresponding to an 84% of COD removal. It was found that the reaction temperature, oxidant concentration. and initial pH of solution significantly affected both p-nitrophenol conversion and COD removal by oxidation. It can be inferred from the experiments that Fe(III) supported on resin was an effective catalyst in the mineralization of p-nitrophenol. In an acidic environment of oxidation, the leaching test showed that there was only a slight leaching effect on the activity of catalytic oxidation. It was also confirmed by the aging test of catalysts in the oxidation.

  13. Comparative kinetic analysis of silent and ultrasound-assisted catalytic wet peroxide oxidation of phenol.

    Science.gov (United States)

    Rokhina, Ekaterina V; Repo, Eveliina; Virkutyte, Jurate

    2010-03-01

    The kinetic study of silent and ultrasound-assisted catalytic wet peroxide oxidation of phenol in water was performed to qualitatively assess the effect of ultrasound on the process kinetics. Various kinetic parameters such as the apparent kinetic rate constants, the surface utilization coefficient and activation energy of phenol oxidation over RuI(3) catalyst were investigated. Comparative analysis revealed that the use of ultrasound irradiation reduced the energy barrier of the reaction but had no impact on the reaction pathway. The activation energy for the oxidation of phenol over RuI(3) catalyst in the presence of ultrasound was found to be 13kJmol(-1), which was four times smaller in comparison to the silent oxidation process (57kJmol(-1)). Finally, 'figures-of-merit' was utilized to assess different experimental strategies such as sonolysis alone, H(2)O(2)-enhanced sonolysis and sono-catalytic oxidation of phenol in order to estimate the electric energy consumption based on the kinetic rate constants of the oxidation process.

  14. Development of wet-proofed catalyst and catalytic exchange process for tritium extraction

    Energy Technology Data Exchange (ETDEWEB)

    Song, Myung Jae; Son, Soon Hwan; Chung, Yang Gun; Lee, Gab Bock [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1995-12-31

    To apply a liquid phase catalytic exchange(LPCE) process for the tritium extraction from tritiated heavy water, the wet proofed catalyst to allow the hydrogen isotopic exchange reaction between liquid water and hydrogen gas was developed. A styrene divinyl benzene copolymer was selected as am effective catalyst support and prepared by suspension copolymerization. After post-treatment, final catalyst supports were dipped in chloroplatinic acid solution. The catalyst support had a good physical properties at a particular preparation condition. The catalytic performance was successfully verified through hydrogen isotopic exchange reaction in the exchange column. A mathematical model for the tritium removal process consisted of LPCE front-ended process and cryogenic distillation process was established using the NTU-HTU method for LPCE column and the FUG method for cryogenic distillation column, respectively. A computer program was developed using the model and then used to investigate optimum design variables which affect the size of columns and tritium inventory (author). 84 refs., 113 figs.

  15. USING WET AIR OXIDATION TECHNOLOGY TO DESTROY TETRAPHENYLBORATE

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K; Daniel McCabe, D; Bill Wilmarth, B

    2007-04-04

    A bench-scale feasibility study on the use of a Wet Air Oxidation (WAO) process to destroy a slurry laden with tetraphenylborate (TPB) compounds has been undertaken. WAO is an aqueous phase process in which soluble and/or insoluble waste constituents are oxidized using oxygen or oxygen in air at elevated temperatures and pressures ranging from 150 C and 1 MPa to 320 C and 22 MPa. The products of the reaction are CO{sub 2}, H{sub 2}O, and low molecular weight oxygenated organics (e.g. acetate, oxalate). Test results indicate WAO is a feasible process for destroying TPB, its primary daughter products [triphenylborane (3PB), diphenylborinic acid (2PB), and phenylboronic acid (1PB)], phenol, and most of the biphenyl byproduct. The required conditions are a temperature of 300 C, a reaction time of 3 hours, 1:1 feed slurry dilution with 2M NaOH solution, the addition of CuSO{sub 4}.5H{sub 2}O solution (500 mg/L Cu) as catalyst, and the addition of 2000 mL/L of antifoam. However, for the destruction of TPB, its daughter compounds (3PB, 2PB, and 1PB), and phenol without consideration for biphenyl destruction, less severe conditions (280 C and 1-hour reaction time with similar remaining above conditions) are adequate.

  16. Catalytic wet peroxidation of pyridine bearing wastewater by cerium supported SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Subbaramaiah, V. [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India); Srivastava, Vimal Chandra, E-mail: vimalcsr@yahoo.co.in [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India); Mall, Indra Deo [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India)

    2013-03-15

    Highlights: ► Cerium supported SBA-15 (Ce/SBA-15) synthesized by two-step synthesis. ► Characterization of Ce/SBA-15 by FTIR, XRD and BET surface area. ► Catalytic peroxidation of pyridine by Ce/SBA-15. ► Optimization of parameters like catalyst dose, H{sub 2}O{sub 2} dose, initial concentration and temperature. ► Catalyst reusability and leaching study performed. -- Abstract: Cerium supported SBA-15 (Ce/SBA-15) was synthesized by two-step synthesis method in acidic medium. It was further characterized by various characterization techniques such as X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy and N{sub 2} adsorption–desorption pore size distribution analysis. The Ce/SBA-15 showed highly ordered meso-structure with pore diameter ≈ 70–100 A and pore volume ≈ 0.025 cm{sup 3}/g. Ce/SBA-15 was further evaluated as a catalyst for the oxidation of highly toxic and non-biodegradable material, pyridine, by catalytic wet-peroxidation method. The effects of various operating parameters such as catalyst dose (0.5–6 g/l), stoichiometric ratio of H{sub 2}O{sub 2}/pyridine (1–6), initial pyridine concentration (50–800 mg/l) and temperature (313–358 K) have been evaluated and optimized. Ce/SBA-15 showed stable performance during reuse for six cycles with negligible cerium leaching. Kinetic and thermodynamic parameters and operation cost have also been determined.

  17. Low-temperature catalytic gasification of wet industrial wastes. FY 1991--1992 interim report

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D.C.; Neuenschwander, G.G.; Hart, T.R.; Phelps, M.R.; Sealock, L.J. Jr.

    1993-07-01

    A catalytic gasification system operating in a pressurized water environment has been developed and refined at Pacific Northwest Laboratory (PNL) for over 12 years. Initial experiments were aimed at developing kinetics information for steam gasification of biomass in the presence of catalysts. The combined use of alkali and metal catalysts was reported for gasification of biomass and its components at low temperatures (350{degrees}C to 450{degrees}C). From the fundamental research evolved the concept of a pressurized, catalytic gasification system for converting wet biomass feedstocks to fuel gas. Extensive batch reactor testing and limited continuous reactor system (CRS) testing were undertaken in the development of this system under sponsorship of the US Department of Energy. A wide range of biomass feedstocks were tested, and the importance of the nickel metal catalyst was identified. Specific use of this process for treating food processing wastes was also studied. The concept application was further expanded to encompass cleanup of hazardous wastewater streams, and results were reported for batch reactor tests and continuous reactor tests. Ongoing work at PNL focuses on refining the catalyst and scaling the system to long-term industrial needs. The process is licensed as the Thermochemical Environmental Energy System (TEES{reg_sign}) to Onsite*Ofsite, Inc., of Duarte, California. This report is a follow-on to the 1989--90 interim report [Elliott et al. 1991], which reviewed the results of the studies conducted with a fixed-bed, continuous-feed, tubular reactor. The discussion here provides an overview of experiments on the wide range of potential feedstock materials conducted in a batch reactor; development of new catalyst materials; and tests performed in continuous-flow reactors at three scales. The appendices contain the history and background of the process development, as well as more detailed descriptions and results of the recent studies.

  18. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E.; Roth, F. von; Hottinger, P.; Truong, T.B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  19. Wet air oxidation induced enhanced biodegradability of distillery effluent.

    Science.gov (United States)

    Malik, S N; Saratchandra, T; Tembhekar, P D; Padoley, K V; Mudliar, S L; Mudliar, S N

    2014-04-01

    The present study reports the feasibility of Wet Air Oxidation (WAO) as a pretreatment option for enhanced biodegradation of complex distillery effluent. Initially, the distillery effluent was pretreated by WAO at different process conditions (pressure, temperature and time) to facilitate enhancement in the biodegradability index (BI = BOD5: COD ratio). The biodegradability of WAO pretreated effluent was evaluated by subjecting it to aerobic biodegradation and anaerobic followed by aerobic biodegradation. Aerobic biodegradation of pretreated effluent with enhanced biodegradability index (BI = 0.4-0.8) showed enhanced COD reduction of up to 67.7%, whereas the untreated effluent (BI = 0.17) indicated poor COD reduction of only 22.5%. Anaerobic followed by aerobic biodegradation of pretreated effluent has shown up to 87.9% COD reduction, while the untreated effluent has shown only 43.1% COD reduction. Bio-kinetic parameters also confirmed the increased rate of bio-oxidation at enhanced BIs. The results indicate that the WAO pretreatment facilitates enhanced bio-oxidation/bio-degradation of complex effluents like the distillery spent wash.

  20. Treatment of hydraulic fracturing wastewater by wet air oxidation.

    Science.gov (United States)

    Wang, Wei; Yan, Xiuyi; Zhou, Jinghui; Ma, Jiuli

    2016-01-01

    Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard.

  1. Catalytic wet oxidation of the pretreated synthetic pulp and paper mill effluent under moderate conditions.

    Science.gov (United States)

    Garg, Anurag; Mishra, I M; Chand, Shri

    2007-01-01

    In the present study, catalytic wet oxidation (CWO) was investigated for the destruction of organic pollutants in the thermally pretreated effluent from a pulp and paper mill under moderate temperature and pressure conditions. The thermal pretreatment studies were conducted at atmospheric pressure and 368K using copper sulfate as a catalyst. The thermal pretreatment reduced COD by about 61%. The filtrate of the thermal pretreatment step was used at pH 8.0 for CWO at 383-443K temperature and a total pressure of 0.85MPa for 4h. Catalysts used for the reaction include copper sulfate, 5% CuO/95% activated carbon, 60% CuO/40% MnO(2), and 60% CuO/40% CeO(2). Maximum COD reduction was found to be 89% during CWO step using 5% CuO/95% activated carbon with a catalyst loading of 8gl(-1) at 443K and 0.85MPa total pressure. Overall COD reduction for the pretreatment and the CWO was found to be 96%. Besides this, 60% CuO/40% CeO(2) catalyst also exhibited the similar activity as that of obtained with 5% CuO/95% activated carbon catalyst at 423K temperature and 0.85MPa total pressure. The pH of the solution during the experimental runs decreases initially due to the formation of carboxylic acid and then increases due to the decomposition of acids.

  2. Catalytic wet peroxidation of pyridine bearing wastewater by cerium supported SBA-15.

    Science.gov (United States)

    Subbaramaiah, V; Srivastava, Vimal Chandra; Mall, Indra Deo

    2013-03-15

    Cerium supported SBA-15 (Ce/SBA-15) was synthesized by two-step synthesis method in acidic medium. It was further characterized by various characterization techniques such as X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy and N2 adsorption-desorption pore size distribution analysis. The Ce/SBA-15 showed highly ordered meso-structure with pore diameter≈70-100Ǻ and pore volume≈0.025cm(3)/g. Ce/SBA-15 was further evaluated as a catalyst for the oxidation of highly toxic and non-biodegradable material, pyridine, by catalytic wet-peroxidation method. The effects of various operating parameters such as catalyst dose (0.5-6g/l), stoichiometric ratio of H2O2/pyridine (1-6), initial pyridine concentration (50-800mg/l) and temperature (313-358K) have been evaluated and optimized. Ce/SBA-15 showed stable performance during reuse for six cycles with negligible cerium leaching. Kinetic and thermodynamic parameters and operation cost have also been determined.

  3. Catalytic wet peroxide oxidation of azo dye (Congo red) using modified Y zeolite as catalyst.

    Science.gov (United States)

    Kondru, Arun Kumar; Kumar, Pradeep; Chand, Shri

    2009-07-15

    The present study explores the degradation of azo dye (Congo red) by catalytic wet peroxide oxidation using Fe exchanged commercial Y zeolite as a catalyst. The effects of various operating parameters like temperature, initial pH, hydrogen peroxide concentration and catalyst loading on the removal of dye, color and COD from an aqueous solution were studied at atmospheric pressure. The percent removals of dye, color and COD at optimum pH(0) 7, 90 degrees C using 0.6 ml H(2)O(2)/350 ml solution and 1g/l catalyst was 97% (in 4h), 100% (in 45 min) and 58% (in 4h), respectively. The % dye removal has been found to be less in comparison to % color removal at all conditions, e.g. dye removal in 45 min and at above conditions was 82%, whereas the color removal was 100%. The results indicate that the Fe exchanged Y zeolite is a promising catalyst for dye removal. Fe exchanged catalyst is characterized using XRD, SEM/EDAX, surface area analyzer and FTIR. Though the dye, color and COD removals were maximum at pH(0) 2 but as the leaching of Fe from the catalyst was more in acidic pH range, pH(0) 7 was taken as operating pH due to almost comparable removals as of pH(0) 2 and no leaching of Fe ions.

  4. Chloride ions promoted the catalytic wet peroxide oxidation of phenol over clay-based catalysts.

    Science.gov (United States)

    Zhou, Shiwei; Zhang, Changbo; Xu, Rui; Gu, Chuantao; Song, Zhengguo; Xu, Minggang

    2016-01-01

    Catalytic wet peroxide oxidation (CWPO) of phenol over clay-based catalysts in the presence and absence of NaCl was investigated. Changes in the H2O2, Cl(-), and dissolved metal ion concentration, as well as solution pH during phenol oxidation, were also studied. Additionally, the intermediates formed during phenol oxidation were detected by liquid chromatography-mass spectroscopy and the chemical bonding information of the catalyst surfaces was analyzed by X-ray photoelectron spectroscopy (XPS). The results showed that the presence of Cl(-) increased the oxidation rate of phenol to 155%, and this phenomenon was ubiquitous during the oxidation of phenolic compounds by H2O2 over clay-based catalysts. Cl(-)-assisted oxidation of phenol was evidenced by several analytical techniques such as mass spectroscopy (MS) and XPS, and it was hypothesized that the rate-limiting step was accelerated in the presence of Cl(-). Based on the results of this study, the CWPO technology appears to be promising for applications in actual saline phenolic wastewater treatment.

  5. Activity and leaching features of zinc-aluminum ferrites in catalytic wet oxidation of phenol.

    Science.gov (United States)

    Xu, Aihua; Yang, Min; Qiao, Ruiping; Du, Hongzhang; Sun, Chenglin

    2007-08-17

    A series of ZnFe(2-x)Al(x)O(4) spinel type catalysts prepared by sol-gel method have been characterized and tested for catalytic wet oxidation (CWO) of phenol with pure oxygen. The iron species existed in these materials as aggregated iron oxide clusters and Fe3+ species in octahedral sites. With a decrease in iron content the concentration of the first iron species decreased and the latter increased. Complete phenol conversions and high chemical oxygen demand (COD) removals were obtained for all catalysts during phenol degradation at mild reaction conditions (160 degrees C and 1.0 MPa of oxygen pressure). Increasing with the concentration of Fe3+ species in octahedral sites, induction period became significantly shortened. After phenol was completely degraded, the concomitant recycling of the leaching Fe3+ ions back to the catalyst surface was observed, and in this case it is possible to perform successful CWO reactions with some cycles. It is also suggested that during the reaction the Fe3+ cations coordinated in octahedral sites in the ZnFe(2-x)Al(x)O(4) catalysts are resistant to acid leaching, but the reduced Fe2+ cations become much more labile, leading to increased Fe leaching.

  6. Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater.

    Science.gov (United States)

    Sanabria, Nancy R; Peralta, Yury M; Montañez, Mardelly K; Rodríguez-Valencia, Nelson; Molina, Rafael; Moreno, Sonia

    2012-01-01

    The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater.

  7. Heterogeneous catalytic wet peroxide oxidation systems for the treatment of an industrial pharmaceutical wastewater.

    Science.gov (United States)

    Melero, J A; Martínez, F; Botas, J A; Molina, R; Pariente, M I

    2009-09-01

    The aim of this work was to assess the treatment of wastewater coming from a pharmaceutical plant through a continuous heterogeneous catalytic wet peroxide oxidation (CWPO) process using an Fe(2)O(3)/SBA-15 nanocomposite catalyst. This catalyst was preliminary tested in a batch stirred tank reactor (STR), to elucidate the influence of significant parameters on the oxidation system, such as temperature, initial oxidant concentration and initial pH of the reaction medium. In that case, a temperature of 80 degrees C using an initial oxidant concentration corresponding to twice the theoretical stoichiometric amount for complete carbon depletion and initial pH of ca. 3 allow TOC degradation of around 50% after 200 min of contact time. Thereafter, the powder catalyst was extruded with bentonite to prepare pellets that could be used in a fixed bed reactor (FBR). Results in the up-flow FBR indicate that the catalyst shows high activity in terms of TOC mineralization (ca. 60% under steady-state conditions), with an excellent use of the oxidant and high stability of the supported iron species. The activity of the catalyst is kept constant, at least, for 55h of reaction. Furthermore, the BOD(5)/COD ratio is increased from 0.20 to 0.30, whereas the average oxidation stage (AOS) changed from 0.70 to 2.35. These two parameters show a high oxidation degree of organic compounds in the outlet effluent, which enhances its biodegradability, and favours the possibility of a subsequent coupling with a conventional biological treatment.

  8. Ruthenium versus platinum on cerium materials in wet air oxidation of acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Gaalova, J. [Institute of Chemical Process Fundamentals of the CAS, Rozvojova 135, 165 02 Prague 6, CZ (Czech Republic); Barbier, J., E-mail: Jacques.barbier.jr@univ-poitiers.fr [University of Poitiers, LACCO UMR 6503, Laboratoire de Catalyse par les Metaux, 40 Avenue du Recteur Pineau, F-86022 POITIERS Cedex (France); Rossignol, S. [University of Limoges, ENSCI, 47 Avenue Albert Thomas 87000 Limoges France (France)

    2010-09-15

    This study was a comparison between Ru-catalysts and similar, previously investigated, Pt-catalysts. In this paper, ruthenium catalysts for catalytic wet air oxidation are prepared, characterized and tested. Both catalysts were supported on commercial CeO{sub 2} as well as mixed oxide Zr{sub 0.1}(Ce{sub 0.75}Pr{sub 0.25}){sub 0.9}O{sub 2}. The catalysts were characterized by measuring the oxygen storage capacities (OSC), BET, XRD, FTIR and chemisorption of hydrogen. In addition, the effect of sintering (treatments under H{sub 2}) was compared with both of the catalysts. The comparison of the results showed that initial intrinsic activity of ruthenium is not significantly influenced by the type of the support, which is contrast to platinum. Furthermore, the particle size of Ru had an important effect on CWAO activity: the higher the particle size, the better the activity. This was different with Pt-catalysts, where the optimal particle size was smaller, having about 15% of metal dispersion.

  9. Enhanced wet hydrogen peroxide catalytic oxidation performances based on CuS nanocrystals/reduced graphene oxide composites

    Science.gov (United States)

    Qian, Jing; Wang, Kun; Guan, Qingmeng; Li, Henan; Xu, Hui; Liu, Qian; Liu, Wei; Qiu, Baijing

    2014-01-01

    CuS nanocrystals/reduced graphene oxide (CuS NCs/rGO) composites were prepared by a facile one-pot solvothermal reaction. In this solvothermal system, thioacetamide was found to perform the dual roles of sulphide source and reducing agent, resulting in the formation of CuS NCs and simultaneous reduction of graphene oxide (GO) sheets to rGO sheets. In addition, CuS NCs/rGO composites were further used as heterogeneous catalysts in the wet hydrogen peroxide catalytic oxidation process, with methylene blue as a model organic dye. The introduction of rGO to CuS NCs could effectively enhance the catalytic activity of CuS NCs, and the resultant CuS NCs/rGO composites with a starting GO amount of 5 wt% showed the highest catalytic activity. Furthermore, the CuS NCs/rGO composites showed high catalytic activity over a broad pH operation range from 3.0 to 11.0 under ambient conditions, and still retained 90% of the original catalytic activity after reuse in five cycles.

  10. Unprecedented Catalytic Wet Oxidation of Glucose to Succinic Acid Induced by the Addition of n-Butylamine to a Ru(III) Catalyst.

    Science.gov (United States)

    Podolean, Iunia; Rizescu, Cristina; Bala, Camelia; Rotariu, Lucian; Parvulescu, Vasile I; Coman, Simona M; Garcia, Hermenegildo

    2016-09-08

    A new pathway for the catalytic wet oxidation (CWO) of glucose is described. Employing a cationic Ru@MNP catalyst, succinic acid is obtained in unprecedently high yield (87.5 %) for a >99.9 % conversion of glucose, most probably through a free radical mechanism combined with catalytic didehydroxylation of vicinal diols and hydrogenation of the resulted unsaturated intermediate.

  11. Ruthenium catalysts supported on high-surface-area zirconia for the catalytic wet oxidation of N,N-dimethyl formamide.

    Science.gov (United States)

    Sun, Guanglu; Xu, Aihua; He, Yu; Yang, Min; Du, Hongzhang; Sun, Chenglin

    2008-08-15

    Three weight percent ruthenium catalysts were prepared by incipient-wet impregnation of two different zirconium oxides, and characterized by BET, XRD and TPR. Their activity was evaluated in the catalytic wet oxidation (CWO) of N,N-dimethyl formamide (DMF) in an autoclave reactor. Due to a better dispersion, Ru catalyst supported on a high-surface-area zirconia (Ru/ZrO(2)-A) possessed higher catalytic properties. Due to over-oxidation of Ru particles, the catalytic activity of the both catalysts decreased during successive tests. The effect of oxygen partial pressure and reaction temperature on the DMF reactivity in the CWO on Ru/ZrO(2)-A was also investigated. 98.6% of DMF conversion was obtained through hydrothermal decomposition within 300 min at conditions of 200 degrees C and 2.0 MPa of nitrogen pressure. At 240 degrees C and 2.0 MPa of oxygen pressure 98.3% of DMF conversion was obtained within 150 min.

  12. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques.

    Science.gov (United States)

    Azabou, Samia; Najjar, Wahiba; Bouaziz, Mohamed; Ghorbel, Abdelhamid; Sayadi, Sami

    2010-11-15

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H(2)O(2)/ultraviolet radiations) at 25°C and ((Al-Fe)PILC/H(2)O(2)) at 50°C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H(2)O(2)), system operating at 50°C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H(2)O(2)) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  13. Wet air oxidation of formic acid using nanoparticle-modified polysulfone hollow fibers as gas-liquid contactors.

    Science.gov (United States)

    Hogg, Seth R; Muthu, Satish; O'Callaghan, Michael; Lahitte, Jean-Francois; Bruening, Merlin L

    2012-03-01

    Catalytic wet air oxidation (CWAO) using membrane contactors is attractive for remediation of aqueous pollutants, but previous studies of even simple reactions such as formic acid oxidation required multiple passes through tubular ceramic membrane contactors to achieve high conversion. This work aims to increase single-pass CWAO conversions by using polysulfone (PS) hollow fibers as contactors to reduce diffusion distances in the fiber lumen. Alternating adsorption of polycations and citrate-stabilized platinum colloids in fiber walls provides catalytically active PS hollow fibers. Using a single PS fiber, 50% oxidation of a 50 mM formic acid feed solution results from a single pass through the fiber lumen (15 cm length) with a solution residence time of 40 s. Increasing the number of PS fibers to five while maintaining the same volumetric flow rate leads to over 90% oxidation, suggesting that further scale up in the number of fibers will facilitate high single pass conversions at increased flow rates. The high conversion compared to prior studies with ceramic fibers stems from shorter diffusion distances in the fiber lumen. However, the activity of the Pt catalyst is 20-fold lower than in previous ceramic fibers. Focusing the Pt deposition near the fiber lumen and limiting pore wetting to this region might increase the activity of the catalyst.

  14. Photo-catalytic activity of Zn1-x Mn x S nanocrystals synthesized by wet chemical technique

    Directory of Open Access Journals (Sweden)

    Singh Karamjit

    2011-01-01

    Full Text Available Abstract Polyvinyl pyrrolidone capped Zn1-x Mn x S (0 ≤ x ≤ 0.1 nanocrystals have been synthesized using wet chemical co-precipitation method. Crystallographic and morphological characterization of the synthesized materials have been done using X-ray diffraction and transmission electron microscope. Crystallographic studies show the zinc blende crystals having average crystallite size approx. 3 nm, which is almost similar to the average particle size calculated from electron micrographs. Atomic absorption spectrometer has been used for qualitative and quantitative analysis of synthesized nanomaterials. Photo-catalytic activity has been studied using methylene blue dye as a test contaminant. Energy resolved luminescence spectra have been recorded for the detailed description of radiative and non-radiative recombination mechanisms. Photo-catalytic activity dependence on dopant concentration and luminescence quantum yield has been studied in detail.

  15. A kinetic model of municipal sludge degradation during non-catalytic wet oxidation.

    Science.gov (United States)

    Prince-Pike, Arrian; Wilson, David I; Baroutian, Saeid; Andrews, John; Gapes, Daniel J

    2015-12-15

    Wet oxidation is a successful process for the treatment of municipal sludge. In addition, the resulting effluent from wet oxidation is a useful carbon source for subsequent biological nutrient removal processes in wastewater treatment. Owing to limitations with current kinetic models, this study produced a kinetic model which predicts the concentrations of key intermediate components during wet oxidation. The model was regressed from lab-scale experiments and then subsequently validated using data from a wet oxidation pilot plant. The model was shown to be accurate in predicting the concentrations of each component, and produced good results when applied to a plant 500 times larger in size. A statistical study was undertaken to investigate the validity of the regressed model parameters. Finally the usefulness of the model was demonstrated by suggesting optimum operating conditions such that volatile fatty acids were maximised.

  16. Catalytic wet oxidation of ammonia solution: activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst.

    Science.gov (United States)

    Hung, Chang-Mao

    2009-04-15

    Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H(2)PtCl(6), Pd(NO(3))(3) and Rh(NO(3))(3). Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes.

  17. Impact of ultra-viscous drops: air-film gliding and extreme wetting

    KAUST Repository

    Langley, K.

    2017-01-23

    A drop impacting on a solid surface must push away the intervening gas layer before making contact. This entails a large lubricating air pressure which can deform the bottom of the drop, thus entrapping a bubble under its centre. For a millimetric water drop, the viscous-dominated flow in the thin air layer counteracts the inertia of the drop liquid. For highly viscous drops the viscous stresses within the liquid also affect the interplay between the drop and the gas. Here the drop also forms a central dimple, but its outer edge is surrounded by an extended thin air film, without contacting the solid. This is in sharp contrast with impacts of lower-viscosity drops where a kink in the drop surface forms at the edge of the central disc and makes a circular contact with the solid. Larger drop viscosities make the central air dimple thinner. The thin outer air film subsequently ruptures at numerous random locations around the periphery, when it reaches below 150 nm thickness. This thickness we measure using high-speed two-colour interferometry. The wetted circular contacts expand rapidly, at orders of magnitude larger velocities than would be predicted by a capillary-viscous balance. The spreading velocity of the wetting spots is independent of the liquid viscosity. This may suggest enhanced slip of the contact line, assisted by rarefied-gas effects, or van der Waals forces in what we call extreme wetting. Myriads of micro-bubbles are captured between the local wetting spots.

  18. A review of wet air oxidation and Thermal Hydrolysis technologies in sludge treatment.

    Science.gov (United States)

    Hii, Kevin; Baroutian, Saeid; Parthasarathy, Raj; Gapes, Daniel J; Eshtiaghi, Nicky

    2014-03-01

    With rapid world population growth and strict environmental regulations, increasingly large volumes of sludge are being produced in today's wastewater treatment plants (WWTP) with limited disposal routes. Sludge treatment has become an essential process in WWTP, representing 50% of operational costs. Sludge destruction and resource recovery technologies are therefore of great ongoing interest. Hydrothermal processing uses unique characteristics of water at elevated temperatures and pressures to deconstruct organic and inorganic components of sludge. It can be broadly categorized into wet oxidation (oxidative) and thermal hydrolysis (non-oxidative). While wet air oxidation (WAO) can be used for the final sludge destruction and also potentially producing industrially useful by-products such as acetic acid, thermal hydrolysis (TH) is mainly used as a pre-treatment method to improve the efficiency of anaerobic digestion. This paper reviews current hydrothermal technologies, roles of wet air oxidation and thermal hydrolysis in sludge treatment, and challenges faced by these technologies.

  19. Humidifying system design of PEMFC test platform based on the mixture of dry and wet air

    Directory of Open Access Journals (Sweden)

    Tiancai Ma

    2015-01-01

    Full Text Available Based on the present humidifying system of PEMFC test platform, a novel design based on dry and wet air mixture is proposed. Key parameters are calculated, and test platform is built. Three experiments are implemented to test the performance of proposed design. Results show that the new design can meet the requirements, and realize the quick response and accurate control.

  20. Evaluation of wet air oxidation variables for removal of organophosphorus pesticide malathion using Box-Behnken design.

    Science.gov (United States)

    Isgoren, Melike; Gengec, Erhan; Veli, Sevil

    2017-02-01

    This paper deals with finding optimum reaction conditions for wet air oxidation (WAO) of malathion aqueous solution, by Response Surface Methodology. Reaction conditions, which affect the removal efficiencies most during the non-catalytic WAO system, are: temperature (60-120 °C), applied pressure (20-40 bar), the pH value (3-7), and reaction time (0-120 min). Those were chosen as independent parameters of the model. The interactions between parameters were evaluated by Box-Behnken and the quadratic model fitted very well with the experimental data (29 runs). A higher value of R(2) and adjusted R(2) (>0.91) demonstrated that the model could explain the results successfully. As a result, optimum removal efficiency (97.8%) was obtained at pH 5, 20 bars of pressure, 116 °C, and 96 min. These results showed that Box-Behnken is a suitable design to optimize operating conditions and removal efficiency for non-catalytic WAO process. The EC20 value of raw wastewater was measured as 35.40% for malathion (20 mg/L). After the treatment, no toxicity was observed at the optimum reaction conditions. The results show that the WAO is an efficient treatment system for malathion degradation and has the ability of converting malathion to the non-toxic forms.

  1. Catalytic aerobic oxidation of phenols to ortho-quinones with air-stable copper precatalysts.

    Science.gov (United States)

    Askari, M S; Rodríguez-Solano, L A; Proppe, A; McAllister, B; Lumb, J-P; Ottenwaelder, X

    2015-07-21

    A range of air-stable copper species was examined for catalytic activity in the catalytic aerobic transformation of phenols into ortho-quinones. Efficient catalysis was obtained with commercially available copper(II) acetate. The stability of all constituents before mixing makes for a practical process that advances previously reported copper(I)-based oxygenations.

  2. 40 CFR 424.40 - Applicability; description of the covered calcium carbide furnaces with wet air pollution control...

    Science.gov (United States)

    2010-07-01

    ... covered calcium carbide furnaces with wet air pollution control devices subcategory. 424.40 Section 424.40... FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Covered Calcium Carbide Furnaces With Wet Air Pollution Control Devices Subcategory § 424.40 Applicability; description of the covered calcium carbide...

  3. Air-side performance of a micro-channel heat exchanger in wet surface conditions

    Directory of Open Access Journals (Sweden)

    Srisomba Raviwat

    2017-01-01

    Full Text Available The effects of operating conditions on the air-side heat transfer, and pressure drop of a micro-channel heat exchanger under wet surface conditions were studied experimentally. The test section was an aluminum micro-channel heat exchanger, consisting of a multi-louvered fin and multi-port mini-channels. Experiments were conducted to study the effects of inlet relative humidity, air frontal velocity, air inlet temperature, and refrigerant temperature on air-side performance. The experimental data were analyzed using the mean enthalpy difference method. The test run was performed at relative air humidities ranging between 45% and 80%; air inlet temperature ranges of 27, 30, and 33°C; refrigerant-saturated temperatures ranging from 18 to 22°C; and Reynolds numbers between 128 and 166. The results show that the inlet relative humidity, air inlet temperature, and the refrigerant temperature had significant effects on heat transfer performance and air-side pressure drop. The heat transfer coefficient and pressure drop for the micro-channel heat exchanger under wet surface conditions are proposed in terms of the Colburn j factor and Fanning f factor.

  4. Wet hydrogen peroxide catalytic oxidation of phenol with FeAC (iron-embedded activated carbon) catalysts.

    Science.gov (United States)

    Liou, Rey-May; Chen, Shih-Hsiung; Huang, Cheng-Hsien; Hung, Mu-Ya; Chang, Jing-Song; Lai, Cheng-Lee

    2010-01-01

    This investigation aims at exploring the catalytic oxidation activity of iron-embedded activated carbon (FeAC) and the application for the degradation of phenol in the wet hydrogen peroxide catalytic oxidation (WHPCO). FeAC catalysts were prepared by pre-impregnating iron in coconut shell with various iron loadings in the range of 27.5 to 46.5% before they were activated. The FeAC catalysts were characterised by measuring their surface area, pore distribution, functional groups on the surface, and X-ray diffraction patterns. The effects of iron loading strongly inhibited the pore development of the catalyst but benefited the oxidation activity in WHPCO. It was found that the complete conversion of phenol was observed with all FeAC catalysts in oxidation. High level of chemical oxygen demand (COD) abatement can be achieved within the first 30 minutes of oxidation. The iron embedded in the activated carbon showed good performance in the degradation and mineralisation of phenol during the oxidation due to the active sites as iron oxides formed on the surface of the activated carbon. It was found that the embedding irons were presented in gamma-Fe(2)O(3), alpha-Fe(2)O(3), and alpha-FeCOOH forms on the activated carbon. The aging tests on FeAC catalysts showed less activity loss, and less iron leaching was found after four oxidation runs.

  5. Kinetics of wet air oxidation of glyoxalic acid and oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. (Univ. of Bombay (India). Dept. of Chemical Technology)

    1994-12-01

    Oxidation of lower molecular weight monobasic and dibasic acids such as formic acid, acetic acid, glyoxalic acid, and oxalic acid is often the rate-controlling step during wet air oxidation (WAO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WAO of glyoxalic acid and oxalic acid was studied in absence and presence of a cupric sulfate catalyst in the temperature range of 120--245 C and oxygen partial pressure of 0.345--1.380 MPa. The wet oxidation of oxalic acid was found to require more severe conditions as compared to glyoxalic acid. The reaction mechanism and kinetic model have been discussed.

  6. Relative influence of process variables during non-catalytic wet oxidation of municipal sludge.

    Science.gov (United States)

    Baroutian, Saeid; Smit, Anne-Marie; Gapes, Daniel James

    2013-11-01

    Individual and interactive effects of process variables on the degradation of fermented municipal sludge were examined during wet oxidation. The process was carried out at 220-240°C using 1:1-2:1 oxygen to biomass ratio and 300-500 rpm stirring speed. Response surface methodology coupled with a faced-centred central composite design was used to evaluate the effect of these variables on total suspended solids, volatile suspended solids and total chemical oxygen demand. Multivariate analysis was conducted for the initial and near completion stages of reaction: 5 and 60 min treatments, respectively. Temperature had the most significant effect on degradation rate throughout. During the initial stage the effect of mixing intensity was less significant than that of oxygen ratio. Mixing intensity did not influence degradation rate at the later stage in the process. During the near completion stage, the interaction of temperature and oxygen ratio had significant effect on sludge degradation.

  7. Inhibition and deactivation effects in catalytic wet oxidation of high-strength alcohol-distillery liquors

    Energy Technology Data Exchange (ETDEWEB)

    Belkacemi, K.; Larachi, F.; Hamoudi, S.; Turcotte, G.; Sayari, A. [Laval Univ., Sainte-Foy, Quebec (Canada)

    1999-06-01

    The removal efficiency of total organic carbon (TOC) from raw high-strength alcohol-distillery waste liquors was evaluated using three different treatments: thermolysis (T), noncatalytic wet oxidation (WO), and solid-catalyzed wet oxidation (CWO). The distillery liquors (TOC = 22,500 mg/l, sugars = 18,000 mg/l, and proteins = 13,500 mg/l) were produced by alcoholic fermentation of enzymatic hydrolyzates from steam-exploded timothy grass. TOC-abatement studies were conducted batchwise in a stirred autoclave to evaluate the influence of the catalyst (7:3, MnO{sub 2}/CeO{sub 2} mixed oxide), oxygen partial pressure (0.5--2.5 MPa), and temperature (453--523 K) on T, WO, and CWO processes. Although CWO outperformed T and WO, TOC conversions did not exceed {approximately}60% at the highest temperature used. Experiments provided prima facie evidence for a gradual fouling of the catalyst and a developing inhibition in the liquors which impaired deep TOC removals. Occurrence of catalyst deactivation by carbonaceous deposits was proven experimentally through quantitative and qualitative experiments such as elemental analysis and X-ray photoelectron spectroscopy. Inhibition toward further degradation of the liquors was ascribed to the occurrence of highly stable antioxidant intermediates via the Maillard reactions between dissolved sugars and proteins. A lumping kinetic model involving both reaction inhibition by dissolved intermediates and catalyst deactivation by carbonaceous deposits was proposed to account for the distribution of carbon in the liquid, solid, and the vapor phases.

  8. Oxidation mechanism of Fe–16Cr alloy as SOFC interconnect in dry/wet air

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhi-Yuan [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Li-Jun, E-mail: lijunwang@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Li, Fu-Shen [School of Material Science Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Chou, Kuo-Chih [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2013-10-15

    Highlights: •A special thermodynamic description corresponding to the kinetics was applied. •We reported the relationships of degradation time with temperature and moisture. •”Turning time” in the Fe–16Cr alloy oxidation kinetic model was given. •The oxidation mechanism of Fe–16Cr alloy in the wet air was discussed. -- Abstract: Experimental study on the oxidation corrosions of Fe–16Cr alloy was carried out at 800–1100 °C under dry/wet air conditions. Faster oxidation rate was observed at higher temperature and water vapor content. The degradation time t{sub d} between two stages in oxidation process showed an exponential relationship with elevating corrosion temperature in dry air, and a linear relationship with the water content in the case of water vapor introduced to the system. The mechanism of oxidation corrosions of Fe–16Cr alloy was suggested by the Real Physical Picture (RPP) model. It was found that the break-away oxidation in stage II was controlled by diffusion at initial both in dry and wet air, then became linear with the exposure time, which implied that the oxidation rate was then controlled by chemical reaction of the interface between the metal and the oxidized scale. Moreover, the effect of water in the oxidation process is not only to supply more oxygen into system, but also to modify the structures of oxide scale due to the existence of hydrogen atom, which results in the accelerated corrosions.

  9. Treatment of refractory nano-filtration reject from a tannery using Pd-catalyzed wet air oxidation.

    Science.gov (United States)

    Tripathi, Pranav K; Rao, Nageswara N; Chauhan, Chetan; Pophali, Girish R; Kashyap, Sanjay M; Lokhande, Satish K; Gan, Lihua

    2013-10-15

    We attempted catalytic wet air oxidation (CWAO) of nanofiltration (NF)-reject using Pd based catalyst viz., Pd/activated charcoal (AC) and PdCl2 with the objective of degradation of refractory organic pollutants. Refractory organic pollutants in NF-reject before and after WAO and CWAO were confirmed by GC-MS analysis. Experiments were conducted to investigate the effects of temperature, catalyst dosage and air partial pressure on the rate of removal of total organic carbon (TOC). The reaction kinetics can be conveniently described by considering two-stage first order kinetics. The use of Pd/AC afforded 85% TOC removal, the corresponding rate constant (k) was 2.90 ± 0.075 × 10(-3)min(-1) (Pd/AC, 100mg/L; T, 473.15K; Pair, 0.69 MPa). On the other hand, 75% TOC was removed with k=2.31 ± 0.075 × 10(-3)min(-1) using Pd(2+) catalyst (Pd(2+), 16.66 mg/L; T, 473.15K; Pair, 0.69 MPa). The observed rate of mineralization under Pd-catalyzed conditions was significantly higher than that of the uncatalyzed oxidation (41%) under the similar experimental conditions. Catalyst stability experiments were performed and TEM, SEM, XRD, Raman and XPS characterization data collected. Despite some morphological transformation of support, Pd catalyst was stable under CWAO conditions.

  10. Catalytic wet peroxide oxidation of aniline in wastewater using copper modified SBA-15 as catalyst.

    Science.gov (United States)

    Kong, Liming; Zhou, Xiang; Yao, Yuan; Jian, Panming; Diao, Guowang

    2016-01-01

    SBA-15 mesoporous molecular sieves modified with copper (Cu-SBA-15) were prepared by pH-adjusting hydrothermal method and characterized by X-ray diffraction, BET, transmission electron microscopy, UV-Vis and (29)Si MAS NMR. The pH of the synthesis gel has a significant effect on the amount and the dispersion of copper on SBA-15. The Cu-SBA-15(4.5) (where 4.5 denotes the pH value of the synthesis gel) modified with highly dispersed copper was used as catalyst for the oxidation of aniline by H2O2. The Cu-SBA-15(4.5) shows a higher catalytic activity compared to CuO on the surface of SBA-15. The influences of reaction conditions, such as initial pH of the aqueous solutions, temperature, as well as the dosages of H2O2 and catalyst were investigated. Under weakly alkaline aqueous solution conditions, the aniline conversion, the H2O2 decomposition and the total organic carbon (TOC) removal could be increased significantly compared to the acid conditions. The percentage of leaching Cu(2+) could be decreased from 45.0% to 3.66% when the initial pH of solution was increased from 5 to 10. The TOC removal could be enhanced with the increases of temperature, H2O2 and catalyst dosage, but the aniline conversion and H2O2 decomposition change slightly with further increasing dosage of catalyst and H2O2. At 343 K and pH 8.0, 100% aniline conversion and 66.9% TOC removal can be achieved under the conditions of 1.0 g/L catalyst and 0.05 mol/L H2O2 after 180 min. Although copper might be slightly leached from catalyst, the homogeneous Cu(2+) contribution to the whole catalytic activity is unimportant, and the highly dispersed copper on SBA-15 plays a dominant role.

  11. Treatment of desizing wastewater from the textile industry by wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH,CODCr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 % CODCr reduction and 80 % TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD5/CODCr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

  12. Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

    Science.gov (United States)

    Abraham, Martin; Fisher, John W.

    1995-01-01

    The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

  13. Low-temperature catalytic gasification of wet industrial wastes. FY 1993--1994 interim report

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D.C.; Hart, T.R.; Neuenschwander, G.G.; Deverman, G.S.; Werpy, T.A.; Phelps, M.R.; Baker, E.G.; Sealock, L.J. Jr.

    1995-03-01

    Process development research is continuing on a low-temperature, catalytic gasification system that has been demonstrated to convert organics in water (dilute or concentrated) to useful and environmentally safe gases. The system, licensed under the trade name Thermochemical Environmental Energy System (TEESO), treats a wide variety of feedstocks ranging from hazardous organics in water to waste sludges from food processing. The current research program is focused on the use of continuous-feed, tubular reactors systems for testing catalysts and feedstocks in the process. A range of catalysts have been tested, including nickel and other base metals, as well as ruthenium and other precious metals. Results of extensive testing show that feedstocks, ranging from 2% para-cresol in water to potato waste and spent grain, can be processed to > 99% reduction of chemical oxygen demand (COD). The product fuel gas contains from 40% up to 75% methane, depending on the feedstock. The balance of the gas is mostly carbon dioxide with < 5% hydrogen and usually < 1% ethane and higher hydrocarbons. The byproduct water stream carries residual organics from 10 to 1,000 mg/l COD, depending on the feedstock. The level of development of TEES has progressed to the initial phases of industrial process demonstration. Testing of industrial waste streams is under way at both the bench scale and engineering scale of development.

