In this work, the absorption-hydration hybrid method was used to recover （hydrogen ＋ nitrogen） from （hydrogen ＋ nitrogen ＋ methane ＋ argon） tail gas mixtures of synthetic ammonia plant through hydrate formatio...In this work, the absorption-hydration hybrid method was used to recover （hydrogen ＋ nitrogen） from （hydrogen ＋ nitrogen ＋ methane ＋ argon） tail gas mixtures of synthetic ammonia plant through hydrate formation/dissociation. A high-pressure reactor with magnetic stirrer was used to study the separation efficiency. The in-fluences of the concentration of anti-agglomerant, temperature, pressure, initial gas-liquid volume ratio, and oil-water volume ratio on the separation efficiency were systematically investigated in the presence of tetrahydro-furan （THF）. Anti-agglomerant was used to disperse hydrate particles into the condensate phase for water-in-oil emulsion system. Since nitrogen is the material for ammonia production, the objective production in our separation process is （hydrogen ＋ nitrogen）. Our experimental results show that by adopting appropriate operating conditions, high concentration of （hydrogen ＋ nitrogen） can be obtained using the proposed technology based on forming hydrate.展开更多
Fractionation of metals in acid sandy loam soil amended withalkaline-stabilised sewage sludge biosolids was conducted in order toassess metal bioavailability and environmental mobility. Soilsolution was extracted by a...Fractionation of metals in acid sandy loam soil amended withalkaline-stabilised sewage sludge biosolids was conducted in order toassess metal bioavailability and environmental mobility. Soilsolution was extracted by a centrifugation and filtration technique.Meal speciation in the soil solution was determined by a cationexchange resin method. Acetic acid and EDTA extracting solutions wereused for extraction of metals in soil solid surfaces. Metaldistribution in different fractions of soil solid phase wasdetermined using a three-step sequential extraction scheme.展开更多
The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffrac...The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffractometer and atomic absorption spectrophotometer （AAS）, respectively. Performance efficiency studies were conducted to determine the best combination ratio of sand-clay/pebbles. Sand-clay fortified with pebbles in the ratio 3：1 gave the optimum water purification while combination ratio 1：3 gave the least. The fortified sand-clays were used in the treatment of wastewater from rural locality. On the other hand, bacteria play an important role in determining the properties and behavior of clay minerals in natural environments and such interactions have great potential for creating stable biofilms and carbon storage sites in soils, but our knowledge of these interactions are far from complete. The purpose of this study was to understand better the effects of bacteria-generated biofilms on clay interlayer expansion. Mixtures of a colloidal, 2-water smectite clay and Pseudomonas aereginosae in a minimal media suspension evolve into a polysaccharide-rich biofilm aggregate in time-series experiments lasting up to 1 week. X-ray diffraction analysis reveals that upon aggregation, the clay undergoes an initial interlayer contraction.展开更多
A fugacity model was developed for prediction of mixed refrigerant gas hydrates formation conditions based on the molecule congregation and solution theories. In this model, gas hydrates were regarded as non-ideal sol...A fugacity model was developed for prediction of mixed refrigerant gas hydrates formation conditions based on the molecule congregation and solution theories. In this model, gas hydrates were regarded as non-ideal solid solution composed of water groups and guest molecules, and the expressions of fugacity of guest molecules in hydrate phase was proposed accordingly. It has been shown that the developed model can indicate successfully the effect of guest-guest molecule interaction. The results showed that the model can describe better the characteristics of phase equilibrium of mixed refrigerant gas hydrates and predictions are in good agreement with experimental data.展开更多
Stereochemical control is an important issue in carbohydrate synthesis.Glycosyl donors with participating acyl protective groups on 2-O have been shown to give 1,2-trans glycosides reliably under the pre-activation ba...Stereochemical control is an important issue in carbohydrate synthesis.Glycosyl donors with participating acyl protective groups on 2-O have been shown to give 1,2-trans glycosides reliably under the pre-activation based reaction condition.In this work,the effects of additives and reaction solvents on stereoselectivity were examined using donors without participating protective groups on 2-O.While several triflate salt additives did not have major effects,the amount of AgOTf was found to significantly impact the reaction outcome.Excess AgOTf led to lower stereochemical control presumably due to its coordination with the glycosyl triflate intermediate and a more SN1 like reaction pathway.In contrast,the stereoselectivity could be directed by reaction solvents,with diethyl ether favoring the formation of glycosides and dichloromethane leading to β isomers.The trend of stereochemical dependence on reaction solvent was applicable to a variety of building blocks including the selective formation of β-mannosides.展开更多
基金Supported by the National/qatural Science Foundation of China （20925623, 21006126）, the Special Funds for Major State Basic Research Program of China （No. 2009CB219504）, the Research Funds of China University of Petroleum, Beijing （BJBJRC-2010-01）, and Beijing Nova Program （2010B069）.
