Magnetotactic bacteria （MTB） as biosorbents for the adsorption of Au（Ⅲ） and Cu（Ⅱ） ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH sc...Magnetotactic bacteria （MTB） as biosorbents for the adsorption of Au（Ⅲ） and Cu（Ⅱ） ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH scope of 1-5.5 for Au（Ⅲ） and 2.0-4.5 for Cu（Ⅱ）, room temperature, biomass concentration of 10.0g.L^-1 and sorotion du-ration more than 10 min. When the initial metal concentration were within 500mg.L^-1, the maximum biosorption capacity of 1.0g of MTB （dry mass basis） for Au（Ⅲ） and Cu（Ⅱ） were calculated as 505.2mg of Au（Ⅲ） and 493.1mg of.Cu（Ⅱ） by Langmuir model in single system, respectively. The isotherm equilibrium of Au（Ⅲ） and Cu（Ⅱ） ions in the Au-Cu binary system reflected a unique phenomenon that the adsorption of Au（Ⅲ） was rein-forced and that of Cu（Ⅱ） prohibited, compared respectively-with their performances in the single metal system.When the,concentration of-Au（Ⅲ） and Cu（Ⅱ）. were below 80mg.L^-1, the waste waterafter MTB treating, wasbelow 1.0mg.L^-1, which is in conformity with Environmental Performance Standards （EPS） of Canada. Besides, all the kinetic data were fitted well to the pseudo second-order kinetic model with a high correlation coefficient （R^2〉0.999）.展开更多
The high cost and poor atom utilization efficiency of noble metal catalysts have limited their industrial applications. Herein, we designed CeO2-supported single Au（Ⅲ） ion catalysts with ultra-low gold loading that...The high cost and poor atom utilization efficiency of noble metal catalysts have limited their industrial applications. Herein, we designed CeO2-supported single Au（Ⅲ） ion catalysts with ultra-low gold loading that can enhance the utilization efficiency of gold atoms and bridge the gap between homogeneous and heterogeneous gold catalysis. These catalysts were highly active and reusable for the reaction of 1,3-dicarbonyls with alcohols. The catalytic turnover number of CeO2-supported single Au（III） ion catalysts was much higher than that of the homogeneous catalyst NaAuCI4. In addition, the effects of gold loading and the drying method for the catalysts on the organic reactions were systematically explored. In-depth investigation of the structure-property relationship by high- resolution transmission electron microscop~ hydrogen temperature-programmed reduction, X-ray absorption near edge structure analysis, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy revealed that the isolated Au（III） ions were related to the active sites for the synthesis of β-substituted cyclohexenone and that CeO2 was responsible for yielding ketonic ester.展开更多
A novel alkoxycarbonyl thiourea resin(ATR)was synthesized by monomer polymerization of oxydiethane-2,1-diyl dicarbonisothiocyanatidate and polyethylene polyamine,and characterized by FT-IR.The adsorption properties of...A novel alkoxycarbonyl thiourea resin(ATR)was synthesized by monomer polymerization of oxydiethane-2,1-diyl dicarbonisothiocyanatidate and polyethylene polyamine,and characterized by FT-IR.The adsorption properties of ATR were investigated by batch test.The adsorption capacities for Au(Ⅲ),Ag(Ⅰ),Cu(Ⅱ),Zn(Ⅱ),Fe(Ⅲ),Ca(Ⅱ)and Mg(Ⅱ)are 4.65,4.40,0.40,0.90,0.86,0.0080 and 0.016 mmol/g,respectively,when the adsorption condition is as follows:contact time 24 h,temperature 30℃,initial concentration of Au(Ⅲ)5.08 mmol/L and that of other metals 0.10 mol/L,and concentration of acid 1.0 mol/L.The adsorption capacity for Au(Ⅲ)increases with the increase of contact time,temperature and initial concentration of Au(Ⅲ).The capacity after five adsorption-desorption cycles remains 90%that of the first time,and the separation factors of ATR for binary metal ion solutions are larger than 995,indicating that ATR is of good regeneration property and selectivity.XPS results show that the functional atoms of ATR supply electrons for Au and coordinate with Au during the adsorption.展开更多
基金Supported by the National Natural Science Foundation of China （No.20206024） and the Natural Science Foundation of Tianjin （No.07JCYBJC06800）.