  14. Bench-scale reactor tests of low-temperature, catalytic gasification of wet, industrial wastes

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D.C.; Neuenschwander, G.G.; Baker, E.G.; Butner, R.S.; Sealock, L.J.

    1990-04-01

    Bench-scale reactor tests are under way at Pacific Northwest Laboratory to develop a low-temperature, catalytic gasification system. The system, licensed under the trade name Thermochemical Environmental Energy System (TEES{reg sign}), is designed for to a wide variety of feedstocks ranging from dilute organics in water to waste sludges from food processing. The current research program is focused on the use of a continuous-feed, tubular reactor. The catalyst is nickel metal on an inert support. Typical results show that feedstocks such as solutions of 2% para-cresol or 5% and 10% lactose in water or cheese whey can be processed to >99% reduction of chemical oxygen demand (COD) at a rate of up to 2 L/hr. The estimated residence time is less than 5 min at 360{degree}C and 3000 psig, not including 1 to 2 min required in the preheating zone of the reactor. The liquid hourly space velocity has been varied from 1.8 to 2.9 L feedstock/L catalyst/hr depending on the feedstock. The product fuel gas contains 40% to 55% methane, 35% to 50% carbon dioxide, and 5% to 10% hydrogen with as much as 2% ethane, but less than 0.1% ethylene or carbon monoxide, and small amounts of higher hydrocarbons. The byproduct water stream carries residual organics amounting to less than 500 mg/L COD. 9 refs., 1 fig., 4 tabs.

  15. Removal of Xylene fromWaste Air Stream Using Catalytic Ozonation Process

    Directory of Open Access Journals (Sweden)

    H Mokarami

    2010-10-01

    Full Text Available "n "n "nBackgrounds and Objectives: Volatile organic compounds (VOCs are one of the common groups of contaminants encountered in the industrial activities, emitted through air stream into the atmosphere. To prevent the human and environmental health from the adverse effects of VOCs, air streams containing VOCs need to be treated before discharging to environment. This study was aimed at investigating the catalytic ozonation process for removing xylene from a contaminated air stream."nMaterials and Methods: In the present work, a bench scale experimental setup was constructed and used for catalytic ozonation of xylene. The performance of catalytic ozonation process was compared with that of single adsorption and ozonation in removal of several concentration of xylene under the similar experimental conditions."nResults: The results indicated that the efficiency of catalytic ozonation was higher than that of single adsorption and ozonation in removal of xylene. The emerging time and elimination capacity of xylene for inlet concentration of 300 ppm was 1.4 and 5.8 times of those in adsorption system. The activated carbon acted as catalyst in the presence of ozone and thus attaining the synergistic effect for xylene degradation."nConclusion: catalytic ozonation process is an efficient technique the treatment of air streams containing high concentrations of xylene. The adsorption systems can also be simply retrofitted to catalytic ozonation process and thereby improving their performance for treating VOCs.

  16. Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2015-01-01

    Full Text Available This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h and catalytic oxidation bed average temperature (20°C to 560°C within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry.

  17. CATALYTIC WET PEROXIDE OXIDATION OF HYDROQUINONE WITH Co(Ⅱ)/ACTIVE CARBON CATALYST LOADED IN STATIC BED

    Institute of Scientific and Technical Information of China (English)

    LI Chunxiang; YAN Yongsheng; XU Wanzhen

    2008-01-01

    Catalysts based on Co(Ⅱ) supported on active carbon were prepared and loaded in static bed.The hydroquinone wouid be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(Ⅱ)/active carbon catalyst.After activate treatment, the active carbon was immerged in cobaltoas nitrate solution, then put into a drying oven, Co(Ⅱ) could be loaded on the micro-surface of carbon.Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(Ⅱ) was used to reduce activation energy of hydroquinone.Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard.Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(Ⅱ).The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40℃, pH 5 and reaction time 2.5h.

  18. CATALYTIC WET PEROXIDE OXIDATION OF HYDROQUINONE WITH Co(II)/ACTIVE CARBON CATALYST LOADED IN STATIC BED

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Catalysts based on Co(II) supported on active carbon were prepared and loaded in static bed. The hydroquinone would be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(II)/active carbon catalyst. After activate treatment, the active carbon was immerged in cobaltous nitrate solution, then put into a drying oven, Co(II) could be loaded on the micro-surface of carbon. Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(II) was used to reduce activation energy of hydroquinone. Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard. Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(II). The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40℃ , pH 5 and reaction time 2.5h.

  19. Resting Study of Tracer Experiment on Catalytic Wet Oxidation Reactor under Micro-gravity and Earth Gravity Conditions

    Institute of Scientific and Technical Information of China (English)

    YANG Ji; JIA Jin-ping

    2005-01-01

    The International Space Station(ISS) employs catalytic wet oxidation carried out in a Volatile Reactor Assembly (VRA) for water recycling. Previous earth gravity experiments show that the VRA is very effective at removing polar,low molecular weight organics. To compare the reactor performance under micro-gravity and Earth gravity conditions,a tracer study was performed on a space shuttle in 1999 by using 0. 2% potassium carbonate as the chemical tracer.In this paper, the experimental data were analyzed and it is indicated that the reactor can be considered as a plug flow one under both micro-gravity and earth gravity experimental conditions. It has also been proved that dispersion is not important in the VRA reactor under the experimental conditions. Tracer retardation was observed in the experiments and it is most likely caused by catalyst adsorption. It is concluded that the following reasons may also have influence on the retardation of mean residence time: (1) the liquid can be held by appurtenances, which will retard the mean residence time; (2) the pores can hold the tracer, which can also retard the mean residence time.

  20. Treatment of refractory organic pollutants in industrial wastewater by wet air oxidation

    Directory of Open Access Journals (Sweden)

    Mingming Luan

    2017-02-01

    Full Text Available Wet air oxidation (WAO is one of the most economical and environmentally-friendly advanced oxidation processes. It makes a promising technology for the treatment of refractory organic pollutants in industrial wastewaters. In wet air oxidation aqueous waste is oxidized in the liquid phase at high temperatures (125–320 °C and pressures (0.5–20 MPa in the presence of an oxygen-containing gas (usually air. The advantages of the process include low operating costs and minimal air pollution discharges. The present review is concerned about the literature published in the treatment of refractory organic pollutants in industrial wastewaters, such as dyes. Phenolics were taken as model pollutants in most cases. Reports on effect of treatment for the WAO of refractory organic pollutants in industrial wastewaters are reviewed, such as emulsified wastewater, TNT red water, etc. Discussions are also made on the mechanism and kinetics of WAO and main technical parameters influencing WAO. Finally, development direction of WAO is summed up.

  1. Standardization methods for testing photo-catalytic air remediation materials: Problems and solution

    Science.gov (United States)

    Ifang, S.; Gallus, M.; Liedtke, S.; Kurtenbach, R.; Wiesen, P.; Kleffmann, J.

    2014-07-01

    In the present study, problems of different methods used for quantifying the air remediation activity of photo-catalytic active surfaces are described. It is demonstrated that in bed photo-reactors (e.g. ISO), transport limitations can lead to underestimation of the activity, if fast heterogeneous reactions are investigated. In contrast, in stirred tank photo-reactors (e.g. UNI), complex secondary chemistry may lead to an overestimation of the photo-catalytic remediation of NOx, if NO2 is also present. In addition, the quantities, used for ranking the photo-catalytic air remediation activity in the different methods are not independent of the applied experimental conditions, and thus, make any intercomparison between the different methods or the extrapolation to atmospheric conditions very difficult. Furthermore, unrealistic high NOx levels are used, for which the chemical kinetics may already be affected by surface saturation problems. Finally, it is shown that the use of only nitrogen monoxide (NO) will not enable users to judge about the quality and effectiveness of a photo-catalytic surface for improving air quality, since surfaces which are active toward NO may be completely non-reactive toward other important atmospheric pollutants. A modified method for quantifying the air remediation activity of photo-catalytic surfaces is proposed here to overcome these problems.

  2. Evaporative cooling of air in an adiabatic channel with partially wetted zones

    Science.gov (United States)

    Terekhov, V. I.; Gorbachev, M. V.; Khafaji, H. Q.

    2016-03-01

    The paper deals with the numerical study of heat and mass transfer in the process of direct evaporation air cooling in the laminar flow of forced convection in a channel between two parallel insulated plates with alternating wet and dry zones along the length. The system of Navier-Stokes equations and equations of energy and steam diffusion are being solved in two-dimensional approximation. At the channel inlet, all thermal gas-dynamic parameters are constant over the cross section, and the channel walls are adiabatic. The studies were carried out with varying number of dry zones ( n = 0-16), their relative length ( s/l = 0-1) and Reynolds number Re = 50-1000 in the flow of dry air (φ0 = 0) with a constant temperature at the inlet (T 0 = 30 °C). The main attention is paid to optimization analysis of evaporation cell characteristics. It is shown that an increase in the number of alternating steps leads to an increase in the parameters of thermal and humid efficiency. With an increase in Re number and a decrease in the extent of wet areas, the efficiency parameter reduces.

  3. Small-angle neutron scattering investigation of polyurethane aged in dry and wet air

    Directory of Open Access Journals (Sweden)

    Q. Tian

    2014-05-01

    Full Text Available The microstructures of Estane 5703 aged at 70°C in dry and wet air have been studied by small-angle neutron scattering. The samples were swollen in deuterated toluene for enhancing the contrast. The scattering data show the characteristic domain structure of polyurethanes consisting of soft and hard segments. Debye-Anderson-Brumberger function used with hard sphere structure factor, and the Teubner-Strey model are used to analyze the two-phase domain structure of the polymer. The combined effects of temperature and humidity have a strong disruption effect on the microstructures of Estane. For the sample aged at 70°C in wet air for 1 month, the domain size, described by the correlation length, increases from 2.3 to 3.8 nm and their distance, expressed by hard-sphere interaction radius, increases from 8.4 to 10.6 nm. The structure development is attributed to degradation of polymer chains as revealed by gel permeation chromatography. The hydrolysis of ester links on polymer backbone at 70°C in the presence of water humidity is the main reason for the changes of the microstructure. These findings can contribute to developing predictive models for the safety, performance, and lifetime of polyurethanes.

  4. Treatment of desizing wastewater from the textile industry by wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH,CODCr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 % CODCr reduction and 80 % TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD5/CODCr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

  5. Alkaline peroxide assisted wet air oxidation pretreatment approach to enhance enzymatic convertibility of rice husk.

    Science.gov (United States)

    Banerjee, Saumita; Sen, Ramkrishna; Mudliar, Sandeep; Pandey, R A; Chakrabarti, Tapan; Satpute, Dewanand

    2011-01-01

    Pretreatment of rice husk by alkaline peroxide assisted wet air oxidation (APAWAO) approach was investigated with the aim to enhance the enzymatic convertibility of cellulose in pretreated rice husk. Rice husk was presoaked overnight in 1% (w/v) H(2)O(2) solution (pH adjusted to 11.5 using NaOH) (equivalent to 16.67 g H(2)O(2) and 3.63 g NaOH per 100 g dry, untreated rice husk) at room temperature, followed by wet air oxidation (WAO). APAWAO pretreatment resulted in solubilization of 67 wt % of hemicellulose and 88 wt % of lignin initially present in raw rice husk. Some amount of oligomeric glucose (˜8.3 g/L) was also observed in the APAWAO liquid fraction. APAWAO pretreatment resulted in 13-fold increase in the amount of glucose that could be obtained from otherwise untreated rice husk. Up to 86 wt % of cellulose in the pretreated rice husk (solid fraction) could be converted into glucose within 24 hours, yielding over 21 g glucose per 100 g original rice husk. Scanning electron microscopy was performed to visualize changes in biomass structure following the APAWAO pretreatment. Enzymatic cellulose convertibility of the pretreated slurry at high dry matter loadings was also investigated.

  6. The Study of LeachateTreatment by Using Three Advanced Oxidation Process Based Wet air Oxidation

    Directory of Open Access Journals (Sweden)

    Behroz Karimi

    2013-01-01

    Full Text Available Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300[degree sign] as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter.

  7. The study of leachate treatment by using three advanced oxidation process based wet air oxidation.

    Science.gov (United States)

    Karimi, Behroz; Ehrampoush, Mohammad Hassan; Ebrahimi, Asghar; Mokhtari, Mehdi

    2013-01-02

    Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300° as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency) for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter.

  8. Analysis of a wet scrubber network in the air remediation of industrial workplaces: benefit for the city air quality

    CERN Document Server

    Avveduto, Alessandro; Pace, Lorenzo; Curci, Gabriele; Monaco, Alessio; De Giovanni, Marina; Giammaria, Franco; Spanto, Giuseppe; Tripodi, Paolo

    2015-01-01

    Industrial activities carried out in confined spaces are characterized by a very specific type of air pollution. The extended exposure to this kind of pollution is often highly harmful, resulting in dramatic effects both on health and safety aspects. The indoor industrial abatement systems, adopted to purify the air, are typically applied to the emission points. The processed air is subsequently emitted outside. In this study we present the experimental results of three-stage wet scrubber systems installed in the industrial workplace of a (i) fiberglass processing plant, where the highest exposure levels to volatile compounds are nowadays today monitored,and of a (ii) waste-to-energy plant, characterized by a very high particulate matter level. The adopted technology, to be used as complementing strategy,does not require special disposal procedures and the processed air is re-emitted in the same work environment for the benefit of the work operators. The operation of the scrubbers network during the working a...

  9. Characteristics of CuO-MoO3-P2O5 catalyst and its catalytic wet oxidation (CWO) of dye wastewater under extremely mild conditions.

    Science.gov (United States)

    Ma, Hongzhu; Zhuo, Qiongfang; Wang, Bo

    2007-11-01

    In order to develop a catalyst with high activity for catalytic wet oxidation (CWO) processing at lower temperatures (35 degrees C) and atmospheric pressure, a new CuO-MoO3-P2O5 catalystwas synthesized by a solid-state reaction method and was characterized by X-ray diffraction (XRD), Fourier transformation infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), selected area electronic diffraction (SAED), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS) for elemental mapping. Methylene blue (MB) was adopted to investigate the catalytic activity of CuO-MoO3-P2O5 in CWO processing. The results show that this new catalyst has a high catalytic activity to decolorize MB under mild condition. The color removal of MB (the initial concentration was 0.3 g L(-1) and initial pH was 5) can reach to 99.26% within 10 min at 35 degrees C and atmospheric pressure. Catalyst lifespan and selectivity were also tested, and the results show that after the catalyst was used three times, catalyst activity still remains. Selectivity testing shows that CuO-MoO3-P2O5 has high catalytic activity on degradation of MB, whereas this catalyst has less impact on methyl orange (the color removal was 99.65% for MB and 55% for methyl orange under the same conditions). According to the experimental results, a possible mechanism of catalytic degradation of MB was proposed.

  10. Role of Bismuth Oxide in Bi-MCo2O4(M=Co,Ni,Cu,Zn) Catalysts for Wet Air Oxidation of Acetic Acid

    Institute of Scientific and Technical Information of China (English)

    JIANG Peng-bo; CHENG Tie-xin; ZHUANG Hong; CUI Xiang-hao; BI Ying-li; ZHEN Kai-ji

    2004-01-01

    Two series of cobalt(Ⅲ)-containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acetic acid than those without dopant bismuth oxide. The catalysts were investigated by XRD, TEM, ESR, UV-DRS and XPS, and the interaction between Co and Bi was studied as well. It has been found that nano-sized bismuth oxide is paved on the surface of cobalt spinel crystal and the structures of cobalt(Ⅲ)-containing spinel are still maintained. The shift of the binding energy of Bi4f7/2 is related to the catalytic activity of these catalysts doped with bismuth oxide.

  11. Degradation of H-acid in aqueous solution by microwave assisted wet air oxidation using Ni-loaded GAC as catalyst

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao-bin; QUAN Xie; ZHAO Hui-min; CHEN Shuo; YANG Feng-lin

    2005-01-01

    A novel process, microwave assisted catalytic wet air oxidation(MW-CWO), was applied for the degradation of H-acid( 1-amino8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon (GAG), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC.

  12. Methanol/air fuel cells: catalytic aspects and experimental diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.F.; Sieben, J.M.; Pilla, A.S.; Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion, Depto. de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2008-07-15

    Methanol/air fuel cell with direct feed of methanol has received growing attention due to the possibility of using a liquid fuel of simple storing. This work comments studies on the preparation of PtRu catalysts for methanol oxidation and on the influence of different operative parameter on the performance of a lab scale fuel cell. The best conditions for PtRu catalysts preparation using metal electrodeposition techniques were found. Different carbon materials were used, such as glassy carbon, carbon paper and graphite fiber cloths and felts. The more active materials were found to be graphite felts after being preoxidized electrochemically to obtain a higher surface oxide concentration. Acceptable performance of the fuel cell was obtained working at 90 C and low methanol concentration, because in these conditions the potential, the transport process rates and the electrode reaction kinetics increase. (author)

  13. Air trichloroethylene oxidation in a corona plasma-catalytic reactor

    Science.gov (United States)

    Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A. A.; Vesali-Naseh, M.; Mortazavi, Y.

    2014-08-01

    The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnOx, CoOx. The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnOx and CoOx catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition.

  14. Reuse of a dyehouse effluent after being treated with the combined catalytic wet peroxide oxidation process and the aerated constructed wetland.

    Science.gov (United States)

    Lee, D K; Kim, S C; Yoon, J H

    2007-01-01

    A catalytic wet peroxide oxidation process was combined with the aerated constructed wetland in order to treat the raw dyehouse wastewater to in acceptable level for reuse as washing process water. More than 90% of BOD and CODs could be removed with the wet peroxide oxidation reactor and the remaining pollutants in the treated water were transformed into biodegradable ones which could have been successfully treated at the following aerated constructed wetland. The highest values of BOD5, CODMn, CODCr, SS and T-N in the treated water were 1.6, 1.8, 2.1, 0.5 and 12.8 mg/L, respectively. These values were low enough for the treated water to be reused at the washing process.

  15. Catalytic wet oxidation of dyehouse effluents with Cu/Al{sub 2}O{sub 3} and Al-Cu pillared clays

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.K.; Kim, S.C.; Kim, D.S.; Lee, G.S.; Yoon, S.B. [Dept. of Chemical Engineering/Environmental Protection, Environment and Regional Development Inst., Gyeongsang National Univ., Gyeongnam (Korea)

    2003-07-01

    Catalytic wet oxidation of real dyehouse effluents was performed in a batch reactor and a continuous flow pilot plant scale reactor by using Cu/Al{sub 2}O{sub 3} and Al-Cu-PILC catalysts. Hydrogen peroxide was used as the oxidant. The removal of TOC and color was strongly related to the consumption of H{sub 2}O{sub 2} and the subsequent formation of HO-. Copper components in the catalysts, especially in the Al-Cu-PILCs, showed successful activity toward complete removal of TOC and color. In addition the Al-Cu-PILC catalysts were extremely stable against copper leaching. (orig.)

  16. Experimental evaluation of dry/wet air-cooled heat exchangers. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, S.G.; Gruel, R.L.; Huenefeld, J.C.; Eschbach, E.J.; Johnson, B.M.; Kreid, D.K.

    1982-08-01

    The ultimate goal of this project was to contribute to the development of improved cooling facilities for power plants. Specifically, the objective during FY-81 was to experimentally determine the thermal performance and operating characteristics of an air-cooled heat exchanger surface manufactured by the Unifin Company. The performance of the spiral-wound finned tube surface (Unifin) was compared with two inherently different platefin surfaces (one developed by the Trane Co. and the other developed by the HOETERV Institute) which were previously tested as a part of the same continuing program. Under dry operation the heat transfer per unit frontal area per unit inlet temperature difference (ITD) of the Unifin surface was 10% to 20% below that of the other two surfaces at low fan power levels. At high fan power levels, the performances of the Unifin and Trane surfaces were essentially the same, and 25% higher than the HOETERV surface. The design of the Unifin surface caused a significantly larger air-side pressure drop through the heat exchanger both in dry and deluge operation. Generally higher overall heat transfer coefficients were calculated for the Unifin surface under deluged operation. They ranged from 2.0 to 3.5 Btu/hr-ft/sup 2/-/sup 0/F as compared to less than 2.0 Btu hr-ft/sup 2/-/sup 0/F for the Trane and HOETERV surfaces under similar conditions. The heat transfer enhancement due to the evaporative cooling effect was also measureably higher with the Unifin surface as compared to the Trane surface. This can be primarily attributed to the better wetting characteristics of the Unifin surface. If the thermal performance of the surfaces are compared at equal face velocities, the Unifin surface is as much as 35% better. This method of comparison accounts for the wetting characteristics while neglecting the effect of pressure drop. Alternatively the surfaces when compared at equal pressure drop essentially the same thermal performance.

  17. [Catalytic wet air oxidation of phenol and aniline over multi-walled carbon nanotubes].

    Science.gov (United States)

    Li, Xiang; Yang, Shao-xi; Zhu, Wan-peng; Wang, Jian-bing; Wang, Li

    2008-09-01

    Multi-walled carbon nanotubes (MWNTs) without any metal ions were used as the catalyst, and investigated in the CWAO of phenol and aniline in a batch reactor. The structures of the MWNTs were characterized by means of SEM and TEM. It showed that the MWNTs, treated with the mixed acid (HNO3-H2SO4), displayed excellent activity and stability in the CWAO. Under the reaction temperature of 160 degrees C, the total pressure of 2.5 MPa, the initial concentration of 1000 mg/L and loading the catalyst of 1.6 g/L, 100% phenol and 86% COD were removed after 120 min reaction in CWAO of phenol. At the same operating conditions, 83% aniline and 68% COD removals were obtained in the CWAO of aniline solution when the initial concentration of aniline was 2 000 mg/L. The surface functional groups played the important role for the high activity of the MWNTs in CWAO of organic compounds.

  18. Effect of CeO2 doping on catalytic activity of Fe2O3/gamma-Al2O(3) catalyst for catalytic wet peroxide oxidation of azo dyes.

    Science.gov (United States)

    Liu, Yan; Sun, Dezhi

    2007-05-08

    In order to find a catalyst with high activity and stability for catalytic wet peroxide oxidation (CWPO) process under normal condition, with Fe(2)O(3)/gamma-Al(2)O(3) and Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) catalysts prepared by impregnation method, the effect of CeO(2) doping on the structure and catalytic activity of Fe(2)O(3)/gamma-Al(2)O(3) for catalytic wet peroxide oxidation of azo dyes at 25 degrees C and atmospheric pressure is evaluated using BET, SEM, XRF, XRD, XPS and chemical analysis techniques, and test results show that, better dispersion and smaller size of Fe(2)O(3) crystal can be achieved by adding CeO(2), and the content of chemisorbed oxygen can also be increased on the surface of catalyst. CWPO experimental results indicate that azo dyes in simulated wastewater can be efficiently mineralized and the catalytic activity of Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) can be increased by about 10% compared with that of Fe(2)O(3)/gamma-Al(2)O(3) because of the promotion of the structural and redox properties of the ferric oxide by ceria doped. Leaching tests indicate that Fe(2)O(3)/gamma-Al(2)O(3) and Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) are stable with a negligible amount of irons found in the aqueous solution after reaction for 2h. It can therefore be concluded from results and discussion that in comparison with Fe(2)O(3)/gamma-Al(2)O(3), Fe(2)O(3)-CeO(2)/gamma-Al(2)O(3) is a suitable catalyst, which can effectively degrade contaminants at normal temperature and atmospheric pressure.

  19. Catalytically stabilized combustion of lean methane-air-mixtures: a numerical model

    Energy Technology Data Exchange (ETDEWEB)

    Dogwiler, U.; Benz, P.; Mantharas, I. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The catalytically stabilized combustion of lean methane/air mixtures has been studied numerically under conditions closely resembling the ones prevailing in technical devices. A detailed numerical model has been developed for a laminar, stationary, 2-D channel flow with full heterogeneous and homogeneous reaction mechanisms. The computations provide direct information on the coupling between heterogeneous-homogeneous combustion and in particular on the means of homogeneous ignitions and stabilization. (author) 4 figs., 3 refs.

  20. Methodology to determine the appropriate amount of excess air for the operation of a gas turbine in a wet environment

    Energy Technology Data Exchange (ETDEWEB)

    Lugo-Leyte, R.; Zamora-Mata, J.M.; Torres-Aldaco, A. [Universidad Autonoma Metropolitana-Iztapalapa, Departamento de Ingenieria de Procesos e Hidraulica, San Rafael Atlixco 186, Col Vicentina 09340, Iztapalapa, Mexico, D.F. (Mexico); Toledo-Velazquez, M. [Instituto Politecnico Nacional, Escuela Superior de Ingenieria Mecanica y Electrica, Seccion de Estudios de Posgrado e Investigacion, Laboratorio de Ingenieria Termica e Hidraulica Aplicada, Unidad Profesional Adolfo Lopez Mateos, Edificio 5, 3er piso SEPI-ESIME, C.P. 07738, Col. Lindavista, Mexico D.F. (Mexico); Salazar-Pereyra, M. [Tecnologico de Estudios Superiores de Ecatepec, Division de Ingenieria Mecatronica e Industrial, Posgrado en Ciencias en Ingenieria Mecatronica, Av. Tecnologico s/n, Col. Valle de Anahuac, C.P. 55210, Ecatepec de Morelos, Estado de Mexico (Mexico)

    2010-02-15

    This paper addresses the impact of excess air on turbine inlet temperature, power, and thermal efficiency at different pressure ratios. An explicit relationship is developed to determine the turbine inlet temperature as a function of excess air, pressure ratio and relative humidity. The effect of humidity on the calculation of excess air to achieve a pre-established power output is analyzed and presented. Likewise it is demonstrated that dry air calculations provide a valid upper bound for the performance of a gas turbine under a wet environment. (author)

  1. Pretreatment of Afyon alcaloide factory's wastewater by wet air oxidation (WAO).

    Science.gov (United States)

    Kaçar, Y; Alpay, E; Ceylan, V K

    2003-03-01

    In this study, pretreatment of Afyon (Turkey) alcaloide factory wastewater, a typical high strength industrial wastewater (chemical oxygen demand (COD)=26.65 kgm(-3), biological oxygen demand (BOD(5))=3.95 kgm(-3)), was carried out by wet air oxidation process. The process was performed in a 0.75 litre specially designed bubble reactor. Experiments were conducted to see the advantages of one-stage and two-stage oxidation and the effects of pressure, pH, temperature, catalyst type, catalyst loading and air or oxygen as gas source on the oxidation of the wastewater. In addition, BOD(5)/COD ratios of the effluents, which are generally regarded as an important index of biodegradability of a high-strength industrial wastewater, were determined at the end of some runs. After a 2h oxidation (T=150 degrees C, P=0.65 MPa, airflowrate=1.57 x 10(-5)m(3)s(-1), pH=7.0), the BOD(5)/COD ratio was increased from 0.15 to above 0.5 by using the salts of metals such as Co(2+),Fe(2+),Fe(2+)+Ni(2+),Cu(2+)+Mn(2+) as catalyst.

  2. Catalytic wet oxidation of phenol by using Fe/active carbon catalysts%Fe/AC催化剂对苯酚模拟废水的催化湿式氧化

    Institute of Scientific and Technical Information of China (English)

    赵建军

    2011-01-01

    采用浸渍法制备了Fe/AC(活性炭)系列催化剂;用苯酚的湿式催化氧化作为模型反应,研究了催化剂的催化性能.结果表明,在pH=3.0,常压和90 ℃的反应条件下,Fe(5%)/AC催化剂具有相对较优的对苯酚废水的催化氧化活性,该催化剂对苯酚模拟废水的化学需氧量(COD)去除率约为70%.通过催化剂表征,表明该催化剂活性与其表面性质存在一定的关系.%The catalytic wet air oxidation ( CWAO ) of phenol was investigated in the presence of Fe/AC ( active carbon) catalysts, which were obtained by conventional impregnation method. The experiment results showed that the phenol removal was about 70% with addition of the Fe(5% )/AC catalyst at pH = 3.0, 90 ℃ and normal atmospheric pressure. In this catalyst, characterization data showed a very good relation between the catalytic activity and the surface properties of the catalysts.

  3. Experimental coupling and modelling of wet air oxidation and packed-bed biofilm reactor as an enhanced phenol removal technology.

    Science.gov (United States)

    Minière, Marine; Boutin, Olivier; Soric, Audrey

    2017-01-25

    Experimental coupling of wet air oxidation process and aerobic packed-bed biofilm reactor is presented. It has been tested on phenol as a model refractory compound. At 30 MPa and 250 °C, wet air oxidation batch experiments led to a phenol degradation of 97% and a total organic carbon removal of 84%. This total organic carbon was mainly due to acetic acid. To study the interest of coupling processes, wet air oxidation effluent was treated in a biological treatment process. This step was made up of two packed-bed biofilm reactors in series: the first one acclimated to phenol and the second one to acetic acid. After biological treatment, phenol and total organic carbon removal was 99 and 97% respectively. Thanks to parameters from literature, previous studies (kinetic and thermodynamic) and experimental data from this work (hydrodynamic parameters and biomass characteristics), both treatment steps were modelled. This modelling allows the simulation of the coupling process. Experimental results were finally well reproduced by the continuous coupled process model: relative error on phenol removal efficiency was 1 and 5.5% for wet air oxidation process and packed-bed biofilm reactor respectively.

  4. 14 CFR 119.53 - Wet leasing of aircraft and other arrangements for transportation by air.

    Science.gov (United States)

    2010-01-01

    ... wet lease, the Administrator determines which party to the agreement has operational control of the... otherwise authorized by the Administrator, prior to conducting operations involving a wet lease, each... shall provide the Administrator with a copy of the wet lease to be executed which would lease...

  5. Study on dynamics characteristics of wet air oxidation of non-ionic surfactants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Wet air oxidation is an effective method to deal with highly concentrated nondegradable emulsification wastewater which contains non-ionic surfactants. This article illustrates our investigation on dynamic characteristics of wet air oxidation of typical non-ionic surfactants like polyether, phenol ether and widely used alcohol ether. The experimental results indicated that the oxidation rate of polyether, phenol ether and alcohol ether obviously ascended as the temperature rose. A good oxidation effect was available at 240℃. The TOC removal rate could reach 88.0%, 94% and 91.5%, after 125 min reaction. Alcohol ether was prone to an easier oxidation compared with polyether and phenol ether when the temperature was 220℃ or below. The oxidation rate of alcohol ether was higher than that of polyether at 160℃, while the oxidation rate of polyether was higher than that of phenol ether between 180℃ and 220℃. During the later period of the reaction at 240℃, the rate of phenol ether was higher than that of alcohol ether, which was still higher than that of polyether. Partitioned first order kinetics model analy-sis showed that the apparent activation energy of alcohol ether was lower than that of both polyether and phenol ether in the leading stage and lagging stage, and it was easy to acquire a higher oxidation rate for alcohol ether at low temperature. Three parameter general dynamics model analyses showed that the reason why the oxidation rate of polyether was lower than that of alcohol ether was that the oxidation of polyether was more apt to be converted to intermediate production than that of alcohol ether, whereas between 200℃ and 220℃, the direct oxidation rate of polyether and the oxidation rate of intermediate product were obviously lower than that of alcohol ether. The apparent activation energy of direct and indirect oxidation of polyether was 43.37 and 60.45 kJ?mol?1, respectively, while the corre-sponding apparent activation energy of alcohol

  6. Study on dynamics characteristics of wet air oxidation of non-ionic surfactants

    Institute of Scientific and Technical Information of China (English)

    ZENG XinPing; TANG WenWei; ZHAO JianFu; GU GuoWei

    2008-01-01

    Wet air oxidation is an effective method to deal with highly concentrated nondegradable emulsification wastewater which contains non-ionic surfactants. This article illustrates our investigation on dynamic characteristics of wet air oxidation of typical non-ionic surfactants like polyether, phenol ether and widely used alcohol ether. The experimental results indicated that the oxidation rate of polyether, phenol ether and alcohol ether obviously ascended as the temperature rose. A good oxidation effect was available at 240℃. The TOC removal rate could reach 88.0%, 94% and 91.5%, after 125 min reaction. Alcohol ether was prone to an easier oxidation compared with polyether and phenol ether when the temperature was 220℃ or below. The oxidation rate of alcohol ether was higher than that of polyether at 160℃, while the oxidation rate of polyether was higher than that of phenol ether between 180℃ and 220℃. During the later period of the reaction at 240℃, the rate of phenol ether was higher than that of alcohol ether, which was still higher than that of polyether. Partitioned first order kinetics model analysis showed that the apparent activation energy of alcohol ether was lower than that of both polyether and phenol ether in the leading stage and lagging stage, and it was easy to acquire a higher oxidation rate for alcohol ether at low temperature. Three parameter general dynamics model analyses showed that the reason why the oxidation rate of polyether was lower than that of alcohol ether was that the oxidation of polyether was more apt to be converted to intermediate production than that of alcohol ether, whereas between 200℃ and 220℃, the direct oxidation rate of polyether and the oxidation rate of intermediate product were obviously lower than that of alcohol ether. The apparent activation energy of direct and indirect oxidation of polyether was 43.37 and 60.45 kJ·mol-1, respectively, while the corresponding apparent activation energy of alcohol

  7. Wet air oxidation as a pretreatment option for selective biodegradability enhancement and biogas generation potential from complex effluent.

    Science.gov (United States)

    Padoley, K V; Tembhekar, P D; Saratchandra, T; Pandit, A B; Pandey, R A; Mudliar, S N

    2012-09-01

    This study looks at the possibility of wet air oxidation (WAO) based pretreatment of complex effluent to selectively enhance the biodegradability (without substantial COD destruction) and facilitate biogas generation potential. A lab-scale wet air oxidation reactor with biomethanated distillery wastewater (B-DWW) as a model complex effluent (COD 40,000 mg L(-1)) was used to demonstrate the proof-of-concept. The studies were conducted using a designed set of experiments and reaction temperature (150-200°C), air pressure (6-12 bar) and reaction time (15-120 min) were the main process variables of concern for WAO process optimization. WAO pretreatment of B-DWW enhanced the biodegradability of the complex wastewater by the virtue of enhancing its biodegradability index (BI) from 0.2 to 0.88, which indicate favorable Biochemical Methane Potential (BMP) for biogas generation. The kinetics of COD destruction and BI enhancement has also been reported.

  8. Effects of operational conditions on sludge degradation and organic acids formation in low-critical wet air oxidation.

    Science.gov (United States)

    Chung, Jinwook; Lee, Mikyung; Ahn, Jaehwan; Bae, Wookeun; Lee, Yong-Woo; Shim, Hojae

    2009-02-15

    Wet air oxidation processes are to treat highly concentrated organic compounds including refractory materials, sludge, and night soil, and usually operated at supercritical water conditions of high temperature and pressure. In this study, the effects of operational conditions including temperature, pressure, and oxidant dose on sludge degradation and conversion into subsequent intermediates such as organic acids were investigated at low critical wet oxidation conditions. The reaction time and temperature in the wet air oxidation process was shown an important factor affecting the liquefaction of volatile solids, with more significant effect on the thermal hydrolysis reaction rather than the oxidation reaction. The degradation efficiency of sludge and the formation of organic acids were improved with longer reaction time and higher reaction temperature. For the sludge reduction and the organic acids formation under the wet air oxidation, the optimal conditions for reaction temperature, time, pressure, and oxidant dose were shown approximately 240 degrees C, 30min, 60atm, and 2.0L/min, respectively.

  9. Survey the Efficiency of Catalytic Ozonation Process with Carbosieve in the Removal of Benzene from Polluted Air Stream

    Directory of Open Access Journals (Sweden)

    M. Samarghandi

    2014-01-01

    Full Text Available Introduction & Objective: Benzene is one of the most common volatile organic compounds in the indoor and outdoor environments that has always been considered as one of the causes of air pollution. Thus before being discharged to the environment, it must be treated from pol-luted air stream. The aim of this study was to determine the efficiency of catalytic ozonation process with carbosieve in the removal of benzene from polluted air stream. Materials & Methods: The study was experimental in which catalytic ozonation process with carbosieve was used in the removal of benzene from polluted air stream. The experiments were carried out in a reactor with continuous system and the results of catalytic ozonation were compared with the results of single ozonation and carbosieve adsorbent .The sampling, benzene analyzing and determining of ozone concentration in samples were done with 1501 NMAM method by GC equipped with FID detector and iodometry , respectively. Results: The results of this study showed that the removal effectiveness of single ozonation process is averagely less than 19%. Also the efficiency of absorbent decreased with the con-centration increase of benzene.The increase ratio of efficiency in catalytic ozonation process to efficiency of carbosieve adsorbent was averagely 45%. Conclusion: With regard to high efficiency of catalytic ozonation process and increasing the benzene removal , the catalytic ozonation process is suggested as a promising and alternative technology for elimination of VOCs from the polluted air stream. (Sci J Hamadan Univ Med Sci 2014; 20 (4:303-311

  10. Treatment of biomass gasification wastewater using a combined wet air oxidation/activated sludge process

    Energy Technology Data Exchange (ETDEWEB)

    English, C.J.; Petty, S.E.; Sklarew, D.S.

    1983-02-01

    A lab-scale treatability study for using thermal and biological oxidation to treat a biomass gasification wastewater (BGW) having a chemical oxygen demand (COD) of 46,000 mg/l is described. Wet air oxidation (WA0) at 300/sup 0/C and 13.8 MPa (2000 psi) was used to initially treat the BGW and resulted in a COD reduction of 74%. This was followed by conventional activated sludge treatment using operating conditions typical of municipal sewage treatment plants. This resulted in an additional 95% COD removal. Overall COD reduction for the combined process was 99%. A detailed chemical analysis of the raw BGW and thermal and biological effluents was performed using gas chromatography/mass spectrometry (GC/MS). These results showed a 97% decrease in total extractable organics with WA0 and a 99.6% decrease for combined WA0 and activated sludge treatment. Components of the treated waters tended to be fewer in number and more highly oxidized. An experiment was conducted to determine the amount of COD reduction caused by volatilization during biological treatment. Unfortunately, this did not yield conclusive results. Treatment of BGW using WA0 followed by activated sludge appears to be very effective and investigations at a larger scale are recommended.

  11. ESR ST study of hydroxyl radical generation in wet peroxide system catalyzed by heterogeneous ruthenium

    NARCIS (Netherlands)

    Rokhina, E.V.; Golovina, E.A.; As, van H.; Virkutyte, J.

    2009-01-01

    Ru-based catalysts gained popularity because of their applicability for a variety of processes, including carbon monoxide oxidation, wet air catalytic oxidation and wastewater treatment. The focus of a current study was generation of hydroxyl radicals in the wet peroxide system catalyzed by heteroge

  12. Catalytic wet peroxide oxidation of azo dye (Direct Blue 15) using solvothermally synthesized copper hydroxide nitrate as catalyst.

    Science.gov (United States)

    Zhan, Yuzhong; Zhou, Xiang; Fu, Bei; Chen, Yiliang

    2011-03-15

    Copper hydroxide nitrate (Cu(2)(OH)(3)NO(3)) was synthesized solvothermally in anhydrous ethanol and characterized by XRD, FTIR, TG-DTA and SEM. The peroxide degradation of an azo dye (Direct Blue 15) on this material was evaluated by examining catalyst loading, initial pH, hydrogen peroxide dosage, initial dye concentration and temperature. The leaching of Cu from the copper hydroxide nitrate during the reaction was also measured. The copper hydroxide nitrate synthesized solvothermally, which was of a novel spherical morphology with complex secondary structures and contained high-dispersed Cu(2)O impurity, showed good performance for oxidation degradation of the azo dye, especially high catalytic activity, high utilization of hydrogen peroxide and a wide pH range, whereas the copper hydroxide nitrate synthesized by the direct reaction of copper nitrate and sodium hydroxide showed low catalytic activity.

  13. An investigation of turbulent catalytically stabilized channel flow combustion of lean hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mantzaras, I.; Benz, P.; Schaeren, R.; Bombach, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The catalytically stabilised thermal combustion (CST) of lean hydrogen-air mixtures was investigated numerically in a turbulent channel flow configuration using a two-dimensional elliptic model with detailed heterogeneous and homogeneous chemical reactions. Comparison between turbulent and laminar cases having the same incoming mean properties shows that turbulence inhibits homogeneous ignition due to increased heat transport away from the near-wall layer. The peak root-mean-square temperature and species fluctuations are always located outside the extent of the homogeneous reaction zone indicating that thermochemical fluctuations have no significant influence on gaseous combustion. (author) 4 figs., 6 refs.

  14. Sewage-sludge-derived carbonaceous materials for catalytic wet hydrogen peroxide oxidation of m-cresol in batch and continuous reactors.

    Science.gov (United States)

    Yu, Yang; Wei, Huangzhao; Yu, Li; Wang, Wei; Zhao, Ying; Gu, Bin; Sun, Chenglin

    2016-01-01

    In this study, four sewage-sludge-derived carbonaceous materials (SWs) were evaluated for their catalytic wet hydrogen peroxide oxidation (CWPO) performance of m-cresol in batch reactor and continuous reactor, respectively. The SWs were produced by carbonization (SW); carbonization with the addition of CaO (CaO-SW); HNO3 pretreatment (HNO3-SW) and steam activation (Activated-SW). The properties of SW catalysts were assessed by thermogravimetric analysis, Brunauer-Emmett-Teller, Fourier Transform Infrared Spectroscopy, X-ray Fluorescence, Scanning electron microscopy, energy dispersive X-ray analysis and zeta potential. The results showed that SW treated by HNO3 (HNO3-SW) had a high conversion of m-cresol in batch reactor and continuous reactor, respectively. Under the conditions of batch reaction (Cm-cresol = 100 mg L(-1), CH2O2 = 15.7 mmol L(-1), initial pH=7.0, 0.5 g L(-1) catalyst, 80°C, 180 min adsorption and 210 min oxidation), the conversion of m-cresol reached 100% and total organic carbon removal was 67.1%. It had a high catalytic activity and stability on the treatment of m-cresol in CWPO for more than 1100 h. Furthermore, a possible reaction mechanism for the oxidation of m-cresol to 2-methyl-p-benzoquinone by CWPO was proposed.

  15. Treatment of ammonia by catalytic wet oxidation process over platinum-rhodium bimetallic catalyst in a trickle-bed reactor: effect of pH.

    Science.gov (United States)

    Hung, Chang-Mao; Lin, Wei-Bang; Ho, Ching-Lin; Shen, Yun-Hwei; Hsia, Shao-Yi

    2010-08-01

    This work adopted aqueous solutions of ammonia for use in catalytic liquid-phase reduction in a trickle-bed reactor with a platinum-rhodium bimetallic catalyst, prepared by the co-precipitation of chloroplatinic acid (H2PtCl6) and rhodium nitrate [Rh(NO3)3]. The experimental results demonstrated that a minimal amount of ammonia was removed from the solution by wet oxidation in the absence of any catalyst, while approximately 97.0% of the ammonia was removed by wet oxidation over the platinum-rhodium bimetallic catalyst at 230 degrees C with an oxygen partial pressure of 2.0 MPa. The oxidation of ammonia has been studied as a function of pH, and the main reaction products were determined. A synergistic effect is manifest in the platinum-rhodium bimetallic structure, in which the material has the greatest capacity to reduce ammonia. The reaction pathway linked the oxidizing ammonia to nitric oxide, nitrogen, and water.

