The adsorption equilibrium of a fluoride solution on 1-2 mm granular activated alumina modified by Fe2(SO4)3 solution was investigated.The experiments were conducted using a wide range of initial fluoride concentratio...The adsorption equilibrium of a fluoride solution on 1-2 mm granular activated alumina modified by Fe2(SO4)3 solution was investigated.The experiments were conducted using a wide range of initial fluoride concentrations(0.5 to 180 mg·L-1 at pH～7.0) and an adsorbent dose of 1.0 g·L-1.The application of Langmuir and Freundlich adsorption isotherm models(linear and nonlinear forms) generally showed that a single Langmuir or Freundlich equation cannot fit the entire concentration gap.Experimental data on low equilibrium concentrations(0.1 to 5.0 mg·L-1) was in line with both Langmuir and Freundlich isotherm models,whereas that of high equilibrium concentrations(5.0 to 150 mg·L-1) was more in line with the Freundlich isotherm model.A new LangmuirFreundlich function was used for the entire concentration gap,as well as for low and high concentrations.展开更多
Gold bearing pyrite leaching was conducted in H2SO4-Fe2（SO4）3 system at different reaction temperatures,with different ferric ion concentrations,sulfuric acid concentrations and stirring speeds.The leaching kinetics...Gold bearing pyrite leaching was conducted in H2SO4-Fe2（SO4）3 system at different reaction temperatures,with different ferric ion concentrations,sulfuric acid concentrations and stirring speeds.The leaching kinetics and mechanism were studied.When the temperature ranged between 30-75 °C,the pyrite leaching was mainly controlled by chemical reaction with positive correlation to the ferric ion concentration.The activation energy obtained from Arrhenius empirical formula is 51.39 k J/mol.The EDS and XPS analyses suggest that the oxidation of sulfur within pyrite is through a series of intermediate stages,and eventually is oxidized to sulphate accompanied with the formation of element sulfur.This indicates a thiosulfate oxidation pathway of the gold bearing pyrite oxidation in H2SO4-Fe2（SO4）3 system.展开更多
The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluene...The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.展开更多
基金Supported by the Major National Science and Technology Special Project on Treatment and Control of Water Pollution(2009ZX07425-006)the State Key laboratory of Environmental Simulation and Pollution Control (09K04ESPCT)
文摘The adsorption equilibrium of a fluoride solution on 1-2 mm granular activated alumina modified by Fe2(SO4)3 solution was investigated.The experiments were conducted using a wide range of initial fluoride concentrations(0.5 to 180 mg·L-1 at pH～7.0) and an adsorbent dose of 1.0 g·L-1.The application of Langmuir and Freundlich adsorption isotherm models(linear and nonlinear forms) generally showed that a single Langmuir or Freundlich equation cannot fit the entire concentration gap.Experimental data on low equilibrium concentrations(0.1 to 5.0 mg·L-1) was in line with both Langmuir and Freundlich isotherm models,whereas that of high equilibrium concentrations(5.0 to 150 mg·L-1) was more in line with the Freundlich isotherm model.A new LangmuirFreundlich function was used for the entire concentration gap,as well as for low and high concentrations.
基金Project(51474075)supported by the National Natural Science Foundation of China
文摘Gold bearing pyrite leaching was conducted in H2SO4-Fe2（SO4）3 system at different reaction temperatures,with different ferric ion concentrations,sulfuric acid concentrations and stirring speeds.The leaching kinetics and mechanism were studied.When the temperature ranged between 30-75 °C,the pyrite leaching was mainly controlled by chemical reaction with positive correlation to the ferric ion concentration.The activation energy obtained from Arrhenius empirical formula is 51.39 k J/mol.The EDS and XPS analyses suggest that the oxidation of sulfur within pyrite is through a series of intermediate stages,and eventually is oxidized to sulphate accompanied with the formation of element sulfur.This indicates a thiosulfate oxidation pathway of the gold bearing pyrite oxidation in H2SO4-Fe2（SO4）3 system.
文摘The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters.The catalysts generally preferred are sulfuric acid or p-toluenesulfonic acid.But the products esters were racemic when（S）-3-（2′-oxocyclohexyl） propionic acid reacts with alcohols in the presence of sulfuric acid or with p-toluenesulfonic acid as catalyst.We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst.The optical compound（S）-methyl-3-（2′-oxocyclohexyl）propionate,（（S）-ethyl-3-）（2′-oxocyclohexyl）propionate and（S）-n-butyl-3-（2′-oxocyclohexyl）propionate were obtained.In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate（R）TTCA·K as the chiral catalyst to afford optically active（S）-3-（2′-oxocy-clohexyl） propionate.The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of（R）TTCA·K as the catalyst would be a complex process.
