A new high-capacity imidazole type chelating resin was synthesized via surface-initiated atom transfer radical polymerization(SI-ATRP) method.1-Vinylimidazole(VIM) was grafted onto the surface of the chloromethyl polystyrene resin by SI-ATRP using organic metal compound formed in the CuBr/2,2’-bipyridine(Bpy) system as catalyst at room temperature.The chelating resin was characterized by means of isoelectronic X ray spectrum,elementary analysis and electron microscopy,and its adsorption properties,parameters of kinetics and thermodynamics were determined.The amount of VIM on the surface of polystyrene resin was calculated to be 1.008 mg/m2.Adsorption capacity for cadmium(Ⅱ) and zinc(Ⅱ) increased with increasing initial metal ion concentration and temperature,and its highest values were 653.1 mg/g for cadmium(Ⅱ) at pH 3.6 and 793.3 mg/g for zinc(Ⅱ) at pH 2.4.The experimental results showed that the equilibrium adsorption data fitted well to both Langmuir and Freundlich isotherms.The thermodynamic equilibrium functions were also determined as follows:ΔG<0,ΔH=24.47 kJ/mol,ΔS>0,so the adsorption was spontaneous,endothermic and entropy increasing.The kinetic experimental data were correlated with second-order kinetic model.
关键词
咪唑型螯合树脂表面引发原子转移自由基聚合法吸附性能Cd2+Zn2+动力学热力学
Keywords
imidazole type chelating resinsurface-initiated atom transfer radical polymerization(SI ATRP)adsorption propertyCd(Ⅱ)Zn(Ⅱ)kineticsthermodynamics