The new solvent extraction system for gold() from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organ...The new solvent extraction system for gold() from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organic phase, molar ratio of CPBAu(CN)2-, extraction time, aqueous/organic phase ratio, different initial gold concentration, equilibrium temperature, different diluent, different types of extractants and surfactants etc., was inspected. The results show that gold() can be extracted quantitatively by controlling the quantity of surfactant (CPB); both the equilibrium pH and diluent hardly influence percent extraction. Gold() percent extraction reaches more than 98% under the optimal experimental conditions. 30% vol TBP diluted by sulphonating kerosene can load gold() to rather high levels. Loading capacity is in excess of 38 g/L. The extraction mechanism is discussed and the overall extraction reaction is deduced.展开更多
The effects of surfactant on the solvent extraction in leachingsphalerite were investigated. It is found that sodium dodecylsulfonate is the effective surfactant in improving the zinc recoveryfrom sphalerite in the aq...The effects of surfactant on the solvent extraction in leachingsphalerite were investigated. It is found that sodium dodecylsulfonate is the effective surfactant in improving the zinc recoveryfrom sphalerite in the aqueous FeCl_3-HCl-tetrachloroethylene system.Through the measurements of surface tension and viscosity of thesphalerite Slurry modified with different surfactants, it isconcluded that sodium dodecyl sulfonate in the concentration rang Of0.05 to 0.2 g·L^-1 can improve the viscosity of sphalerite slurry inthe water, decrease the surface tension of Leaching solution, preventthe aggregation of ore particles, and give very high zinc extraction.展开更多
Macroscopic SiO2 spheres with a homogeneous amine distribution were synthesized by a one-step emulsion based synthesis approach in a flow column reactor. The CO2 adsorption capacity of the nanostructured amine-functio...Macroscopic SiO2 spheres with a homogeneous amine distribution were synthesized by a one-step emulsion based synthesis approach in a flow column reactor. The CO2 adsorption capacity of the nanostructured amine-functionalized silica spheres was studied in absence and presence of H2O. The structural properties were adjusted by varying solvents and surfactants during the synthesis and, at constant amine loadings, were found to be the main factor for influencing the CO2 sorption capacities. Under water-free conditions CO2 is bound to the amino groups via the formation of carbamates, which require two neighboring amino groups to adsorb one CO2 molecule. At constant amine concentrations sorbents with lower surface area allow to establish a higher amine density on the surface, which enhances the CO2 uptake capacities under dry conditions. In presence of H2O the CO2 adsorption changes to 1：1 stoichiometry due to stabilization of carbamates by protonation of H2O and formation of further species such as bicarbonates, which should in principle double the adsorption capacities. Low concentrations of physisorbed H2O（0.3 mmol/g） did not impair the adsorption capacity of the adsorbents for CO2, while at higher water uptakes（0.6 and 1.1 mmol/g） the CO2 uptake is reduced, which could be attributed to capillary condensation of H2O or formation of bulky reaction products blocking inner pores and access to active sites.展开更多
A new solvent extraction system of Au by surfactant CTMAB-TBP-inert diluent-Au（CN）-2-H2O was investigated and established. The infrared spectra and the conductivities of loaded organic phases containing （Au） were ...A new solvent extraction system of Au by surfactant CTMAB-TBP-inert diluent-Au（CN）-2-H2O was investigated and established. The infrared spectra and the conductivities of loaded organic phases containing （Au） were recorded stage by stage. It was reported that in the presence of salting-out agents the pencent extraction of Au decreased, and the conversion of emulsions from W/O to O/W happened in the extraction processed. The results demonstrate that the extraction process of Au（CN）-2 is carried out by two steps. First, an associated molecule between CTMA+ and TBP, as (C16H33)（CH3）3N+·H2O·OP（OC4H9）3, is formed by dint of water molecule, then it will pull Au（CN）-2 into the organic phase based on the electro-neutrality.展开更多
The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the hal...The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the half-life of the activity of the coated lipase was ca 10 h, the enzyme activity became less changed after 12 h and the residual activity was 39% of the initial value. The coated lipase obeyed a first-order deactivation model with a deactivation energy of 29.9J.mol-1.展开更多
采用溶剂-非溶剂的方法,通过加入不同的晶形控制剂制备超细CL-20,并对晶形控制剂的种类和用量、加料方式等因素进行了分析。结果表明,晶形控制剂的种类、用量及样品溶剂加料方式严重地影响着超细CL-20的晶形。对于2.0 g CL-20原料,采用3...采用溶剂-非溶剂的方法,通过加入不同的晶形控制剂制备超细CL-20,并对晶形控制剂的种类和用量、加料方式等因素进行了分析。结果表明,晶形控制剂的种类、用量及样品溶剂加料方式严重地影响着超细CL-20的晶形。对于2.0 g CL-20原料,采用3.5 mL质量浓度2%聚乙烯醇类化合物(PV)晶形控制剂,所得到的超细粉末晶形大多为块状,晶体粒径最小可达到1μm;采用6.5 mL质量浓度5%聚氧乙烯醚类化合物(PT)晶形控制剂,所得到的超细粉末晶形也大多为块状,晶体粒径最小可达到2μm。采用喷壶方式加料,使用6.5 mL质量浓度5%PT晶形控制剂可使晶形呈椭圆形,晶体粒径最小可达到1μm,细化后的CL-20热敏感性更高,晶型仍为ε型。展开更多
文摘The new solvent extraction system for gold() from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organic phase, molar ratio of CPBAu(CN)2-, extraction time, aqueous/organic phase ratio, different initial gold concentration, equilibrium temperature, different diluent, different types of extractants and surfactants etc., was inspected. The results show that gold() can be extracted quantitatively by controlling the quantity of surfactant (CPB); both the equilibrium pH and diluent hardly influence percent extraction. Gold() percent extraction reaches more than 98% under the optimal experimental conditions. 30% vol TBP diluted by sulphonating kerosene can load gold() to rather high levels. Loading capacity is in excess of 38 g/L. The extraction mechanism is discussed and the overall extraction reaction is deduced.