  16. Investigation of the catalytic wet peroxide oxidation of phenol over different types of Cu/ZSM-5 catalyst.

    Science.gov (United States)

    Valkaj, K Maduna; Katovic, A; Zrncević, S

    2007-06-18

    In this work oxidation of phenol with hydrogen peroxide on Cu/ZSM-5 catalysts was studied. The catalysts samples were prepared by two different methods: by ionic exchange from the protonic form of commercial ZSM-5 zeolite, and by direct hydrothermal synthesis. Characterization of the catalysts extends to X-ray diffraction (XRD), while the adsorption techniques were used for the measurement of the specific surface area. The catalytic tests were carried out in a stainless steel Parr reactor in batch operation mode at the atmospheric pressure and the temperature range from 50 to 80 degrees C. The mass ratio of the active metal component on the zeolite was in the range of 1.62-3.24 wt.%. for catalyst prepared by direct hydrothermal synthesis and 2.23-3.52 wt.% for catalyst prepared by ion exchange method. The initial concentration of phenol and hydrogen peroxide was 0.01 and 0.1 mol dm(-3), respectively. The influence of different methods of Cu/ZSM-5 preparation on their catalytic performance was monitored in terms of phenol conversion and degree of metal leached into aqueous solution.

  17. Research on Synergy of Combining Electrochemical Oxidation and Catalytic Wet Oxidation%电场效应与催化湿式氧化协同作用研究

    Institute of Scientific and Technical Information of China (English)

    王华; 李光明; 张芳; 黄菊文

    2009-01-01

    A new catalytic wet oxidation fixed-bed reactor combined with three-dimensional electric-field was developed to investigate catalytic wet oxidation, electrochemical oxidation and electroassisted catalytic wet oxidation of the solution containing phenol in the presence of a catalyst Mn-Sn-Sb-3/γ-Al_2O_3 . Good eleetroassisted catalytic wet oxidation efficiency was obtained in the setup for the combination system even at mild conditions ( T = 130℃, po_2 =1.0 MPa) that the phenol conversion and TOC reduction were up to 94.0% and 88.4% after 27 min treatment, respectively. The result also shows that the rate constants of electroassisted catalytic wet oxidation are much higher than that of not only both catalytic wet oxidation and electrochemical oxidation process alone but also additive efficiencies of catalytic wet oxidation and electrochemical oxidation processes, which indicates an apparent synergetic effect between CWO and ECO processes.%在自行研制开发的一套固定床和复合三维电场一体化连续式催化湿式氧化反应器中,采用浸渍法制备的Mn-Sn-Sb-3/γAl_2O_3催化剂,实验研究了苯酚催化湿式氧化、电催化氧化以及电场效应下的催化湿式氧化过程的行为.结果表明,一体化反应器在较低反应温度(T=130℃)和氧分压(Po_2=1.0 MPa)下即可获得相当满意的处理效果,空时仅为27min时苯酚和TOC的去除率就分别可达到94.0%和88.4%.电场效应下的催化湿式氧化协同降解苯酚的反应速率常数大于单独电催化或催化湿式氧化降解苯酚的反应速率常数,而且还大大超过两者之和,电催化氧化对催化湿式氧化工艺存在明显的协同增效作用.

  18. THREE-DIMENSIONAL REGULARITIES OF DISTRIBUTION OF AIR-INLET CHARACTERISTIC VELOCITY IN NATURAL-DRAFT WET COOLING TOWER

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; SUN Feng-zhong; ZHAO Yuan-bin; GAO Ming; SHI Yue-tao

    2008-01-01

    A model for heat and mass transfer in a natural-draft wet cooling tower was established. Numerical simulation with the k-ε turbulent model was conducted. Distribution rules of air inlet aerodynamic field were studied. Field experiments were done in a cooling tower in power plant, and the test data was compared with the related results. The definition of characteristic air velocity was proposed and its influencing factors, such as the cross-wind velocity and circumferential angle, were quantitatively studied. It can be used to evaluate the performance of cooling tower and to calculate the ventilation quantity and resistance of air inlet. It is also a theoretical basis for cooling tower design and performance optimization.

  19. Wet air oxidation of pretreatment of pharmaceutical wastewater by Cu2+ and [PxWmOy]q- co-catalyst system.

    Science.gov (United States)

    Wang, Guowen; Wang, Dong; Xu, Xiaochen; Liu, Lifen; Yang, Fenglin

    2012-05-30

    This study concentrates on the pretreatment of real wastewater using catalytic wet air oxidation (CWAO). WO(3-) and PO(4)(3-) contained in fosfomycin pharmaceutical wastewater (FPW) and Cu(2+) contained in berberine pharmaceutical wastewater (BPW) were studied as CWAO influent. Mixture of this two streams were reused to form Cu(2+) and [P(x)W(m)O(y)](q-), namely polyoxometalates (POMs) as co-catalyst system to treat themselves. Experiments were conducted to investigate the effects of the initial oxygen pressure and temperature on the COD (chemical oxygen demand), TOC (total organic carbon) removal and biodegradable enhancement, it was discovered that over 40% of COD and TOC removal can be easily realized in an hour of WAO oxidation at 523 K, 1.4 MPa. The BOD(5)/COD (BOD(5), biochemical oxygen demand in 5 days) of this two pharmaceutical mixture ascended from nonexistent to maximum 0.41 depends on the optimal FPW:BPW volume ratio 4:1, to compose POM co-catalyst system. Organic pollutants were incompletely oxidized to propionic acid and other intermediates. Some properties (e.g., TGA, IR, XRF) of POM catalyst separated from effluent, were obtained to provide additional information.

  20. Microlith-Based Catalytic Reactor for Air Quality and Trace Contaminant Control Applications

    Science.gov (United States)

    Vilekar, Saurabh; Hawley, Kyle; Junaedi, Christian; Crowder, Bruce; Prada, Julian; Mastanduno, Richard; Perry, Jay L.; Kayatin, Matthew J.

    2015-01-01

    Traditionally, gaseous compounds such as methane, carbon monoxide, and trace contaminants have posed challenges for maintaining clean air in enclosed spaces such as crewed spacecraft cabins as they are hazardous to humans and are often difficult to remove by conventional adsorption technology. Catalytic oxidizers have provided a reliable and robust means of disposing of even trace levels of these compounds by converting them into carbon dioxide and water. Precision Combustion, Inc. (PCI) and NASA - Marshall (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI's patented Microlith® technology to meet the requirements of future extended human spaceflight explorations. Current efforts have focused on integrating the HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight while also reducing its energy requirements. Previous efforts relied on external heat exchangers to recover the waste heat and recycle it to the oxidizer to minimize the system's power requirements; however, these units contribute weight and volume burdens to the overall system. They also result in excess heat loss due to the separation of the HTCO and the heat recuperator, resulting in lower overall efficiency. Improvements in the recuperative efficiency and close coupling of HTCO and heat recuperator lead to reductions in system energy requirements and startup time. Results from testing HTCO units integrated with heat recuperators at a variety of scales for cabin air quality control and heat melt compactor applications are reported and their benefits over previous iterations of the HTCO and heat recuperator assembly are quantified in this paper.

  1. Factors influencing catalytic wet peroxide oxidation of maleic acid in aqueous phase over copper/micelle templated silica-3-aminopropyltrimethoxysilane catalyst.

    Science.gov (United States)

    Daniel, Lilian; Katima, Jamidu H Y

    2009-01-01

    Catalytic wet peroxide oxidation (CWPO) of initial maleic acid feed concentration (0.005 to 0.03 M) was carried out in a temperature range of 20-50 degrees Celsius, on micelle templated silica-3-aminopropyltrimethoxysilane (MTS-AMP) supported copper catalyst. The influence of various operating parameters such as initial feed concentration of maleic acid, temperature, catalyst loading and the stability of the catalyst were investigated. CWPO reactions were performed in a stirred batch reactor at an atmospheric pressure in the presence of H(2)O(2) as an oxidant. Total conversion of maleic acid into acetic acid was obtained under mild conditions (i.e. atmospheric pressure and 40 degrees Celsius). Blank experiments showed no measurable maleic acid conversion (i.e. only approximately 0.5% conversion of initial maleic acid), indicating that a significant oxidation reaction of maleic acid is enhanced by the presence of a catalyst. Copper on micelle templated silica-3-aminopropyltrimethoxysilane catalyst therefore was found to be suitable for aqueous phase oxidation of maleic acid with 100% of maleic acid conversion.

  2. Development of a New Type of Green Switch Air Entraining Agent for Wet-Mix Shotcrete and Its Engineering Application

    Directory of Open Access Journals (Sweden)

    Guoming Liu

    2016-01-01

    Full Text Available Air entraining agent (AEA can bring a lot of microbubbles into fresh concrete for improving its fluidity; however, high fluidity has adverse effect on the shootability of wet-mix shotcrete. In order to solve the contradictory issue, the paper developed a new type of green switch air entraining agent (GSAE that can improve both the pumpability and shootability. The single-admixture and combination tests containing foaming ability and surface tension were performed with Deer agitator and automatic tension meter. The new AEA was developed with two constituents A and B. A was prepared with Sapindus mukorossi(S-1, dodecyl trimethyl ammonium chloride(1231, and polyacrylamide. B was prepared with lauryl sodium sulfate (K12 and silicone oil. The mass mix proportion was S-1 : 1231 : polyacrylamide : K12 : silicone oil = 1 : 0.33 : 0.2 : 0.33 : 0.47. The application method of GSAE proposed that A was premixed with fresh concrete and then B was added at nozzle. Experimental investigation showed that the optimal mixing amount of GSAE was 0.1%–0.2% relative to cement. All performance measured of wet-mix shotcrete with 0.12% GSAE met the first-grade product requirements of the China National Standard. Compared with the conventional type of AEA, the proposed GSAE is capable of effectively improving pumpability and shootability.

  3. The optimization, kinetics and mechanism of m-cresol degradation via catalytic wet peroxide oxidation with sludge-derived carbon catalyst.

    Science.gov (United States)

    Wang, Yamin; Wei, Huangzhao; Zhao, Ying; Sun, Wenjing; Sun, Chenglin

    2017-03-15

    The sludge-derived carbon catalyst modified with 0°C HNO3 solution was tested in catalytic wet peroxide oxidation of m-cresol (100mgL(-1)) with systematical mathematical models and theoretical calculation for the first time. The reaction conditions were optimized by response surface methodology (RSM) as T=60°C, initial pH=3.0, C0,H2O2(30%)=1.20gL(-1) (lower than the stoichiometric amount of 1.80gL(-1)) and Ccat=0.80gL(-1), with 96% of m-cresol and 47% of TOC converted after 16min and 120min of reaction, respectively, and ξ (mg TOC/g H2O2 fed)=83.6mg/g. The end time of the first kinetic period in m-cresol model was disclosed to be correlated with the fixed residue m-cresol concentration of about 33%. Furthermore, the kinetic constants in models of TOC and H2O2 exactly provide convincing proof of three-dimensional response surfaces analysis by RSM, which showed the influence of the interaction between organics and H2O2 on effective H2O2 utilization. The reaction intermediates over time were identified by gas chromatography-mass spectrometer based on kinetics analysis. Four degradation pathways for m-cresol were proposed, of which the possibility and feasibility were well proven by frontier molecule orbital theory and atomic charge distribution via density functional theory method.

  4. Post-treatment of biologically treated wastewater containing organic contaminants using a sequence of H2O2 based advanced oxidation processes: photolysis and catalytic wet oxidation.

    Science.gov (United States)

    Rueda-Márquez, J J; Sillanpää, M; Pocostales, P; Acevedo, A; Manzano, M A

    2015-03-15

    In this paper the feasibility of a multi-barrier treatment (MBT) for the regeneration of synthetic industrial wastewater (SIWW) was evaluated. Industrial pollutants (orange II, phenol, 4-chlorophenol and phenanthrene) were added to the effluent of municipal wastewater treatment plant. The proposed MBT begins with a microfiltration membrane pretreatment (MF), followed by hydrogen peroxide photolysis (H2O2/UVC) and finishing, as a polishing step, with catalytic wet peroxide oxidation (CWPO) using granular activated carbon (GAC) at ambient conditions. During the microfiltration step (0.7 μm) the decrease of suspended solids concentration, turbidity and Escherichia coli in treated water were 88, 94 and 99%, respectively. Also, the effluent's transmittance (254 nm) was increased by 14.7%. Removal of more than 99.9% of all added pollutants, mineralization of 63% of organic compounds and complete disinfection of total coliforms were reached during the H2O2/UVC treatment step (H2O2:TOC w/w ratio = 5 and an UVC average dose accumulated by wastewater 8.80 WUVC s cm(-2)). The power and efficiency of the lamp, the water transmittance and photoreactor geometry are taken into account and a new equation to estimate the accumulated dose in water is suggested. Remaining organic pollutants with a higher oxidation state of carbon atoms (+0.47) and toxic concentration of residual H2O2 were present in the effluent of the H2O2/UVC process. After 2.3 min of contact time with GAC at CWPO step, 90 and 100% of total organic carbon and residual H2O2 were removed, respectively. Also, the wastewater toxicity was studied using Vibrio fischeri and Sparus aurata larvae. The MBT operational and maintenance costs (O&M) was estimated to be 0.59 € m(-3).

  5. Abatement of phenolic mixtures by catalytic wet oxidation enhanced by Fenton's pretreatment: effect of H2O2 dosage and temperature.

    Science.gov (United States)

    Santos, A; Yustos, P; Rodriguez, S; Simon, E; Garcia-Ochoa, F

    2007-07-31

    Catalytic wet oxidation (CWO) of a phenolic mixture containing phenol, o-cresol and p-cresol (500mg/L on each pollutant) has been carried out using a commercial activated carbon (AC) as catalyst, placed in a continuous three-phase reactor. Total pressure was 16 bar and temperature was 127 degrees C. Pollutant conversion, mineralization, intermediate distribution, and toxicity were measured at the reactor outlet. Under these conditions no detoxification of the inlet effluent was found even at the highest catalyst weight (W) to liquid flow rate (Q(L)) ratio used. On the other hand, some Fenton Runs (FR) have been carried out in a batch way using the same phenolic aqueous mixture previously cited. The concentration of Fe(2+) was set to 10mg/L. The influence of the H(2)O(2) amount (between 10 and 100% of the stoichiometric dose) and temperature (30, 50, and 70 degrees C) on phenols conversion, mineralization, and detoxification have been analyzed. Phenols conversion was near unity at low hydrogen peroxide dosage but mineralization and detoxification achieved an asymptotic value at each temperature conditions. The integration of Fenton reagent as pretreatment of the CWO process remarkably improves the efficiency of the CWO reactor and allows to obtain detoxified effluents at mild temperature conditions and relatively low W/Q(L) values. For a given phenolic mixture a temperature range of 30-50 degrees C in the Fenton pretreatment with a H(2)O(2) dosage between 20 and 40% of the stoichiometric amount required can be proposed.

  6. CuZnAl Mixed Oxide Catalyst Prepared from Hydrotalcite-like Precursor for Catalytic Wet Oxidation of Phenol%由类水滑石前驱体制备的CuZnAl复合氧化物催化剂催化湿氧化处理苯酚

    Institute of Scientific and Technical Information of China (English)

    孙颖; 杨民; 窦和瑞; 何雨; 王炜; 孙承林

    2003-01-01

    @@ The efficiency of several noble metals for catalytic wet oxidation (CWO) of various pollutants has been demonstrated[1,2]. However, the noble metals are expensive, affecting greatly the economics of the corresponding process.

  7. Elementary stage rate coefficients of heterogeneous catalytic recombination of dissociated air on thermal protective surfaces from ab initio approach

    Science.gov (United States)

    Buchachenko, A. A.; Kroupnov, A. A.; Kovalev, V. L.

    2015-08-01

    Elementary stage rate coefficients of the full system of kinetic equations describing heterogeneous catalytic recombination of the dissociated air on the surfaces of thermal protective ceramic coatings of β-cristobalite and α-Al2O3 are determined using the quantum-mechanical calculations within the framework of cluster models and literature data. Both the impact and associative recombination processes of adsorbed oxygen and nitrogen atoms are taken into account.

  8. Wet air oxidation pretreatment of biomethanated distillery effluent: mapping pretreatment efficiency in terms color, toxicity reduction and biogas generation.

    Science.gov (United States)

    Sarat Chandra, T; Malik, S N; Suvidha, G; Padmere, M L; Shanmugam, P; Mudliar, S N

    2014-04-01

    The effluents from molasses-based distilleries after biomethanation are beset with problems of intensified dark brown color, high residual COD, low biodegradability index (BOD/COD ratio Wet air oxidation (WAO) pretreatment of biomethanated distillery effluent resulted in substantial enhancement in the biodegradability index (BI) (up to 0.8). WAO pretreated effluent on anaerobic digestion indicated favorable biogas generation with methane content up to 64% along with concomitant COD reduction up to 54.75%. The HPLC analysis indicated that the pretreatment facilitated degradation of major color containing compounds-namely melanoidins, up to 97.8%. The pretreated effluent with enhanced biodegradability along with substantially reduced color also indicated positive effect on seed germination (up to 100%), implying toxicity reduction of the effluent post WAO pretreatment.

  9. Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems

    Science.gov (United States)

    Catalytic destruction of benzene (C6H6), a surrogate for organic hazardous air pollutants (HAPs) produced from coal combustion, was investigated using a commercial selective catalytic reduction (SCR) catalyst for evaluating the potential co-benefit of the SCR technology for reduc...

  10. 湿法烟气脱硫环境下亚硫酸钙的非催化氧化%NON-CATALYTIC OXIDATION KINETICS OF CALCIUM SULFITE IN WET LIMESTONE-GYPSUM FGD PROCESS

    Institute of Scientific and Technical Information of China (English)

    杜谦; 吴少华; 朱群益; 秦裕琨

    2003-01-01

    A study on non-catalytic oxidation kinetics of calcium sulfite is presented under typical conditions of wet flue gas desulfurization (FGD)in this paper. A laboratory-scale mechanically stirred tank reactor is used with continuous feed of both gas and liquid phase. The results show that increasing CaSO3 load from a lower value, the reaction rate increases and is limited by solid sulfite dissolution. The oxidation rate limitation is observed at loads exceeding certain concentration. The rate limitation is possibly caused by solid sulfite solubility or oxygen gas-liquid diffusion. The experimental conclusions are useful for design and operation of the holding tank in forced-oxidation wet FGD.

  11. Preparation of Ti-Ce Complex Oxide Catalysts for Wet Air Oxidation with Acetic Acid as Model Reactant%以乙酸为模型反应物的Ti-Ce复合氧化物湿式氧化催化剂的研制

    Institute of Scientific and Technical Information of China (English)

    付宏祥; 蒋展鹏; 谭亚军

    2000-01-01

    @@ 催化湿式氧化(catalytic wet air oxidation, CWAO)为高浓度难降解有机废水提供了一种有效可行的处理技术[1~8],它可使难降解有机物分子在相对较低的反应温与压力下降解矿化或生成易生物处理的小分子有机物.

  12. Corrosion inhibition of magnesium heated in wet air, by surface fluoridation; Inhibition de la corrosion du magnesium chauffe dans l'air humide, par fluoruration superficielle

    Energy Technology Data Exchange (ETDEWEB)

    Caillat, R.; Darras, R.; Leclercq, D. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The maximum temperature (350 deg. C) of magnesium corrosion resistance in wet air may be raised to 490-500 deg. C by the formation of a superficial fluoride film. This can be obtained by two different ways: either by addition of hydrofluoric acid to the corroding medium in a very small proportion such as 0,003 mg/litre; at atmospheric pressure, or by dipping the magnesium in a dilute aqueous solution of nitric and hydrofluoric acids at room temperature before exposing it to the corroding atmosphere. In both cases the corrosion inhibition is effective over a very long time, even several thousand hours. (author) [French] La temperature limite (350 deg. C) de resistance du magnesium a la corrosion par l'air humide, peut etre elevee jusque 490-500 deg. C par la formation d'une couche fluoruree superficielle. Deux procedes permettent d'obtenir ce resultat: l'atmosphere corrodante peut etre additionnee d'acide fluorhydrique a une concentration aussi faible que 0,003 mg/litre, a la pression atmospherique, ou bien le magnesium peut etre traite a froid, avant exposition a la corrosion, dans une solution aqueuse diluee d'acides nitrique et fluorhydrique. Dans les deux cas, la protection est assuree, meme pour de tres longues durees d'exposition: plusieurs milliers d'heures. (auteur)

  13. Sustainability of the Catalytic Activity of a Silica-Titania Composite (STC) for Long-Term Indoor Air Quality Control

    Science.gov (United States)

    Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.

    2011-01-01

    TiO2-assisted photocatalytic oxidation (PCO) is an emerging technology for indoor air quality control and is also being evaluated as an alternative trace contaminant control technology for crew habitats in space exploration. Though there exists a vast range of literature on the development of photocatalysts and associated reactor systems, including catalyst performance and performance-influencing factors, the critical question of whether photocatalysts can sustain their initial catalytic activity over an extended period of operation has not been adequately addressed. For a catalyst to effectively serve as an air quality control product, it must be rugged enough to withstand exposure to a multitude of low concentration volatile organic compounds (VOCs) over long periods of time with minimal loss of activity. The objective of this study was to determine the functional lifetime of a promising photocatalyst - the silica-titania composite (STC) from Sol Gel Solutions, LLC in a real-world scenario. A bench-scale STC-packed annular reactor under continuous irradiation by a UV-A fluorescent black-light blue lamp ((lambda)max = 365 nm) was exposed to laboratory air continuously at an apparent contact time of 0.27 sand challenged with a known concentration of ethanol periodically to assess any changes in catalytic activity. Laboratory air was also episodically spiked with halocarbons (e.g., octafluoropropane), organosulfur compounds (e.g., sulfur hexafluoride), and organosilicons (e.g., siloxanes) to simulate accidental releases or leaks of such VOCs. Total organic carbon (TOC) loading and contaminant profiles of the laboratory air were also monitored. Changes in STC photocatalytic performance were evaluated using the ethanol mineralization rate, mineralization efficiency, and oxidation intermediate (acetaldehyde) formation. Results provide insights to any potential catalyst poisoning by trace halocarbons and organosulfur compounds.

  14. Simulation Analysis of Sludge Disposal and Volatile Fatty Acids Production from Gravity Pressure Reactor via Wet Air Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gwon Woo [Biomass and Waste Energy Laboratory, KIER, Daejeon (Korea, Republic of); Seo, Tae Wan; Lee, Hong-Cheol; Hwang, In-Ju [Environmental and Plant Engineering Research Institute, KICT, Goyang (Korea, Republic of)

    2016-04-15

    Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

  15. Assessment of methane emission and oxidation at Air Hitam Landfill site cover soil in wet tropical climate.

    Science.gov (United States)

    Abushammala, Mohammed F M; Basri, Noor Ezlin Ahmad; Elfithri, Rahmah

    2013-12-01

    Methane (CH₄) emissions and oxidation were measured at the Air Hitam sanitary landfill in Malaysia and were modeled using the Intergovernmental Panel on Climate Change waste model to estimate the CH₄ generation rate constant, k. The emissions were measured at several locations using a fabricated static flux chamber. A combination of gas concentrations in soil profiles and surface CH₄ and carbon dioxide (CO₂) emissions at four monitoring locations were used to estimate the CH₄ oxidation capacity. The temporal variations in CH₄ and CO₂ emissions were also investigated in this study. Geospatial means using point kriging and inverse distance weight (IDW), as well as arithmetic and geometric means, were used to estimate total CH₄ emissions. The point kriging, IDW, and arithmetic means were almost identical and were two times higher than the geometric mean. The CH₄ emission geospatial means estimated using the kriging and IDW methods were 30.81 and 30.49 gm(−2) day(−1), respectively. The total CH₄ emissions from the studied area were 53.8 kg day(−1). The mean of the CH₄ oxidation capacity was 27.5 %. The estimated value of k is 0.138 year(−1). Special consideration must be given to the CH₄ oxidation in the wet tropical climate for enhancing CH₄ emission reduction.

  16. Wet air oxidation of resorcinol as a model treatment for refractory organics in wastewaters from the wood processing industry.

    Science.gov (United States)

    Weber, Bernd; Chavez, Alma; Morales-Mejia, Julio; Eichenauer, Sabrina; Stadlbauer, Ernst A; Almanza, Rafael

    2015-09-15

    Wastewater treatment systems are important tools to enhance sustainability in terms of reducing environmental impact and complying with sanitary requirements. This work addresses the wet air oxidation (WAO) process for pre-treatment of phenolic wastewater effluents. The aim was to increase biodegradability prior to a subsequent anaerobic stage. In WAO laboratory experiments using a micro-autoclave, the model compound resorcinol was degraded under different oxygen availability regims within the temperature range 150 °C-270 °C. The activation energy was determined to be 51.5 kJ/mol. Analysis of the products revealed that after 3 h of reaction at 230 °C, 97.5% degradation of resorcinol was achieved. At 250 °C and the same reaction time complete removal of resorcinol was observed. In this case the total organic carbon content was reduced down to 29%, from 118.0 mg/L down to 34.4 mg/L. Under these process conditions, the pollutant was only partially mineralized and the ratio of the biological oxygen demand relative to the chemical oxygen demand, which is 0.07 for resorcinol, was increased to a value exceeding 0.5. The main by-product acetic acid, which is a preferred compound for methanogenic bacteria, was found to account for 33% of the total organic carbon.

  17. Correlation between the microstructures of graphite oxides and their catalytic behaviors in air oxidation of benzyl alcohol.

    Science.gov (United States)

    Geng, Longlong; Wu, Shujie; Zou, Yongcun; Jia, Mingjun; Zhang, Wenxiang; Yan, Wenfu; Liu, Gang

    2014-05-01

    A series of graphite oxide (GO) materials were obtained by thermal treatment of oxidized natural graphite powder at different temperatures (from 100 to 200 °C). The microstructure evolution (i.e., layer structure and surface functional groups) of the graphite oxide during the heating process is studied by various characterization means, including XRD, N2 adsorption, TG-DTA, in situ DRIFT, XPS, Raman, TEM and Boehm titration. The characterization results show that the structures of GO materials change gradually from multilayer sheets to a transparent ultrathin 2D structure of the carbon sheets. The concentration of surface COH and HOCO groups decrease significantly upon treating temperature increasing. Benzyl alcohol oxidation with air as oxidant source was carried out to detect the catalytic behaviors of different GO materials. The activities of GO materials decrease with the increase of treating temperatures. It shows that the structure properties, including ultrathin sheets and high specific surface area, are not crucial factors affecting the catalytic activity. The type and amount of surface oxygen-containing functional groups of GO materials tightly correlates with the catalytic performance. Carboxylic groups on the surface of GO should act as oxidative sites for benzyl alcohol and the reduced form could be reoxidized by molecular oxygen.

  18. Kinetics of Passive Oxidation of Hi-Nicalon-S SiC Fibers in Wet Air: Relationships between Si02 Scale Thickness, Crystallization, and Fiber Strength (Preprint)

    Science.gov (United States)

    2012-07-01

    crystallize to cristobalite and tridymite in 100 hours at 1000°C or in one hour at 1300°C. Crystallization kinetics for oxidation in wet air were...measured by TEM. Oxidation initially produces an amorphous scale that starts to crystallize to cristobalite and tridymite in 100 hours at 1000°C or in...using reflected light interference fringes observed by optical microscopy. Cross-sectional TEM specimens were prepared from oxidized fibers by

  19. Study on the active sites of Cu-ZSM-5 in trichloroethylene catalytic combustion with air

    Institute of Scientific and Technical Information of China (English)

    Cheng Hua Xu; Chuan Qi Liu; Yan Zhong; Xiu Zhou Yang; Jian Ying Liu; Ying Chun Yang; Zhi Xiang Ye

    2008-01-01

    The catalytic activity of Cu-ZSM-5 in trichloroethylene (TCE) combustion increases with the increasing skeletal Cu amount and however decreases with the increase of surface amorphous CuO,which is detected by infrared spectroscopy (IR) and diffuse reflectance ultraviolet-visible spectroscopy (DRS-UV-vis),therefore the skeletal Cu species are concluded to be the active sites for the TCE combustion.

  20. Toluene removal from waste air stream by the catalytic ozonation process with MgO/GAC composite as catalyst.

    Science.gov (United States)

    Rezaei, Fatemeh; Moussavi, Gholamreza; Bakhtiari, Alireza Riyahi; Yamini, Yadollah

    2016-04-05

    This paper investigates the catalytic potential of MgO/GAC composite for toluene elimination from waste air in the catalytic ozonation process (COP). The MgO/GAC composite was a micro-porous material with the BET surface area of 1082m(2)/g. Different functional groups including aromatic CC, saturated CO of anhydrates, hydroxyl groups and SH bond of thiols were identified on the surface of MgO/GAC. Effects of residence time (0.5-4s), inlet toluene concentration (100-400ppmv) and bed temperature (25-100°C) were investigated on degradation of toluene in COP. Impregnation of GAC with MgO increased the breakthrough time and removal capacity by 73.9% and 64.6%, respectively, at the optimal conditions. The catalytic potential of the GAC and MgO/GAC for toluene degradation was 11.1% and 90.6%, respectively, at the optimum condition. The highest removal capacity using MgO/GAC (297.9gtoulene/gMgO/GAC) was attained at 100°C, whereas the highest removal capacity of GAC (128.5mgtoulene/gGAC) was obtained at 25°C. Major by-products of the toluene removal in COP with GAC were Formic acid, benzaldehyde, O-nitro-p-cresol and methyl di-phenyl-methane. MgO/GAC could greatly catalyze the decomposition of toluene in COPand formic acid was the main compound desorbed from the catalyst. Accordingly, the MgO/GAC is an efficient material to catalyze the ozonation of hydrocarbon vapors.

  1. The Influence of Slight Protuberances in a Micro-Tube Reactor on Methane/Moist Air Catalytic Combustion

    Directory of Open Access Journals (Sweden)

    Ruirui Wang

    2016-05-01

    Full Text Available The combustion characteristics of methane/moist air in micro-tube reactors with different numbers and shapes of inner wall protuberances are investigated in this paper. The micro-reactor with one rectangular protuberance (six different sizes was studied firstly, and it is shown that reactions near the protuberance are mainly controlled by diffusion, which has little effect on the outlet temperature and methane conversion rate. The formation of cavities and recirculation zones in the vicinity of protuberances leads to a significant increase of the Arrhenius reaction rate of CH4 and gas velocity. Next, among the six different simulated conditions (0–5 rectangular protuberances, the micro-tube reactor with five rectangular protuberances shows the highest methane conversion rate. Finally, the effect of protuberance shape on methane/moist air catalytic combustion is confirmed, and it is found that the protuberance shape has a greater influence on methane conversion rate than the number of protuberances. The methane conversion rate in the micro-tube decreases progressively in the following order: five triangular slight protuberances > five rectangular protuberances > five trapezoidal protuberances > smooth tube. In all tests of methane/moist air combustion conditions, the micro-tube with five triangular protuberances has the peak efficiency and is therefore recommended for high efficiency reactors.

  2. 湿式催化氧化法中催化剂的选择和实验条件的优化%Selection of Catalysts and Optimization of Experimental Condition in Catalytic Wet Oxidation

    Institute of Scientific and Technical Information of China (English)

    董岳刚; 严莲荷; 周进; 周申范

    2001-01-01

    本文研究了湿式催化氧化法(Catalytic Wet Oxidation,CWO)处理高浓度有机水中催化剂的选择和实验条件的优化.在优选催化剂中共计制备十四种催化剂并进行实验,得出Ce、Cu复合催化剂活性最高.在实验条件优化中根据对正交实验数据结果进行的极差分析发现CWO法处理废水时的各影响因素的主次关系是:H2O2用量>Ce、Cu复合催化剂用量>反应时间.

  3. Understanding the wetting properties of nanostructured selenium coatings: the role of nanostructured surface roughness and air-pocket formation

    Directory of Open Access Journals (Sweden)

    Tran PA

    2013-05-01

    Full Text Available Phong A Tran,1,2 Thomas J Webster31Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, VIC, Australia; 2The Particulate Fluid Processing Centre, University of Melbourne, Melbourne, VIC, Australia; 3Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USAAbstract: Wetting properties of biomaterials, in particular nanomaterials, play an important role, as these influence interactions with biological elements, such as proteins, bacteria, and cells. In this study, the wetting phenomenon of titanium substrates coated with selenium nanoparticles was studied using experimental and mathematical modeling tools. Importantly, these selenium-coated titanium substrates were previously reported to increase select protein adsorption (such as vitronectin and fibronectin, to decrease bacteria growth, and increase bone cell growth. Increased selenium nanoparticle coating density resulted in higher contact angles but remained within the hydrophilic regime. This trend was found in disagreement with the Wenzel model, which is widely used to understand the wetting properties of rough surfaces. The trend also did not fit well with the Cassie–Baxter model, which was developed to understand the wetting properties of composite surfaces. A modified wetting model was thus proposed in this study, to understand the contributing factors of material properties to the hydrophilicity/hydrophobicity of these nanostructured selenium-coated surfaces. The analysis and model created in this study can be useful in designing and/or understanding the wetting behavior of numerous biomedical materials and in turn, biological events (such as protein adsorption as well as bacteria and mammalian cell functions.Keywords: hydrophilicity, hydrophobicity, Wenzel model, Cassie–Baxter model, free energy, implant material, proteins, cells, bacteria

  4. Air stable NHCs: a study of stereoelectronics and metallorganic catalytic activity.

    Science.gov (United States)

    Furfari, Samantha K; Gyton, Matthew R; Twycross, Daniel; Cole, Marcus L

    2015-01-04

    The air stable NHC IPrBr is reported. A stereoelectronic study of IPrBr and its similarly stable relative IMesBr demonstrates metal complex specific changes in NHC donicity versus the ubiquitous IPr and IMes. Application to a Suzuki coupling and an iridium transfer hydrogenation gives superior outcomes using IPrBr and IMesBr.

  5. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides in background air in central Europe - investigating parameters affecting wet scavenging of polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Shahpoury, P.; Lammel, G.; Holubová Šmejkalová, A.; Klánová, J.; Přibylová, P.; Váňa, M.

    2015-02-01

    Concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides (CPs) were measured in air and precipitation at a background site in central Europe. ∑ PAH concentrations in air and rainwater ranged from 0.7 to 327.9 ng m-3 and below limit of quantification (< LOQ) to 2.1 × 103 ng L-1. The concentrations of PCBs and CPs in rainwater were < LOQ. ∑ PCB and ∑ CP concentrations in air ranged from < LOQ to 44.6 and < LOQ to 351.7 pg m-3, respectively. The potential relationships between PAH wet scavenging and particulate matter and rainwater properties were investigated. The concentrations of ionic species in particulate matter and rainwater were significantly correlated, highlighting the importance of particle scavenging process. Overall, higher scavenging efficiencies were found for relatively less volatile PAHs, underlining the effect of analyte gas-particle partitioning on scavenging process. The particulate matter removal by rain, and consequently PAH wet scavenging, was more effective when the concentrations of ionic species were high. In addition, the elemental and organic carbon contents of the particulate matter were found to influence the PAH scavenging.

  6. Catalytic Reductive Degradation of Methyl Orange Using Air Resilient Copper Nanostructures

    Directory of Open Access Journals (Sweden)

    Razium Ali Soomro

    2015-01-01

    Full Text Available The study describes the application of oxidation resistant copper nanostructures as an efficient heterogeneous catalyst for the treatment of organic dye containing waste waters. Copper nanostructures were synthesized in an aqueous environment using modified surfactant assisted chemical reduction route. The synthesized nanostructures have been characterized by UV-Vis, Fourier transform infrared spectroscopy FTIR spectroscopy, Atomic force microscopy (AFM, Scanning Electron Microscopy (SEM, and X-ray diffractometry (XRD. These surfactant capped Cu nanostructures have been used as a heterogeneous catalyst for the comparative reductive degradation of methyl orange (MO in the presence of sodium borohydride (NaBH4 used as a potential reductant. Copper nanoparticles (Cu NPs were found to be more efficient compared to copper nanorods (Cu NRds with the degradation reaction obeying pseudofirst order reaction kinetics. Shape dependent catalytic efficiency was further evaluated from activation energy (EA of reductive degradation reaction. The more efficient Cu NPs were further employed for reductive degradation of real waste water samples containing dyes collected from the drain of different local textile industries situated in Hyderabad region, Pakistan.

  7. Effect of inlet temperature on the performance of a catalytic reactor. [air pollution control

    Science.gov (United States)

    Anderson, D. N.

    1978-01-01

    A 12 cm diameter by 15 cm long catalytic reactor was tested with No. 2 diesel fuel in a combustion test rig at inlet temperatures of 700, 800, 900, and 1000 K. Other test conditions included pressures of 3 and 6 x 10 to the 5th power Pa, reference velocities of 10, 15, and 20 m/s, and adiabatic combustion temperatures in the range 1100 to 1400 K. The combustion efficiency was calculated from measurements of carbon monoxide and unburned hydrocarbon emissions. Nitrogen oxide emissions and reactor pressure drop were also measured. At a reference velocity of 10 m/s, the CO and unburned hydrocarbons emissions, and, therefore, the combustion efficiency, were independent of inlet temperature. At an inlet temperature of 1000 K, they were independent of reference velocity. Nitrogen oxides emissions resulted from conversion of the small amount (135 ppm) of fuel-bound nitrogen in the fuel. Up to 90 percent conversion was observed with no apparent effect of any of the test variables. For typical gas turbine operating conditions, all three pollutants were below levels which would permit the most stringent proposed automotive emissions standards to be met.

  8. Combustion of CH4/H2/air mixtures in catalytic microreactors.

    Science.gov (United States)

    Specchia, Stefania; Vella, Luigi D; Burelli, Sara; Saracco, Guido; Specchia, Vito

    2009-03-23

    The combustion of CH(4)/H(2)/HC mixtures in a very small space represents an alternative, innovative way to produce thermal/electrical energy. Pd/NiCrO(4) catalysts are lined on SiC monoliths via in situ solution combustion synthesis (SCS), and the monoliths are then tested by feeding CH(4), H(2), and lean CH(4)/H(2) mixtures into a lab-scale test rig at an output thermal power of 7.6 MW(th) m(-3). In all cases, the combustion temperature shifts to values lower than those observed in non-catalytic combustion. When the power density is kept constant (by adding H(2) to the gas mixture), the value of CH(4)-T(50) (the half-conversion temperature of CH(4)) decreases relative to that of pure CH(4), and the slope of the conversion curve becomes steeper. The higher the H(2) concentration is, the higher the reactivity of the mixture towards CH(4) oxidation-probably due to a higher production of H(2) reactive radicals (OH).

  9. Dry and wet air-side performance of a louver-finned heat exchanger having flat tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun; Kim, Soo Hwan [University of Incheon, Incheon (Korea, Republic of)

    2010-07-15

    A louver-finned flat tube heat exchanger was tested, and the data are compared with those of the state-of-the-art round tube heat exchanger. Both heat exchangers have the same tube perimeter and fin pitch. Tests were conducted under dry and wet condition. Results show that, under dry condition, both j and f factors of the round tube heat exchanger are larger than those of the flat tube heat exchanger. As the Reynolds number decreases, however, the j and f factors of the flat tube heat exchanger increase at steeper slopes than those of the round tube heat exchanger. Under wet condition, contrary to the dry surface, both j and f factors of the flat tube heat exchanger are larger than those of the round tube heat exchanger. Explanation is provided considering the condensate drainage between louvers and fins. Performance evaluation was also performed

  10. 1 - Aromatization of n-hexane and natural gasoline over ZSM-5 zeolite, 2- Wet catalytic oxidation of phenol on fixed bed of active carbon; 1 - Aromatisation de n-hexane et d'essence sur zeolithe ZSM-5, 2 - Oxydation catalytique en voie humide du phenol sur charbon actif

    Energy Technology Data Exchange (ETDEWEB)

    Suwanprasop, S.

    2005-04-15

    I - The production of aromatic hydrocarbons from n-hexane and natural gasoline over Pd loaded ZSM-5 zeolite in a tubular reactor was achieved under the suitable conditions at 400 deg. C, and 0.4 ml/min reactant feeding rate, employing ZSM-5 (0.5% Pd content) as a catalyst. Under these conditions, n-hexane and natural gasoline conversions were found to be 99.7% and 94.3%, respectively (with respective aromatic selectivity of 92.3% and 92.6%). II - Wet catalytic air oxidation of phenol over a commercial active carbon was studied in a three phase fixed bed reactor under mild temperature and oxygen partial pressure. Exit phenol concentration, COD, and intermediates were analysed. Oxidation of phenol was significantly improved when increasing operating temperature, oxygen partial pressure, and liquid space time, while up or down flow modes had only marginal effect. A complete model involving intrinsic kinetics and all mass transfer limitations gave convenient reactor simulation. (author)

  11. 生化剩余污泥湿式氧化减量机理研究%MECHANISM OF BIOCHEMICAL EXCESS SLUDGE REDUCTION BY WET AIR OXIDATION

    Institute of Scientific and Technical Information of China (English)

    李本高; 孙友; 张超

    2014-01-01

    The improvement of sludge dewater ability is essential to the volume reduction of waste activated sludge (WAS). The wet air oxidation process is used for WAS degradation. It is found that the volatile suspended sludge is decomposed into small molecular organic compounds,such as soluble protein,carbohydrate,short-chain fatty acids and ammonia by wet air oxidation,which improves the sludge dewater ability significantly.%改善污泥脱水性能对大幅减少生化剩余污泥体积意义重大。采用湿式氧化方法对生化剩余污泥进行消解,可将污泥的主要污染物高分子挥发性悬浮物降解,使其转变为水溶性蛋白质、糖、有机酸及氨氮等小分子有机物,使污泥脱水性能得到显著改善而容易脱水。

  12. A review of induction and attachment times of wetting thin films between air bubbles and particles and its relevance in the separation of particles by flotation.

    Science.gov (United States)

    Albijanic, Boris; Ozdemir, Orhan; Nguyen, Anh V; Bradshaw, Dee

    2010-08-11

    Bubble-particle attachment in water is critical to the separation of particles by flotation which is widely used in the recovery of valuable minerals, the deinking of wastepaper, the water treatment and the oil recovery from tar sands. It involves the thinning and rupture of wetting thin films, and the expansion and relaxation of the gas-liquid-solid contact lines. The time scale of the first two processes is referred to as the induction time, whereas the time scale of the attachment involving all the processes is called the attachment time. This paper reviews the experimental studies into the induction and attachment times between minerals and air bubbles, and between oil droplets and air bubbles. It also focuses on the experimental investigations and mathematical modelling of elementary processes of the wetting film thinning and rupture, and the three-phase contact line expansion relevant to flotation. It was confirmed that the time parameters, obtained by various authors, are sensitive enough to show changes in both flotation surface chemistry and physical properties of solid surfaces of pure minerals. These findings should be extended to other systems. It is proposed that measurements of the bubble-particle attachment can be used to interpret changes in flotation behaviour or, in conjunction with other factors, such as particle size and gas dispersion, to predict flotation performance.