文摘Magnetotactic bacteria （MTB） as biosorbents for the adsorption of Au（Ⅲ） and Cu（Ⅱ） ions from aqueous solution have been investigated. The optimum adsorption conditions for both metal ions were the initial pH scope of 1-5.5 for Au（Ⅲ） and 2.0-4.5 for Cu（Ⅱ）, room temperature, biomass concentration of 10.0g.L^-1 and sorotion du-ration more than 10 min. When the initial metal concentration were within 500mg.L^-1, the maximum biosorption capacity of 1.0g of MTB （dry mass basis） for Au（Ⅲ） and Cu（Ⅱ） were calculated as 505.2mg of Au（Ⅲ） and 493.1mg of.Cu（Ⅱ） by Langmuir model in single system, respectively. The isotherm equilibrium of Au（Ⅲ） and Cu（Ⅱ） ions in the Au-Cu binary system reflected a unique phenomenon that the adsorption of Au（Ⅲ） was rein-forced and that of Cu（Ⅱ） prohibited, compared respectively-with their performances in the single metal system.When the,concentration of-Au（Ⅲ） and Cu（Ⅱ）. were below 80mg.L^-1, the waste waterafter MTB treating, wasbelow 1.0mg.L^-1, which is in conformity with Environmental Performance Standards （EPS） of Canada. Besides, all the kinetic data were fitted well to the pseudo second-order kinetic model with a high correlation coefficient （R^2〉0.999）.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 21173269 and 21276277）, the Ministry of Science and Technology of China （No. 2011BAK15B05）, the Specialized Research Fund for the Doctoral Program of Higher Education （No. 20130007110003）.
文摘The high cost and poor atom utilization efficiency of noble metal catalysts have limited their industrial applications. Herein, we designed CeO2-supported single Au（Ⅲ） ion catalysts with ultra-low gold loading that can enhance the utilization efficiency of gold atoms and bridge the gap between homogeneous and heterogeneous gold catalysis. These catalysts were highly active and reusable for the reaction of 1,3-dicarbonyls with alcohols. The catalytic turnover number of CeO2-supported single Au（III） ion catalysts was much higher than that of the homogeneous catalyst NaAuCI4. In addition, the effects of gold loading and the drying method for the catalysts on the organic reactions were systematically explored. In-depth investigation of the structure-property relationship by high- resolution transmission electron microscop~ hydrogen temperature-programmed reduction, X-ray absorption near edge structure analysis, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy revealed that the isolated Au（III） ions were related to the active sites for the synthesis of β-substituted cyclohexenone and that CeO2 was responsible for yielding ketonic ester.
基金Projects(20476105,50604016)supported by the National Natural Science Foundation of China
文摘A novel alkoxycarbonyl thiourea resin(ATR)was synthesized by monomer polymerization of oxydiethane-2,1-diyl dicarbonisothiocyanatidate and polyethylene polyamine,and characterized by FT-IR.The adsorption properties of ATR were investigated by batch test.The adsorption capacities for Au(Ⅲ),Ag(Ⅰ),Cu(Ⅱ),Zn(Ⅱ),Fe(Ⅲ),Ca(Ⅱ)and Mg(Ⅱ)are 4.65,4.40,0.40,0.90,0.86,0.0080 and 0.016 mmol/g,respectively,when the adsorption condition is as follows:contact time 24 h,temperature 30℃,initial concentration of Au(Ⅲ)5.08 mmol/L and that of other metals 0.10 mol/L,and concentration of acid 1.0 mol/L.The adsorption capacity for Au(Ⅲ)increases with the increase of contact time,temperature and initial concentration of Au(Ⅲ).The capacity after five adsorption-desorption cycles remains 90%that of the first time,and the separation factors of ATR for binary metal ion solutions are larger than 995,indicating that ATR is of good regeneration property and selectivity.XPS results show that the functional atoms of ATR supply electrons for Au and coordinate with Au during the adsorption.
