The quantification and effects of system pH value on the interactions between Pb（II） and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks （Ex/Em = 280 nm1...The quantification and effects of system pH value on the interactions between Pb（II） and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks （Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B）. The fluorescence intensities of peak B were higher than those of peak A. The fluorophores of both peaks could be largely quenched by Pb（ll）, and the quencher dose for peak B was about half of that for peak A. The modified Stern-Volmer equation well depicted the fluorescence quenching titration. The quenching constant （Ka） values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb（II） due to the occurrence of Pb（OH）2 sediments. The Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins （peak B） played a key role in the interactions between metal ions and the biopolymer.展开更多
A new iminodiacetic acid （IDA） type chelating membrane based on composite matrix formed by covalently coupling the polyglycidyl methacrylate to cotton cellulose fiber was developed. The study focused on the optimal ...A new iminodiacetic acid （IDA） type chelating membrane based on composite matrix formed by covalently coupling the polyglycidyl methacrylate to cotton cellulose fiber was developed. The study focused on the optimal conditions for the preparation of the membrane and the reaction of the chelating agent （iminodiacetic acid, IDA） with the matrix. The physical properties of the chelating membrane were tested by electron micrography and BET surface area instrument. The relationship between flow-rate and backpressure was almost linear. Adsorption isotherm of protein on Cu 2+-IDA membrane was determined by batch experiments. The dissociation constants and the maximum adsorption capacity were obtained. The results of affinity purification of human serum albumin and bovine liver catalase on membrane are comparable with those on gel chromatography presented in literature. The separations performed on the membrane chromatography, however, were 35 times faster than those on gel chromatography. The immobilized metal composite membrane was also successfully used in HPLC for rapid analysis of protein. Thus, the composite membrane reported here, with low backpressure, low cost and long service-life, is quite suitable for rapid and large scale affinity purification and HPLC analysis of biopolymers.展开更多
基金Acknowledgements This work was supported by the Foundation of State Key Laboratory of Pollution Control and Resource Reuse （Tongji University）, China （No. PCRRE16019）, the National Natural Science Foundation of China （Grant Nos. 51678422 and 51378368）, Sheng Yun- Fei College Students Scientific and Technological Innovation Fund, China Scholarship Council （No. 201506260022）, the National Science ＆ Technology Pillar Program （No. 2013BAD21B03）, and the higher school innovative engineering plan （111 Projec0.
文摘The quantification and effects of system pH value on the interactions between Pb（II） and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks （Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B）. The fluorescence intensities of peak B were higher than those of peak A. The fluorophores of both peaks could be largely quenched by Pb（ll）, and the quencher dose for peak B was about half of that for peak A. The modified Stern-Volmer equation well depicted the fluorescence quenching titration. The quenching constant （Ka） values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb（II） due to the occurrence of Pb（OH）2 sediments. The Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins （peak B） played a key role in the interactions between metal ions and the biopolymer.
文摘A new iminodiacetic acid （IDA） type chelating membrane based on composite matrix formed by covalently coupling the polyglycidyl methacrylate to cotton cellulose fiber was developed. The study focused on the optimal conditions for the preparation of the membrane and the reaction of the chelating agent （iminodiacetic acid, IDA） with the matrix. The physical properties of the chelating membrane were tested by electron micrography and BET surface area instrument. The relationship between flow-rate and backpressure was almost linear. Adsorption isotherm of protein on Cu 2+-IDA membrane was determined by batch experiments. The dissociation constants and the maximum adsorption capacity were obtained. The results of affinity purification of human serum albumin and bovine liver catalase on membrane are comparable with those on gel chromatography presented in literature. The separations performed on the membrane chromatography, however, were 35 times faster than those on gel chromatography. The immobilized metal composite membrane was also successfully used in HPLC for rapid analysis of protein. Thus, the composite membrane reported here, with low backpressure, low cost and long service-life, is quite suitable for rapid and large scale affinity purification and HPLC analysis of biopolymers.