  13. Total catalytic wet oxidation of phenol and its chlorinated derivates with MnO2/CeO2 catalyst in a slurry

    Directory of Open Access Journals (Sweden)

    A. J. Luna

    2009-09-01

    Full Text Available In the present work, a synthetic effluent of phenol was treated by means of a total oxidation process-Catalyzed Wet Oxidation (CWO. A mixed oxide of Mn-Ce (7:3, the catalyst, was synthesized by co-precipitation from an aqueous solution of MnCl2 and CeCl3 in a basic medium. The mixed oxide, MnO2/CeO2, was characterized and used in the oxidation of phenol in a slurry reactor in the temperature range of 80-130ºC and pressure of 2.04-4.76 MPa. A phenol solution containing 2.4-dichlorophenol and 2.4-dichlorophenoxyacetic acid was also degraded with good results. A lumped kinetic model, with two parallel reaction steps, fits precisely with the integrated equation and the experimental data. The kinetic parameters obtained are in agreement with the Arrhenius equation. The activation energies were determined to be 38.4 for the total oxidation and 53.4 kJ/mol for the organic acids formed.

  14. Total catalytic wet oxidation of phenol and its chlorinated derivates with MnO{sub 2}/CeO{sub 2} catalyst in a slurry

    Energy Technology Data Exchange (ETDEWEB)

    Luna, A.J. [Instituto Nacional de Propriedade Industrial (INPI), Rio de Janeiro, RJ (Brazil)], e-mail: airtonj@inpi.gov.br; Rojas, L.O.A.; Sousa, J.F. de [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. of Chemical Engineering; Melo, D.M.A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. of Chemistry; Benachour, M. [Universidade Federal de Pernambuco (UFPE)Recife, PE (Brazil). Dept. of Chemical Engineering

    2009-07-15

    In the present work, a synthetic effluent of phenol was treated by means of a total oxidation process - Catalyzed Wet Oxidation (CWO). A mixed oxide of Mn-Ce (7:3), the catalyst, was synthesized by co-precipitation from an aqueous solution of MnCl{sub 2} and CeCl{sub 3} in a basic medium. The mixed oxide, MnO{sub 2}/CeO{sub 2}, was characterized and used in the oxidation of phenol in a slurry reactor in the temperature range of 80-130 deg C and pressure of 2.04-4.76 MPa. A phenol solution containing 2.4-dichlorophenol and 2.4- dichlorophenoxyacetic acid was also degraded with good results. A lumped kinetic model, with two parallel reaction steps, fits precisely with the integrated equation and the experimental data. The kinetic parameters obtained are in agreement with the Arrhenius equation. The activation energies were determined to be 38.4 for the total oxidation and 53.4 kJ/mol for the organic acids formed. (author)

  15. 催化湿式过氧化氢氧化预处理有机磷农药废水的研究%Study on catalytic wet hydrogen peroxide oxidation for the pretreatment of organophosphorus pesticide wastewater

    Institute of Scientific and Technical Information of China (English)

    陈春燕

    2015-01-01

    以自制Fe2O3-CeO2/γ-Al2O3为催化剂,采用催化湿式过氧化氢氧化法(CWPO)预处理有机磷农药废水,通过单因素和正交试验研究了过氧化氢投加量、起始pH、反应温度和反应时间对COD的去除效果及影响规律。结果表明,反应最优条件为H2O2投加量2 mL、起始pH=5、反应温度80℃、反应时间40 min,在此条件下COD的去除率可达85.8%,可生化性提高到B/C=0.43。运用一级动力学模型和Arrhenius经验公式,建立了催化湿式过氧化氢氧化降解COD的动力学方程。%With self-made Fe2O3-CeO2/γ-Al2O3 as catalyst,the phosphate pesticide wastewater has been pretreated by catalytic wet peroxide oxidation(CWPO) process. The removing effect and influencing rules of the factors including dosage of H2O2,initial pH value,reaction temperature,and reaction time on the removing rate of COD are investigated through single factor experiments and orthogonal tests. The results show that the optimal COD removing efficiency is more than 85.8% and biodegradability of wastewater can be up to B/C=0.43,under the following conditions:the dosage of H2O2 is 2 mL,pH value 5,reaction temperature 80℃and reaction time 40 min. The kinetics equation of catalytic wet peroxide oxidation of COD degradation has been established by using the first-order kinetics model and Arrhenius empirical formula.

  16. APPLICATION OF WET TYPE SMOKE DESULFURIZATION DEDUSTING TECHNOLOGY IN TMP CATALYTIC AND CRACKING UNIT%湿式烟气脱硫除尘技术在TMP催化裂化装置的应用

    Institute of Scientific and Technical Information of China (English)

    高传成; 马传波; 王付印

    2014-01-01

    A new smoke desulfurization dedusting unit by adopting sodium magnesium wet type desulfurization technology was built on 0.3 Mt/a TMP catalytic and cracking plant of Hengyuan Petrochemical Company .The industrial running results showed that the new built des-ulfurization dedusting unit had good operational flexibility and economic stability .Minimum con-tent of SO2 in the purified smoke could reach 3 mg/m3 and the removal rate was 99.9%.The av-erage dust content of the purified smoke was 16.3 mg/m3 and preceded the design value .Each control index on the discharged exhaust gas of the TMP catalytic and cracking unit after reforma-tion met the discharge standard requirement , which realized high efficient and continuous run-ning.%恒源石化在0.3 Mt/a的 TMP 催化裂化装置采用钠镁法湿式烟气脱硫技术,新建1套烟气脱硫除尘装置。工业运行结果表明,钠镁法烟气脱硫除尘装置具有良好的操作弹性,运行经济可靠。净化后烟气中的SO2浓度最低能达到3 mg/m3,SO2脱除率达到99.9%,净化烟气平均粉尘含量16.3 mg/m3,优于设计值。实现了高效连续运行,可控外排废气中的各项指标满足排放要求。

  17. Estimation of air to grass -dry and wet deposition rates, velocities, and mass interception factors for iodine for a postulated accidental scenario

    Energy Technology Data Exchange (ETDEWEB)

    Karunakara, N.; Ujwal, P.; Yashodhara, I.; Sudeep Kumara, K. [University Science Instrumentation Centre, Mangalore University (India); Geetha, P.V. [Nuclear Power Corporation of India Limited (India); Dileep, B.N.; Joshi, P.J. [Environmental Survey Laboratory, Kaiga Generating Station (India); Ravi, P.M. [Health Physics Division, Bhabha Atomic Research Centre (India)

    2014-07-01

    Air to grass radionuclide transfer parameters such as dry and wet deposition rates, velocities, and mass interception factors are important basic input parameters for the estimation of radiation dose to the public around a nuclear power plant. We have carried out a study on air to grass transfer of iodine for a postulated emergency situation. A walk-in environmental chamber was designed and fabricated with facilities for exposing the plants grown in pots to controlled levels of radionuclides/stable elements. The temperature, humidity, and airflow inside the environmental chamber can be controlled to required values. The chamber has the facility for generating artificial rainfall. Grass grown in pots was kept inside the environmental chamber. Stable iodine (elemental form) was sublimed and injected into the environmental chamber suddenly to generate known concentration of iodine in the air inside the chamber. This simulated an accidental release of iodine to the environment. The concentration of iodine in the air inside the chamber was monitored continuously by drawing air from the environmental chamber through a bubbling setup (bubbling air through 1% sodium carbonate solution) and the iodine was then separated chemically and the concentration was measured by UV-VIS spectrometry. The concentration of iodine inside the chamber was monitored for every 30 min. The grass was exposed to iodine for 3 h after which the leaves were sampled and analysed for iodine concentration. From the concentration values of iodine in air and grass - the dry deposition rate, deposition velocity, and mass interception rates were estimated. The dry deposition velocity of iodine varied in the range of 0.5x10{sup -5}-3.3x10{sup -5} m s{sup -1} with a mean value of 1.7x10{sup -5} m s{sup -1}. The mass interception factor varied in the range of 0.25-13 m{sup 2} kg{sup -1} with a mean value of 4.2 m{sup 2} kg{sup -1} with respect to fresh weight. The wet deposition velocity varied in the range

  18. Study of Cu-Mn-Fe Compound in Wet Catalytic Oxidation of Phenol Wastewater%Cu-Mn-Fe催化湿式氧化苯酚废水的研究

    Institute of Scientific and Technical Information of China (English)

    秦传高; 崔瑞宇; 高迎明; 乔新平

    2015-01-01

    The Cu-Mn-Fe composite oxide catalysts were synthesized by co-precipitation method. The activity of the catalysts in wet catalytic oxidation of phenol wastewater were investigated and the optimum conditions were determined. The results showed that the optimum preparation conditions were as followed: the amount of catalyst addition was 0.7g/L, the amount of 30%H2O2addition was 50 mL/L, the treatment temperature was 55℃ and the treatment time was 2h. The highest removal rate of COD of phenol wastewater was 71.9%.%采用共沉淀法制取Cu-Mn-Fe复合金属氧化物,考察其催化湿式氧化苯酚废水的活性,并确定最佳工艺条件。结果表明,在催化剂用量为0.7g·L-1,30%过氧化氢用量为50mL·L-1,反应时间2h,反应温度55℃的条件下,苯酚废水的COD去除率最高可达71.9%。

  19. 含湿量对甲烷湿空气自热重整积碳特性的影响%NUMERICAL SIMULATION ON CARBON DEPOSITION CHARACTERISTICS OF HUMIDITY RATIO ON CH4/WET AIR AUTO-THERMAL REFORMING REACTION

    Institute of Scientific and Technical Information of China (English)

    冉景煜; 涂维峰

    2011-01-01

    Catalytic combustion of hydrocarbon fuels has been considered as an effective method in power MEMS. However, the ca talyst deactivation, mainly caused by carbon deposition, is occurred ubiquity in the catalytic reforming progress. In this paper, the effects of humidity ratio on the CH4/wet air auto-thermal reforming reaction with Ni catalyst on the micro-chamber's surface were simulated. The results show that increasing the humidity ratio will promote the methane reforming reaction. The heat dissipating capacity of auto-thermal reforming and the density of carbon deposition reduce with increasing the humidity ratio. The CH4 conversion rate, density of carbon deposition and mass fraction of H2 were changed very little, they reach 53.1%, 3.07% and 2.40x10-6 kmol/m2respectively while the humidity ratio exceeds 1.20 kg/kg and mixture flow rate is 36 g/h.%微动力装置中碳氢燃料催化燃烧被认为是有效的方法,但燃烧室内燃料催化重整普遍存在由积碳导致的催化剂失活等问题.本文采用数值方法研究了微细腔中甲烷湿空气在镍基催化剂上的自热重整反应,重点分析含湿量对甲烷自热重整反应及积碳特性的影响.结果表明:含湿量将增强甲烷重整反应;自热反应散热量和表面积碳浓度均随含湿量增加而降低.混合物质量流量为36 g/h时,当含湿量d>1.20 kg/kg后,甲烷转化率、氢气质量分数和积碳浓度变化幅度很小,分别接近 53.1%、3.07%和2.40x10-6 kmol/m2.

  20. Wet deposition of air pollution at southwest monsoon outbreak and its impact on groundwater resources of Greater Kochi region

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, T.; Nair, M.; Balachandran, K.K.; Nair, K.K.C.

    and the indirect impact of air pollution on the ground water quality can not be fully ruled out in the GKA region. As the total replenishable ground water from normal natural recharge for GKA is estimated as 5659 (th.ha.m/yr), its conservation from industrial...

  1. Control of oil-wetting on technical textiles by means of photo-chemical surface modification and its relevance to the performance of compressed air filters

    Energy Technology Data Exchange (ETDEWEB)

    Bahners, Thomas, E-mail: bahners@dtnw.de [Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW), Adlerstr. 1, 47798 Krefeld (Germany); Mölter-Siemens, Wolfgang; Haep, Stefan [Institut für Energie- und Umwelttechnik e.V. (IUTA), Bliersheimer Str. 60, 47229 Duisburg (Germany); Gutmann, Jochen S. [Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW), Adlerstr. 1, 47798 Krefeld (Germany); Universität Duisburg-Essen, Physikalische Chemie and CENIDE, Universitätsstr. 2, 45141 Essen (Germany)

    2014-09-15

    Highlights: • The oil repellence of textile fabrics was increased following the Wenzel concept. • Fiber surfaces were micro-roughened by means of pulsed UV laser irradiation. • Subsequent UV-induced grafting yielded pronounced oil repellence. • The grafting process conserved the delicate topography of the fiber surfaces. • The modified fabrics showed favorable drainage behavior in oil droplet separation. - Abstract: A two-step process comprising a surface roughening step by excimer laser irradiation and a post-treatment by photo-grafting to decrease the surface free energy was employed to increase the oil repellence of technical fabrics made of poly(ethylene terephthalate) (PET). The modification was designed to improve the performance of multi-layer filters for compressed air filtration, in which the fabrics served to remove, i.e. drain, oil separated from the air stream. In detail, the fibers surfaces were roughened by applying several laser pulses at a wavelength of 248 nm and subsequently photo-grafted with 1H,1H,2H,2H-perfluoro-decyl acrylate (PPFDA). The oil wetting behavior was increased by the treatments from full wetting on the as-received fabrics to highly repellent with oil contact angles of (131 ± 7)°. On surfaces in the latter state, oil droplets did not spread or penetrate even after one day. The grafting of PPFDA alone without any surface roughening yielded an oil contact angle of (97 ± 11)°. However, the droplet completely penetrated the fabric over a period of one day. The drainage performance was characterized by recording the pressure drop over a two-layer model filter as a function of time. The results proved the potential of the treatment, which reduced the flow resistance after 1-h operation by approximately 25%.

  2. Wet Oxidation of PVA-Containing Desizing Wastewater

    Institute of Scientific and Technical Information of China (English)

    雷乐成; 汪大翬

    2000-01-01

    Polyvinyl alcohol (PVA)-containing desizing wastewater was treated by various wet oxidation methods.Parameters such as reaction temperature, initial solution pH, and the dosage of H2O2 were investigated in terms of chemical oxygen demand (CODcr) and total organic carbon (TOC) removal rate. Up to 90% of the initial CODcr was removed by wet air oxidation(WAO) at 270℃ with stoichiometric oxygen supply, while at temperature of 200℃, the CODcr removal rate was found to be 80%. Similar results were obtained by Promoted WAO (PWAO) and wet peroxide oxidation(WPO) at a lower temperature of 150℃. Reaction temperature was found to have a significant effect on the oxidation performance for all the methods. Initial solution pH was observed to play a significant role in PWAO and WPO where H2O2 was employed. Comparison of WAO, CWAO(catalytic wet air oxidation), PWAO and WPO shows that the rate of CODcr removal increases in the order: WAO, CWAO, PWAO and WPO.

  3. Influence of air velocity on droplet's wetting and evaporation conditions on a flat surface

    Energy Technology Data Exchange (ETDEWEB)

    Zapalowicz, Z. (Technical Univ. of Szczecin (Poland). Dept. of Mechanical Engineering)

    The paper presents results of experimental research on influence of air velocity on characteristic dimensions, spreading ratio and evaporation time of a droplet. The relation between the velocity that initiates droplet's motion and the temperature of the surface has been under research, too, and is presented in the paper as well. The research allows determination of the droplet's rest and motion areas on the wall surface.

  4. 催化湿式氧化技术处理苯并三氮唑生产废水的研究%Study on Adopting Catalytic Wet-type Oxidation Technology to Dispose Benzotriazole Production Waste Water

    Institute of Scientific and Technical Information of China (English)

    常建勇; 刘伟

    2011-01-01

    Adopting catalytic wet-type Oxidation to dispose the high concentrated organic waste water produced during the production process of benzotriazole.The experiment demonstrates that the preparation of composite supported catalysts CuO-Co3O4-MnO2/ZrO2-CeO2 have better catalytic activity when disposing the waste water.Through the study of increasing the catalyst investment,reaction temperature,oxygen tension and the PH value of wastewater and other technological conditions,we obtain the optimum technological condition: When catalyst dosing quantity is 10 g/L,reaction temperature is 220℃,oxygen tension is 2.5MPa,the initial PH value of wastewater is 10.5,to react for 120 min under these conditions,CODcr removal rate can reach to 98.2%.%采用催化湿式氧化技术处理在生产苯并三氮唑(BTA)过程中产生的高浓度有机废水。实验证明:制备的复合负载型催化剂CuO-Co3O4-MnO2/ZrO2-CeO2在处理该废水时具有较好的催化活性。通过对催化剂投入增加、反应温度、氧气分压和废水pH值等工艺条件的考察,得出的最佳工艺条件为:催化剂投加量为10g/L,反应温度为220℃,氧气分压为2.5MPa,废水初始pH值为10.5,在此条件下反应120min,CODcr去除率达到98.2%。

  5. TASK TECHNICAL AND QUALITY ASSURANCE PLAN FOR OUT-OF-TANK DESTRUCTION OF TETRAPHENYLBORATE VIA WET AIR OXIDATION TECHNOLOGY: PHASE I - BENCH SCALE TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K

    2006-03-31

    Tank 48H return to service is critical to the processing of high level waste (HLW) at Savannah River Site (SRS). Liquid Waste Disposition (LWD) management has the goal of returning Tank 48H to routine service by January 2010 or as soon as practical. Tank 48H currently holds legacy material containing organic tetraphenylborate (TPB) compounds from the operation of the In-Tank Precipitation process. This material is not compatible with the waste treatment facilities at SRS and must be removed or undergo treatment to destroy the organic compounds before the tank can be returned to Tank Farm service. Tank 48H currently contains {approx}240,000 gallons of alkaline slurry with about 2 wt % potassium and cesium tetraphenylborate (KTPB and CsTPB). The main radioactive component in Tank 48H is {sup 137}Cs. The waste also contains {approx}0.15 wt % Monosodium Titanate (MST) which has adsorbed {sup 90}Sr, U, and Pu isotopes. A System Engineering Evaluation of technologies/ideas for the treatment of TPB identified Wet Air Oxidation (WAO) as a leading alternative technology to the baseline aggregation approach. Over 75 technologies/ideas were evaluated overall. Forty-one technologies/ideas passed the initial screening evaluation. The 41 technologies/ideas were then combined to 16 complete solutions for the disposition of TPB and evaluated in detail. Wet Air Oxidation (WAO) is an aqueous phase process in which soluble or suspended waste components are oxidized using molecular oxygen contained in air. The process operates at elevated temperatures and pressures ranging from 150 to 320 C and 7 to 210 atmospheres, respectively. The products of the reaction are CO{sub 2}, H{sub 2}O, and low molecular weight oxygenated organics (e.g. acetate, oxalate). The basic flow scheme for a typical WAO system is as follows. The waste solution or slurry is pumped through a high-pressure feed pump. An air stream containing sufficient oxygen to meet the oxygen requirements of the waste stream is

  6. Influence of n-hexanol and n-octanol on wetting properties and air entrapment at superhydrophobic surfaces.

    Science.gov (United States)

    Krasowska, Marta; Ferrari, Michele; Liggieri, Libero; Malysa, Kazimierz

    2011-05-28

    Superhydrophobic surfaces have recently attracted a lot of attention due to their self-cleaning properties. The superhydrophobic surfaces used in our studies were prepared using a mixed inorganic-organic coating. In order to check how short chain surface active agents affect the surface energy of such surfaces, their wettability (sessile drop technique) and the kinetics of the three phase contact formation were studied. It was found that with increasing concentrations of n-hexanol and n-octanol the surface energy of these surfaces was only slightly changed, i.e. a small decrease in contact angle values with increasing solution concentration was detected. Even for the most concentrated n-hexanol and n-octanol solutions, the contact angles were in the range 145-155° and the drop rolled off, indicating that the studied surfaces stayed superhydrophobic. Air bubbles, upon collision with such superhydrophobic surfaces, spread over the superhydrophobic surface within milliseconds in the studied solutions.

  7. Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air%使用加热空气的预混天然气催化燃烧的实验研究

    Institute of Scientific and Technical Information of China (English)

    许考; 刘中良; 何洪; 程水源; 马重芳

    2007-01-01

    In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC),NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied.Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃,100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.

  8. Oil sands development and its impact on atmospheric wet deposition of air pollutants to the Athabasca Oil Sands Region, Alberta, Canada.

    Science.gov (United States)

    Lynam, Mary M; Dvonch, J Timothy; Barres, James A; Morishita, Masako; Legge, Allan; Percy, Kevin

    2015-11-01

    Characterization of air pollutant deposition resulting from Athabasca oil sands development is necessary to assess risk to humans and the environment. To investigate this we collected event-based wet deposition during a pilot study in 2010-2012 at the AMS 6 site 30 km from the nearest upgrading facility in Fort McMurray, AB, Canada. Sulfate, nitrate and ammonium deposition was (kg/ha) 1.96, 1.60 and 1.03, respectively. Trace element pollutant deposition ranged from 2 × 10(-5) - 0.79 and exhibited the trend Hg < Se < As < Cd < Pb < Cu < Zn < S. Crustal element deposition ranged from 1.4 × 10(-4) - 0.46 and had the trend: La < Ce < Sr < Mn < Al < Fe < Mg. S, Se and Hg demonstrated highest median enrichment factors (130-2020) suggesting emissions from oil sands development, urban activities and forest fires were deposited. High deposition of the elements Sr, Mn, Fe and Mg which are tracers for soil and crustal dust implies land-clearing, mining and hauling emissions greatly impacted surrounding human settlements and ecosystems.

  9. 室内空气污染物催化氧化研究∗%Study of catalytic oxidation of indoor air pollutants

    Institute of Scientific and Technical Information of China (English)

    张长斌

    2015-01-01

    人一生中约90%的时间在室内度过,因此室内空气质量状况与人体健康息息相关。近年来,随着经济的快速发展,我国室内空气质量污染状况越来越严重,已成为影响人们健康的一大杀手,成为建设稳定和谐社会的制约因素。我国现阶段室内环境中主要的气态污染物是甲醛、苯系物和氨气,对人体健康带来极大危害。本研究针对上述污染物的有效去除,进行了新型高效、低成本催化净化材料和相关技术的研制和开发。一方面,研制了一种室温催化氧化甲醛的Pt基催化剂,并实现了相关技术的产业化应用;第二方面,研制出了针对室内苯系物净化的低温吸附⁃原位升温催化净化材料和方法;第三方面,研制了系列性能优异的室温光催化氧化氨气催化材料,并探讨了其高活性机制。本研究结果对于有效解决我国室内空气污染,改善工作环境,保护人体健康具有重要的的社会和环境意义。%It was reported that for a person about 90% of the time was spent in indoors environment, therefore, the indoor air quality has big effect on people′s health. Recently, the indoor pollution is getting worse in China, and the indoor air pollution control is gaining a lot of attention. Formaldehyde ( HCHO) , BTX ( Benzene, Toluene, Xylene) and NH3 are three major indoor air pollutants which poses the serious health risk to people. In this work, we carried out the study of catalytic oxidation of these indoor air pollutants. First, we developed a novel Pt⁃based catalyst with high dispersed Pt species for ambient HCHO destruction. Without the need of any energy ( such as photon, heat, etc) , HCHO could be catalytically decomposed to H2 O and CO2 at room temperature over this Pt⁃based catalyst. Also, we set up a new type of indoor air cleaner based on the Pt⁃based catalyst, realizing the industrialization of the above basic research

  10. Recovery and characterization of Balanites aegyptiaca Del. kernel proteins. Effect of defatting, air classification, wet sieving and aqueous ethanol treatment on solubility, digestibility, amino acid composition and sapogenin content.

    Science.gov (United States)

    Mohamed, A M; Wolf, W; Spiess, W E

    2000-02-01

    In order to find alternative protein sources in African regions where protein deficiency in nutrition is prevailing, solubility, in-vitro digestibility, amino acid composition and chemical score of Balanites aegyptiaca Del. kernel proteins were investigated as a function of different processing steps including defatting, air classification, wet sieving and aqueous ethanol treatment. Air classification delivered a fine fraction of 58.1% of the total protein. Applying a wet sieving process, a protein concentrate of 72.9% protein content was achieved but the recovery was very low (35.6%). However, in case of isoelectric precipitation followed by aqueous ethanol treatment both protein content (78.2%) and recovery (53.7%) were high. Data concerning the chemical score revealed, that lysine content of the defatted kernel flour amounted to 74.2% of the recommended FAO/WHO standard level. In-vitro protein digestibility was found to be higher than of legume proteins. The digestible protein of the full fat flour, defatted flour, air classified and wet sieved fine fractions and protein concentrate were 91.9, 93.7, 82.0, 86.4 and 94.2%, respectively. The sapogenin content per 100 g protein of the investigated protein preparations was significantly lower (46% to 62%) than of the initial material (oilcake).

  11. Catalytic evaluation on liquid phase oxidation of vanillyl alcohol using air and H2O2 over mesoporous Cu-Ti composite oxide

    Science.gov (United States)

    Saha, Subrata; Hamid, Sharifah Bee Abd; Ali, Tammar Hussein

    2017-02-01

    A mesoporous, highly crystalline Cu-Ti composite oxide catalyst was prepared via facile, simple and modified solution method varying Cu and Ti ratio for selective liquid phase oxidation of vanillyl alcohol. Various spectroscopic procedures were employed to systematically characterize the catalyst structural and physicochemical properties. The defect chemistry of the catalyst was confirmed from the presence of surface defects revealed through HRTEM imagery between the TiO2 (101) and Cu3TiO4 (012) planes, complemented by the XRD profiling. Further, presence of oxygen vacancy evidenced by O 1s XPS spectra were observed on the catalyst surface. Moreover, the stoichiometry of Cu and Ti in the catalyst synthesis protocol was notably found to be the vital determinant to alter the redox properties of Cu-Ti composite oxide catalyst supported by H2-TPR. O2-TPD analysis. Moreover, a rational investigation was done using different oxidants such as air and H2O2 with variables reaction conditions. The catalyst was active for liquid phase oxidation of vanillyl alcohol to vanillin with performance of 66% conversion and 71% selectivity using H2O2 in base free condition. And also, catalytic activity was significantly improved by 94% conversion with 86% selectivity to vanillin in liquid phase aerobic oxidation at the optimum reaction conditions. To expand the superiority of the catalyst, three times reusability study was also examined with appreciable catalytic activity.

  12. DEVELOPMENT OF CONSTRUCTION OF A CATALYTIC REACTOR FOR METHANE OXIDISING IN VENTILATION AIR IN COAL MINES AND THE RESEARCH ON INTEGRATED “HEAT PIPE” RECUPERATOR

    Directory of Open Access Journals (Sweden)

    Lech Hys

    2013-04-01

    Full Text Available The article presents the analysis whose result is the selection of appropriate design and construction of a monolithic CMR reactor intended for oxidising methane from ventilation air in coal mines. The description of “heat-pipe” recuperator cooperating with the reactor was also presented. The research was mainly aimed at verifying the compliance with the work of autothermity premise obtained by the return of part of heat from catalytic reaction. The result of research was to define the range volumetric fume expense ensuring autothermity and the definition of maximum recuperator efficiency. The range of volumetric expense was 18–25 m3/h and maximum value of efficiency coefficient was η = 0.50 for the volumetric expense of 18 m3/h.

  13. Post-treatment of refinery wastewater effluent using a combination of AOPs (H2O2 photolysis and catalytic wet peroxide oxidation) for possible water reuse. Comparison of low and medium pressure lamp performance.

    Science.gov (United States)

    Rueda-Márquez, J J; Levchuk, I; Salcedo, I; Acevedo-Merino, A; Manzano, M A

    2016-03-15

    The main aim of this work was to study the feasibility of multi-barrier treatment (MBT) consisting of filtration, hydrogen peroxide photolysis (H2O2/UVC) and catalytic wet peroxide oxidation (CWPO) for post-treatment of petroleum refinery effluent. Also the possibility of water reuse or safe discharge was considered. The performance of MBT using medium (MP) and low (LP) pressure lamps was compared as well as operation and maintenance (O&M) cost. Decomposition of organic compounds was followed by means of gas chromatography-mass spectrometry (GC-MS), total organic carbon (TOC) and chemical oxygen demand (COD) analysis. After filtration step (25 μm) turbidity and concentration of suspended solids decreased by 92% and 80%, respectively. During H2O2/UVC process with LP lamp at optimal conditions (H2O2:TOC ratio 8 and UVC dose received by water 5.28 WUVC s cm(-2)) removal of phenolic compounds, TOC and COD was 100%, 52.3% and 84.3%, respectively. Complete elimination of phenolic compounds, 47.6% of TOC and 91% of COD was achieved during H2O2/UVC process with MP lamp at optimal conditions (H2O2:TOC ratio 5, UVC dose received by water 6.57 WUVC s cm(-2)). In order to compare performance of H2O2/UVC treatment with different experimental set up, the UVC dose required for removal of mg L(-1) of COD was suggested as a parameter and successfully applied. The hydrophilicity of H2O2/UVC effluent significantly increased which in turn enhanced the oxidation of organic compounds during CWPO step. After H2O2/UVC treatment with LP and MP lamps residual H2O2 concentration was 160 mg L(-1) and 96.5 mg L(-1), respectively. Remaining H2O2 was fully consumed during subsequent CWPO step (6 and 3.5 min of contact time for LP and MP, respectively). Total TOC and COD removal after MBT was 94.7% and 92.2% (using LP lamp) and 89.6% and 95%, (using MP lamp), respectively. The O&M cost for MBT with LP lamp was estimated to be 0.44 € m(-3) while with MP lamp it was nearly five

  14. Study on stability of CuO/γ-Al_2O_3 catalyst in catalytic wet hydrogen peroxide oxidation%双氧水催化氧化中Cu/γ-Al_2O_3催化剂的稳定性研究

    Institute of Scientific and Technical Information of China (English)

    罗平; 范益群

    2011-01-01

    CuO/γ-Al2O3 catalysts for the H2O2 wet oxidation of phenol are prepared by impregnating process.The stability and deactivation of heterogeneous Cu/γ-Al2O3 catalysts were studied at room temperature and atmospheric pressure in the catalytic wet hydrogen peroxide oxidation(CWPO).Results showed that both the catalyst preparation conditions and the catalytic oxidation reaction conditions would affect the dissolution of the Cu2+ active component.The catalyst deactivation was related with the loss of active components and the catalyst surface coverage by the oxidation intermediates.The catalyst can be regenerated by calcination at high-temperature.%针对废水湿式双氧水催化氧化,采用浸渍法制备Cu催化剂,研究非均相Cu催化剂在常温常压湿式双氧水催化氧化中的稳定性与失活问题。研究表明,催化剂制备条件及催化氧化反应条件对催化剂中Cu2+溶出均有影响。研究同时表明,催化剂失活与活性组分流失和活性组分被有机中间产物覆盖有关,高温焙烧可对催化剂再生。

  15. DESTRUCTION OF TETRAPHENYLBORATE IN TANK 48H USING WET AIR OXIDATION BATCH BENCH SCALE AUTOCLAVE TESTING WITH ACTUAL RADIOACTIVE TANK 48H WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K; Paul Burket, P

    2009-03-31

    Wet Air Oxidation (WAO) is one of the two technologies being considered for the destruction of Tetraphenylborate (TPB) in Tank 48H. Batch bench-scale autoclave testing with radioactive (actual) Tank 48H waste is among the tests required in the WAO Technology Maturation Plan. The goal of the autoclave testing is to validate that the simulant being used for extensive WAO vendor testing adequately represents the Tank 48H waste. The test objective was to demonstrate comparable test results when running simulated waste and real waste under similar test conditions. Specifically: (1) Confirm the TPB destruction efficiency and rate (same reaction times) obtained from comparable simulant tests, (2) Determine the destruction efficiency of other organics including biphenyl, (3) Identify and quantify the reaction byproducts, and (4) Determine off-gas composition. Batch bench-scale stirred autoclave tests were conducted with simulated and actual Tank 48H wastes at SRNL. Experimental conditions were chosen based on continuous-flow pilot-scale simulant testing performed at Siemens Water Technologies Corporation (SWT) in Rothschild, Wisconsin. The following items were demonstrated as a result of this testing. (1) Tetraphenylborate was destroyed to below detection limits during the 1-hour reaction time at 280 C. Destruction efficiency of TPB was > 99.997%. (2) Other organics (TPB associated compounds), except biphenyl, were destroyed to below their respective detection limits. Biphenyl was partially destroyed in the process, mainly due to its propensity to reside in the vapor phase during the WAO reaction. Biphenyl is expected to be removed in the gas phase during the actual process, which is a continuous-flow system. (3) Reaction byproducts, remnants of MST, and the PUREX sludge, were characterized in this work. Radioactive species, such as Pu, Sr-90 and Cs-137 were quantified in the filtrate and slurry samples. Notably, Cs-137, boron and potassium were shown as soluble as a

  16. Drop splashing is independent of substrate wetting

    CERN Document Server

    Latka, Andrzej; Nagel, Sidney R; de Pablo, Juan J

    2016-01-01

    A liquid drop impacting a dry solid surface with sufficient kinetic energy will splash, breaking apart into numerous secondary droplets. This phenomenon shows many similarities to forced wetting, including the entrainment of air at the contact line. Because of these similarities and the fact that forced wetting has been shown to depend on the wetting properties of the surface, existing theories predict splashing to depend on wetting properties as well. However, using high-speed interference imaging we observe that wetting properties have no effect on splashing for various liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes equations at length and time scales inaccessible to experiments, we find that the shape and motion of the air-liquid interface at the contact line are independent of wettability. We use these findings to evaluate existing theories and to compare splashing with forced wetting.

  17. Fe salts as catalyst for the wet oxidation of o-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    XU Xin-hua; HE Ping; JIN Jian; HAO Zhi-wei

    2005-01-01

    Catalytic wet air oxidation (CWAO) of o-chlorophenol in wastewater was studied in a stainless steel autoclave using four different Fe catalysts in the temperature range of 100-200 ℃. Experimental results showed that high rate of o-chlorophenol and CODcr (Chemical Oxygen Demand, mg/L) removal by CWAO was obtained at relatively low temperature and pressure. The catalysts Fe2(SO4)3, FeSO4, Fe2O3 and FeCl3 all exhibited high catalytic activity. More than 93.7% of the initial CODCr and nearly100% of o-chlorophenol were removed at 150 ℃ after 150 min with FeSO4 as catalyst. The CWAO of o-chlorophenol was found to be pseudo-first order reaction with respect to o-chlorophenol, with activation energy of 75.56 k J/mol in the temperature range of100-175 ℃.

  18. 液滴碰撞液膜润湿壁面空气夹带数值分析∗%Numerical analysis on air entrapment during droplet impacting on a wetted surface

    Institute of Scientific and Technical Information of China (English)

    李大树; 仇性启; 郑志伟

    2015-01-01

    A numerical model is developed using the coupled level set and volume of fluid method including heat transfer and contact resistance to simulate air entrapment during a droplet impacting on a wetted surface. The dynamic characteristics of the phase interface are analysed. The mechanisms of deformation of the phase interface and formation of entrapped air are explored. The effects of impacting velocity and thickness of liquid film on characteristics of entrapped air are studied. The mechanism of heat transfer is also obtained in this article. The obtained results are as follows. The pressure difference between liquid and gas before the droplet impacting is the main factor determining the deformation of phases interface and the formation of air entrapment. The larger the impacting velocity, the larger the pressure inside the compressed air film is. When the droplet contacts the liquid film, the velocities of the droplet and liquid film increase to their maximum values, and at the impacting axis, they are approximately the same, nearly half the impacting velocity. The velocity distributions of phase interface of the droplet and liquid film are nearly the same in the area of impacting center. The impacting velocity has important effects on the dimensionless arc from bottom to breaking point and the dimensionless diameter of the air. The dimensionless arc and dimensionless diameter decrease with increasing impacting velocity. The dimensionless deforming heights of the droplet and liquid film are closely related to Stokes number: the larger the Stokes number, the larger the dimensionless deforming heights are, and they can be expressed as a power function with Stokes number. The initial thickness of liquid film also affects dimensionless deforming heights of the droplet and liquid film and dimensionless diameter of the entrapped air: the larger the dimensionless thickness of the liquid film, the larger the dimensionless deforming heights are, and the dimensionless

  19. Reactivity and Kinetic Study on Catalytic Wet Oxidation of Succinic Acid over Ru/Mn-Ce/TiO2 Catalysts%Ru/Mn-Ce/TiO2催化剂催化湿式氧化丁二酸的反应活性和动力学研究

    Institute of Scientific and Technical Information of China (English)

    张世鸿; 涂学炎; 王伟; 李自弘; 王颖臻; 周诚德; 陈斌

    2005-01-01

    在二氧化钛载体中通过掺杂Ru,Mn,Ce制备了一系列用于催化湿式氧化的催化剂,利用XRD,TEM,BET等手段对催化剂进行了表征.在反应温度T=210~270 ℃,氧分压PO2=2.1 Mpa条件下,在间歇式高压反应釜中对丁二酸进行了降解实验.催化剂在反应中有很高的催化活性.催化剂在30 min内对丁二酸降解的COD去除率为54.4~98.3%.Ru及Mn,Ce的氧化物对催化活性都有促进作用.建立了丁二酸催化湿式氧化的一级分段动力学模型.基于COD的一段及二段反应的活化能分别为43.74 kJ/mol和54.28 kJ/mol.%A series of catalysts used for catalytic wet oxidation were prepared by doping Ru, Mn, Ce on TiO2 support and characterized with XRD, TEM, BET. Degradation of succinic acid (COD=7000 mg/L) in aqueous solution were carried out using a slurry autoclave at T=210~270 ℃, PO2=2.1 MPa. The catalysts exhibited remarkable reactivity in reaction. COD removal for succinic acid degradation was at the range of 54.4~98.3% for different catalysts in 30 min. Ru and the oxides of Mn, Ce all showed effectiveness on promoting catalytic reactivity. The first order kinetic models based on subsection were setup to characterize the catalytic wet oxidation of succinic acid. The active energy relates to the first and second segment based on COD is 43.74 and 54.28 kJ/mol respectively.

  20. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  1. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent t

  2. Catalytic performance of heteroatom-modified carbon nanotubes in advanced oxidation processes

    Institute of Scientific and Technical Information of China (English)

    João Restivo; Raquel P. Rocha; Adrián M. T. Silva; José J. M. Órfão; Manuel F. R. Pereira; José L. Figueiredo

    2014-01-01

    Multi-walled carbon nanotubes (CNTs) were submitted to chemical and thermal treatments in or-der to incorporate different heteroatoms on the surface. O-, S-and N-containing groups were suc-cessfully introduced onto the CNTs without significant changes of the textural properties. The cata-lytic activity of these heteroatom-modified CNTs was studied in two liquid phase oxidation pro-cesses:catalytic ozonation and catalytic wet air oxidation (CWAO), using oxalic acid and phenol as model compounds. In both cases, the presence of strongly acidic O-containing groups was found to decrease the catalytic activity of the CNTs. On the other hand, the introduction of S species (mainly sulfonic acids) enhanced the removal rate of the model compounds, particularly in the CWAO of phenol. Additional experiments were performed with a radical scavenger and sodium persulfate, in order to clarify the reaction mechanism. Nitrogen functionalities improve the catalytic performance of the original CNTs, regardless of the process or of the pollutant.

  3. 钙钛矿型La1.4Fe03.6处理餐厨废水的湿式氧化催化性能研究%Preparation of Lal.4Fe03.6 Catalyst and Its Application in Wet Catalytic Oxidation

    Institute of Scientific and Technical Information of China (English)

    徐玲; 陈益平

    2012-01-01

    Fe does not produce biological toxicity easily. The oxide formation of perovskite structure aerobic space produces or eliminates the basis of reversible oxidation reduction process -the characteristics. This study adopts La1.4 FeO36 catalysts to treat kitchen wastewater with wet catalytic oxidation method. The atmospheric pressure and room temperature were prepared by impregnating process. The results show that calcination temperature would affect the catalyst's property. The catalysts show a good catalytic activity for conversion of kitchen wastewater.%Fe元素不易产生生物毒性,以氧化物所形成的钙钛矿型结构有氧空位产生或消除为基础进行可逆氧化一还原过程的特征。采用新型的钙钛矿型La1.4Fe03.6催化剂,对餐厨废水进行湿式催化氧化处理,考察钙钛矿型La1.4Fe03.6催化荆的催化性能。研究表明,在140℃氧分压为0.6MPa的条件下催化荆对高浓度餐厨废水具有较高的催化活性,但由于催化剂本身的缺陷,存在催化剂流失的问题。

  4. Reaction mechanism and degradation course of azo dyes by catalytic wet peroxide oxidation(CWPO)%催化湿式过氧化(CWPO)偶氮染料反应机理及降解历程研究

    Institute of Scientific and Technical Information of China (English)

    张蕾; 马宏瑞

    2011-01-01

    采用浸渍法制备出具有较高催化活性的催化剂CuO/γ-Al2O3,通过XRD、电镜等手段对催化剂进行了表征。降解了几种不同结构的偶氮染料,并通过改变CWPO的反应条件推断了其催化反应机理。采用紫外/可见分光光度计(UV-Vis)和傅里叶红外光谱仪(IR)等手段对染料降解过程进行跟踪和分析,对比染料处理前后紫外可见光谱与红外光谱图的变化,说明染料分子结构中的偶氮键发生断裂,破坏了分子结构的偶氮-苯环共轭发色体系,从而达到了脱色的目的。并借助水杨酸验证了CWPO体系中.OH的产生及CWPO反应机理。%The catalyst CuO/γ-Al2O3 with high catalytic activity by impregnation was prepared,and were examined by XRD、SEM to characterize the catalyst.Azo dyes of several different structures were degraded,and the reaction conditions were changed to study the reaction mechanism of CWPO.The UV/Visible spectrophotometer(UV-Vis) and the Fourier transform infrared spectrometer(IR) were used to track and analyze the degradation process of the dyes.Compared the UV-Vis and IR spectra before and after wastewater treatment,indicating the structure of the azo dye molecules bond was broken,destroyed azo benzene conjugated chromophoric system of the molecular structure,so as to achieve the purpose of bleaching.The salicylic acid was used to infer the ·OH generation and reaction mechanism in the CWPO system.

  5. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  6. WetVegEurope

    NARCIS (Netherlands)

    Landucci, Flavia; Řezníčková, Marcela; Šumberová, Kateřina; Hennekens, S.M.; Schaminée, J.H.J.

    2015-01-01

    WetVegEurope is a research project (http://www.sci.muni.cz/botany/vegsci/wetveg) whose goal is to provide a synthesized formalized classification of the aquatic and marsh vegetation across Europe at the level of phytosociological associations. In order to achieve the project objective, a WetVegEu

  7. Soil methane oxidation in both dry and wet temperate eucalypt forests shows a near-identical relationship with soil air-filled porosity

    Science.gov (United States)

    Fest, Benedikt J.; Hinko-Najera, Nina; Wardlaw, Tim; Griffith, David W. T.; Livesley, Stephen J.; Arndt, Stefan K.

