Preparation of High-capacity Imidazole Type Chelating Resin and Its Adsorption Properties to Cd£¨¢ò) and Zn£¨¢ò)

KeyWord:imidazole type chelating resin  surface-initiated atom transfer radical polymerization£¨SI ATRP)  adsorption property  Cd£¨¢ò)  Zn£¨¢ò)  kinetics  thermodynamics

Abstract:

      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£¨¢ò) and zinc£¨¢ò) increased with increasing initial metal ion concentration and temperature£¬and its highest values were 653.1 mg/g for cadmium£¨¢ò) at pH 3.6 and 793.3 mg/g for zinc£¨¢ò) 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:¦¤G<0£¬¦¤H=24.47 kJ/mol£¬¦¤S>0£¬so the adsorption was spontaneous£¬endothermic and entropy increasing.The kinetic experimental data were correlated with second-order kinetic model.