Preparation of Polyvinyl Chloride-Based Thiosemicarbazide Resin and Its Selective Adsorption of Ag(I) and Au(III)

摘要

A thiosemicarbazide resin based on polyvinyl chloride (TPV) was synthesized via the reaction between polyvinyl chloride supported diethylenetriamine (PVC-DETA) and CS _2thiosemicarbazide. Its structure was characterized by elemental analysis and infrared spectra analysis. The adsorption properties for the single ion solutions of Cu(II), Zn(II), Cd(II), Pb(II), Hg(II), Ag(I), Au(III), and binary ion solutions containing Ag(I) or Au(III) were studied. Experimental results indicate that TPV shows high adsorption selectivity for Ag(I) and Au(III). Specifically, the selectivity coefficients for the competitive adsorption of Ag(I) or Au(III) on TPV are ∞, 10.25, 10.92, 34.00, 11.33, and 11.17 from Ag(I)/Zn(II), Ag(I)/Cd(II), Ag(I)/Hg(II), Au(III)/Cu(II), Au(III)/Zn(II), and Au(III)/Pb(II) binary solutions, respectively. Furthermore, adsorption kinetics and adsorption isotherms of Ag(I) and Au(III) on TPV were thoroughly investigated. The pseudo-second-order kinetic model provides a better correlation of the experimental data in comparison to the pseudo-first-order model. The adsorption equilibrium data correlate well with the Langmuir isotherm model with the maximum adsorption capacities of 0.73 mmol/g for Au(III) and 1.69 mmol/g for Ag(I).