    2017-01-01

    Well-drained, aerated soils are important sinks for atmospheric methane (CH4) via the process of CH4 oxidation by methane-oxidising bacteria (MOB). This terrestrial CH4 sink may contribute towards climate change mitigation, but the impact of changing soil moisture and temperature regimes on CH4 uptake is not well understood in all ecosystems. Soils in temperate forest ecosystems are the greatest terrestrial CH4 sink globally. Under predicted climate change scenarios, temperate eucalypt forests in south-eastern Australia are predicted to experience rapid and extreme changes in rainfall patterns, temperatures and wild fires. To investigate the influence of environmental drivers on seasonal and inter-annual variation of soil-atmosphere CH4 exchange, we measured soil-atmosphere CH4 exchange at high-temporal resolution (Ecological Research site, 1700 mm yr-1). Both forest soil systems were continuous CH4 sinks of -1.79 kg CH4 ha-1 yr-1 in Victoria and -3.83 kg CH4 ha-1 yr-1 in Tasmania. Soil CH4 uptake showed substantial temporal variation and was strongly controlled by soil moisture at both forest sites. Soil CH4 uptake increased when soil moisture decreased and this relationship explained up to 90 % of the temporal variability. Furthermore, the relationship between soil moisture and soil CH4 flux was near-identical at both forest sites when soil moisture was expressed as soil air-filled porosity (AFP). Soil temperature only had a minor influence on soil CH4 uptake. Soil nitrogen concentrations were generally low and fluctuations in nitrogen availability did not influence soil CH4 uptake at either forest site. Our data suggest that soil MOB activity in the two forests was similar and that differences in soil CH4 exchange between the two forests were related to differences in soil moisture and thereby soil gas diffusivity. The differences between forest sites and the variation in soil CH4 exchange over time could be explained by soil AFP as an indicator of soil moisture

  8. 新型车用空调平行流蒸发器湿工况性能的研究%A Research on the Wet Performance of New Parallel Flow Evaporator for Automotive Air Conditioners

    Institute of Scientific and Technical Information of China (English)

    施骏业; 瞿晓华; 祁照岗; 陈江平

    2011-01-01

    对新型车用空调平行流蒸发器湿工况性能进行了试验研究,并与层叠式蒸发器进行了比较.动态浸渍试验结果表明平行流蒸发器凝水排除能力较优;焓差法试验结果表明,在不同的稳定工况下,与层叠式蒸发器相比,平行流蒸发器的制冷能力较强(最高差3.3%),空气侧压降较高,全换热系数大21.3%~29%,除湿率略高.试验结果总体表明,新型平行流蒸发器性能优良,完全可以取代层叠式蒸发器.%An experimental study is carried out on the wet performance of new parallel flow evaporator for automotive air conditioners, which is then compared with baseline laminated evaporator.Dynamic dip test results show that parallel flow evaporator has better condensate drainage performance.The results of enthalpy difference test reveal that, under different working conditions, compared with laminated evaporator, the parallel flow evaporator has slightly higher cooling capacity (up to 3.3% difference), higher air side pressure drop, 21.3% ~29% higher over all heat transfer coefficient and slightly higher dehumidify rate.The results of all tests indicate that the new parallel flow evaporator has excellent performance and can by all means replace laminated evaporator.

  9. Hydrodynamics of a Multistage Wet Scrubber Incineration Conditions

    Science.gov (United States)

    Said, M. M.; Manyele, S. V.; Raphael, M. L.

    2012-01-01

    The objective of the study was to determine the hydrodynamics of the two stage counter-current cascade wet scrubbers used during incineration of medical waste. The dependence of the hydrodynamics on two main variables was studied: Inlet air flow rate and inlet liquid flow rate. This study introduces a new wet scrubber operating features, which are…

  10. Wetting Transition in Water

    Science.gov (United States)

    Friedman, S. R.; Khalil, M.; Taborek, P.

    2013-11-01

    Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300°C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185°C, 234°C, and 271°C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

  11. Fe-Zn-Al-柱撑蒙脱石催化剂的制备及其降解酸性橙II性能%Fe-Zn-Al Pillared Montmorillonite for Catalytic Wet Peroxide Oxidation Degradation of Orange Acid II:Preparation Methods and Properties

    Institute of Scientific and Technical Information of China (English)

    牛露; 赵彬侠; 叶维; 邱爽; 关文斌; 刘楠; 张小里

    2016-01-01

    以铁为活性组分,钙基蒙脱石为载体,分别采用传统法、超声和微波辅助法制备了Fe-Zn-Al-柱撑蒙脱石(Fe-Zn-Al-Mt)系列催化剂。表征了催化剂的结构和表面性能,研究了不同Fe/Zn摩尔比、焙烧温度以及制备方法对催化剂性能的影响;并将该催化剂用于催化湿式过氧化氢氧化法(CWPO)降解酸性橙II (OII)染料废水。结果表明:采用Fe/Zn摩尔比为3/7、焙烧温度为500℃、微波辅助制备的Fe-Zn-Al-Mt催化剂在蒙脱石表面形成更多的活性组分(ZnFe2O4纳米粒子),用于CWPO降解OII染料废水时效果最佳,其中色度和化学需氧量(COD)去除率可分别高达99.9%和79.7%,Fe离子溶出量仅为0.27 mg/L。此外,微波辅助制备的Fe-Zn-Al(3/7)-Mt催化剂重复使用5次,均能使废水褪色,COD去除率仅降低了3.1%,总Fe离子溶出仅为0.42 mg/L。表明Fe-Zn-Al-Mt催化剂用于降解OII染料废水时具有较高的催化活性和稳定性。%A series of Fe-Zn-Al-pillared montmorillonite (Mt) catalysts were prepared by three preparation methods (i.e. conventional method, ultrasonic and microwave treatment methods). The structure and surface properties of the (Fe-Zn-Al-Mt) catalysts were characterized. Effects of Fe/Zn molar ratio, calcinated temperature and preparation method on the catalytic performance of Fe-Zn-Al-Mt catalysts were investigated. The prepared catalysts were used for the degradation of Orange II (OII) by a catalytic wet hydrogen peroxide oxidation (CWPO) method. The results show that the catalyst prepared by microwave treatment at Fe/Zn more ratio of 3/7 and calcinated temperature of 500℃ contains more active ingredient (ZnFe2O4 nanoparticles) and exhibits the optimum degradation performance (i.e., degradation of 99.9%, chemical oxygen demand(COD) reduction of 79.7%, and Fe leaching was only 0.27mg/L). Besides, Fe-Zn-Al(3/7)-Mt(500℃) catalyst prepared by microwave treatment method could be reused for

  12. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  13. Study on flaking of wet corn by heating

    Institute of Scientific and Technical Information of China (English)

    WANG Mingming; WANG Defu

    2007-01-01

    Flaking on high-moisture corn (wet corn) by hot-air heating was studied in the paper. The wet-heating approach was beneficial to improve corn gelatinization by experimental results. By the experiments, a set of optimal parameters was obtained: hot-air temperature 120-130 ℃, heating duration 70 min, gap between rollers 0.5-1.0 mm, 150-200 r·min-1 for rotational speed of rollers.

  14. Wet hydrate dissolution plant

    OpenAIRE

    Stanković Mirjana S.; Kovačević Branimir T.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with capacity of 50,000 t/y was manufactured, at "Zeolite Mira", Mira (VE), Italy, in 1997, for increasing detergent zeolite production from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate ...

  15. Traction of Pneumatic Tires on Wet Runways

    Science.gov (United States)

    Horne, Walter B.; Joyner, Upshur T.

    1965-01-01

    Recent work on the traction of pneumatic tires on wet runways is discussed, and it is shown that a loss of tire traction adversely affects cross-wind landings. The effect of runway surface texture is discussed,, and a simple method for measuring surface texture is described. A preliminary correlation of tire traction with surface texture is shown. Results of work at Langley Research Center on the use of air jets to improve tire traction on wet or flooded runways indicate that this is a promising approach for alleviating the large losses in tire braking and sideways traction that occur when tire hydroplaning occurs on a flooded runway.

  16. Electro Catalytic Oxidation (ECO) Operation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Jones

    2011-03-31

    The power industry in the United States is faced with meeting many new regulations to reduce a number of air pollutants including sulfur dioxide, nitrogen oxides, fine particulate matter, and mercury. With over 1,000 power plants in the US, this is a daunting task. In some cases, traditional pollution control technologies such as wet scrubbers and SCRs are not feasible. Powerspan's Electro-Catalytic Oxidation, or ECO{reg_sign} process combines four pollution control devices into a single integrated system that can be installed after a power plant's particulate control device. Besides achieving major reductions in emissions of sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), fine particulate matter (PM2.5) and mercury (Hg), ECO produces a highly marketable fertilizer, which can help offset the operating costs of the process system. Powerspan has been operating a 50-MW ECO commercial demonstration unit (CDU) at FirstEnergy Corp.'s R.E. Burger Plant near Shadyside, Ohio, since February 2004. In addition to the CDU, a test loop has been constructed beside the CDU to demonstrate higher NOx removal rates and test various scrubber packing types and wet ESP configurations. Furthermore, Powerspan has developed the ECO{reg_sign}{sub 2} technology, a regenerative process that uses a proprietary solvent to capture CO{sub 2} from flue gas. The CO{sub 2} capture takes place after the capture of NOx, SO{sub 2}, mercury, and fine particulate matter. Once the CO{sub 2} is captured, the proprietary solution is regenerated to release CO{sub 2} in a form that is ready for geological storage or beneficial use. Pilot scale testing of ECO{sub 2} began in early 2009 at FirstEnergy's Burger Plant. The ECO{sub 2} pilot unit is designed to process a 1-MW flue gas stream and produce 20 tons of CO{sub 2} per day, achieving a 90% CO{sub 2} capture rate. The ECO{sub 2} pilot program provided the opportunity to confirm process design and cost estimates, and prepare for large

  17. Mathematical model and general laws of wet compression

    Institute of Scientific and Technical Information of China (English)

    王永青; 刘铭; 廉乐明; 何健勇; 严家騄

    2002-01-01

    Wet compression is an effective way to enhance the performance of gas turbines and it has attracted a good deal of attention in recent years. The one-sidedness and inaccuracy of previous studies,which took concentration gradient as mass transfer potential are discussed. The mass transfer process is analyzed from the viewpoint of non-equilibrium thermodynamics,by taking generalized thermodynamic driving force as mass transfer potential,and the corresponding mass-transfer coefficient is obtained using the heat and mass transfer equilibrium occurring between moist air and water droplets at wet-bulb temperature for the sake of avoiding complex tests and providing more accurate formulas. A mathematical model of wet compression is therefore established,and the general laws of wet compression are investigated. The results show that the performance of atomizer is critical for wet compression and wet compression is more suitable for compressors with higher pressure ratio and longer compression time.

  18. Using wet FGD systems to absorb mercury

    Energy Technology Data Exchange (ETDEWEB)

    Renninger, S.A.; Farthing, G.A.; Ghorishi, S.B. (and others) [Babcock and Wilcox Co. (US)

    2004-10-01

    For the past 12 years, the Babcock and Wilcox Company has been striving to develop mercury-reduction techniques that utilize, whenever possible, existing plant pollution control devices. This article discusses one such technique, which has demonstrated the potential for removing more than 95% of oxidized mercury in a wet flue gas desulfurization system at a low incremental cost and with little or no impact on the system's operation or SO{sub 2} removal performance. B & W's techniques enhance the mercury control ability of wet FGD systems using sodium hydrosulfide injection. This has been tested in a combined air quality control system at Mt. Storm Power Station in West Virginia comprising an SCR system and ESP with a wet FGD system. 6 figs.

  19. Wrinkling of wet paper

    Science.gov (United States)

    Kim, Ho-Young; Kim, Jungchul; Mahadevan, L.

    2011-11-01

    It is a mundane experience that paper stained with water wrinkles. It is because a wetted portion of paper, which swells due to the hygroexpansive nature of the cellulose fiber network, deforms out of its original plane. Here we quantify the dynamics of wrinkling of wet paper coupled to the capillary imbibition of water into paper using a combination of experiment and theory. While supplying water from a capillary tube that touches the center of a paper strip, we measure the spreading rate of the wet area, wait time for the out-of-plane buckling, and temporal growth of a wrinkling magnitude. Using a theoretical model assuming a linear increase of the strain and an exponential decay of the elastic modulus with the water concentration, we construct scaling laws to predict the simultaneous capillary imbibition and wrinkling rates. This work was supported by the Wyss Institute of Harvard University.

  20. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  1. Wet Macular Degeneration

    Science.gov (United States)

    ... macular degeneration Overview By Mayo Clinic Staff Wet macular degeneration is a chronic eye disease that causes blurred vision or a blind spot in your visual field. It's generally caused by abnormal blood vessels that leak fluid or blood into ... macular degeneration is one of two types of age-related ...

  2. 微通道内甲烷/湿空气重整转化效率实验研究%EXPERIMENTAL STUDY ON METHANE CONVERSION OF METHANE WET-AIR CATALYTIC REFORMING IN MICRO-CHANNEL

    Institute of Scientific and Technical Information of China (English)

    周劲; 张苗; 张力

    2012-01-01

    At present the experimental study on carbon dioxide dry capture is mainly giv en priority to with mechanism, in industrialized device research has not seen the report. With supported solid carbonate as the adsorbent, the experimental study on carbon dioxide capture from flue gas is carried out with fluidized bed adsorption reactor. Experiment measured the effect on the adsorption of different adsorbent, temperature, reaction time, and adsorbent regeneration performance test. The results showed that the adsorbent is the solid sodium carbonate, in the range of 65 'C-85 'C. Moreover, absorption time is about 4 min-10 min. In this case, the removal rate of carbon dioxide can reach 97. 5%, and adsorbent can reach steady state after 10 times re generation, so adsorbent can use long-term.%用沉淀法制备了涂覆在微通道内壁面的Ni/Al2O3催化剂,在自行搭建的实验系统上进行了微通道内甲烷/湿空气催化重整的实验研究,考察了催化壁面温度、空碳比及甲烷体积流量对甲烷/湿空气重整转化效率的影响,并与数值计算结果进行对比.结果表明,随着催化温度的升高,甲烷转化率不断升高;相同水碳比下,甲烷的催化转化率随着空碳比的增大而增大;随着甲烷体积流量的增大,甲烷转化效率呈现先增大后减小的变化规律.反应温度为1 023 K,甲烷体积流量为20 mL/min时,实验所得甲烷转化率达到最大值,为61.3%.

  3. Composition and installation debugging of the wet air regeneration (WAR) unit for the spent activated carbon%废炭泥湿式空气再生(WAR)装置结构及安装调试

    Institute of Scientific and Technical Information of China (English)

    周健生

    2014-01-01

    A great deal of sludge and spent activated carbon from the petrochemical wastewater which was treated by the PACT (powdered activated carbon biochemical treatment ) process has been regenerated by the WAR (wet air regeneration) unit built by the wastewater treatment plant of Anqing Petrochemical Branch Co.,SINOPEC. The results show that the adsorption capacity of activated carbon regenerated by WAR unit can meet the requirements of wastewater biochemical treatment. The oxidation waste gas from WAR unit and the regenerated activated carbon can be back to PACT system and used,so as to reduce the discharge of oxidation waste gas and the consumption of fresh activated carbon. The regenerated activated carbon amounts to 9 010 kg/d ,which is 90.5% of the daily amount of powdered activated carbon for biochemical treatment. Since the cost has been reduced ,the recycling of wastewater , waste carbon and waste gas are realized and the environment pollution caused by the“three wastes”is avoided.%利用中国石化安庆分公司污水处理场建设的湿式空气再生(WAR)装置,对粉末活性炭生化技术(PACT)处理石化污水产生的大量污泥和废活性炭进行再生。结果表明,经WAR装置再生的活性炭的吸附性能满足污水生化处理要求,再生活性炭和WAR装置产生的氧化废气可重返PACT系统使用,减少了氧化废气外排及新鲜活性炭用量。再生活性炭回用量达9010 kg/d,占生化处理粉末活性炭日用量的90.5%,降低了成本,实现了废水、废炭、废气的回收利用,避免了“三废”排放造成的环境污染。

  4. WET SOLIDS FLOW ENHANCEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-03-25

    The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally.

  5. Controlled synthesis of porous platinum nanostructures for catalytic applications.

    Science.gov (United States)

    Cao, Yanqin; Zhang, Junwei; Yang, Yong; Huang, Zhengren; Long, Nguyen Viet; Nogami, Masayuki

    2014-02-01

    Porous platinum, that has outstanding catalytic and electrical properties and superior resistant characteristics to corrosion, has been widely applied in chemical, petrochemical, pharmaceutical, electronic, and automotive industries. As the catalytic activity and selectivity depend on the size, shape and structure of nanomaterials, the strategies for controlling these factors of platinum nanomaterials to get excellent catalytic properties are discussed. Here, recent advances in the design and preparation of various porous platinum nanostructures are reviewed, including wet-chemical synthesis, electro-deposition, galvanic replacement reaction and de-alloying technology. The applications of various platinum nanostructures are also discussed, especially in fuel cells.

  6. Writing on wet paper

    Science.gov (United States)

    Fridrich, Jessica; Goljan, Miroslav; Lisonek, Petr; Soukal, David

    2005-03-01

    In this paper, we show that the communication channel known as writing in memory with defective cells is a relevant information-theoretical model for a specific case of passive warden steganography when the sender embeds a secret message into a subset C of the cover object X without sharing the selection channel C with the recipient. The set C could be arbitrary, determined by the sender from the cover object using a deterministic, pseudo-random, or a truly random process. We call this steganography "writing on wet paper" and realize it using low-density random linear codes with the encoding step based on the LT process. The importance of writing on wet paper for covert communication is discussed within the context of adaptive steganography and perturbed quantization steganography. Heuristic arguments supported by tests using blind steganalysis indicate that the wet paper steganography provides improved steganographic security for embedding in JPEG images and is less vulnerable to attacks when compared to existing methods with shared selection channels.

  7. Physicochemical properties and combustion behavior of duckweed during wet torrefaction.

    Science.gov (United States)

    Zhang, Shuping; Chen, Tao; Li, Wan; Dong, Qing; Xiong, Yuanquan

    2016-10-01

    Wet torrefaction of duckweed was carried out in the temperature range of 130-250°C to evaluate the effects on physicochemical properties and combustion behavior. The physicochemical properties of duckweed samples were investigated by ultimate analysis, proximate analysis, FTIR, XRD and SEM techniques. It was found that wet torrefaction improved the fuel characteristics of duckweed samples resulting from the increase in fixed carbon content, HHVs and the decrease in nitrogen and sulfur content and atomic ratios of O/C and H/C. It can be seen from the results of FTIR, XRD and SEM analyses that the dehydration, decarboxylation, solid-solid conversion, and condensation polymerization reactions were underwent during wet torrefaction. In addition, the results of thermogravimetric analysis (TGA) in air indicated that wet torrefaction resulted in significant changes on combustion behavior and combustion kinetics parameters. Duckweed samples after wet torrefaction behaved more char-like and gave better combustion characteristics than raw sample.

  8. Methods and apparatus for catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C.; Butner, Robert Scott; Neuenschwander, Gary G.; Zacher, Alan H.; Hart, Todd R.

    2012-08-14

    Continuous processing of wet biomass feedstock by catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent separation of sulfur contaminants, or combinations thereof. Treatment further includes separating the precipitates out of the wet feedstock, removing sulfur contaminants, or both using a solids separation unit and a sulfur separation unit, respectively. Having removed much of the inorganic wastes and the sulfur that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogeneous catalyst for gasification.

  9. Wet oxidation of salicylic acid solutions.

    Science.gov (United States)

    Collado, Sergio; Garrido, Laura; Laca, Adriana; Diaz, Mario

    2010-11-15

    Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

  10. The roles of various plasma species in the plasma and plasma-catalytic removal of low-concentration formaldehyde in air.

    Science.gov (United States)

    Fan, Xing; Zhu, Tianle; Sun, Yifei; Yan, Xiao

    2011-11-30

    The contributions of various plasma species to the removal of low-concentration formaldehyde (HCHO) in air by DC corona discharge plasma in the presence and absence of downstream MnO(x)/Al(2)O(3) catalyst were systematically investigated in this study. Experimental results show that HCHO can be removed not only by short-living active species in the discharge zone, but also by long-living species except O(3) downstream the plasma reactor. O(3) on its own is incapable of removing HCHO in the gas phase but when combined with the MnO(x)/Al(2)O(3) catalyst, considerable HCHO conversion is seen, well explaining the greatly enhanced HCHO removal by combining plasma with catalysis. The plasma-catalysis hybrid process where HCHO is introduced through the discharge zone and then the catalyst bed exhibits the highest energy efficiency concerning HCHO conversion, due to the best use of plasma-generated active species in a two-stage HCHO destruction process. Moreover, the presence of downstream MnO(x)/Al(2)O(3) catalyst significantly reduced the emission of discharge byproducts (O(3)) and organic intermediates (HCOOH).

  11. Wetting in Color

    Science.gov (United States)

    Burgess, Ian Bruce

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly selective colorimetric indicator for organic liquids. The technology exploits chemically-encoded inverse-opal photonic crystals to control the infiltration of fluids to liquid-specific spatial patterns, projecting minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. It is shown experimentally and corroborated with theoretical modeling using percolation theory that the high selectivity of wetting, upon-which the sensitivity of the indicator relies, is caused by the highly symmetric structure of our large-area, defect-free SiO2 inverse-opals. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid - naturally coupling the optical and fluidic responses. Surface modification protocols are developed, requiring only silanization and selective oxidation, to facilitate the deterministic design of an indicator that differentiates a broad range of liquids. The resulting tunable, built-in horizontal and vertical chemistry gradients allow the wettability threshold to be tailored to specific liquids across a continuous range, and make the readout rely only on countable color differences. As wetting is a generic fluidic phenomenon, Wetting in Color technology could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries. However, the generic nature of the response also ensures chemical non-specificity. It is shown

  12. Phoenix's Wet Chemistry Lab

    Science.gov (United States)

    2008-01-01

    This is an illustration of soil analysis on NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL will attempt to determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  13. Phoenix's Wet Chemistry Lab

    Science.gov (United States)

    2008-01-01

    This is an illustration of the analytical procedure of NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. 煤矿乏风低浓度甲烷催化氧化数值模拟%NUMERICAL SIMULATION OF CATALYTIC OXIDATION OF COAL MINE VENTILATION AIR LOW CONCENTRIATION METHANE

    Institute of Scientific and Technical Information of China (English)

    王鹏飞; 冯涛; 陈丽娟; 郝小礼

    2012-01-01

    应用计算流体力学软件FLUENT,通过导入CHEMKIN格式详细化学反应机理对煤矿乏风低浓度甲烷气体在壁面涂有Pt催化剂的蜂窝陶瓷通道表面的催化氧化过程进行数值研究,计算分析了有、无催化剂情况下乏风低浓度甲烷在通道内的反应情况,同时进一步分析了乏风甲烷浓度、入口进气速度、通道壁面温度及通道直径对甲烷氧化率的影响。结果表明:在蜂窝陶瓷通道内壁负载Pt金属催化剂不仅可以降低乏风中低浓度甲烷氧化所需的温度,而且可以大大提高甲烷的氧化率;甲烷氧化率随着乏风甲烷浓度和通道壁面温度的升高而增大,随着入口进气速度和通道直径的增大而下降。%With importing the detailed methane/air chemical reaction mechanism, the computational fluid dynamics software FLUENT was applied to numerically simulate the catalytic oxidation of coal mine ventilation air methane in microchannel of honeycomb ceramic which was coated with catalyst Pt. It was analyzed the reaction of vetilation air low concentration methane in microchannel with and without catalyst Pt, and it was further analyzed the effect of methane concentration, gas speed, wall temperature and the diameter of microchannel on the methane oxidation rate. The results show that: 1 ) with catalyst Pt coated on microchannel,it not only drops the temperature of methane oxidation,and also improves the methane oxidation rate ; 2 ) the methane oxidation rate increases with the increase of methane concentration and wall temperature ; 3 ) the methane oxidation rate decreases with the increase of gas speed and the diameter of microchannel.

  15. Wet steam wetness measurement in a 10 MW steam turbine

    OpenAIRE

    Kolovratník Michal; Bartoš Ondřej

    2014-01-01

    The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  16. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  17. Energy and exergy analysis of counter flow wet cooling towers

    Directory of Open Access Journals (Sweden)

    Saravanan Mani

    2008-01-01

    Full Text Available Cooling tower is an open system direct contact heat exchanger, where it cools water by both convection and evaporation. In this paper, a mathematical model based on heat and mass transfer principle is developed to find the outlet condition of water and air. The model is solved using iterative method. Energy and exergy analysis infers that inlet air wet bulb temperature is found to be the most important parameter than inlet water temperature and also variation in dead state properties does not affect the performance of wet cooling tower. .

  18. Wetting and Minimal Surfaces

    CERN Document Server

    Bachas, C; Wiese, K J; Bachas, Constantin; Doussal, Pierre Le; Wiese, Kay Joerg

    2006-01-01

    We study minimal surfaces which arise in wetting and capillarity phenomena. Using conformal coordinates, we reduce the problem to a set of coupled boundary equations for the contact line of the fluid surface, and then derive simple diagrammatic rules to calculate the non-linear corrections to the Joanny-de Gennes energy. We argue that perturbation theory is quasi-local, i.e. that all geometric length scales of the fluid container decouple from the short-wavelength deformations of the contact line. This is illustrated by a calculation of the linearized interaction between contact lines on two opposite parallel walls. We present a simple algorithm to compute the minimal surface and its energy based on these ideas. We also point out the intriguing singularities that arise in the Legendre transformation from the pure Dirichlet to the mixed Dirichlet-Neumann problem.

  19. Wet solids flow enhancemant

    Energy Technology Data Exchange (ETDEWEB)

    Caram, H.S.; Foster, N.; Wildman, D.J. [USDOE Pittsburgh Energy Technology Center, PA (United States)

    1996-12-31

    WE used glass beads of different sizes as.a model system to study the flow enhancing properties of Octadecyltrichlorosilane (OTS). 0TS provides Si(CH{sub 2}){sub 17}CH{sub 3} groups that bind with the surface hydrox groups to make it hydrophobic. Experimental data showed, indeed, that surface hydrophobicity promotes the flow of wet granular materials. Mixtures of different percentage of silanized/unsilanized particles were prepared for tensile strength measurements. The tensile strength decreased as more silanized particles were added to the samples. The relationship between dimensionless tensile strength and void fraction followed the correlation found by Pierrat (1994). Contact angles were larger for the silanized particles, as compared with unsilanized ones.

  20. Low-temperature catalytic oxidation of aldehyde mixtures using wood fly ash: kinetics, mechanism, and effect of ozone.

    Science.gov (United States)

    Kolar, Praveen; Kastner, James R

    2010-02-01

    Poultry rendering emissions contain volatile organic compounds (VOCs) that are nuisance, odorous, and smog and particulate matter precursors. Present treatment options, such as wet scrubbers, do not eliminate a significant fraction of the VOCs emitted including, 2-methylbutanal (2-MB), 3-methylbutanal, and hexanal. This research investigated the low-temperature (25-160 degrees C) catalytic oxidation of 2-MB and hexanal vapors in a differential, plug flow reactor using wood fly ash (WFA) as a catalyst and oxygen and ozone as oxidants. The oxidation rates of 2-MB and hexanal ranged between 3.0 and 3.5 x 10(-9)mol g(-1)s(-1) at 25 degrees C and the activation energies were 2.2 and 1.9 kcal mol(-1), respectively. The catalytic activity of WFA was comparable to other commercially available metal and metal oxide catalysts. We theorize that WFA catalyzed a free radical reaction in which 2-butanone and CO(2) were formed as end products of 2-MB oxidation, while CO(2), pentanal, and butanal were formed as end products of hexanal oxidation. When tested as a binary mixture at 25 and 160 degrees C, no inhibition was observed. Additionally, when ozone was tested as an oxidant at 160 degrees C, 100% removal was achieved within a 2-s reaction time. These results may be used to design catalytic oxidation processes for VOC removal at poultry rendering facilities and potentially replace energy and water intensive air pollution treatment technologies currently in use.

  1. Wetting front instability in an initially wet unsaturated fracture

    Energy Technology Data Exchange (ETDEWEB)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1992-12-31

    Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport.

  2. Catalytic processes for space station waste conversion

    Science.gov (United States)

    Schoonover, M. W.; Madsen, R. A.

    1986-01-01

    Catalytic techniques for processing waste products onboard space vehicles were evaluated. The goal of the study was the conversion of waste to carbon, wash water, oxygen and nitrogen. However, the ultimate goal is conversion to plant nutrients and other materials useful in closure of an ecological life support system for extended planetary missions. The resulting process studied involves hydrolysis at 250 C and 600 psia to break down and compact cellulose material, distillation at 100 C to remove water, coking at 450 C and atmospheric pressure, and catalytic oxidation at 450 to 600 C and atmospheric pressure. Tests were conducted with a model waste to characterize the hydrolysis and coking processes. An oxidizer reactor was sized based on automotive catalytic conversion experience. Products obtained from the hydrolysis and coking steps included a solid residue, gases, water condensate streams, and a volatile coker oil. Based on the data obtained, sufficient component sizing was performed to make a preliminary comparison of the catalytic technique with oxidation for processing waste for a six-man spacecraft. Wet oxidation seems to be the preferred technique from the standpoint of both component simplicity and power consumption.

  3. Optimization of m?cresol degradation by sludge?derived carbon in catalytic wet peroxide oxidation using response surface methodology%响应面法优化污泥炭催化湿式过氧化氢氧化降解间甲酚模拟废水

    Institute of Scientific and Technical Information of China (English)

    赵颖; 王亚旻; 卫皇曌; 于杨; 孙承林

    2016-01-01

    In this study, nitric acid modified activated carbon prepared from excess sludge produced in sewage treatment plant was employed to degrade m?cresol simulated wastewater by catalytic wet peroxide oxidation ( CWPO ) , which helps to recycle and re?utilize the waste sludge. Physical adsorption, temperature programmed desorption ( TPD) and X ray fluorescence spectrometry ( XRF) were used to determine the physical and chemical characteristics of the sludge?derived activated carbon, and the response surface methodology ( RSM ) was applied to optimize the reaction conditions. Reaction temperature, reaction time, initial pH value, hydrogen peroxide ( H2 O2 ) dosage, catalyst dosage were selected as factors while total organic carbon ( TOC) removal rate was the response. An quadratic polynomial mathematical model between the response and 5 impact factors was derived using the central composite design ( CCD ) , refined using the backward regression method, and examined through the analysis of variance ( ANOVA ) . The optimized reaction conditions in CWPO process were found out to the reaction temperature of 60℃, the reaction time of 120 min, initial pH=3.00, H2O2 dosage of 2.03 g?L-1, catalyst dosage of 0.78 g?L-1. TOC removal rate and m?cresol conversion reached their optimal values at 44.6% and 100%, respectively.Under these conditions, The TOC removal rate in the validation experiment was 46.6%. This experimental optimal TOC removal rate is only 2.0% more than its theoretical optimum and is within the 95% confidence interval. The intermediate products from the m?cresol degradation process by sludge derived activated carbon were also analyzed using GC?MS.%以污水处理厂剩余污泥为原料制备硝酸改性活性炭,用于催化湿式过氧化氢氧化(CWPO)处理间甲酚模拟废水,以实现剩余污泥的资源化利用.使用物理吸附、程序升温脱附(TPD)、X射线荧光光谱(XRF)等表征方法对污泥炭的物理化学性质进行测定.而后采

  4. Wet oxidation of phenol on Ce{sub 1{minus}x}Cu{sub x}O{sub 2{minus}{delta}} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hocevar, S.; Batista, J. [National Inst. of Chemistry, Ljubljana (Slovenia). Lab. of Catalysis and Chemical Reaction Engineering; Levec, J. [National Inst. of Chemistry, Ljubljana (Slovenia). Lab. of Catalysis and Chemical Reaction Engineering]|[Univ. of Ljubljana (Slovenia). Dept. of Chemical Engineering

    1999-05-15

    Ce{sub 1{minus}x}Cu{sub x}O{sub 2{minus}{delta}} catalysts with 0.05 < x < 0.20 for catalytic wet oxidation of phenol in aqueous solutions have been synthesized using the coprecipitation method. The three most important synthesis parameters, the concentration of the mixed metal salt solution, the rate of coprecipitant addition and the stirrer speed during coprecipitation, were optimized with central composite design using the catalytic activity as a response function. The catalytic activity strongly depends on stirrer speed during coprecipitation. A high mutual dispersion of copper oxide and ceria, having the average crystallite size of about 9 nm, enhances solid solution formation. The unit cell parameter of ceria decreases when the overall concentration of copper in the catalyst increases, most probably obeying Vegard`s law. The catalysts proved to be very stable in hydrothermal reaction conditions at low pH values. After 5 h of reaction in the semibatch CST reactor less than 100 ppm of Cu was leached out of catalyst samples that were calcined in a flow of air for 2 h above 1033 K, and only a very low quantity of carbonaceous deposits were formed on the surface of the catalysts (0.6 wt%). The kinetics of phenol degradation could be interpreted by an equation valid for homogeneous autocatalytic reactions, in which the rate constant depends linearly on the heterogeneous catalyst (Cu) concentrations. This demonstrates that the reaction proceeds through a heterogeneous-homogeneous radical-branched chain mechanism.

  5. Catalytic combustor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mercea, J.; Grecu, E.; Fodor, T.; Kreibik, S.

    1982-01-01

    The performance of catalytic combustors for hydrogen using platinum-supported catalysts is described. Catalytic plates of different sizes were constructed using fibrous and ceramic supports. The temperature distribution as well as the reaction efficiency as a function of the fuel input rate was determined, and a comparison between the performances of different plates is discussed.

  6. Wick wetting for water condensation systems

    Energy Technology Data Exchange (ETDEWEB)

    Hering, Susanne Vera; Spielman, Steven Russel; Lewis, Gregory Stephen; Kreisberg, Nathan Michael

    2017-04-04

    A system and method for particle enlargement with continuously wetted wicks includes a container into which a flow of particle-laden air is introduced in a laminar manner through an inlet and to an outlet. The container has a first section, a second section and a third section though which the particle-laden air flows between the inlet and the outlet. The temperature of the second section is warmer than that of the first section at the inlet and the third section at the outlet. In one embodiment, a continuous wick spanning an interior wall of the first second, second section and third section, said wick being capable of internally transporting liquid water along its length is provided.

  7. Recycled High-Density Polyethylene and Rice Husk as a Wetted Pad in Evaporative Cooling System

    Directory of Open Access Journals (Sweden)

    Nitipong Soponpongpipat

    2011-01-01

    Full Text Available Problem statement: The low cost and easy-to-find materials, for being used as wetted pad of evaporative cooling system, are necessary for agriculture. This study, thus, studied the evaporative cooling efficiency and pressure drop of recycled High-Density Polyethylene (HDPE and rice husk as a wetted pad in evaporative cooling system. Approach: The study was done by establishing the tested wetted pad with 25.4 and 50.8 mm of thickness. The velocity air flow through wetted pad was controlled at 1, 2 and 3 m sec−1 respectively. In addition, the dry bulb and wet bulb temperatures of inlet air were controlled at 30.1 ± 1.0°C and 23.2 ± 1.1°C, respectively. The commercial wetted pad was also tested in order to compare results with rice husk and recycled HDPE. Results: It was found that rice husk wetted pad gave the average saturation efficiency of 55.9 %, while HDPE gave the average saturation efficiency of 29.1%. However, the pressure drop across wetted pad of rice husk and recycled HDPE was significantly higher than that of commercial wetted pad. For the effect of air velocity on saturation efficiency and pressure drop, it was found that higher air velocity decreased saturation efficiency and increased pressure drop across wetted pad. Conclusion: Finally, the rice husk has a potential as wetted pad material. However, further study about optimum point between operation cost and materials cost of using rice husk wetted pad is needed.

  8. 40 CFR 63.524 - Standards for wet strength resins manufacturers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards for wet strength resins... National Emission Standards for Hazardous Air Pollutants for Epoxy Resins Production and Non-Nylon Polyamides Production § 63.524 Standards for wet strength resins manufacturers. (a) Owners or operators...

  9. Research progress of catalysts for producing N-phosphonomethyl glycine by air (oxygen) catalytic oxidation%空气(氧气)催化氧化合成草甘膦催化剂的研究进展

    Institute of Scientific and Technical Information of China (English)

    陈丹; 李国儒; 黄敏建; 陈标华; 银凤翔

    2014-01-01

    用于空气(氧气)催化氧化双甘膦合成草甘膦的催化剂主要有活性炭催化剂、贵金属催化剂和过渡金属催化剂。本文分别概述了这3种催化剂的研究进展,分析比较了这些催化剂的优点和缺点:活性炭催化剂成本低廉、制备简单但是套用次数少,副产甲醛含量高;贵金属催化剂不仅收率高、产品质量好,而且催化剂可多次套用,但是成本过高,制备和再生也困难;过渡金属催化剂属均相催化,催化剂和产物易分离,但是产品收率较低。最后结合国内现状,认为开发一种催化效果更优、生产成本更低廉、使用和再生简单且环境友好的催化剂是国内草甘膦生产企业亟待解决的问题。%There are mainly three kinds of catalysts used for producing N-phosphonomethyl glycine by air (oxygen) catalytic oxidation:activated carbon,noble metal and transition metal catalysts. The research progress of these catalysts and their relative merits for applications in N-phosphonomethyl glycine synthesis are summarized and analyzed in this paper. Activated carbon catalysts are low cost and can be simply prepared,but they possess short working life and leave too much formaldehyde as by-product. Noble metal catalysts have long operation life and the obtained product is high yield with good quality,but the catalysts are high cost and difficult to be prepared and regenerated. Transition metal catalysts belong to homogeneous catalysts and can be easily separated from products but with low yield. Hence,to address the domestic problems faced by glyphosate enterprises,catalysts,which are low cost,environmental friendly and easily prepared and regenerated,with high activities are urgently required.

  10. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Laster, W. R.; Anoshkina, E.

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy’s National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1- Implementation Plan, Phase 2- Validation Testing and Phase 3 – Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  11. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    W. R. Laster; E. Anoshkina

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy's National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1 - Implementation Plan, Phase 2 - Validation Testing and Phase 3 - Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  12. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the diffusi

  13. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  14. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  15. Catalytic distillation process

    Science.gov (United States)

    Smith, L.A. Jr.

    1982-06-22

    A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  16. Development studies of a novel wet oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, T.W.; Dhooge, P.M. [Delphi Research, Inc., Albuquerque, NM (United States)

    1995-10-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials.

  17. Catalytic distillation structure

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-04-17

    Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

  18. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann

    2012-12-01

    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.

  19. Olefin metathesis in air.

    Science.gov (United States)

    Piola, Lorenzo; Nahra, Fady; Nolan, Steven P

    2015-01-01

    Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  20. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  1. SETAC-U.S. EPA WET INITIATIVES: ALL WET AND NOTHING BUT WET

    Science.gov (United States)

    To ensure that sould scientific principles and sound science are applied to the challenging issues in t he Whole Effluent Toxicity (WET) process, the Society of Environmental Toxicology and Chemistry (SETAC) Foundation for Environmental Education was awarded a cooperative agreem...

  2. Water recovery by catalytic treatment of urine vapor

    Science.gov (United States)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  3. Hydrogen production by catalytic partial oxidation of methane

    OpenAIRE

    Enger, Bjørn Christian

    2008-01-01

    Hydrogen production by catalytic partial oxidation of natural gas was investigated using tools ranging from theoretical calculations to experimental work and sophisticated characterization techniques.Catalytic partial oxidation (CPO) was carried out in a conventional continuous flow experimental apparatus using a xed-bed reactor, and operating at 1 atm and furnace temperatures in the range from ambient to 1073 K. The feed typically consisted of a mixture of methane and air, with a CH4/O2 rati...

  4. Development of Pillared Clays for Wet Hydrogen Peroxide Oxidation of Phenol and Its Application in the Posttreatment of Coffee Wastewater

    Directory of Open Access Journals (Sweden)

    Nancy R. Sanabria

    2012-01-01

    Full Text Available This paper focuses on the use of pillared clays as catalysts for the Fenton-like advanced oxidation, specifically wet hydrogen peroxide catalytic oxidation (WHPCO. This paper discusses the limitations on the application of a homogeneous Fenton system, development of solid catalysts for the oxidation of phenol, advances in the synthesis of pillared clays, and their potential application as catalysts for phenol oxidation. Finally, it analyzes the use of pillared clays as heterogeneous Fenton-like catalysts for a real wastewater treatment, emphasizing the oxidation of phenolic compounds present in coffee wastewater. Typically, the wet hydrogen peroxide catalytic oxidation in a real effluent system is used as pretreatment, prior to biological treatment. In the specific case of coffee wet processing wastewater, catalytic oxidation with pillared bentonite with Al-Fe is performed to supplement the biological treatment, that is, as a posttreatment system. According to the results of catalytic activity of pillared bentonite with Al-Fe for oxidation of coffee processing wastewater (56% phenolic compounds conversion, 40% selectivity towards CO2, and high stability of active phase, catalytic wet hydrogen peroxide oxidation emerges as a viable alternative for management of this type of effluent.

  5. Wet sipping system at Wolsong-1

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.Y.; Shin, J.C.; Kim, Y.C.; Park, C.H.; Choi, T.Y.; Park, C.J., E-mail: jyoulpark@knfc.co.kr [Korea Nuclear Fuel Co. Ltd. (KNF), Yousong, Daejeon (Korea, Republic of); Manger, A.M. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada)

    2010-07-01

    After many years of operation, the on-power failed fuel detection and location systems along with alarm area gamma monitors at Wolsong-1 have successfully demonstrated that most, if not all, defective and suspect fuel bundles can be located before discharge to the fuel bay. Today, discharged bundles are now being transferred from the fuel bay to the AECL designed Modular Air-Cooled Storage (MACSTOR) canister facilities. Since these canisters are licensed for storing intact fuel bundles only, a procedure was needed at Wolsong-1 to separate any suspect or defective bundles that do not release fission products in detectable quantities. Therefore, KNF designed and built a wet sipper to enclose an irradiated bundle inside a sealed container at the bottom of the fuel bay. Various techniques were then used to enhance the release of water soluble fission products from defective fuel elements before circulating water samples from the immediate vicinity of an irradiated fuel bundle to an inspection station located at the top of the fuel bay. Any water samples with elevated levels of gamma activity were direct indications of a fuel cladding breach. The presence of defective fuel elements were then verified by visual inspection. The system performance test was performed in the Wolsong-1 nuclear power plant on March 2009.This paper describes the results of the wet sipping tests. (author)

  6. Fabrication of Core-Shell Structural SiO2@H3[PM12O40] Material and Its Catalytic Activity

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2014-01-01

    Full Text Available Through a natural tree grain template and sol-gel technology, the heterogeneous catalytic materials based on polyoxometalate compounds H3[PM12O40] encapsulating SiO2: SiO2@H3[PM12O40] (SiO2@PM12, M = W, Mo with core-shell structure had been prepared. The structure and morphology of the core-shell microspheres were characterized by the XRD, IR spectroscopy, UV-Vis absorbance, and SEM. These microsphere materials can be used as heterogeneous catalysts with high activity and stability for catalytic wet air oxidation of pollutant dyes safranine T (ST at room condition. The results show that the catalysts have excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 94% of color can be removed within 60 min. Under different cycling runs, it is shown that the catalysts are stable under such operating conditions and the leaching tests show negligible leaching effect owing to the lesser dissolution.

  7. Catalytic hydrotreating process

    Science.gov (United States)

    Karr, Jr., Clarence; McCaskill, Kenneth B.