文摘In this work, the absorption-hydration hybrid method was used to recover （hydrogen ＋ nitrogen） from （hydrogen ＋ nitrogen ＋ methane ＋ argon） tail gas mixtures of synthetic ammonia plant through hydrate formation/dissociation. A high-pressure reactor with magnetic stirrer was used to study the separation efficiency. The in-fluences of the concentration of anti-agglomerant, temperature, pressure, initial gas-liquid volume ratio, and oil-water volume ratio on the separation efficiency were systematically investigated in the presence of tetrahydro-furan （THF）. Anti-agglomerant was used to disperse hydrate particles into the condensate phase for water-in-oil emulsion system. Since nitrogen is the material for ammonia production, the objective production in our separation process is （hydrogen ＋ nitrogen）. Our experimental results show that by adopting appropriate operating conditions, high concentration of （hydrogen ＋ nitrogen） can be obtained using the proposed technology based on forming hydrate.
基金National Natural Science Foundation of China(Nos.49831070 and 40125005)theNational Key Basic Research Support Foundation of China (No. G1999011807)the Jiangsu Provincial Foundation for Young Scientists (No. BQ98050).
文摘Fractionation of metals in acid sandy loam soil amended withalkaline-stabilised sewage sludge biosolids was conducted in order toassess metal bioavailability and environmental mobility. Soilsolution was extracted by a centrifugation and filtration technique.Meal speciation in the soil solution was determined by a cationexchange resin method. Acetic acid and EDTA extracting solutions wereused for extraction of metals in soil solid surfaces. Metaldistribution in different fractions of soil solid phase wasdetermined using a three-step sequential extraction scheme.
文摘The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffractometer and atomic absorption spectrophotometer （AAS）, respectively. Performance efficiency studies were conducted to determine the best combination ratio of sand-clay/pebbles. Sand-clay fortified with pebbles in the ratio 3：1 gave the optimum water purification while combination ratio 1：3 gave the least. The fortified sand-clays were used in the treatment of wastewater from rural locality. On the other hand, bacteria play an important role in determining the properties and behavior of clay minerals in natural environments and such interactions have great potential for creating stable biofilms and carbon storage sites in soils, but our knowledge of these interactions are far from complete. The purpose of this study was to understand better the effects of bacteria-generated biofilms on clay interlayer expansion. Mixtures of a colloidal, 2-water smectite clay and Pseudomonas aereginosae in a minimal media suspension evolve into a polysaccharide-rich biofilm aggregate in time-series experiments lasting up to 1 week. X-ray diffraction analysis reveals that upon aggregation, the clay undergoes an initial interlayer contraction.
文摘A fugacity model was developed for prediction of mixed refrigerant gas hydrates formation conditions based on the molecule congregation and solution theories. In this model, gas hydrates were regarded as non-ideal solid solution composed of water groups and guest molecules, and the expressions of fugacity of guest molecules in hydrate phase was proposed accordingly. It has been shown that the developed model can indicate successfully the effect of guest-guest molecule interaction. The results showed that the model can describe better the characteristics of phase equilibrium of mixed refrigerant gas hydrates and predictions are in good agreement with experimental data.
基金the National Institutes of Health (R01-GM-72667) for financial support of this work
文摘Stereochemical control is an important issue in carbohydrate synthesis.Glycosyl donors with participating acyl protective groups on 2-O have been shown to give 1,2-trans glycosides reliably under the pre-activation based reaction condition.In this work,the effects of additives and reaction solvents on stereoselectivity were examined using donors without participating protective groups on 2-O.While several triflate salt additives did not have major effects,the amount of AgOTf was found to significantly impact the reaction outcome.Excess AgOTf led to lower stereochemical control presumably due to its coordination with the glycosyl triflate intermediate and a more SN1 like reaction pathway.In contrast,the stereoselectivity could be directed by reaction solvents,with diethyl ether favoring the formation of glycosides and dichloromethane leading to β isomers.The trend of stereochemical dependence on reaction solvent was applicable to a variety of building blocks including the selective formation of β-mannosides.