基金Supported by the National Natural Science Foundation of China (No. 29836130).
文摘The effects of surfactant on the solvent extraction in leachingsphalerite were investigated. It is found that sodium dodecylsulfonate is the effective surfactant in improving the zinc recoveryfrom sphalerite in the aqueous FeCl_3-HCl-tetrachloroethylene system.Through the measurements of surface tension and viscosity of thesphalerite Slurry modified with different surfactants, it isconcluded that sodium dodecyl sulfonate in the concentration rang Of0.05 to 0.2 g·L^-1 can improve the viscosity of sphalerite slurry inthe water, decrease the surface tension of Leaching solution, preventthe aggregation of ore particles, and give very high zinc extraction.
基金supported by the German Research Council(DFG)within the priority program(Schwerpunktprogramm),“Poröse Medien mit definierter Porenstruktur in der Verfahrenstechnik–Modellierung,Anwendngen,Synthese”(SPP 1570)under the projects LE 1187/10 and SP 648/4the framework of the DFG Excellence Initiative the Cluster of Excellence“Engineering of Advanced Materials”(DFG EXC 415)funding via the DFG research training group GRK 1896
文摘Macroscopic SiO2 spheres with a homogeneous amine distribution were synthesized by a one-step emulsion based synthesis approach in a flow column reactor. The CO2 adsorption capacity of the nanostructured amine-functionalized silica spheres was studied in absence and presence of H2O. The structural properties were adjusted by varying solvents and surfactants during the synthesis and, at constant amine loadings, were found to be the main factor for influencing the CO2 sorption capacities. Under water-free conditions CO2 is bound to the amino groups via the formation of carbamates, which require two neighboring amino groups to adsorb one CO2 molecule. At constant amine concentrations sorbents with lower surface area allow to establish a higher amine density on the surface, which enhances the CO2 uptake capacities under dry conditions. In presence of H2O the CO2 adsorption changes to 1：1 stoichiometry due to stabilization of carbamates by protonation of H2O and formation of further species such as bicarbonates, which should in principle double the adsorption capacities. Low concentrations of physisorbed H2O（0.3 mmol/g） did not impair the adsorption capacity of the adsorbents for CO2, while at higher water uptakes（0.6 and 1.1 mmol/g） the CO2 uptake is reduced, which could be attributed to capillary condensation of H2O or formation of bulky reaction products blocking inner pores and access to active sites.
基金Project(29876016) supported by the National Natural Science Foundation of China Project(9808K) supported by theYunnan Peking University Research and Development Cooperation Foundation
文摘A new solvent extraction system of Au by surfactant CTMAB-TBP-inert diluent-Au（CN）-2-H2O was investigated and established. The infrared spectra and the conductivities of loaded organic phases containing （Au） were recorded stage by stage. It was reported that in the presence of salting-out agents the pencent extraction of Au decreased, and the conversion of emulsions from W/O to O/W happened in the extraction processed. The results demonstrate that the extraction process of Au（CN）-2 is carried out by two steps. First, an associated molecule between CTMA+ and TBP, as (C16H33)（CH3）3N+·H2O·OP（OC4H9）3, is formed by dint of water molecule, then it will pull Au（CN）-2 into the organic phase based on the electro-neutrality.
基金Supported by the National Natural Science Foundation of China(No.29876031)
文摘The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the half-life of the activity of the coated lipase was ca 10 h, the enzyme activity became less changed after 12 h and the residual activity was 39% of the initial value. The coated lipase obeyed a first-order deactivation model with a deactivation energy of 29.9J.mol-1.