    1978-01-01

    Carbonaceous liquids boiling above about 300.degree. C such as tars, petroleum residuals, shale oils and coal-derived liquids are catalytically hydrotreated by introducing the carbonaceous liquid into a reaction zone at a temperature in the range of 300.degree. to 450.degree. C and a pressure in the range of 300 to 4000 psig for effecting contact between the carbonaceous liquid and a catalytic transition metal sulfide in the reaction zone as a layer on a hydrogen permeable transition metal substrate and then introducing hydrogen into the reaction zone by diffusing the hydrogen through the substrate to effect the hydrogenation of the carbonaceous liquid in the presence of the catalytic sulfide layer.

  8. Squeezing wetting and nonwetting liquids.

    Science.gov (United States)

    Samoilov, V N; Persson, B N J

    2004-01-22

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n-->n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly wetting lubricant fluids are better boundary lubricants than the less wetting ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the wetting case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application.

  9. Wet flue gas desulfurization processes

    Directory of Open Access Journals (Sweden)

    Hayrunnisa Çavuşoğlu

    2013-04-01

    Full Text Available The wet flue gas desulfurization process is widely used for the treatment of exhaust gases in power stations. Due to its high level of effectiveness over the already available processes, it has also been the mostly preferred method by industry. Its high SO2 removal efficiency, wide applicability of absorption chemicals and the ease of the chemical process handling which does not require comprehensive konowledge are among the main advantages of this process. In this article, various wet flue gas desulfurization processes such as lime/limestone have beendiscussed.

  10. Robust non-wetting PTFE surfaces by femtosecond laser machining.

    Science.gov (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie

    2014-08-08

    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  11. Performance characterization of a hydrogen catalytic heater.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry Alan; Kanouff, Michael P.

    2010-04-01

    This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.

  12. Why do pigeon feathers repel water? Hydrophobicity of pennae, Cassie-Baxter wetting hypothesis and Cassie-Wenzel capillarity-induced wetting transition.

    Science.gov (United States)

    Bormashenko, Edward; Bormashenko, Yelena; Stein, Tamir; Whyman, Gene; Bormashenko, Ester

    2007-07-01

    Wetting of pigeon feathers has been studied. It was demonstrated that the Cassie-Baxter wetting regime is inherent for pigeon pennae. The water drop, supported by network formed by barbs and barbules, sits partially on air pockets. Small static apparent angle hysteresis justifies the Cassie-Baxter wetting hypothesis. A twofold structure of a feather favors large contact angles and provides its water repellency. Cassie-Wenzel transition has been observed under drop evaporation, when drop radius becomes small enough for capillarity-induced water penetration into the protrusions, formed by barbules.

  13. Dentinal tubules driven wetting of dentin: Cassie-Baxter modelling

    Science.gov (United States)

    Ramos, S. M. M.; Alderete, L.; Farge, P.

    2009-10-01

    We investigate the wetting properties of dentin surfaces submitted to a phosphoric acid etching followed by an air drying procedure, as in clinical situations of adhesive dentistry. The surface topography of the etched surfaces was characterized by AFM, and the wetting properties of water on these rough and heterogeneous surfaces were studied, by contact angle measurements. We showed that the contact angle increases with the acid exposure time and consequently with both surface roughness and the organic-mineral ratio of the dentin components. From the whole results, obtained on dentin and also on synthesized hydroxyapatites samples, we inferred a water contact angle of ˜ 133° on the dentinal tubule. These experimental results may be described by the Cassie-Baxter approach, and it is suggested that small air pockets could be formed inside the dentinal tubules.

  14. Inhibiting Wet Oxidation of Ammonia

    Science.gov (United States)

    Onisko, D. B. L.

    1985-01-01

    Simple modification of wet-oxidation process for treating organicwaste reduces loss of fixed nitrogen, potentially valuable byproduct of process. Addition of sufficient sulfuric acid to maintain reaction pH below 3 greatly reduces oxidation of ammonia to free nitrogen. No equipment modification required.

  15. Wet deposition in the northeastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J; Mohnen, V; Kadlecek, J

    1980-12-01

    Attempts are made to examine concentration and wet deposition of pollutant material at selected stations within the northeastern United States and to characterize as many events as possible with respect to air mass origin. Further attempts are made to develop a regional pattern for the deposition of dominant ion species. MAP3S (US Multistate Atmospheric Power Production Pollution Study) data for 1977 to 1979 are used to determine concentration and deposition on an event basis from which monthly, seasonal, annual, and cumulative averages are developed. The ARL-ATAD trajectory model is used to characterize individual events as to air mass origin. Case studies are examined to illustrate variability in the chemical composition of precipitation originating from distinctly different air mass trajectories. A difference in concentration of pollution-related ions in precipitation is noted between Midwest/Ohio Valley and Great Lakes/Canadian air mass origins for carefully selected cases. Total deposition of the major ions is examined in an effort to develop a regional pattern for deposition over a period of at least one year. For that purpose, total deposition is normalized to remove the variability in precipitation amounts for inter-station comparison. No marked gradient is noted in the normalized deposition totals within the northeast of the United States. The Adirondack region exhibited the lowest normalized ion deposition value, while the Illinois station showed the highest of the MAP3S network. The data analysis suggest that the acid rain phenomena covers the entire northeast. The concept of large scale mixing emerges to account for the lack of a significant gradient in the normalized deposition.

  16. Effects of carrier and Mn loading on supported manganese oxide catalysts for catalytic combustion of methane

    Institute of Scientific and Technical Information of China (English)

    Jinyan Hu; Wei Chu; Limin Shi

    2008-01-01

    Supported manganese oxide catalysts were prepared by incipient wetness impregnation method for methane cat-alytic combustion, and effects of the support (Al2O3, SiO2 and TiO2) and Mn loading were investigated. These catalysts were characterized with N2 adsorption, X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. Methane conversion varied in a large range depending on supports or Mn loading. Al2O3 supported 15% Mn cata-lyst exhibited better activity toward methane catalytic oxidation. The manganese state and oxygen species played an important role in the catalytic performance.

  17. Catalytic efficiency of designed catalytic proteins.

    Science.gov (United States)

    Korendovych, Ivan V; DeGrado, William F

    2014-08-01

    The de novo design of catalysts that mimic the affinity and specificity of natural enzymes remains one of the Holy Grails of chemistry. Despite decades of concerted effort we are still unable to design catalysts as efficient as enzymes. Here we critically evaluate approaches to (re)design of novel catalytic function in proteins using two test cases: Kemp elimination and ester hydrolysis. We show that the degree of success thus far has been modest when the rate enhancements seen for the designed proteins are compared with the rate enhancements by small molecule catalysts in solvents with properties similar to the active site. Nevertheless, there are reasons for optimism: the design methods are ever improving and the resulting catalyst can be efficiently improved using directed evolution.

  18. Catalytic Phosphination and Arsination

    Institute of Scientific and Technical Information of China (English)

    Kwong Fuk Yee; Chan Kin Shing

    2004-01-01

    The catalytic, user-friendly phosphination and arsination of aryl halides and triflates by triphenylphosphine and triphenylarsine using palladium catalysts have provided a facile synthesis of functionalized aryl phosphines and arsines in neutral media. Modification of the cynaoarisne yielded optically active N, As ligands which will be screened in various asymmetric catalysis.

  19. Andreas Acrivos Dissertation Award: Onset of Dynamic Wetting Failure - The Mechanics of High-Speed Fluid Displacement

    Science.gov (United States)

    Vandre, Eric

    2014-11-01

    Dynamic wetting is crucial to processes where a liquid displaces another fluid along a solid surface, such as the deposition of a coating liquid onto a moving substrate. Dynamic wetting fails when process speed exceeds some critical value, leading to incomplete fluid displacement and transient phenomena that impact a variety of applications, such as microfluidic devices, oil-recovery systems, and splashing droplets. Liquid coating processes are particularly sensitive to wetting failure, which can induce air entrainment and other catastrophic coating defects. Despite the industrial incentives for careful control of wetting behavior, the hydrodynamic factors that influence the transition to wetting failure remain poorly understood from empirical and theoretical perspectives. This work investigates the fundamentals of wetting failure in a variety of systems that are relevant to industrial coating flows. A hydrodynamic model is developed where an advancing fluid displaces a receding fluid along a smooth, moving substrate. Numerical solutions predict the onset of wetting failure at a critical substrate speed, which coincides with a turning point in the steady-state solution path for a given set of system parameters. Flow-field analysis reveals a physical mechanism where wetting failure results when capillary forces can no longer support the pressure gradients necessary to steadily displace the receding fluid. Novel experimental systems are used to measure the substrate speeds and meniscus shapes associated with the onset of air entrainment during wetting failure. Using high-speed visualization techniques, air entrainment is identified by the elongation of triangular air films with system-dependent size. Air films become unstable to thickness perturbations and ultimately rupture, leading to the entrainment of air bubbles. Meniscus confinement in a narrow gap between the substrate and a stationary plate is shown to delay air entrainment to higher speeds for a variety of

  20. Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System.

    Science.gov (United States)

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-10-26

    The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction.

  1. A Novel Cu-Mo/ZSM-5 Catalyst for NOx Catalytic Reduction with Ammonia

    Institute of Scientific and Technical Information of China (English)

    Zhe Li; Dang Li; Wei Huang; Kechang Xie

    2005-01-01

    The Cu-Mo/ZSM-5 catalysts with different Cu/Mo ratios were prepared by wet impregnation method, and their catalytic performance for selective catalytic reduction of NOx was studied. The results showed that Cu-Mo/ZSM-5 is a very effective catalyst for NOx catalytic reduction with ammonia, especially when Cu/Mo molar ratio is about 1.5. It not only exhibited the extremely high catalytic activity, but also showed good stability for O2. The bulk phase structure of Cu-Mo/ZSM-5 catalysts was determined by XRD technique, and the results indicated that there is a maximum dispersion for Cu species when Cu/Mo molar ratio is 1.5, and an interaction between Cu and Mo along with HZSM-5 may be present in Cu-Mo/ZSM-5, which may possibly result in a special structure favorable for the catalytic reduction of NOx over Cu-Mo/ZSM-5 catalyst.

  2. Methods for sulfate removal in liquid-phase catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C; Oyler, James

    2013-12-17

    Processing of wet biomass feedstock by liquid-phase catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a pre-treatment temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent removal of soluble sulfate contaminants, or combinations thereof. Processing further includes reacting the soluble sulfate contaminants with cations present in the feedstock material to yield a sulfate-containing precipitate and separating the inorganic precipitates and/or the sulfate-containing precipitates out of the wet feedstock. Having removed much of the inorganic wastes and the sulfate contaminants that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogenous catalyst for gasification.

  3. IDENTIFICATION AND RESPONSES TO POTENTIAL EFFECTS OF SCR AND WET SCRUBBERS ON SUBMICRON PARTICULATE EMISSIONS AND PLUME CHARACTERISTICS

    Science.gov (United States)

    Applications of selective catalytic reduction (SCR) systems and wet flue gas desulfurization (FGD) scrubbers on coal-fired boilers have led to substantial reductions in emissions of nitrogen oxides (NOX) and sulfur dioxide (SO2). However, observations of pilot- and full-scale tes...

  4. Trends in wetting behavior for Ag–CuO braze alloys on Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) at elevated temperatures in air

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Vineet V.; Meier, Alan; Darsell, Jens; Weil, K. Scott; Bowden, Mark

    2013-06-21

    Ba0.5Sr0.5Co0.80.2O(3-δ)(BSCF) is a potential oxygen separation membrane material for advanced coal based power plants. For this application, BSCF must be joined to a metal. In the current study, Ag-CuO, a reactive air brazing (RAB) alloy was evaluated for brazing BSCF. In-situ contact angle tests were performed on BSCF using Ag-CuO binary mixtures at 950 and 1000°C and the interfacial microstructures were evaluated. Wetting contact angles (θ< 90°) were obtained at short times at 950°C and the contact angles remained constant at 1000°C for 1, 2 and 8 mol% CuO contents. Microstructural analysis revealed the dissolution of copper oxide into the BSCF matrix to form copper-cobalt-oxygen rich dissolution products along the BSCF grain boundary. The formation of a thick interfacial reaction product layer and ridging at the sessile drop triple point indicate that the reaction kinetics are very rapid and that it will require careful process control to obtain the desired thin but continuous interfacial product layer.

  5. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  6. Wetting hysteresis induced by nanodefects.

    Science.gov (United States)

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-19

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles.

  7. Wetting of flexible fibre arrays.

    Science.gov (United States)

    Duprat, C; Protière, S; Beebe, A Y; Stone, H A

    2012-02-23

    Fibrous media are functional and versatile materials, as demonstrated by their ubiquity both in natural systems such as feathers and adhesive pads and in engineered systems from nanotextured surfaces to textile products, where they offer benefits in filtration, insulation, wetting and colouring. The elasticity and high aspect ratios of the fibres allow deformation under capillary forces, which cause mechanical damage, matting self-assembly or colour changes, with many industrial and ecological consequences. Attempts to understand these systems have mostly focused on the wetting of rigid fibres or on elastocapillary effects in planar geometries and on a fibre brush withdrawn from an infinite bath. Here we consider the frequently encountered case of a liquid drop deposited on a flexible fibre array and show that flexibility, fibre geometry and drop volume are the crucial parameters that are necessary to understand the various observations referred to above. We identify the conditions required for a drop to remain compact with minimal spreading or to cause a pair of elastic fibres to coalesce. We find that there is a critical volume of liquid, and, hence, a critical drop size, above which this coalescence does not occur. We also identify a drop size that maximizes liquid capture. For both wetting and deformation of the substrates, we present rules that are deduced from the geometric and material properties of the fibres and the volume of the drop. These ideas are applicable to a wide range of fibrous materials, as we illustrate with examples for feathers, beetle tarsi, sprays and microfabricated systems.

  8. 174 Reduction in Allergic Rhinitis Index by Decreasing Aero-Allergens and Malodor Causing Volatile Organic Compounds by Luna Air Purifiers Using Photo-Catalytic Oxidation (PCO) Technology

    OpenAIRE

    Ghosh, Nabarun; Aguaiza, Cristina; Guzman, Alicia; Chudasama, Jay; Bennert, Jeff; Das, A. B.

    2012-01-01

    Background The quality of the environment within buildings is a topic of major importance for public health. Breathing pure and clean air allows us to think more clearly, sleep more soundly, and stay healthier. Studies show that we receive 56% of our energy from the air we breathe, more than from water and food combined. On average we breathe 37 pounds of air a day. It has been established that the use of negative ions in a purification system is an effective means of eradicating aeroallergen...

  9. Underwater sustainability of the "Cassie" state of wetting.

    Science.gov (United States)

    Bobji, Musuvathi S; Kumar, S Vijay; Asthana, Ashish; Govardhan, Raghuraman N

    2009-10-20

    A rough hydrophobic surface when immersed in water can result in a "Cassie" state of wetting in which the water is in contact with both the solid surface and the entrapped air. The sustainability of the entrapped air on such surfaces is important for underwater applications such as reduction of flow resistance in microchannels and drag reduction of submerged bodies such as hydrofoils. We utilize an optical technique based on total internal reflection of light at the water-air interface to quantify the spatial distribution of trapped air on such a surface and its variation with immersion time. With this technique, we evaluate the sustainability of the Cassie state on hydrophobic surfaces with four different kinds of textures. The textures studied are regular arrays of pillars, ridges, and holes that were created in silicon by a wet etching technique, and also a texture of random craters that was obtained through electrodischarge machining of aluminum. These surfaces were rendered hydrophobic with a self-assembled layer of fluorooctyl trichlorosilane. Depending on the texture, the size and shape of the trapped air pockets were found to vary. However, irrespective of the texture, both the size and the number of air pockets were found to decrease with time gradually and eventually disappear, suggesting that the sustainability of the "Cassie" state is finite for all the microstructures studied. This is possibly due to diffusion of air from the trapped air pockets into the water. The time scale for disappearance of air pockets was found to depend on the kind of microstructure and the hydrostatic pressure at the water-air interface. For the surface with a regular array of pillars, the air pockets were found to be in the form of a thin layer perched on top of the pillars with a large lateral extent compared to the spacing between pillars. For other surfaces studied, the air pockets are smaller and are of the same order as the characteristic length scale of the texture

  10. 49 CFR 173.159 - Batteries, wet.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Batteries, wet. 173.159 Section 173.159... Batteries, wet. (a) Electric storage batteries, containing electrolyte acid or alkaline corrosive battery fluid (wet batteries), may not be packed with other materials except as provided in paragraphs (g)...

  11. European wet deposition maps based on measurements

    NARCIS (Netherlands)

    Leeuwen EP van; Erisman JW; Draaijers GPJ; Potma CJM; Pul WAJ van; LLO

    1995-01-01

    To date, wet deposition maps on a European scale have been based on long-range transport model results. For most components wet deposition maps based on measurements are only available on national scales. Wet deposition maps of acidifying components and base cations based on measurements are needed

  12. Catalytic Synthesis of Nitriles in Continuous Flow

    DEFF Research Database (Denmark)

    Nordvang, Emily Catherine

    , alternative path to acetonitrile from ethanol via the oxidative dehydrogenation of ethylamine. The catalytic activity and product ratios of the batch and continuous flow reactions are compared and the effect of reaction conditions on the reaction is investigated. The effects of ammonia in the reaction...... dehydrogenation of ethylamine and post-reaction purging.Chapter 4 outlines the application of RuO2/Al2O3 catalysts to the oxidative dehydrogenation of benzylamine in air, utilizing a new reaction setup. Again, batch and continuous flow reactions are compared and the effects of reaction conditions, ammonia...

  13. Soil aeration status in a lowland wet grassland

    Science.gov (United States)

    Barber, K. R.; Leeds-Harrison, P. B.; Lawson, C. S.; Gowing, D. J. G.

    2004-02-01

    The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0.01) between redox potential and water-table depth exists for data measured at 0.1 m depth, but no relationship could be found for data from 0.4 m depth.

  14. Catalytic Combustion Characteristics of H2/n-CaH10/Air Mixtures in Swiss-Roll Combustor%H2/n-C4H10/Air预混气在Swiss—roll燃烧器中的催化燃烧特性

    Institute of Scientific and Technical Information of China (English)

    杨帆; 钟北京

    2012-01-01

    In micro catalytic combustion, due to the competitive adsorption between fuel and oxygen molecular on the catalyst surface, the lower combustion limits are at the fuel rich condition. To enhance the utilization of fuel and enlarge the flammable range, hydrogen was added into the n-butane/air mixtures. Then catalytic combustion characteristics of H2/n-C4H10/air mixtures in Swiss-roll combustor were studied. Experimental results indicate that the addition of hydrogen and enlarge the flammable range of n-butane and the lower limits is fuel lean. Thus the utilization of fuel is high. The steady state combustion experiments show that the highest temperature of combustor is at fuel rich.%在微尺度催化燃烧中,由于燃料和氧气对于催化剂表面活性位的竞争,导致了可燃下限为富燃的情况。为了提高燃料利用率,拓宽可燃范围,本文在正丁烷/空气的混合气中加入一定量的氢气,在Swiss—roll燃烧器内研究了氯气/正丁烷/空气预混气的燃烧特性。结果表明,氢气能够有效拓宽正丁烷的可燃范围,可燃下限能够低于1,以贫燃的条件实现高燃料利用率。对于稳定燃烧温度的实验结果表明,燃烧器最高温度出现在富燃料一侧。

  15. Wet Work and Barrier Function.

    Science.gov (United States)

    Fartasch, Manigé

    2016-01-01

    Wet work defined as unprotected exposure to humid environments/water; high frequencies of hand washing procedures or prolonged glove occlusion is believed to cause irritant contact dermatitis in a variety of occupations. This review considers the recent studies on wet-work exposure and focuses on its influence on barrier function. There are different methods to study the effect of wet work on barrier function. On the one hand, occupational cohorts at risk can be monitored prospectively by skin bioengineering technology and clinical visual scoring systems; on the other hand, experimental test procedures with defined application of water, occlusion and detergents are performed in healthy volunteers. Both epidemiological studies and the results of experimental procedures are compared and discussed. A variety of epidemiological studies analyze occupational cohorts at risk. The measurement of transepidermal water loss, an indicator of the integrity of the epidermal barrier, and clinical inspection of the skin have shown that especially the frequencies of hand washing and water contact/contact to aqueous mixtures seem to be the main factors for the occurrence of barrier alterations. On the other hand, in a single cross-sectional study, prolonged glove wearing (e.g. occlusion for 6 h per shift in clean-room workers) without exposure to additional hazardous substances seemed not to affect the skin negatively. But regarding the effect of occlusion, there is experimental evidence that previously occluded skin challenged with sodium lauryl sulfate leads to an increased susceptibility to the irritant with an aggravation of the irritant reaction. These findings might have relevance for the real-life situation in so far as after occupational glove wearing, the skin is more susceptible to potential hazards to the skin even during leisure hours.

  16. Catalytic pyrolysis of olive mill wastewater sludge

    Science.gov (United States)

    Abdellaoui, Hamza

    From 2008 to 2013, an average of 2,821.4 kilotons/year of olive oil were produced around the world. The waste product of the olive mill industry consists of solid residue (pomace) and wastewater (OMW). Annually, around 30 million m3 of OMW are produced in the Mediterranean area, 700,000 m3 year?1 in Tunisia alone. OMW is an aqueous effluent characterized by an offensive smell and high organic matter content, including high molecular weight phenolic compounds and long-chain fatty acids. These compounds are highly toxic to micro-organisms and plants, which makes the OMW a serious threat to the environment if not managed properly. The OMW is disposed of in open air evaporation ponds. After evaporation of most of the water, OMWS is left in the bottom of the ponds. In this thesis, the effort has been made to evaluate the catalytic pyrolysis process as a technology to valorize the OMWS. The first section of this research showed that 41.12 wt. % of the OMWS is mostly lipids, which are a good source of energy. The second section proved that catalytic pyrolysis of the OMWS over red mud and HZSM-5 can produce green diesel, and 450 °C is the optimal reaction temperature to maximize the organic yields. The last section revealed that the HSF was behind the good fuel-like properties of the OMWS catalytic oils, whereas the SR hindered the bio-oil yields and quality.

  17. Single-metalloprotein wet biotransistor

    Science.gov (United States)

    Alessandrini, Andrea; Salerno, Marco; Frabboni, Stefano; Facci, Paolo

    2005-03-01

    Metalloproteins are redox molecules naturally shuttling electrons with high efficiency between molecular partners. As such, they are candidates of choice for bioelectronics. In this work, we have used bacterial metalloprotein azurin, hosted in a nanometer gap between two electrically biased gold electrodes, to demonstrate an electrochemically gated single-molecule transistor operating in an aqueous environment. Gold-chemisorbed azurin shows peaks in tunneling current upon changing electrode potential and a related variation in tunneling barrier transparency which can be exploited to switch an electron current through it. These results suggest the wet approach to molecular electronics as a viable method for exploiting electron transfer of highly specialized biomolecules.

  18. Wetting properties of nanostructured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Canut, S. [Laboratoire de Physique de la Matiere Condensee et Nanostructures (UMR CNRS 5586), Universite Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)]. E-mail: ramos@lpmcn.univ-lyon1.fr

    2006-04-15

    Swift heavy ion irradiation is a powerful tool to tailor surfaces under controlled conditions at a nanometric scale. The growing importance of nanostructured surfaces for a wide variety of applications and fundamental investigations is now well established. In this paper I will mainly discuss the interest of such surfaces for investigations concerning solid-liquid interfaces. The role played by topographical defects on wetting properties of solid surfaces, and both the dissipative and the confinement effects on the interface will be demonstrated by simple examples.

  19. Full scale calcium bromide injection with subsequent mercury oxidation and removal within wet flue gas desulphurization system: Experience at a 700 MW coal-fired power facility

    Science.gov (United States)

    Berry, Mark Simpson

    The Environmental Protection Agency promulgated the Mercury and Air Toxics Standards rule, which requires that existing power plants reduce mercury emissions to meet an emission rate of 1.2 lb/TBtu on a 30-day rolling average and that new plants meet a 0.0002 lb/GWHr emission rate. This translates to mercury removals greater than 90% for existing units and greater than 99% for new units. Current state-of-the-art technology for the control of mercury emissions uses activated carbon injected upstream of a fabric filter, a costly proposition. For example, a fabric filter, if not already available, would require a 200M capital investment for a 700 MW size unit. A lower-cost option involves the injection of activated carbon into an existing cold-side electrostatic precipitator. Both options would incur the cost of activated carbon, upwards of 3M per year. The combination of selective catalytic reduction (SCR) reactors and wet flue gas desulphurization (wet FGD) systems have demonstrated the ability to substantially reduce mercury emissions, especially at units that burn coals containing sufficient halogens. Halogens are necessary for transforming elemental mercury to oxidized mercury, which is water-soluble. Plants burning halogen-deficient coals such as Power River Basin (PRB) coals currently have no alternative but to install activated carbon-based approaches to control mercury emissions. This research consisted of investigating calcium bromide addition onto PRB coal as a method of increasing flue gas halogen concentration. The treated coal was combusted in a 700 MW boiler and the subsequent treated flue gas was introduced into a wet FGD. Short-term parametric and an 83-day longer-term tests were completed to determine the ability of calcium bromine to oxidize mercury and to study the removal of the mercury in a wet FGD. The research goal was to show that calcium bromine addition to PRB coal was a viable approach for meeting the Mercury and Air Toxics Standards rule

  20. Microwave assisted wet oxidation of p-nitrophenol

    Institute of Scientific and Technical Information of China (English)

    BO; Longli; CHEN; Shuo; QUAN; Xie; LIU; Xitao; ZHAO; Huimin

    2005-01-01

    Aqueous solution of p-nitrophenol (PNP) was treated continuously by microwave assisted wet oxidation while flowing through a granular activated carbon (GAC) fixed bed. PNP was pre-adsorbed onto GAC prior to being put into the reactor so as to prevent PNP adsorption on GAC during microwave irradiation. PNP solutions with different initial concentration (218.6 mg/L and 1200 mg/L) were treated under conditions of microwave power 500 W, liquid flow 6.4 mL/min and air flow 40 mL/min or 60 mL/min. The results indicated that the removal of PNP was higher than 90% and more than 65% PNP was mineralized. Phenol, nitrobenzene, hydroquinone and benzoquinone occurred as course products during the operation process, which were degraded further. The biodegradability of the outflow was improved greatly by microwave assisted wet oxidation.

  1. Olefin metathesis in air

    Directory of Open Access Journals (Sweden)

    Lorenzo Piola

    2015-10-01

    Full Text Available Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  2. Olefin metathesis in air

    Science.gov (United States)

    Piola, Lorenzo; Nahra, Fady

    2015-01-01

    Summary Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance. PMID:26664625

  3. Mold management of wetted carpet.

    Science.gov (United States)

    Ong, Kee-Hean; Dixit, Anupma; Lewis, Roger D; MacDonald Perkins, Maureen; Backer, Denis; Condoor, Sridhar; Emo, Brett; Yang, Mingan

    2014-01-01

    This study evaluated the growth and removal of fungi on wetted carpet using newly designed technologies that rely on physical principles of steam, heat, and fluid flow. Sixty samples of carpet were embedded with heat-treated house dust, followed by embedding, wearing with a hexapod, and wetting. Samples were inoculated using a liquid suspension of Cladosporium sphaerospermum prior to placement over a water-saturated foam pad. Incubation times were 24 hr, 7 days, and 30 days. Cleaning was performed using three methods; high-flow hot water extraction, hot water and detergent, and steam. Fungal loading increased from approximately 1500 colony forming units per area (CFU/cm(2)) in 24 hr to a maximum of approximately 10,200 CFU/cm(2) after 7 days with a slight decline to 9700 CFU/cm(2) after 30 days incubation. Statistically significant differences were found among all three methods for removal of fungi for all three time periods (p Steam-vapor was significantly better than the alternative methods (p steam has a consistent fungal removal rate, the detergent and high-flow, hot water methods decline in efficiency with increasing incubation time.

  4. Elucidating the mysteries of wetting.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Edmund Blackburn, III (,; ); Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.

    2005-11-01

    Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial wetting. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent wetting allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.

  5. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  6. Wetting and Non-Wetting Models of Black Carbon Activation

    Science.gov (United States)

    Henson, B. F.; Laura, S.

    2006-12-01

    We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a

  7. Hydrolysis of Miscanthus for bioethanol production using dilute acid presoaking combined with wet explosion pre-treatment and enzymatic treatment

    DEFF Research Database (Denmark)

    Sørensen, Annette; Teller, Philip Johan; Hilstrøm, Troels

    2008-01-01

    xylose prior to wet explosion. The acid presoaking extracted 63.2% xylose and 5.2% glucose. Direct enzymatic hydrolysis of the presoaked biomass was found to give only low sugar yields of 24-26% glucose. Wet explosion is a pre-treatment method that combines wet-oxidation and steam explosion. The effect......Miscanthus is a high yielding bioenergy crop. In this study we used acid presoaking, wet explosion, and enzymatic hydrolysis to evaluate the combination of the different pre-treatment methods for bioethanol production with Miscanthus. Acid presoaking is primarily carried out in order to remove...... of wet explosion on non-presoaked and presoaked Miscanthus was investigated using both atmospheric air and hydrogen peroxide as the oxidizing agent. All wet explosion pre-treatments showed to have a disrupting effect on the lignocellulosic biomass, making the sugars accessible for enzymatic hydrolysis...

  8. Humidifiers: Air Moisture Eases Skin, Breathing Symptoms

    Science.gov (United States)

    ... mist with a rotating disk. Evaporators use a fan to blow air through a wet wick, filter ... guidelines recommended by the manufacturer. These tips for portable humidifiers also can help: Use distilled or demineralized ...

  9. Fabrication of catalytic electrodes for molten carbonate fuel cells

    Science.gov (United States)

    Smith, James L.

    1988-01-01

    A porous layer of catalyst material suitable for use as an electrode in a molten carbonate fuel cell includes elongated pores substantially extending across the layer thickness. The catalyst layer is prepared by depositing particulate catalyst material into polymeric flocking on a substrate surface by a procedure such as tape casting. The loaded substrate is heated in a series of steps with rising temperatures to set the tape, thermally decompose the substrate with flocking and sinter bond the catalyst particles into a porous catalytic layer with elongated pores across its thickness. Employed as an electrode, the elongated pores provide distribution of reactant gas into contact with catalyst particles wetted by molten electrolyte.

  10. Reactive wetting properties of TiO2 nanoparticles predicted by ab initio molecular dynamics simulations

    Science.gov (United States)

    Brandt, Erik G.; Agosta, Lorenzo; Lyubartsev, Alexander P.

    2016-07-01

    Small-sized wet TiO2 nanoparticles have been investigated by ab initio molecular dynamics simulations. Chemical and physical adsorption of water on the TiO2-water interface was studied as a function of water content, ranging from dry nanoparticles to wet nanoparticles with monolayer coverage of water. The surface reactivity was shown to be a concave function of water content and driven by surface defects. The local coordination number at the defect was identified as the key factor to decide whether water adsorption proceeds through dissociation or physisorption on the surface. A consistent picture of TiO2 nanoparticle wetting at the microscopic level emerges, which corroborates existing experimental data and gives further insight into the molecular mechanisms behind nanoparticle wetting. These calculations will facilitate the engineering of metal oxide nanoparticles with a controlled catalytic water activity.Small-sized wet TiO2 nanoparticles have been investigated by ab initio molecular dynamics simulations. Chemical and physical adsorption of water on the TiO2-water interface was studied as a function of water content, ranging from dry nanoparticles to wet nanoparticles with monolayer coverage of water. The surface reactivity was shown to be a concave function of water content and driven by surface defects. The local coordination number at the defect was identified as the key factor to decide whether water adsorption proceeds through dissociation or physisorption on the surface. A consistent picture of TiO2 nanoparticle wetting at the microscopic level emerges, which corroborates existing experimental data and gives further insight into the molecular mechanisms behind nanoparticle wetting. These calculations will facilitate the engineering of metal oxide nanoparticles with a controlled catalytic water activity. Electronic supplementary information (ESI) available: Simulation data on equilibration of energies and structures (root-mean-square-deviations and

  11. Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler.

    Science.gov (United States)

    Wu, Chengli; Cao, Yan; Dong, Zhongbing; Cheng, Chinmin; Li, Hanxu; Pan, Weiping

    2010-01-01

    Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.

  12. Simulation on Toxic Gases in Vehicle Exhaust Equipped with Modified Catalytic Converter : A Review

    Directory of Open Access Journals (Sweden)

    Leman A.M.

    2016-01-01

    Full Text Available Air pollution and global warming is a major issue nowadays. One of the main contributors to be the emission of harmful gases produced by vehicle exhausts lines. The harmful gases like NOx, CO, unburned HC and particulate matter increases the global warming, so catalytic converter plays a vital role in reducing harmful gases. Catalytic converters are used on most vehicles on the road today. This research deals with the gas emission flow in the catalytic converter involving the heat transfer, velocity flow, back pressure and others chemical reaction in the modified catalytic converter by using FeCrAl as a substrate that is treated using the ultrasonic bath and electroplating techniques. The objective of this study is to obtain a quantitative description of the gas emission in the catalytic converter system of automobile exhaust gas using ANSYS Software. The description of the gas emission in the catalytic converter system of automobile exhaust gas using ANSYS Software was simulated in this research in order to provide better efficiency and ease the reusability of the catalytic converter by comparing experimental data with software analysing data. The result will be expected to demonstrate a good approximation of gas emission in the modified catalytic converter simulation data compared to experimental data in order to verify the effectiveness of modified catalytic converter. Therefore studies on simulation of flow through the modified catalytic converter are very important to increase the accuracy of the obtained emission result.

  13. HYDROGEN TRANSFER IN CATALYTIC CRACKING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hydrogen transfer is an important secondary reaction of catalytic cracking reactions, which affects product yield distribution and product quality. It is an exothermic reaction with low activation energy around 43.3 kJ/mol. Catalyst properties and operation parameters in catalytic cracking greatly influence the hydrogen transfer reaction. Satisfactory results are expected through careful selection of proper catalysts and operation conditions.

  14. Optimized wet clutches:simulation and tribotesting

    OpenAIRE

    2006-01-01

    Wet clutches are used in a variety of different machinery. Wet clutches and brakes are frequently used to distribute torque in vehicle drive-trains. The clutches can be located in e.g. automatic transmissions or limited slip differentials. Their frictional behavior is of great importance for the overall vehicle behavior and has to be thoroughly investigated when designing new wet clutch applications. Frictional behavior is normally investigated in test rigs where complete friction discs are t...

  15. Externally Wetted Ionic Liquid Thruster

    Science.gov (United States)

    Lozano, P.; Martinez-Sanchez, M.; Lopez-Urdiales, J. M.

    2004-10-01

    This paper presents initial developments of an electric propulsion system based on ionic liquid ion sources (ILIS). Propellants are ionic liquids, which are organic salts with two important characteristics; they remain in the liquid state at room temperature and have negligible vapor pressure, thus allowing their use in vacuum. The working principles of ILIS are similar to those of liquid metal ion sources (LMIS), in which a Taylor cone is electrostatically formed at the tip of an externally wetted needle while ions are emitted directly from its apex. ILIS have the advantage of being able to produce negative ions that have similar masses than their positive counterparts with similar current levels. This opens up the possibility of achieving plume electrical neutrality without electron emitters. The possible multiplexing of these emitters is discussed in terms of achievable thrust density for applications other than micro-propulsion.

  16. Wet granular walkers and climbers

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Z S; Steinberger, A; Seemann, R; Herminghaus, S, E-mail: audrey.steinberger@ens-lyon.fr [Max Planck Institute for Dynamics and Self-Organization, Bunsenstrasse 10, D-37073 Goettingen (Germany)

    2011-05-15

    Mechanisms of locomotion in microscopic systems are of great interest not only for technological applications but also for the sake of understanding, and potentially harnessing, processes far from thermal equilibrium. Downscaling is a particular challenge and has led to a number of interesting concepts, including thermal ratchet systems and asymmetric swimmers. Here we present a granular ratchet system employing a particularly robust mechanism that can be implemented in various settings. The system consists of wetted spheres of different sizes that adhere to each other, and are subject to a symmetric oscillating, zero average external force field. An inherent asymmetry in the mutual force network leads to force rectification and hence to locomotion. We present a simple model that accounts for the observed behaviour, underscores its robustness and suggests a potential scalability of the concept.

  17. The Wet-Dog Shake

    CERN Document Server

    Dickerson, Andrew; Bauman, Jay; Chang, Young-Hui; Hu, David

    2010-01-01

    The drying of wet fur is a critical to mammalian heat regulation. In this fluid dynamics video, we show a sequence of films demonstrating how hirsute animals to rapidly oscillate their bodies to shed water droplets, nature's analogy to the spin cycle of a washing machine. High-speed videography and fur-particle tracking is employed to determine the angular position of the animal's shoulder skin as a function of time. X-ray cinematography is used to track the motion of the skeleton. We determine conditions for drop ejection by considering the balance of surface tension and centripetal forces on drops adhering to the animal. Particular attention is paid to rationalizing the relationship between animal size and oscillation frequency required to self-dry.

  18. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  19. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  20. Catalytic mechanism of cationic red GTL at wide pH using the Mo-Zn-Al-O nanocatalyst under room conditions.

    Science.gov (United States)

    Xu, Yin; Li, Xiaoyi; Sun, Dezhi

    2014-09-01

    Catalytic mechanism of cationic red GTL at wide pH using the Mo-Zn-Al-O nanocatalyst under room conditions was investigated. The experimental results indicate that initial pH significantly affected the removal of cationic red GTL, the removal of COD, the pH value and residual oxygen in the reaction. In the range of pH value from 4 to 10, decolorization of cationic red GTL was almost above 90%. COD removal efficiency was enhanced with the decrease of pH in CWAO process and 79% of the COD was removed at pH 4.0, whereas only 57% COD removal was observed at pH 10.0. The terminal pH was in the range of 5.0-6.0 and the highest terminal concentrations of aqueous oxygen with 5.5 mg/L were observed at pH = 4.0. The radical inhibition experiments also carried out and the generation of *OH and 1O2 in catalytic wet air oxidation process were detected. It was found that the degradation of cationic red GTL occurs mainly via oxidation by 1O2 radical generated by Mo-Zn-Al-O nanocatalyst under acid conditions and *OH radical under alkaline conditions.

  1. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  2. Modified Wenzel and Cassie equations for wetting on rough surfaces

    CERN Document Server

    Xu, Xianmin

    2016-01-01

    We study a stationary wetting problem on rough and inhomogeneous solid surfaces. We derive a new formula for the apparent contact angle by asymptotic two-scale homogenization method. The formula reduces to a modified Wenzel equation for geometrically rough surfaces and a modified Cassie equation for chemically inhomogeneous surfaces. Unlike the classical Wenzel and Cassie equations, the modified equations correspond to local minimizers of the total interface energy in the solid-liquid-air system, so that they are consistent with experimental observations. The homogenization results are proved rigorously by a variational method.

  3. Removal efficiencies of PCDDs/PCDFs by air pollution control devices in municipal solid waste incinerators.

    Science.gov (United States)

    Kim, S C; Jeon, S H; Jung, I R; Kim, K H; Kwon, M H; Kim, J H; Yi, J H; Kim, S J; You, J C; Jung, D H

    2001-01-01

    Removal efficiencies of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) by air pollution control devices (APCDs) in the commercial-scale municipal solid waste (MSW) incinerators with a capacity of above 200 ton/day were evaluated. The removal efficiencies of PCDDs/PCDFs were up to 95% when the activated carbon (AC) was injected in front of electrostatic precipitator (EP). Spray dryer absorber/bag filter (SDA/BF) had high removal efficiency (99%)) of PCDDs/PCDFs when a mixture of lime and AC was sprayed into the SDA. When the AC was not added in scrubbing solution, the whole congeners of PCDDs/PCDFs were enriched in the wet scrubber (WS) with negative removal efficiencies of -25% to -5731%. Discharge of PCDDs/PCDFs was decreased with increasing the proportions of AC added in scrubbing solution. Selective catalytic reduction (SCR) system had the removal efficiencies of up to 93% during the test operation.

  4. Unsteady catalytic processes and sorption-catalytic technologies

    Energy Technology Data Exchange (ETDEWEB)

    Zagoruiko, A N [G.K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-07-31

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  5. Preliminary evaluation of wet/dry cooling concepts for power plants

    Energy Technology Data Exchange (ETDEWEB)

    Loscutoff, W.V.

    1976-01-01

    A large number of possible combinations of air and water flow arrangements and sequences are analyzed in the study presented. First, the heat transfer effectiveness of each was established, based on the assumption of constant size of the dry and wet subsystems. Next, the water consumption required to augment a constant-sized dry subsystem for maintaining cooling capability at a dry bulb temperature in excess of the design conditions for the dry system alone was determined. Results are presented which point to a number of significant conclusions relative to the preferred arrangement of the dry and wet subsystems in dry/wet heat rejection systems. The conclusions are based on the assumption that the wet cooling is used only to augment the dry cooling capability and that minimum consumption of water is a primary consideration.

  6. Time-varying wetting behavior on copper wafer treated by wet-etching

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Sheng-Hung; Wu, Chuan-Chang [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China); Wu, Hsing-Chen [Advanced Technology Materials Inc, Hsinchu 310, Taiwan, ROC (China); Cheng, Shao-Liang [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China); Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Tsao, Heng-Kwong, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China)

    2015-06-30

    Graphical abstract: - Highlights: • A thin oxide layer always remains on surfaces of Cu wafers after aqueous etching. • A pure Cu wafer is obtained by the HAc treatment and the water CA is about 45°. • The oxide layer and CA grow with time after the Cu wafer is exposed to air. • Surface roughness and hydrophobicity of pure Cu wafers grow rapidly in vacuum. - Abstract: The wet cleaning process in semiconductor fabrication often involves the immersion of the copper wafer into etching solutions and thereby its surface properties are significantly altered. The wetting behavior of a copper film deposited on silicon wafer is investigated after a short dip in various etching solutions. The etchants include glacial acetic acid and dilute solutions of nitric acid, hydrofluoric acid, and tetramethylammonium hydroxide. It was found that in most cases a thin oxide layer still remains on the surface of as-received Cu wafers when they are subject to etching treatments. However, a pure Cu wafer can be obtained by the glacial acetic acid treatment and its water contact angle (CA) is about 45°. As the pure Cu wafer is placed in the ambient condition, the oxide thickness grows rapidly to the range of 10–20 Å within 3 h and the CA on the hydrophilic surface also rises. In the vacuum, it is surprising to find that the CA and surface roughness of the pure Cu wafer can grow significantly. These interesting results may be attributed to the rearrangement of surface Cu atoms to reduce the surface free energy.

  7. Fast and Slow Wetting Dynamics on nanostructured surfaces

    Science.gov (United States)

    Nandyala, Dhiraj; Rahmani, Amir; Cubaud, Thomas; Colosqui, Carlos

    2015-11-01

    This talk will present force-displacement and spontaneous drop spreading measurements on diverse nanostructured surfaces (e.g., mesoporous titania thin films, nanoscale pillared structures, on silica or glass substrates). Experimental measurements are performed for water-air and water-oil systems. The dynamics of wetting observed in these experiments can present remarkable crossovers from fast to slow or arrested dynamics. The emergence of a slow wetting regime is attributed to a multiplicity of metastable equilibrium states induced by nanoscale surface features. The crossover point can be dramatically advanced or delayed by adjusting specific physical parameters (e.g., viscosity of the wetting phases) and geometric properties of the surface nanostructure (e.g., nanopore/pillar radius and separation). Controlling the crossover point to arrested dynamics can effectively modify the degree of contact angle hysteresis and magnitude of liquid adhesion forces observed on surfaces of different materials. This work is supported by a SEED Award from The Office of Brookhaven National Laboratory Affairs at Stony Brook University.

  8. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  9. Curvature controlled wetting in two dimensions

    DEFF Research Database (Denmark)

    Gil, Tamir; Mikheev, Lev V.

    1995-01-01

    . As the radius of the substrate r0→∞, the leading effect of the curvature is adding the Laplace pressure ΠL∝r0-1 to the pressure balance in the film. At temperatures and pressures under which the wetting is complete in planar geometry, Laplace pressure suppresses divergence of the mean thickness of the wetting...

  10. 7 CFR 29.2570 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2570 Section 29.2570 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2570 Wet (W). Any sound tobacco...

  11. 7 CFR 29.3567 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3567 Section 29.3567 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3567 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is...

  12. 7 CFR 29.2316 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2316 Section 29.2316 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2316 Wet...

  13. 7 CFR 29.3077 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3077 Section 29.3077 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Wet (W). Any sound tobacco containing excessive moisture to the extent that it is in an unsafe...

  14. 7 CFR 29.1083 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.1083 Section 29.1083 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1083 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is...

  15. Catalytic combustor for integrated gasification combined cycle power plant

    Science.gov (United States)

    Bachovchin, Dennis M.; Lippert, Thomas E.

    2008-12-16

    A gasification power plant 10 includes a compressor 32 producing a compressed air flow 36, an air separation unit 22 producing a nitrogen flow 44, a gasifier 14 producing a primary fuel flow 28 and a secondary fuel source 60 providing a secondary fuel flow 62 The plant also includes a catalytic combustor 12 combining the nitrogen flow and a combustor portion 38 of the compressed air flow to form a diluted air flow 39 and combining at least one of the primary fuel flow and secondary fuel flow and a mixer portion 78 of the diluted air flow to produce a combustible mixture 80. A catalytic element 64 of the combustor 12 separately receives the combustible mixture and a backside cooling portion 84 of the diluted air flow and allows the mixture and the heated flow to produce a hot combustion gas 46 provided to a turbine 48. When fueled with the secondary fuel flow, nitrogen is not combined with the combustor portion.

  16. Laboratory Evaluation of Electrostatic Spray Wet Scrubber to Control Particulate Matter Emissions from Poultry Facilities

    Science.gov (United States)

    Particulate matter (PM) is a major air pollutant emitted from animal production and has significant impacts on health and the environment. Abatement of PM emissions is imperative and effective PM control technologies are strongly needed. In this work, an electrostatic spray wet scrubber (ESWS) techn...

  17. Catalytic combustion over high temperature stable metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Berg, M. [TPS Termiska Processer AB, Nykoeping (Sweden)

    1996-12-31

    This thesis presents a study of the catalytic effects of two interesting high temperature stable metal oxides - magnesium oxide and manganese substituted barium hexa-aluminate (BMA) - both of which can be used in the development of new monolithic catalysts for such applications. In the first part of the thesis, the development of catalytic combustion for gas turbine applications is reviewed, with special attention to alternative fuels such as low-BTU gas, e.g. produced in an air blown gasifier. When catalytic combustion is applied for such a fuel, the primary advantage is the possibility of decreasing the conversion of fuel nitrogen to NO{sub x}, and achieving flame stability. In the experimental work, MgO was shown to have a significant activity for the catalytic combustion of methane, lowering the temperature needed to achieve 10 percent conversion by 270 deg C compared with homogeneous combustion.The reaction kinetics for methane combustion over MgO was also studied. It was shown that the heterogeneous catalytic reactions were dominant but that the catalytically initiated homogeneous gas phase reactions were also important, specially at high temperatures. MgO and BMA were compared. The latter showed a higher catalytic activity, even when the differences in activity decreased with increasing calcination temperature. For BMA, CO{sub 2} was the only product detected, but for MgO significant amounts of CO and C{sub 2}-hydrocarbons were formed. BMA needed a much lower temperature to achieve total conversion of other fuels, e.g. CO and hydrogen, compared to the temperature for total conversion of methane. This shows that BMA-like catalysts are interesting for combustion of fuel mixtures with high CO and H{sub 2} content, e.g. gas produced from gasification of biomass. 74 refs

  18. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  19. Catalytic gasification of biomass

    Science.gov (United States)

    Robertus, R. J.; Mudge, L. K.; Sealock, L. J., Jr.; Mitchell, D. H.; Weber, S. L.

    1981-12-01

    Methane and methanol synthesis gas can be produced by steam gasification of biomass in the presence of appropriate catalysts. This concept is to use catalysts in a fluidized bed reactor which is heated indirectly. The objective is to determine the technical and economic feasibility of the concept. Technically the concept has been demonstrated on a 50 lb per hr scale. Potential advantages over conventional processes include: no oxygen plant is needed, little tar is produced so gas and water treatment are simplified, and yields and efficiencies are greater than obtained by conventional gasification. Economic studies for a plant processing 2000 T/per day dry wood show that the cost of methanol from wood by catalytic gasification is competitive with the current price of methanol. Similar studies show the cost of methane from wood is competitive with projected future costs of synthetic natural gas. When the plant capacity is decreased to 200 T per day dry wood, neither product is very attractive in today's market.

  20. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  1. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  2. Complex Wall Boundary Conditions for Modeling Combustion in Catalytic Channels

    Science.gov (United States)

    Zhu, Huayang; Jackson, Gregory

    2000-11-01

    Monolith catalytic reactors for exothermic oxidation are being used in automobile exhaust clean-up and ultra-low emissions combustion systems. The reactors present a unique coupling between mass, heat, and momentum transport in a channel flow configuration. The use of porous catalytic coatings along the channel wall presents a complex boundary condition when modeled with the two-dimensional channel flow. This current work presents a 2-D transient model for predicting the performance of catalytic combustion systems for methane oxidation on Pd catalysts. The model solves the 2-D compressible transport equations for momentum, species, and energy, which are solved with a porous washcoat model for the wall boundary conditions. A time-splitting algorithm is used to separate the stiff chemical reactions from the convective/diffusive equations for the channel flow. A detailed surface chemistry mechanism is incorporated for the catalytic wall model and is used to predict transient ignition and steady-state conversion of CH4-air flows in the catalytic reactor.

  3. NiMo/Al{sub 2}O{sub 3}-MgO (x) catalysts. The effect of the prolonged exposure to ambient air on the textural and catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Solis, D.; Klimova, T.; Ramirez, J. [Departamento de Ingenieria Quimica, Facultad de Quimica, UNAM. Cd. Universitaria,, Coyoacan (Mexico); Cortez, T. [Instituto Mexicano del Petroleo, Tratamiento de Crudo Maya, Eje central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, C.P. (Mexico)

    2004-11-24

    In the search to obtain stable catalysts for selective elimination of sulfur from gasoline, maintaining octane number, NiMo catalysts supported on Al-Mg mixed oxides were prepared by the sol-gel method and evaluated after 6-month storage in contact with ambient air, the results were compared with the freshly prepared samples. Both, freshly prepared and aged samples were characterized by nitrogen physisorption measurements (S{sub BET}), infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD) and high-resolution electron microscopy (HREM), they were tested in the thiophene hydrodesulfurization reaction.The results indicate that the incorporation of small amounts of magnesia (5mol%) into the alumina support, leads to the catalyst with low hydrogenation function and appropriate stability during prolonged contact with ambient conditions.

  4. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    洪文明; 王梓坤

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brown-ian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d = 3.

  5. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brownian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d=3.

  6. Structured materials for catalytic and sensing applications

    Science.gov (United States)

    Hokenek, Selma

    The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts is, therefore, an attractive option. Similarly, the optical properties of nanoscale materials used for sensing must be attuned to their application. By adjusting the shape and composition of nanoparticles used in such applications, very fine changes can be made to the frequency of light that they absorb most efficiently. The design, synthesis, and characterization of (i) size controlled monometallic palladium nanoparticles for catalytic applications, (ii) nickel-palladium bimetallic nanoparticles and (iii) silver-palladium nanoparticles with applications in drug detection and biosensing through surface plasmon resonance, respectively, will be discussed. The composition, size, and shape of the nanoparticles formed were controlled through the use of wet chemistry techniques. After synthesis, the nanoparticles were analyzed using physical and chemical characterization techniques such as X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy- Energy-Dispersive Spectrometry (STEM-EDX). The Pd and Ni-Pd nanoparticles were then supported on silica for catalytic testing using mass spectrometry. The optical properties of the Ag-Pd nanoparticles in suspension were further investigated using ultraviolet-visible spectrometry (UV-Vis). Monometallic palladium particles have

  7. 40 CFR 63.5870 - How do I calculate annual uncontrolled and controlled organic HAP emissions from my wet-out area...

    Science.gov (United States)

    2010-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Reinforced Plastic... and controlled organic HAP emissions from my wet-out area(s) and from my oven(s) for...

  8. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  9. Catalytic glycerol steam reforming for hydrogen production

    Science.gov (United States)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  10. Wet chemical method for synthesizing 3D graphene/gold nanocomposite: catalytic reduction of methylene blue

    Science.gov (United States)

    Xie, Jiliang; Yang, Xujie; Xu, Xingyou

    2017-04-01

    In this paper, a simple and environmentally-friendly approach was reported to synthesize a novel 3D composite of graphene/gold nanoparticles (3DG/Au NPs) in one step. A 3D interlaced framework of graphene, which exhibited hierarchically porous structures, generated directly through the distinct driving force during the hydrothermal growth. Meanwhile, Au NPs with high dispersity, which displayed tunable morphologies, were immobilized on the framework, where the as-prepared graphene was employed as the endogenous reducing agent. Compared with AuNPs, the obtained 3DG/Au NPs exhibited remarkably convenient recyclability and high activity for the reduction of methylene blue which is a kind of organic dye.

  11. Catalytic Hydrothermal Conversion of Wet Biomass Feedstocks and Upgrading – Process Design and Optimization

    DEFF Research Database (Denmark)

    Hoffmann, Jessica; Toor, Saqib; Rosendahl, Lasse

    Liquid biofuels will play a major role for a more sustainable energy system of the future. The CatLiq® process is a 2nd generation biomass conversion process that is based on hydrothermal liquefaction. Hydrothermal liquefaction offers a very efficient and feedstock flexible way of converting...... biomass to bio-oil. Bio-oils from hydrothermal liquefaction are characterised by their high feedstock flexibility. Upgrading of complete bio-oils derived from hydrothermal conversion has not yet been extensively studied. Purpose of this work is to reduce the oxygen content of the bio-oil to improve...

  12. Forced wetting of a reactive surface.

    Science.gov (United States)

    Blake, T D

    2012-11-01

    The dynamic wetting of water on gelatin-coated poly(ethylene terephthalate) (GC-PET) has been investigated by forced wetting over a wide speed range and compared with earlier data obtained with unmodified PET. The results were analysed according to the molecular-kinetic theory of dynamic wetting (MKT). Both substrates show complex behaviour, with separate low- and high-speed modes. For the GC-PET, this is attributed to a rapid change in the wettability of the substrate on contact with water, specifically a surface molecular transformation from hydrophobic to hydrophilic. This results in a smooth wetting transition from one mode to the other. For the PET, the bimodal behaviour is attributed to surface heterogeneity, with the low-speed dynamics dominated by interactions with polar sites on the substrate that become masked at higher speeds. In this case, the transition is discontinuous. The study has general ramifications for the investigation of any wetting processes in which a physicochemical transformation takes place at the solid surface on contact with the liquid. In particular, it shows how forced wetting, combined with the MKT, can reveal subtle details of the processes involved. It is unlikely that similar insight could be gained from spontaneous wetting studies, such as spreading drops.

  13. Catalytic Conversion of Biofuels

    DEFF Research Database (Denmark)

    Jørgensen, Betina

    oxidation of ethanol to form acetyl compounds. The steam reforming has been covered by a literature study of the research work done so far giving an introduction to the use of ethanol as a feedstock. The partial oxidation of ethanol has been studied experimentally using gold and vanadium based heterogeneous...... catalysts, and two different experimental methods, namely, a batch system and a continuous flow system. In the batch reaction the process was carried out in the liquid phase using a gold catalyst and atmospheric air as the oxidant. Experiments were conducted at moderate pressures and temperatures (90-200 °C...

  14. WETTING OF COPPER BY LEAD-FREE Sn-Cu SOLDERS AND SHEAR STRENGTH OF Cu – Cu JOINTS

    Directory of Open Access Journals (Sweden)

    Pavol Šebo

    2009-04-01

    Full Text Available Developing and microstructure of lead-free Sn-Cu solders containing 3, 5 and 10 wt. % of copper in bulk as well as in ribbon form is presented. Wetting of copper substrate by these solders at the temperatures 300, 350 and 400°C in air (partially in N2+10H2 during 1800 s was studied by sessile drop method. Joints Cu – solder – Cu were prepared at 300°C and 1800 s in air as well as in gas mix and their shear strength was measured. The microstructure was studied by light and scanning electron microscopy (SEM equipped with energy dispersive X-ray analyzer and standard X-ray diffraction machine. Wetting angle decreases with increasing wetting temperature. Wetting angle increased for higher (10 wt. % amount of copper in solder. Shear strength of the joints decreases with increasing the copper concentration in solder.

  15. Wetting transitions at soft, sliding interfaces

    Science.gov (United States)

    Martin, A.; Clain, J.; Buguin, A.; Brochard-Wyart, F.

    2002-03-01

    We observe (by optical interferometry) the contact of a rubber cap squeezing a nonwetting liquid against a plate moving at velocity U. At low velocities, the contact is dry. It becomes partially wet above a threshold velocity Vc1, with two symmetrical dry patches on the rear part. Above a second velocity Vc2, the contact is totally wet. This regime U>Vc2 corresponds to the hydroplaning of a car (decelerating on a wet road). We interpret the transitions at Vc1, Vc2 in terms of a competition between (a) liquid invasion induced by shear (b) spontaneous dewetting of the liquid (between nonwettable surfaces).

  16. A Simplified Method to Calculate the Wet Bulb Globe Temperature(WBGT)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; MENG Qing-lin; ZHAO Li-hua; ZHANG Yu-feng

    2009-01-01

    Wet bulb globe temperature(WBGT) is a comprehensive index obtained mainly from three pa-rameters:black globe temperature(Tg),wet bulb temperature(Tw),and dry bulb temperature(Ta).While in field observation and numerical simulation,black globe temperature and wet bulb temperature were not easy to obtain, so WBGT was difficult to measure and calculate directly.In order to solve this problem,air dry bulb temperature, wet bulb temperature,globe temperature,relative humidity,mean air velocity,solar radiation and wet bulb globe temperature were collected during the summer(July)in Guangzhou.Correlation analysis and regression analysis were used to get a simplified method to calculate WBGT.The results showed that dry bulb temperature,relative humidity,solar radiation and WBGT were interrelated to some extent.These three pa-rameters could be used in the simplified method to predict WBGT,and the linear correlation and precision of this model were high.In addition,we used the measured data to verify the simplified method,and the results showed that the error of the calculated value and the measured value was all below 5%,which means the simpli-fied calculating method is feasible and can be used in field observation and simulation research of urban thermal environment.

  17. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Richard Rhudy

    2006-06-30

    -based catalyst began with almost 98% elemental mercury oxidation across the catalyst, but declined to 79% oxidation after nearly 13 months in service. The other two catalysts, an SCR-type catalyst (titanium/vanadium) and an experimental fly-ash-based catalyst, were significantly less active. The palladium-based and SCR-type catalysts were effectively regenerated at the end of the long-term test by flowing heated air through the catalyst overnight. The carbon-based catalyst was not observed to regenerate, and no regeneration tests were conducted on the fourth, fly-ash-based catalyst. Preliminary process economics were developed for the palladium and carbon-based catalysts for a scrubbed, North Dakota lignite application. As described above, the pilot-scale results showed the catalysts could not sustain 90% or greater oxidation of elemental mercury in the flue gas for a period of two years. Consequently, the economics were based on performance criteria in a later DOE NETL solicitation, which required candidate mercury control technologies to achieve at least a 55% increase in mercury capture for plants that fire lignite. These economics show that if the catalysts must be replaced every two years, the catalytic oxidation process can be 30 to 40% less costly than conventional (not chemically treated) activated carbon injection if the plant currently sells their fly ash and would lose those sales with carbon injection. If the plant does not sell their fly ash, activated carbon injection was estimated to be slightly less costly. There was little difference in the estimated cost for palladium versus the carbon-based catalysts. If the palladium-based catalyst can be regenerated to double its life to four years, catalytic oxidation process economics are greatly improved. With regeneration, the catalytic oxidation process shows over a 50% reduction in mercury control cost compared to conventional activated carbon injection for a case where the plant sells its fly ash. At Spruce Plant

  18. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Richard Rhudy

    2006-06-30

    -based catalyst began with almost 98% elemental mercury oxidation across the catalyst, but declined to 79% oxidation after nearly 13 months in service. The other two catalysts, an SCR-type catalyst (titanium/vanadium) and an experimental fly-ash-based catalyst, were significantly less active. The palladium-based and SCR-type catalysts were effectively regenerated at the end of the long-term test by flowing heated air through the catalyst overnight. The carbon-based catalyst was not observed to regenerate, and no regeneration tests were conducted on the fourth, fly-ash-based catalyst. Preliminary process economics were developed for the palladium and carbon-based catalysts for a scrubbed, North Dakota lignite application. As described above, the pilot-scale results showed the catalysts could not sustain 90% or greater oxidation of elemental mercury in the flue gas for a period of two years. Consequently, the economics were based on performance criteria in a later DOE NETL solicitation, which required candidate mercury control technologies to achieve at least a 55% increase in mercury capture for plants that fire lignite. These economics show that if the catalysts must be replaced every two years, the catalytic oxidation process can be 30 to 40% less costly than conventional (not chemically treated) activated carbon injection if the plant currently sells their fly ash and would lose those sales with carbon injection. If the plant does not sell their fly ash, activated carbon injection was estimated to be slightly less costly. There was little difference in the estimated cost for palladium versus the carbon-based catalysts. If the palladium-based catalyst can be regenerated to double its life to four years, catalytic oxidation process economics are greatly improved. With regeneration, the catalytic oxidation process shows over a 50% reduction in mercury control cost compared to conventional activated carbon injection for a case where the plant sells its fly ash. At Spruce Plant

  19. Oxygen transfer materials with catalytic properties for biomass gasification[Dissertation 17302

    Energy Technology Data Exchange (ETDEWEB)

    Pecho, J.

    2007-06-15

    By application of olivine as bed material in a biomass gasifier such as the FICFB type (Fast Internal Circulating Fluidized Bed) in Guessing, Austria, an improvement of the gasification process was observed. Reduction of tars was measured and oxygen increase in the process was calculated. However, it took a while before these properties became clear. Aim of the project was to elucidate the mechanism with which olivine influences the system and to find a new material with improved properties for the gasification process. There were some factors which had be taken into account, e.g., amount of free lattice oxygen, reaction enthalpy, selectivity, mechanical and chemical stability, costs, desulphurization and decarbonisation. Several studies have shown that natural olivine ((Fe{sub x}Mg{sub 1-x}){sub 2}SiO{sub 4}) lowers tar formation in fluidized bed gasification of biomass. According to most authors, the phenomenon is related to the presence of iron oxide (Fe{sub 2}O{sub 3}) which is, e.g., formed during the calcination of olivine in air. To elucidate the role of the iron oxide, synthetic olivine with a molar ratio of Fe:Mg equal to unity has been exposed to gases that contained either wet methane or wet toluene as the only carbon source in a thermobalance interfaced to on-line gas analysis. The results provide strong evidence that the conversion of the carbon species is dominated by the stoichiometric reaction of binary iron oxide with hydrocarbons in the beginning of the reaction while catalytic reactions such as steam reforming contribute little to the observed tar reduction. This reaction path straightforwardly explains the influence of the olivine's origin or the pre-treatment on its chemical reactivity as it was reported by the various authors. To improve the catalytic properties and oxygen capacity of bed materials, we put our focus on perovskite type oxides La{sub x}Sr{sub 1-x}Cr{sub y}Mn{sub 1-y}O{sub 3} and Ba{sub 0.3}Sr{sub 0.7}Fe{sub 0.9}Mn{sub 0.1}O

  20. Consumer sensory acceptance and value of wet-aged and dry-aged beef steaks.

    Science.gov (United States)

    Sitz, B M; Calkins, C R; Feuz, D M; Umberger, W J; Eskridge, K M

    2006-05-01

    To determine sensory preference and value of fresh beef steak differing in aging technique, strip steaks were evaluated by consumers in Denver (n = 132 consumers) and Chicago (n = 141 consumers). Wet-aged Choice strip loins were matched with dry-aged Choice strip loins, whereas wet-aged Prime strip loins were matched with dry-aged Prime strip loins. Dry-aged strip loins were commercially aged in air in a controlled environment for 30 d and vacuum-aged for 7 d during shipping and storage. Wet-aged strip loins were vacuum-packaged and aged for 37 d in a 1 degrees C cooler. Pairs of strip loins were matched to similar Warner-Bratzler shear force values and marbling scores. Twelve sensory evaluation panels (of 12 scheduled panelists each) were conducted over a 3-d period in each city. Individual samples from a pair of steaks were evaluated by the panelists for sensory traits. Bids were placed on the samples after sensory traits were obtained utilizing a variation of the Vickery auction with silent, sealed bids. No significant differences for sensory traits of flavor, juiciness, tenderness, or overall acceptability were detected between wet-aged Choice samples and dry-aged Choice samples. Although wet-aged Choice samples were numerically superior for all sensory traits, consumers placed similar bid values (P = 0.12) on wet- and dry-aged Choice samples ($3.82 per 0.45 kg and $3.57 per 0.45 kg, respectively). Wet-aged Prime samples were rated more desirable (P dry-aged Prime samples. Wet-aged Prime samples were valued at $4.02 per 0.45 kg, whereas dry-aged Prime samples brought $3.58 per 0.45 kg (P = 0.008). Consumers (29.3%) who preferred the dry-aged Choice samples over the wet-aged Choice samples were willing to pay $1.99/0.45 kg more (P dry-aged samples. The consumers who preferred the wet-aged Choice over the dry-aged Choice samples (39.2%) were willing to pay $1.77/0.45 kg more (P aged Prime over dry-aged Prime samples (45.8%) paid $1.92/0.45 kg more (P dry

  1. Structure of Wet Specimens in Electron Microscopy

    Science.gov (United States)

    Parsons, D. F.

    1974-01-01

    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  2. Adult Bed-Wetting: A Concern?

    Science.gov (United States)

    ... D. Bed-wetting that starts in adulthood (secondary enuresis) is uncommon and requires medical evaluation. Causes of ... Erik P. Castle, M.D. References Adult nocturnal enuresis. National Association for Continence. http://www.nafc.org/ ...

  3. Wetting behavior of alternative solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    1993-07-01

    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  4. National Ignition Facility wet weather construction plan

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, A N

    1998-01-01

    This report presents a wet weather construction plan for the National Ignition Facility (NIF) construction project. Construction of the NIF commenced in mid- 1997, and excavation of the site was completed in the fall. Preparations for placing concrete foundations began in the fall, and above normal rainfall is expected over the tinter. Heavy rainfall in late November impacted foundation construction, and a wet weather construction plan was determined to be needed. This wet weather constiction plan recommends a strategy, techniques and management practices to prepare and protect the site corn wet weather effects and allow construction work to proceed. It is intended that information in this plan be incorporated in the Stormwater Pollution Prevention Plan (SWPPP) as warranted.

  5. Wet granular matter a truly complex fluid

    CERN Document Server

    Herminghaus, Stephan

    2013-01-01

    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  6. Tualatin River - Wet Prairie Restoration Phase III

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Forty five acres of wet prairie and 11 acres of adjacent lands were treated for reed canarygrass in this ongoing project. Federally threatened Nelson’s...

  7. Critical point wetting drop tower experiment

    Science.gov (United States)

    Kaukler, W. F.; Tcherneshoff, L. M.; Straits, S. R.

    1984-01-01

    Preliminary results for the Critical Point Wetting CPW Drop Tower Experiment are produced with immiscible systems. Much of the observed phenomena conformed to the anticipated behavior. More drops will be needed to test the CPW theory with these immiscible systems.

  8. ROE Wet Sulfate Deposition 2009-2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  9. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  10. ROE Wet Nitrate Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  11. A WET TALE: TOXICITY OF COMPLEX EFFLUENTS

    Science.gov (United States)

    This course covers standards, regulations, policy, guidance and technical aspects of implementing the whole effluent toxicity program. The curriculum incorporates rationale and information on WET test requirements from USEPA documents, such as the Technical Support Document for W...

  12. Quantification of activated carbon contents in soils and sediments using chemothermal and wet oxidation methods.

    Science.gov (United States)

    Brändli, Rahel C; Bergsli, Anders; Ghosh, Upal; Hartnik, Thomas; Breedveld, Gijs D; Cornelissen, Gerard

    2009-12-01

    Activated carbon (AC) strongly sorbs organic pollutants and can be used for remediation of soils and sediments. A method for AC quantification is essential to monitor AC (re)distribution. Since AC is black carbon (BC), two methods for BC quantification were tested for AC mixed in different soils and sediments: i) chemothermal oxidation (CTO) at a range of temperatures and ii) wet-chemical oxidation with a potassium dichromate/sulfuric acid solution. For three soils, the amount of AC was accurately determined by CTO at 375 degrees C. For two sediments, however, much of the AC disappeared during combustion at 375 degrees C, which could probably be explained by catalytic effects by sediment constituents. CTO at lower temperatures (325-350 degrees C) was a feasible alternative for one of the sediments. Wet oxidation effectively functioned for AC quantification in sediments, with almost complete AC recovery (81-92%) and low remaining amounts of native organic carbon (5-16%).

  13. Utilization and mitigation of VAM/CMM emissions by a catalytic combustion gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, K.; Yoshino, Y.; Kashihara, H. [Kawasaki Heavy Industries Ltd., Hyougo (Japan); Kajita, S.

    2013-07-01

    A system configured with a catalytic combustion gas turbine generator unit is introduced. The system has been developed using technologies produced by Kawasaki Heavy Industries, Ltd., such as small gas turbines, recuperators and catalytic combustors, and catalytic oxidation units which use exhaust heat from gas turbines. The system combusts (oxidizes) ventilation air methane (less than 1% concentration) and low concentration coal mine methane (30% concentration or less) discharged as waste from coal mines. Thus, it cannot only reduce the consumption of high- quality fuel for power generation, but also mitigate greenhouse gas emissions.

  14. Biodegradation of wet-white leather

    OpenAIRE

    Ollé Otero, Lluís; Jorba Rafart, Montse; Font Vallès, Joaquim; Shendrik, Alexander; Bacardit Dalmases, Anna

    2011-01-01

    This paper deals with the study of the physical, chemical and biological processes associated with the deterioration of wet-white leather. The samples of leather were exposed for eight months to outdoor weathering and then their properties were subsequently evaluated. The results indicate that resistance and dimensional stability of wet-white (THPS-syntan) leather is higher than that of chrometanned leather. The comparative work with chrome leather was described earlier.

  15. Wetting and phase separation at surfaces

    Indian Academy of Sciences (India)

    Sanjay Puri; Kurt Binder

    2005-06-01

    We study the problem of surface-directed spinodal decomposition, viz., the dynamical interplay of wetting and phase separation at surfaces. In particular, we focus on the kinetics of wetting-layer growth in a semi-infinite geometry for arbitrary surface potentials and mixture compositions. We also present representative results for phase separation in confined geometries, e.g., cylindrical pores, thin films, etc.

  16. ENHANCED CONTROL OF MERCURY BY WET FLUE GAS DESULFURIZATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    G. Blythe; B. Marsh; S. Miller; C. Richardson; M. Richardson

    2001-06-01

    The U.S. Department of Energy and EPRI have co-funded this project to improve the control of mercury emissions from coal-fired power plants equipped with wet flue gas desulfurization (FGD) systems. The project investigated catalytic oxidation of vapor-phase elemental mercury to a form that is more effectively captured in wet FGD systems. If successfully developed, the process could be applicable to over 90,000 MW of utility generating capacity with existing FGD systems and to future FGD installations. Field tests have been conducted to determine whether candidate catalyst materials remain active towards mercury oxidation after extended flue gas exposure. Catalyst life will have a large impact on the cost effectiveness of this potential process. A mobile catalyst test unit has been used to test the activity of four different catalyst materials for a period of up to six months at each of three utility sites. Catalyst testing was completed at the first site, which fires Texas lignite, in December 1998 and at the second test site, which fires a Powder River Basin subbituminous coal in the fall of 1999. Testing at the third site, which fires a medium- to high-sulfur bituminous coal, began in June 2000 and was completed at the end of January 2001. This Topical Reports includes results from Site 3; results from Sites 1 and 2 were reported previously. At Site 3, catalysts were tested in two forms, including powders dispersed in sand bed reactors and in a commercially available form as a coated honeycomb structure. Field testing has been supported by laboratory tests to screen catalysts for activity at specific flue gas compositions, to investigate catalyst deactivation mechanisms and methods for regenerating spent catalysts. Laboratory results related to the Site 3 field effort are also included and discussed in this Topical Report.

  17. Improvement of Heating Method for Measuring the Wetness of Flowing Wet Steam

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    In this paper,an improvement of heating method for measuring wetness of the flowing wet steam is developed,the basic principle of the heating method is presented and the mathematical model has been built for analyzing the thermodynamics problems during the process of heating,Moreover,an instrument for measuring wetness of wet steam flow was designed and made out.This instument has been used for measuring wetness of the wet steam flow at the outlet of the nozzle rig in Thermal Turbine Laboratory,Xi'an Jiaotong University,By analyzing the relative error of the result,it was found that this instrument has fairly high accuracy,it can be used as the prototype of practical instrument and has an important applicable value in engineering.

  18. Selenium Speciation and Management in Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Searcy, K; Richardson, M; Blythe, G; Wallschlaeger, D; Chu, P; Dene, C

    2012-02-29

    This report discusses results from bench- and pilot-scale simulation tests conducted to determine the factors that impact selenium speciation and phase partitioning in wet FGD systems. The selenium chemistry in wet FGD systems is highly complex and not completely understood, thus extrapolation and scale-up of these results may be uncertain. Control of operating parameters and application of scrubber additives have successfully demonstrated the avoidance or decrease of selenite oxidation at the bench and pilot scale. Ongoing efforts to improve sample handling methods for selenium speciation measurements are also discussed. Bench-scale scrubber tests explored the impacts of oxidation air rate, trace metals, scrubber additives, and natural limestone on selenium speciation in synthetic and field-generated full-scale FGD liquors. The presence and concentration of redox-active chemical species as well as the oxidation air rate contribute to the oxidation-reduction potential (ORP) conditions in FGD scrubbers. Selenite oxidation to the undesirable selenate form increases with increasing ORP conditions, and decreases with decreasing ORP conditions. Solid-phase manganese [Mn(IV)] appeared to be the significant metal impacting the oxidation of selenite to selenate. Scrubber additives were tested for their ability to inhibit selenite oxidation. Although dibasic acid and other scrubber additives showed promise in early clear liquor (sodium based and without calcium solids) bench-scale tests, these additives did not show strong inhibition of selenite oxidation in tests with higher manganese concentrations and with slurries from full-scale wet FGD systems. In bench-tests with field liquors, addition of ferric chloride at a 250:1 iron-to-selenium mass ratio sorbed all incoming selenite to the solid phase, although addition of ferric salts had no impact on native selenate that already existed in the field slurry liquor sample. As ORP increases, selenite may oxidize to selenate more

  19. Non-evaporative effects of a wet mid layer on heat transfer through protective clothing.

    Science.gov (United States)

    Bröde, Peter; Havenith, George; Wang, Xiaoxin; Candas, Victor; den Hartog, Emiel A; Griefahn, Barbara; Holmér, Ingvar; Kuklane, Kalev; Meinander, Harriet; Nocker, Wolfgang; Richards, Mark

    2008-09-01

    In order to assess the non-evaporative components of the reduced thermal insulation of wet clothing, experiments were performed with a manikin and with human subjects in which two layers of underwear separated by an impermeable barrier were worn under an impermeable overgarment at 20 degrees C, 80% RH and 0.5 ms(-1) air velocity. By comparing manikin measurements with dry and wetted mid underwear layer, the increase in heat loss caused by a wet layer kept away from the skin was determined, which turned out to be small (5-6 W m(-2)), irrespective of the inner underwear layer being dry or wetted, and was only one third of the evaporative heat loss calculated from weight change, i.e. evaporative cooling efficiency was far below unity. In the experiments with eight males, each subject participated in two sessions with the mid underwear layer either dry or wetted, where they stood still for the first 30 min and then performed treadmill work for 60 min. Reduced heat strain due to lower insulation with the wetted mid layer was observed with decreased microclimate and skin temperatures, lowered sweat loss and cardiac strain. Accordingly, total clothing insulation calculated over the walking period from heat balance equations was reduced by 0.02 m(2) degrees C W(-1) (16%), while for the standing period the same decrease in insulation, representing 9% reduction only showed up after allowing for the lower evaporative cooling efficiency in the calculations. As evaporation to the environment and inside the clothing was restricted, the observed small alterations may be attributed to the wet mid layer's increased conductivity, which, however, appears to be of minor importance compared to the evaporative effects in the assessment of the thermal properties of wet clothing.

  20. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  1. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne;

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  2. Catalytic Decoupling of Quantum Information

    DEFF Research Database (Denmark)

    Majenz, Christian; Berta, Mario; Dupuis, Frédéric

    2017-01-01

    The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... of an uncorrelated ancilla system. This removes a restriction on the standard notion of decoupling, which becomes important for structureless resources, and yields a tight characterization in terms of the max-mutual information. Catalytic decoupling naturally unifies various tasks like the erasure of correlations...... and quantum state merging, and leads to a resource theory of decoupling....

  3. Pt-TiO2/MWCNTs Hybrid Composites for Monitoring Low Hydrogen Concentrations in Air

    Directory of Open Access Journals (Sweden)

    Stefano Trocino

    2012-09-01

    Full Text Available Hydrogen is a valuable fuel for the next energy scenario. Unfortunately, hydrogen is highly flammable at concentrations higher than 4% in air. This aspect makes the monitoring of H2 leaks an essential issue for safety reasons, especially in the transportation field. In this paper, nanocomposites based on Pt-doped TiO2/multiwalled carbon nanotubes (MWCNTs have been introduced as sensitive materials for H2 at low temperatures. Pt-TiO2/MWNTs nanocomposites with different composition have been prepared by a simple wet chemical procedure and their morphological, microstructural and electrical properties were investigated. Resistive thick-film devices have been fabricated printing the hybrid nanocomposites on alumina substrates provided with Pt interdigitated electrodes. Electrical tests in air have shown that embedding MWCNTs in the TiO2 matrix modify markedly the electrical conductivity, providing a means to decrease the resistance of the sensing layer. Pt acts as a catalytic additive. Pt-TiO2/MWNTs-based sensors were found to be sensitive to hydrogen at concentrations between 0.5 and 3% in air, satisfying the requisites for practical applications in hydrogen leak detection devices.

  4. Advanced Catalytic Converter in Gasoline Enginer Emission Control: A Review

    Directory of Open Access Journals (Sweden)

    Leman A.M.

    2017-01-01

    Full Text Available Exhaust emission from automobile source has become a major contributor to the air pollution and environmental problem. Catalytic converter is found to be one of the most effective tools to reduce the overwhelming exhaust pollutants in our environment. The development of sustainable catalytic converter still remains a critical issue due to the stringent exhaust emission regulations. Another issue such as price and availability of the precious metal were also forced the automotive industry to investigate the alternatives for producing a better replacement for the material used in catalytic converter. This paper aims at reviewing the present development and improvement on the catalytic converter used on the reduction of exhaust emission in order to meet the regulations and market demand. The use of new catalyst such as to replace the noble metal material of Platinum (Pt, Palladium (Pd and Rhodium (Rh has been reviewed. Material such as zeolite, nickel oxide and metal oxide has been found to effectively reduce the emission than the commercial converter. The preparation method of the catalyst has also evolved through the years as it is to ensure a good characteristic of a good monolith catalyst. Ultrasonic treatment with combination of electroplating technique, citrate method and Plasma Electrolytic Oxidation (PEO has been found as the latest novel preparation method on producing an effective catalyst in reducing the exhaust emission.

  5. Catalytic oxidation of volatile organic compounds (VOCs) - A review

    Science.gov (United States)

    Kamal, Muhammad Shahzad; Razzak, Shaikh A.; Hossain, Mohammad M.

    2016-09-01

    Emission of volatile organic compounds (VOCs) is one of the major contributors to air pollution. The main sources of VOCs are petroleum refineries, fuel combustions, chemical industries, decomposition in the biosphere and biomass, pharmaceutical plants, automobile industries, textile manufacturers, solvents processes, cleaning products, printing presses, insulating materials, office supplies, printers etc. The most common VOCs are halogenated compounds, aldehydes, alcohols, ketones, aromatic compounds, and ethers. High concentrations of these VOCs can cause irritations, nausea, dizziness, and headaches. Some VOCs are also carcinogenic for both humans and animals. Therefore, it is crucial to minimize the emission of VOCs. Among the available technologies, the catalytic oxidation of VOCs is the most popular because of its versatility of handling a range of organic emissions under mild operating conditions. Due to that fact, there are numerous research initiatives focused on developing advanced technologies for the catalytic destruction of VOCs. This review discusses recent developments in catalytic systems for the destruction of VOCs. Review also describes various VOCs and their sources of emission, mechanisms of catalytic destruction, the causes of catalyst deactivation, and catalyst regeneration methods.

  6. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; Conor Braman; Katherine Dombrowski; Tom Machalek

    2010-12-31

    This document is the final technical report for Cooperative Agreement DE-FC26-04NT41992, 'Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,' which was conducted over the time-period January 1, 2004 through December 31, 2010. The objective of this project has been to demonstrate at pilot scale the use of solid catalysts and/or fixed-structure mercury sorbents to promote the removal of total mercury and oxidation of elemental mercury in flue gas from coal combustion, followed by wet flue gas desulfurization (FGD) to remove the oxidized mercury at high efficiency. The project was co-funded by the U.S. DOE National Energy Technology Laboratory (DOE-NETL), EPRI, Great River Energy (GRE), TXU Energy (now called Luminant), Southern Company, Salt River Project (SRP) and Duke Energy. URS Group was the prime contractor. The mercury control process under development uses fixed-structure sorbents and/or catalysts to promote the removal of total mercury and/or oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury not adsorbed is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The project has tested candidate materials at pilot scale and in a commercial form, to provide engineering data for future full-scale designs. Pilot-scale catalytic oxidation tests have been completed for periods of approximately 14 to19 months at three sites, with an additional round of pilot-scale fixed-structure sorbent tests being conducted at one of those sites. Additionally, pilot-scale wet FGD tests have been conducted downstream of mercury oxidation catalysts at a total of four sites. The sites include the two of three sites from this project and two sites where catalytic oxidation pilot testing was conducted as part of a previous DOE-NETL project. Pilot-scale wet FGD tests were also conducted at a fifth site, but with no catalyst or fixed

  7. Catalytic performance of symmetrical and unsymmetrical sulfur-containing pincer complexes: synthesis and tandem catalytic activity of the first PCS-pincer palladium complex

    NARCIS (Netherlands)

    Gagliardo, M.; Selander, N.; Mehendale, N.C.; van Koten, G.; Klein Gebbink, R.J.M.; Szabó, K.J.

    2008-01-01

    The synthesis and catalytic applications of a new aryl-based unsymmetrical PCS-pincer complex are reported. Preparation of the robust air- and moisture-stable PCS-pincer palladium complex 5[X] started from the symmetrical ,-dibromo-meta-xylene and involved the selective substitution of one bromide b

  8. Membrane-based wet electrostatic precipitation.

    Science.gov (United States)

    Bayless, David J; Shi, Liming; Kremer, Gregory; Stuart, Ben J; Reynolds, James; Caine, John

    2005-06-01

    Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at FirstEnergy's Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with approximately 15% less collecting area.

  9. WET STRENGTH PAPER REPULPING:LABORATORY EVALUATION

    Institute of Scientific and Technical Information of China (English)

    Nishi K. Bhardwaj; Vikas Rajan; A.G. Kulkarni

    2004-01-01

    The recycling of wet strength papers in a normal recycling mill is often troublesome due to the severe operating conditions required to defibre wet strength papers. The various methods are presented which will quickly allow mills to determine the most effective pulping aids to use when repulping wet strength papers. The repulping of wet strength paper with inorganic chemicals was investigated in the laboratory. The effects of major variables, that is,repulping time, pulp consistency, soaking time,temperature, and reactant concentration in the repulping stage were examined using Plackett-Burman design. The repulping time was the most crucial & influential process variable affecting repulping characteristic and formation related properties. The more significant repulping process variables affecting pulp yield were repulping time,soaking temperature and pulp consistency whereas for formation index and feature size, repulping time,pulp consistency, soaking temperature and time were the more important variables. The formation index is increased by an increase in repulping time, pulp consistency and soaking time whereas the feature size is decreased by an increase in repulping time,soaking temperature and pulp consistency. The formation index and the rejects were more sensitive to changes in process variables than were the feature size or the pulp yield. The pulp recycled from wet strength waste paper had good physical strength properties.

  10. Performance of some surfactants as wetting agents

    Energy Technology Data Exchange (ETDEWEB)

    Shalaby, M.N.; El-Shanny, O.A.A. [Egyptian Petroleum Research Institute (EPRI), Cairo (Egypt). Evaluation and Analysis Dept.

    2005-12-01

    The wetting power of anionic surfactant: sodium dodecyl sulfate (SDS), and nonionic surfactants: polyoxyethelene(14)monolaurate [La(EO){sub 14}] and polyoxyethelene(14)monoeleate [OI(EO){sub 14}] has been studied to determine their performance as wetting agents. The study reveals that the nonionic compound with a long hydrophobic chain exhibits higher wettability than the shorter one when used at very low cocentrations (below CMC) and the reverse is shown with high concentrations (above CMC). the wetting power of the investigated surfactants increases as the CMC values increases. In case of the nonionic compounds and at surfactant concentrations equal their CMC values, OI(EO){sub 14} shows a higher wetting power than La(EO){sub 14} while is possesses a lower HLB value. The anionic surfactant shows an optimum wetting in comparison with the tested nonionic one. The wettability of all the investigated samples increases as the surface tension of their solutions increases to the allowed limit that can be reached in the presence of surfactant. (orig.)

  11. Wetting and adsorption modification in the system

    Directory of Open Access Journals (Sweden)

    Yuliya Bogdanova

    2015-09-01

    Full Text Available Regularities of wetting and adsorption modification of surfaces of continual membranes made from highly permeable glassy polymers poly[1-(trimethylsilyl-1-propyne] (PTMSP and poly(4-methyl-2-pentyn (PMP with aqueous ethanol solutions and alcohol solutions containing organic dyes (Solvent Blue 35 and Remazol Brilliant Blue were investigated. Isotherms of stress wetting of polymer membrane surface by etanol solutions were found out to have maximums in the range of concentrations corresponding to the beginning of liquid sorption into the membrane and polymer swelling. Thus, the principal possibility of optimization of nanofiltration experiments by liquid wetting angle measurements on continuous polymer membrane surfaces was shown. The presence of the dye was shown not to affect PMP wetting. But in the case of PTMSP, it leads to shear of the maximum of stress wetting isotherms to the range of higher concentrations. It was found out the effectiveness of the adsorption surface modification of continuous polymer membrane surfaces by ethanol solutions containing dyes does not dependent on chemical nature of the dye. At the same time, there are different trends in the energy characteristics of the membrane surface.

  12. Epimacular brachytherapy for wet AMD: current perspectives.

    Science.gov (United States)

    Casaroli-Marano, Ricardo P; Alforja, Socorro; Giralt, Joan; Farah, Michel E

    2014-01-01

    Age-related macular degeneration (AMD) is considered the most common cause of blindness in the over-60 age group in developed countries. There are basically two forms of presentation: geographic (dry or atrophic) and wet (neovascular or exudative). Geographic atrophy accounts for approximately 85%-90% of ophthalmic frames and leads to a progressive degeneration of the retinal pigment epithelium and the photoreceptors. Wet AMD causes the highest percentage of central vision loss secondary to disease. This neovascular form involves an angiogenic process in which newly formed choroidal vessels invade the macular area. Today, intravitreal anti-angiogenic drugs attempt to block the angiogenic events and represent a major advance in the treatment of wet AMD. Currently, combination therapy for wet AMD includes different forms of radiation delivery. Epimacular brachytherapy (EMBT) seems to be a useful approach to be associated with current anti-vascular endothelial growth factor agents, presenting an acceptable efficacy and safety profile. However, at the present stage of research, the results of the clinical trials carried out to date are insufficient to justify extending routine use of EMBT for the treatment of wet AMD.

  13. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  14. Tunable Reactive Wetting of Sn on Microporous Cu Layer

    Institute of Scientific and Technical Information of China (English)

    Qingquan Lai; Lei Zhang; Cai Chen; J.K. Shang

    2012-01-01

    Wetting of microporous Cu layer by liquid Sn resulted in contact angles from 0 to 33 deg., tunable by varying wetting temperature and porous microstructure. The wetting was dominated by the interracial metallurgical reaction, which can lead to pore closure phenomenon, as the liquid infiltration facilitating the wetting process.

  15. The Analysis of Characteristics in Dry and Wet Environments of Silicon Nanowire-Biosensor.

    Science.gov (United States)

    Choi, Hyoun Mo; Shin, Dong Jae; Lee, Jung Han; Mo, Hyun-Sun; Park, Tae Jung; Park, Byung-Gook; Kim, Dong Myong; Choi, Sung-Jin; Kim, Dae Hwan; Park, Jisun

    2016-05-01

    Our study investigates differences in sensitivity of dry and wet environment in the field of biosensing experiment in detail and depth. The sensitivity of biosensing varies by means of surrounding conditions of silicon nanowire field effect transistor (SiNW FET). By examining charged polymer reaction in the silicon nanowire transistor (SiNW), we have discovered that the threshold voltage (V(T)) shift and change of subthreshold slope (SS) in wet environment are smaller than that of the air. Furthermore, we analyzed the sensitivity through modifying electrolyte concentration in the wet condition, and confirmed that V(T) shift increases in low concentration condition of phosphate buffered saline (PBS) due to the Debye length. We believe that the results we have found in this study would be the cornerstone in contributing to advanced biosensing experiment in the future.

  16. Assessing wet snow avalanche activity using detailed physics based snowpack simulations

    Science.gov (United States)

    Wever, N.; Vera Valero, C.; Fierz, C.

    2016-06-01

    Water accumulating on microstructural transitions inside a snowpack is often considered a prerequisite for wet snow avalanches. Recent advances in numerical snowpack modeling allow for an explicit simulation of this process. We analyze detailed snowpack simulations driven by meteorological stations in three different climate regimes (Alps, Central Andes, and Pyrenees), with accompanying wet snow avalanche activity observations. Predicting wet snow avalanche activity based on whether modeled water accumulations inside the snowpack locally exceed 5-6% volumetric liquid water content is providing a higher prediction skill than using thresholds for daily mean air temperature, or the daily sum of the positive snow energy balance. Additionally, the depth of the maximum water accumulation in the simulations showed a significant correlation with observed avalanche size. Direct output from detailed snow cover models thereby is able to provide a better regional assessment of dangerous slope aspects and potential avalanche size than traditional methods.

  17. Wetting of microstructured alumina fabricated by epitaxial growth of Al4B2O9 whiskers

    Science.gov (United States)

    Wang, Yifeng; Feng, Jicai; Chen, Zhe; Song, Xiaoguo; Cao, Jian

    2015-12-01

    Topographical microstructures were fabricated on alumina by epitaxial growth of Al4B2O9 whiskers in air. The products were characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The whiskers were found to grow along the [0 0 1] crystallographic direction, and the lattice mismatch between Al2O3 and Al4B2O9 was determined to be 0.03%. The wetting of the Al4B2O9-whisker-coated surfaces by Ag-36.7Cu-8.0Ti at.% alloy was studied. The time needed to reach the equilibrium stage reduced as the temperature increased, and the final contact angle for liquid alloy on the rough surface was 27° at 880 °C. The wetting dynamics of the whiskers coated surfaces was investigated. After wetting, a whisker-interconnected region was formed between alumina and the alloy.

  18. Evaporation from rain-wetted forest in relation to canopy wetness, canopy cover, and net radiation

    NARCIS (Netherlands)

    Klaassen, W.

    2001-01-01

    Evaporation from wet canopies is commonly calculated using E-PM, the Penman-Monteith equation with zero surface resistance. However, several observations show a lower evaporation from rain-wetted forest. Possible causes for the difference between E-PM and experiments are evaluated to provide rules f

  19. Static and Dynamic Wetting Behavior of Triglycerides on Solid Surfaces.

    Science.gov (United States)

    Michalski; Saramago

    2000-07-15

    Triglyceride wetting properties on solid surfaces of different hydro-phobicities were investigated using three different methods, namely, the sessile drop method for static contact angle measurements, the Wilhelmy method for dynamic contact angle measurements, and the captive bubble method to investigate thin triglyceride film stability. For solid surfaces having a surface free energy higher than the surface tension of triglycerides (tributyrin, tricaprylin, and triolein), a qualitative correlation was observed between wetting and solid/triglyceride relative hydrophobicities. On surfaces presenting extreme hydrophobic or hydrophilic properties, medium-chain triglycerides had a behavior similar to that of long-chain unsaturated ones. On a high-energy surface (glass), tricaprylin showed an autophobic effect subsequent to molecular adsorption in trident conformation on the solid, observed with the three methods. Thin triglyceride films between an air bubble and a solid surface were stable for a short time, for solids with a surface free energy larger than the triglyceride surface tension. If the solid surface had a lower surface free energy, the thin film collapsed after a time interval which increased with triglyceride viscosity. Copyright 2000 Academic Press.

  20. Simple, chemoselective, catalytic olefin isomerization.

    Science.gov (United States)

    Crossley, Steven W M; Barabé, Francis; Shenvi, Ryan A

    2014-12-01

    Catalytic amounts of Co(Sal(tBu,tBu))Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.

  1. Catalytic Asymmetric Bromocyclization of Polyenes.

    Science.gov (United States)

    Samanta, Ramesh C; Yamamoto, Hisashi

    2017-02-01

    The first catalytic asymmetric bromonium ion-induced polyene cyclization has been achieved by using a chiral BINOL-derived thiophosphoramide catalyst and 1,3-dibromo-5,5-dimethylhydantoin as an electrophilic bromine source. Bromocyclization products are obtained in high yields, with good enantiomeric ratios and high diastereoselectivity, and are abundantly found as scaffolds in natural products.

  2. Pre- and post-treatment enhance the protein enrichment from milling and air classification of legumes

    NARCIS (Netherlands)

    Pelgrom, P.J.M.; Wang, J.; Boom, R.M.; Schutyser, M.A.I.

    2015-01-01

    Air classification is a milder and more sustainable method to obtain protein-enriched fractions than commonly used wet fractionation. The protein content of air-classified fractions is generally lower than obtained with wet methods, therefore we applied pre- and post-treatments to increase the prote

  3. Experimental investigation of the link between static and dynamic wetting by forced wetting of nylon filament.

    Science.gov (United States)

    Vega, M J; Gouttière, C; Seveno, D; Blake, T D; Voué, M; De Coninck, J; Clarke, A

    2007-10-09

    Forced wetting experiments with various liquids were conducted to study the dynamic wetting properties of nylon filament. The molecular-kinetic theory of wetting (MKT) was used to interpret the dynamic contact angle data and evaluate the contact-line friction zeta0 at the microscopic scale. By taking account of the viscosity of the liquid, zeta0 could be related exponentially to the reversible work of adhesion. This clearly establishes an experimental link between the static and dynamic wetting properties of the material. Moreover, statistical analysis of the equilibrium molecular displacement frequency K0 and the length of the displacements lambda reveals that these two fundamental parameters of the MKT are strongly correlated, not only in the linearized form of the theory (valid close to equilibrium) but also when the nonlinear form of the equations has to be considered at higher wetting speeds.

  4. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  5. Mechanical Properties of Sheared Wet Granular Piles

    Science.gov (United States)

    Seemann, Ralf; Schaber, Marc; Karmakar, Somnath; Hippler, Anna-Lena; Scheel, Mario; di Michiel, Marco; Brinkmann, Martin

    2015-03-01

    The mechanical properties of dry and wet granulates are explored when being sheared with a parabolic profile at constant shear volume. The dissipated energy increase linearly with external pressure both for a wet and a dry granulate. However, the dissipated energy for wet a granulate has a finite value for the limiting case of vanishing external pressure and increases slower with external pressure compared to the dry granulate. Using a down sized version of the shear cell the reorganization of a granulate and liquid is additionally imaged in real time using x-ray micro-tomography. With the insight from x-ray tomography the contribution of the breaking capillary bridges to the dissipated energy can be analyzed. We could also shed light on the influence of dilatation effects on the dissipated energy upon inverting the shear direction.

  6. Molecular Dynamics Simulations for Predicting Surface Wetting

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2014-06-01

    Full Text Available The investigation of wetting of a solid surface by a liquid provides important insights; the contact angle of a liquid droplet on a surface provides a quantitative measurement of this interaction and the degree of attraction or repulsion of that liquid type by the solid surface. Molecular dynamics (MD simulations are a useful way to examine the behavior of liquids on solid surfaces on a nanometer scale. Thus, we surveyed the state of this field, beginning with the fundamentals of wetting calculations to an examination of the different MD methodologies used. We highlighted some of the advantages and disadvantages of the simulations, and look to the future of computer modeling to understand wetting and other liquid-solid interaction phenomena.

  7. Handling of wet residues in industry

    DEFF Research Database (Denmark)

    Villanueva, Alejandro

    , to remove from it the substances which presence impedes reusing the water. These substances accumulate in a by-product called wet residue. An integral part of water recycling projects in the industry is the handling and disposal of the wet residues generated. The treatment, utilisation and disposal of wet...... residues depend totally on the industrial sector of origin and the composition of the water to be recycled. Treatment is more problematic in some cases than in others, but in all water recycling applications it is an issue of concern. The present study addresses this concern by providing a package...... to water bodies and uses of such bodies, distance to available agricultural land, characteristics of the local wastewater treatment plant, local and national legislation, or availability of subsidies. This study uses as example the geographical, legislative, economic and social boundary conditions...

  8. NANOFILLERS FOR PAPERMAKING WET END APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2010-05-01

    Full Text Available The papermaking industry can benefit a lot from nanotechnology. This versatile technology can also be used in the area of fillers for papermaking wet end applications. In such applications the main technological examples currently available include wet end addition of commercially available nanofillers, formation of nanofiller/fiber or nanofiller/fibril hybrids, development of novel categories of nanofillers such as high aspect ratio nanofillers, and combination of microfillers with nanostructures by specially controlled routes to obtain composite nanofillers. It is worth noting that there are certain challenges associated with nanofillers, such as high cost, difficulty in structure and performance control, poor dispersability and retention, possible severe negative effects on paper strength, possible detrimental interactions between nanofillers with some wet end additives, and the industry-related limitations. However, in the long run, the research and development in the area of nanofillers will surely create many fruitful results.

  9. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  10. Sphere impact and penetration into wet sand

    Science.gov (United States)

    Marston, J. O.; Vakarelski, I. U.; Thoroddsen, S. T.

    2012-08-01

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  11. Grain boundary wetness of partially molten dunite

    Science.gov (United States)

    Mu, S.; Faul, U.

    2013-12-01

    The grain scale melt distribution plays a key role for physical properties of partially molten regions in Earth's upper mantle, but our current understanding of the distribution of basaltic melt at the grain scale is still incomplete. A recent experimental study shows that wetted two-grain boundaries are a common feature of partially molten dunite at small melt fractions (Garapic et al., G3, 2013). In early ideal models which assume isotropic surface energy, the grain scale melt distribution is uniquely determined by knowing the melt fraction and the dihedral angle between two crystalline grains and the melt (von Bargen and Waff, JGR, 1986). Olivine is anisotropic in surface energy, hence the grain scale melt distribution at given melt fraction cannot be characterized by the dihedral angle alone. The grain boundary wetness, which is defined as the ratio of solid-liquid boundary area over the total interfacial area (Takei, JGR, 1998), is a more objective measure of the grain scale melt distribution. The aim of this study is to quantify the relationship between grain size, melt fraction, temperature and grain boundary wetness of partially molten dunite under dry conditions. We annealed olivine-basalt aggregates with melt fractions from 0.03% to 6% at a range of temperatures and 1 GPa in a piston cylinder for 1 to 336 hours, with resulting mean grain sizes of 10 to 60 μm. The samples were sectioned, polished and imaged at high resolution by using a field emission SEM. Each image had a size of 2048 x 1536 pixels with a resolution of 0.014 to 0.029 μm/pixel, depending on magnification. For each sample, depending on grain sizes, we made mosaics of 3 x 3 or 6 x 6 overlapping images. Measurements of melt fraction, grain boundary wetness and grain size were carried out on these high resolution mosaics by using ImageJ software. Analyses of mosaics show that grain boundary wetness increases with increasing melt fraction at constant grain size to values well above those

  12. Fabrication of fuel cell electrodes and other catalytic structures

    Science.gov (United States)

    Smith, J.L.

    1987-02-11

    A porous layer of catalyst material suitable for use as an electrode in a molten carbonate fuel cell includes elongated pores substantially extending across the layer thickness. The catalyst layer is prepared by depositing particulate catalyst material into polymeric flocking on a substrate surface by a procedure such as tape casting. The loaded substrate is heated in a series of steps with rising temperatures to set the tape, thermally decompose the substrate with flocking and sinter bond the catalyst particles into a porous catalytic layer with elongated pores across its thickness. Employed as an electrode, the elongated pores provide distribution of reactant gas into contact with catalyst particles wetted by molten electrolyte. 1 fig.

  13. Wet scrubbing of biomass producer gas tars using vegetable oil

    Science.gov (United States)

    Bhoi, Prakashbhai Ramabhai

    The overall aims of this research study were to generate novel design data and to develop an equilibrium stage-based thermodynamic model of a vegetable oil based wet scrubbing system for the removal of model tar compounds (benzene, toluene and ethylbenzene) found in biomass producer gas. The specific objectives were to design, fabricate and evaluate a vegetable oil based wet scrubbing system and to optimize the design and operating variables; i.e., packed bed height, vegetable oil type, solvent temperature, and solvent flow rate. The experimental wet packed bed scrubbing system includes a liquid distributor specifically designed to distribute a high viscous vegetable oil uniformly and a mixing section, which was designed to generate a desired concentration of tar compounds in a simulated air stream. A method and calibration protocol of gas chromatography/mass spectroscopy was developed to quantify tar compounds. Experimental data were analyzed statistically using analysis of variance (ANOVA) procedure. Statistical analysis showed that both soybean and canola oils are potential solvents, providing comparable removal efficiency of tar compounds. The experimental height equivalent to a theoretical plate (HETP) was determined as 0.11 m for vegetable oil based scrubbing system. Packed bed height and solvent temperature had highly significant effect (p0.05) effect on the removal of model tar compounds. The packing specific constants, Ch and CP,0, for the Billet and Schultes pressure drop correlation were determined as 2.52 and 2.93, respectively. The equilibrium stage based thermodynamic model predicted the removal efficiency of model tar compounds in the range of 1-6%, 1-4% and 1-2% of experimental data for benzene, toluene and ethylbenzene, respectively, for the solvent temperature of 30° C. The NRTL-PR property model and UNIFAC for estimating binary interaction parameters are recommended for modeling absorption of tar compounds in vegetable oils. Bench scale

  14. Formaldehyde: catalytic oxidation as a promising soft way of elimination.

    Science.gov (United States)

    Quiroz Torres, Jhon; Royer, Sébastien; Bellat, Jean-Pierre; Giraudon, Jean-Marc; Lamonier, Jean-François

    2013-04-01

    Compared to other molecules such as benzene, toluene, xylene, and chlorinated compounds, the catalytic oxidation of formaldehyde has been studied rarely. However, standards for the emission level of this pollutant will become more restrictive because of its extreme toxicity even at very low concentrations in air. As a consequence, the development of a highly efficient process for its selective elimination is needed. Complete catalytic oxidation of formaldehyde into CO2 and H2 O using noble-metal-based catalysts is a promising method to convert this pollutant at room temperature, making this process energetically attractive from an industrial point of view. However, the development of a less expensive active phase is required for a large-scale industrial development. Nanomaterials based on oxides of manganese are described as the most promising catalysts. The objective of this Minireview is to present promising recent studies on the removal of formaldehyde through heterogeneous catalysis to stimulate future research in this topic.

  15. PARAMETRIC EVALUATION OF VOC CONVERSION VIA CATALYTIC INCINERATION

    Directory of Open Access Journals (Sweden)

    Kaskantzis Neto G.

    1997-01-01

    Full Text Available Abstract - A pilot-scale catalytic incineration system was used to investigate the effectiveness of catalytic incineration as a means of reducing volatile organic compound (VOC air pollutants. The objectives of the study were: 1 to investigate the effects of operating and design variables on the reduction efficiency of VOCs; and 2 to evaluate reduction efficiencies for specific compounds in different chemical classes. The study results verified that the following factors affect the catalyst performance: inlet temperature, space velocity, compound type, and compound inlet concentration. Tests showed that reduction efficiencies exceeding 98% were possible, given sufficiently high inlet gas temperatures for the following classes of compounds: alcohols, acetates, ketones, hydrocarbons, and aromatics

  16. Airborne bacterial contaminations in typical Chinese wet market with live poultry trade.

    Science.gov (United States)

    Gao, Xin-Lei; Shao, Ming-Fei; Luo, Yi; Dong, Yu-Fang; Ouyang, Feng; Dong, Wen-Yi; Li, Ji

    2016-12-01

    Chinese wet markets with live poultry trade have been considered as major sources of pathogen dissemination, and sites for horizontal transfer of bacterial and viral pathogens. In this study, the pathogenic bacteria and antibiotic resistant genes (ARGs) in air samples collected at a typical Chinese wet market had been analysis and quantified. Corynebacterium minutissimum and other pathogenic bacteria accounted for 0.81-8.02% of the whole microbial community in different air samples. The four ARGs quantified in this study showed a comparable relative concentration (copies/ng_DNA) with municipal wastewater. Poultry manures were demonstrated to be important microbial contamination source in wet market, which was supported by both microbial composition based source tracking and the quantification of airborne microbial density. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination. Our results indicate bioaerosols acted as important route for the transmissions of pathogens and ARGs. Continued surveillance of airborne microbial contamination is required in poultry trade wet market.

  17. Wet foams hydrophobized by amphiphiles to give Al2O3 porous ceramics

    Science.gov (United States)

    Pokhrel, Ashish; Park, Jung Gyu; Kim, Ik Jin

    2012-05-01

    Wet chemical method to prepare ceramic foams with antecedent stability using inorganic particles (Al2O3,SiO2 etc.) which are in situ hydrophobized upon adsorption of short-chain amphiphilic molecules in the wet state and heightened mechanical property in the sintered state was developed. These wet foams are stable over several days and show no bubble coarsening nor drainage or creaming. This long-term stability is achieved through the irreversible adsorption of partially hydrophobized colloidal particles to the air-water interface using short-chain amphiphiles to in situ modify the wetting behavior of the particle surface based on the observations of Pickering emulsions. As a result, the suspension is foamed homogeneously throughout its entire volume and porous bulk materials can be produced upon drying and sintering. Wet foams featuring average bubble sizes between 30 and 300μm and sintered foams with porosity from 50 to 85% were obtained by adjusting the amphiphile - particle concentration, and additives in the initial suspension. Cells were mostly closed with an average size of approximately 150 μm. Single cells were separated by walls with minimum thicknesses of 1-3 μm.

  18. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  19. High-Throughput Continuous Flow Synthesis of Nickel Nanoparticles for the Catalytic Hydrodeoxygenation of Guaiacol

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Emily J.; Habas, Susan E.; Wang, Lu; Ruddy, Daniel A.; White, Erick A.; Baddour, Frederick G.; Griffin, Michael B.; Schaidle, Joshua A.; Malmstadt, Noah; Brutchey, Richard L.

    2016-11-07

    The translation of batch chemistries to high-throughput continuous flow methods dresses scaling, automation, and reproducibility concerns associated with the implementation of colloidally prepared nanoparticle (NP) catalysts for industrial catalytic processes. Nickel NPs were synthesized by the high-temperature amine reduction of a Ni2+ precursor using a continuous millifluidic (mF) flow method, achieving yields greater than 60%. The resulting Ni NP catalysts were compared against catalysts prepared in a batch reaction under conditions analogous to the continuous flow conditions with respect to total reaction volume, time, and temperature and by traditional incipient wetness (IW) impregnation for the hydrodeoxygenation (HDO) of guaiacol under ex situ catalytic fast pyrolysis conditions. Compared to the IW method, the colloidally prepared NPs displayed increased morphological control and narrowed size distributions, and the NPs prepared by both methods showed similar size, shape, and crystallinity. The Ni NP catalyst synthesized by the continuous flow method exhibited similar H-adsorption site densities, site-time yields, and selectivities towards deoxygenated products as compared to the analogous batch reaction, and outperformed the IW catalyst with respect to higher selectivity to lower oxygen content products and a 6.9-fold slower deactivation rate. These results demonstrate the utility of synthesizing colloidal Ni NP catalysts using continuous flow methods while maintaining the catalytic properties displayed by the batch equivalent. This methodology can be extended to other catalytically relevant base metals for the high-throughput synthesis of metal NPs for the catalytic production of biofuels.

  20. Differential photoacoustic cell to study the wetting process during porous silicon formation

    Energy Technology Data Exchange (ETDEWEB)

    German Espinosa-Arbelaez, Diego [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Posgrado en Ciencia e Ingenieria de Materiales, Edificio de Posgrado, Coyoacan, CP 04530, Mexico D. F. (Mexico); Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Blvd Juriquilla 3001, Campus Juriquilla, CP 76230, Queretaro, Qro. (Mexico); Velazquez-Hernandez, Ruben [Division de Investigacion y Posgrado, Facultad de Ingenieria, Universidad Autonoma de Queretaro, Cerro de las Campanas, CP 76010, Queretaro, Qro (Mexico); Petricioli-Carranco, Julio; Quintero-Torres, Rafael; Rodriguez-Garcia, Mario Enrique [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Blvd Juriquilla 3001, Campus Juriquilla, CP 76230, Queretaro, Qro. (Mexico)

    2011-06-15

    This paper shows the in-situ study of the wetting process in Silicon during anodization process using an electrochemical Differential photoacoustic Cell (DPC). The Photoacoustic amplitude and phase signals were obtained for samples in air, ethanol, ethanol/HF and finally air. According to these results ethanol is responsible for a mechanical contact reducing the superficial tension and ethanol/HF produce the removing of the SiO{sub x} and SiO{sub 2}species on the Silicon surface. It was found that the DPC is a powerful technique to study the wet surface before the formation of the porous silicon layer (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Ethanol-selective catalytic reduction of NO by Ag/Al2O3 catalysts: Activity and deactivation by alkali salts

    DEFF Research Database (Denmark)

    Schill, Leonhard; Putluru, Siva Sankar Reddy; Jacobsen, Casper Funk;

    2012-01-01

    Ag/Al2O3 catalysts with and without potassium doping were prepared by incipient wetness impregnation and characterized by N2 physisorption, XRPD, NH3-TPD and SEM. The influence of the Ag content from 1 to 5 wt.% was investigated for the selective catalytic reduction (SCR) of NO with ethanol. The 3...

  2. Green technology for conversion of renewable hydrocarbon based on plasma-catalytic approach

    Science.gov (United States)

    Fedirchyk, Igor; Nedybaliuk, Oleg; Chernyak, Valeriy; Demchina, Valentina

    2016-09-01

    The ability to convert renewable biomass into fuels and chemicals is one of the most important steps on our path to green technology and sustainable development. However, the complex composition of biomass poses a major problem for established conversion technologies. The high temperature of thermochemical biomass conversion often leads to the appearance of undesirable byproducts and waste. The catalytic conversion has reduced yield and feedstock range. Plasma-catalytic reforming technology opens a new path for biomass conversion by replacing feedstock-specific catalysts with free radicals generated in the plasma. We studied the plasma-catalytic conversion of several renewable hydrocarbons using the air plasma created by rotating gliding discharge. We found that plasma-catalytic hydrocarbon conversion can be conducted at significantly lower temperatures (500 K) than during the thermochemical ( 1000 K) and catalytic (800 K) conversion. By using gas chromatography, we determined conversion products and found that conversion efficiency of plasma-catalytic conversion reaches over 85%. We used obtained data to determine the energy yield of hydrogen in case of plasma-catalytic reforming of ethanol and compared it with other plasma-based hydrogen-generating systems.

  3. Aqueous Wetting Films on Fused Quartz.

    Science.gov (United States)

    Mazzoco; Wayner

    1999-06-15

    Using an image analyzing interferometer, IAI, the interfacial characteristics of an isothermal constrained vapor bubble, CVB, in a quartz cuvette were studied as a precursor to heat transfer research. The effects of pH and electrolyte concentration on the meniscus properties (curvature and adsorbed film thickness) and the stability of the aqueous wetting films were evaluated. The surface potential in the electric double layer was a function of the cleaning and hydroxylation of the quartz surface. The disjoining pressure isotherm for pure water was very close to that predicted by the Langmuir equation. For aqueous solutions of moderate electrolyte concentration, the Gouy-Chapman theory provided a good representation of the electrostatic effects in the film. The effect of temperature on the film properties of aqueous solutions and pure water was also evaluated: The meniscus curvature decreased with increasing temperature, while Marangoni effects, intermolecular forces, and local evaporation and condensation enhanced waves on the adsorbed film layer. Pure water wetting films were mechanically metastable, breaking into droplets and very thin films (less than 10 nm) after a few hours. Aqueous wetting films with pH 12.4 proved to be stable during a test of several months, even when subjected to temperature and mechanical perturbations. The mechanical stability of wetting films can explain the reported differences between the critical heat fluxes of pure water and aqueous solutions. The IAI-CVB technique is a simple and versatile experimental technique for studying the characteristics of interfacial systems. Copyright 1999 Academic Press.

  4. Wet oxidation of a spacecraft model waste

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T.

    1985-01-01

    Wet oxidation was used to oxidize a spacecraft model waste under different oxidation conditions. The variables studied were pressure, temperature, duration of oxidation, and the use of one homogeneous and three heterogeneous catalysts. Emphasis is placed on the final oxidation state of carbon and nitrogen since these are the two major components of the spacecraft model waste and two important plant nutrients.

  5. Towards hydrodynamic simulations of wet particle systems

    NARCIS (Netherlands)

    Roy, S.; Luding, S.; Weinhart, T.

    2015-01-01

    This paper presents the rheology of weakly wetted granular materials in the slow frictional regime, using Discrete Element Method (DEM) simulations. In a split-bottom ring shear cell geometry a slow, quasi-static deformation leads to wide shear bands away from the walls. Dry non-cohesive and cohesiv

  6. Determination of fungal spore release from wet building materials.

    Science.gov (United States)

    Kildesø, J; Würtz, H; Nielsen, K F; Kruse, P; Wilkins, K; Thrane, U; Gravesen, S; Nielsen, P A; Schneider, T

    2003-06-01

    The release and transport of fungal spores from water-damaged building materials is a key factor for understanding the exposure to particles of fungal origin as a possible cause of adverse health effects associated to growth of fungi indoors. In this study, the release of spores from nine species of typical indoor fungi has been measured under controlled conditions. The fungi were cultivated for a period of 4-6 weeks on sterilized wet wallpapered gypsum boards at a relative humidity (RH) of approximately 97%. A specially designed small chamber (P-FLEC) was placed on the gypsum board. The release of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum and Trichoderma harzianum), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied in the study may also be useful for field studies and for generation of spores for exposure studies.

  7. Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures

    OpenAIRE

    Tsai, Peichun; Lammertink, Rob G. H.; Wessling, Matthias; Lohse, Detlef

    2010-01-01

    When placed on rough hydrophobic surfaces, water droplets of diameter larger than a few millimeters can easily form pearls, as they are in the Cassie-Baxter state with air pockets trapped underneath the droplet. Intriguingly, a natural evaporating process can drive such a Fakir drop into a completely wetting (Wenzel) state. Our microscopic observations with simultaneous side and bottom views of evaporating droplets upon transparent hydrophobic microstructures elucidate the water-filling dynam...

  8. Management of Herbaceous Seeps and Wet Savannas for Threatened and Endangered Species.

    Science.gov (United States)

    1998-04-01

    especially in providing information about Coastal Plain depression ponds. Richard A. Fischer (WES) and Matthew Hohmann provided information on the...Depression marsh FNAI and The Nature Conservancy (TNC) 1995 NAS Pensacola and Outlying Field, Branson Wet prairie FNAI (1988) GA Air Force Moody AFB...virtually all remaining virgin forest in the South (Frost 1993). From approximately 1920 to the present, logged forests were converted to plantations, and

  9. Template electrodeposition of catalytic nanomotors.

    Science.gov (United States)

    Wang, Joseph

    2013-01-01

    The combination of nanomaterials with electrode materials has opened new horizons in electroanalytical chemistry, and in electrochemistry in general. Over the past two decades we have witnessed an enormous activity aimed at designing new electrochemical devices based on nanoparticles, nanotubes or nanowires, and towards the use of electrochemical routes--particularly template-assisted electrodeposition--for preparing nanostructured materials. The power of template-assisted electrochemical synthesis is demonstrated in this article towards the preparation and the realization of self-propelled catalytic nanomotors, ranging from Pt-Au nanowire motors to polymer/Pt microtube engines. Design considerations affecting the propulsion behavior of such catalytic nanomotors are discussed along with recent bioanalytical and environmental applications. Despite recent major advances, artificial nanomotors have a low efficiency compared to their natural counterparts. Hopefully, the present Faraday Discussion will stimulate other electrochemistry teams to contribute to the fascinating area of artificial nanomachines.

  10. Epimacular brachytherapy for wet AMD: current perspectives

    Directory of Open Access Journals (Sweden)

    Casaroli-Marano RP

    2014-08-01

    Full Text Available Ricardo P Casaroli-Marano,1,2 Socorro Alforja,1 Joan Giralt,1 Michel E Farah2 1Instituto Clínic de Oftalmología (Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain; 2Department of Ophthalmology and Visual Sciences, Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Sao Paulo, Brazil Abstract: Age-related macular degeneration (AMD is considered the most common cause of blindness in the over-60 age group in developed countries. There are basically two forms of presentation: geographic (dry or atrophic and wet (neovascular or exudative. Geographic atrophy accounts for approximately 85%–90% of ophthalmic frames and leads to a progressive degeneration of the retinal pigment epithelium and the photoreceptors. Wet AMD causes the highest percentage of central vision loss secondary to disease. This neovascular form involves an angiogenic process in which newly formed choroidal vessels invade the macular area. Today, intravitreal anti-angiogenic drugs attempt to block the angiogenic events and represent a major advance in the treatment of wet AMD. Currently, combination therapy for wet AMD includes different forms of radiation delivery. Epimacular brachytherapy (EMBT seems to be a useful approach to be associated with current anti-vascular endothelial growth factor agents, presenting an acceptable efficacy and safety profile. However, at the present stage of research, the results of the clinical trials carried out to date are insufficient to justify extending routine use of EMBT for the treatment of wet AMD. Keywords: macular degeneration, radiation, vascular endothelial growth factor, combined therapy, intravitreal therapy, vitrectomy

  11. Radiation/Catalytic Augmented Combustion.

    Science.gov (United States)

    1980-09-01

    NATIO& NAk H(fJI At tl TANUAHTOb 19 A ~omm.81-0287 LVL RADIATION/CATALYTIC AUGMENTED COMBUST ION MOSHE LAVID CORPORATE RESEARCH-TECHNOLOGY FEASIBILITY...refinements as necessary. i. Perform cannular combustor experiments to Investigate ignition and flame attachment in flowing, liquid -fuel, unpremixed...stabilizer, with a sintered metal disk on the downstream side through which hot gases or products of partial fuel oxidation can be passed. Experimental

  12. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    Science.gov (United States)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  13. Catalytic removal of carbon monoxide over carbon supported palladium catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Avanish Kumar [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Saxena, Amit [Centre for Fire Explosive and Environmental Safety, Timarpur, Delhi-110054 (India); Shah, Dilip; Mahato, T.H. [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Singh, Beer, E-mail: beerbs5@rediffmail.com [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Shrivastava, A.R.; Gutch, P.K. [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Shinde, C.P. [School of Studies in Chemistry, Jiwaji University, Gwalior-474002 (MP) (India)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Carbon supported palladium (Pd/C) catalyst was prepared. Black-Right-Pointing-Pointer Catalytic removal of CO over Pd/C catalyst was studied under dynamic conditions. Black-Right-Pointing-Pointer Effects of Pd %, CO conc., humidity, GHSV and reaction environment were studied. - Abstract: Carbon supported palladium (Pd/C) catalyst was prepared by impregnation of palladium chloride using incipient wetness technique, which was followed by liquid phase reduction with formaldehyde. Thereafter, Pd/C catalyst was characterized using X-ray diffractometery, scanning electron microscopy, atomic absorption spectroscopy, thermo gravimetry, differential scanning calorimetry and surface characterization techniques. Catalytic removal of carbon monoxide (CO) over Pd/C catalyst was studied under dynamic conditions. Pd/C catalyst was found to be continuously converting CO to CO{sub 2} through the catalyzed reaction, i.e., CO + 1/2O{sub 2} {yields} CO{sub 2}. Pd/C catalyst provided excellent protection against CO. Effects of palladium wt%, CO concentration, humidity, space velocity and reaction environment were also studied on the breakthrough behavior of CO.

  14. Thermodynamics of catalytic nanoparticle morphology

    Science.gov (United States)

    Zwolak, Michael; Sharma, Renu; Lin, Pin Ann

    Metallic nanoparticles are an important class of industrial catalysts. The variability of their properties and the environment in which they act, from their chemical nature & surface modification to their dispersion and support, allows their performance to be optimized for many chemical processes useful in, e.g., energy applications and other areas. Their large surface area to volume ratio, as well as varying sizes and faceting, in particular, makes them an efficient source for catalytically active sites. These characteristics of nanoparticles - i.e., their morphology - can often display intriguing behavior as a catalytic process progresses. We develop a thermodynamic model of nanoparticle morphology, one that captures the competition of surface energy with other interactions, to predict structural changes during catalytic processes. Comparing the model to environmental transmission electron microscope images of nickel nanoparticles during carbon nanotube (and other product) growth demonstrates that nickel deformation in response to the nanotube growth is due to a favorable interaction with carbon. Moreover, this deformation is halted due to insufficient volume of the particles. We will discuss the factors that influence morphology and also how the model can be used to extract interaction strengths from experimental observations.

  15. Catalytic polarographic currents of oxidizers

    Energy Technology Data Exchange (ETDEWEB)

    Zajtsev, P.M.; Zhdanov, S.I.; Nikolaeva, T.D. (Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Khimicheskikh Reaktivov i Osobo Chistykh Veshchestv, Moscow (USSR))

    1982-06-01

    The state of theory and practice of an important direction in polarography, i.e. catalytic currents of oxidizers-substrates that have found a wide application in the development of highly sensitive methods of determination of a large number of substrates, catalysts and polarographically nonactive ligands, is considered. Transition and some non-transition elements serve as catalysts of reactions that cause catalytic polarographic currents of substrates. Catalytic activity of an inorganic catalyst increases with the increase in the number of its d-orbit. Complex formation in most cases leads to the increase of catalyst activity, however, sometimes a reverse phenomenon takes place. For many catalysts the maximum activity is observed at pH values close to pK value of their hydrolysis. The properties of oxidizers-substrates is revealed by H/sub 2/O/sub 2/, ClO/sub 3//sup -/, BrO/sub 3//sup -/, IO/sub 3//sup -/, ClO/sub 4//sup -/, IO/sub 4//sup -/, NO/sub 2//sup -/, NO/sub 3//sup -/, NH/sub 2/OH, V(5), V(4), S/sub 2/O/sub 8//sup 2 -/, H/sub 2/SO/sub 4/, H/sub 2/C/sub 2/O/sub 4/, COHCOOH, alkenes compounds, organic halogen , sulfur- and amine-containing compounds.

  16. A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions

    Science.gov (United States)

    Thomas, Evan A.; Graf, John C.; Weislogel, Mark M.

    2010-01-01

    The invention, a static phase separator (SPS), uses airflow and capillary wetting characteristics to passively separate a two-phase (liquid and air) flow. The device accommodates highly variable liquid wetting characteristics. The resultant design allows for a range of wetting properties from about 0 to over 90 advancing contact angle, with frequent complete separation of liquid from gas observed when using appropriately scaled test conditions. Additionally, the design accommodates a range of air-to-liquid flow-rate ratios from only liquid flow to over 200:1 air-to-liquid flow rate. The SPS uses a helix input section with an ice-cream-cone-shaped constant area cross section (see figure). The wedge portion of the cross section is on the outer edge of the helix, and collects the liquid via centripetal acceleration. The helix then passes into an increasing cross-sectional area vane region. The liquid in the helix wedge is directed into the top of capillary wedges in the liquid containment section. The transition from diffuser to containment section includes a 90 change in capillary pumping direction, while maintaining inertial direction. This serves to impinge the liquid into the two off-center symmetrical vanes by the airflow. Rather than the airflow serving to shear liquid away from the capillary vanes, the design allows for further penetration of the liquid into the vanes by the air shear. This is also assisted by locating the air exit ports downstream of the liquid drain port. Additionally, any droplets not contained in the capillary vanes are re-entrained downstream by a third opposing capillary vane, which directs liquid back toward the liquid drain port. Finally, the dual air exit ports serve to slow the airflow down, and to reduce the likelihood of shear. The ports are stove-piped into the cavity to form an unfriendly capillary surface for a wetting fluid to carryover. The liquid drain port is located at the start of the containment region, allowing for

  17. Preparation of improved catalytic materials for water purification

    Science.gov (United States)

    Cherkezova-Zheleva, Z.; Paneva, D.; Tsvetkov, M.; Kunev, B.; Milanova, M.; Petrov, N.; Mitov, I.

    2014-04-01

    The aim of presented paper was to study preparation of catalytic materials for water purification. Iron oxide (Fe3O4) samples supported on activated carbon were prepared by wet impregnation method and low temperature heating in an inert atmosphere. The as-prepared, activated and samples after catalytic test were characterized by Mössbauer spectroscopy and X-ray diffraction. The obtained X-ray diffraction patterns of prepared samples show broad and low-intensity peaks of magnetite phase and the characteristic peaks of the activated carbon. The average crystallite size of magnetite particles was calculated below 20 nm. The registered Mössbauer spectra of prepared materials show a superposition of doublet lines or doublet and sextet components. The calculated hyperfine parameters after spectra evaluation reveal the presence of magnetite phase with nanosize particles. Relaxation phenomena were registered in both cases, i.e. superparamagnetism or collective magnetic excitation behavior, respectively. Low temperature Mössbauer spectra confirm this observation. Application of materials as photo-Fenton catalysts for organic pollutions degradation was studied. It was obtained high adsorption degree of dye, extremely high reaction rate and fast dye degradation. Photocatalytic behaviour of a more active sample was enhanced using mechanochemical activation (MCA). The nanometric size and high dispersion of photocatalyst particles influence both the adsorption and degradation mechanism of reaction. The results showed that all studied photocatalysts effectively decompose the organic pollutants under UV light irradiation. Partial oxidation of samples after catalytic tests was registered. Combination of magnetic particles with high photocatalytic activity meets both the requirements of photocatalytic degradation of water contaminants and that of recovery for cyclic utilization of material.

  18. 40 CFR 60.2680 - What if I do not use a wet scrubber to comply with the emission limitations?

    Science.gov (United States)

    2010-07-01

    ... Emissions Guidelines and Compliance Times for Commercial and Industrial Solid Waste Incineration Units that... air pollution control device other than a wet scrubber, or limit emissions in some other manner, to... comply with the emission limitations? 60.2680 Section 60.2680 Protection of Environment...

  19. Gecko Adhesion on Wet and Dry Patterned Substrates.

    Science.gov (United States)

    Stark, Alyssa Y; Palecek, Amanda M; Argenbright, Clayton W; Bernard, Craig; Brennan, Anthony B; Niewiarowski, Peter H; Dhinojwala, Ali

    2015-01-01

    Perhaps one of the most astounding characteristics of the gecko adhesive system is its versatility. Geckos can locomote across complex substrates in a variety of conditions with apparent ease. In contrast, many of our synthetic pressure sensitive adhesives fail on substrates that are dirty, wet or rough. Although many studies have investigated the effect of environmental challenges on performance, the interaction of multiple, potentially compromising variables is studied less often. Here we focus on substrate structure and surface water, both of which are highly relevant to the biological system and to synthetic design. To do this we utilized a highly controlled, patterned substrate (Sharklet®, by Sharklet® Technologies Inc.). This allowed us to test independently and jointly the effects of reduced surface area substrates, with a defined pattern, on adhesion in both air and water. Our results show that adhesion is not significantly impaired in air, whereas surface area and pattern significantly affect adhesion in water. These findings highlight the need to study multiple parameters that are relevant to the gecko adhesive system to further improve our understanding of the biological system and to design better, more versatile synthetics.

  20. Gecko Adhesion on Wet and Dry Patterned Substrates.

    Directory of Open Access Journals (Sweden)

    Alyssa Y Stark

    Full Text Available Perhaps one of the most astounding characteristics of the gecko adhesive system is its versatility. Geckos can locomote across complex substrates in a variety of conditions with apparent ease. In contrast, many of our synthetic pressure sensitive adhesives fail on substrates that are dirty, wet or rough. Although many studies have investigated the effect of environmental challenges on performance, the interaction of multiple, potentially compromising variables is studied less often. Here we focus on substrate structure and surface water, both of which are highly relevant to the biological system and to synthetic design. To do this we utilized a highly controlled, patterned substrate (Sharklet®, by Sharklet® Technologies Inc.. This allowed us to test independently and jointly the effects of reduced surface area substrates, with a defined pattern, on adhesion in both air and water. Our results show that adhesion is not significantly impaired in air, whereas surface area and pattern significantly affect adhesion in water. These findings highlight the need to study multiple parameters that are relevant to the gecko adhesive system to further improve our understanding of the biological system and to design better, more versatile synthetics.