High-capacity Polyvinyltetrazole-grafted Chelating Resin for Adsorption of Heavy Metal Ions

A novel polyvinyltetrazole-grafted chelating resin was prepared by grafting poly(acrylonitrile) onto the chloromethylated polystyrene beads via surface-initiated atom transfer radical polymerization(SI-ATRP), and followed by the reaction of cyano-tetrazole conversion under microwave assistance. The structure of the resin was characterized by Fourier transform infrared spectroscopy and elemental analysis, and the adsorption properties were evaluated with Pb(II), Ni(II) and Cd(II). It was found that an increase in the polymerization time leads to the increases in grafting degree of acrylonitrile, the binding amount of tetrazoles and adsorption capacities of Pb(II), Ni(II), and Cd(II). The results suggested that the polymerization of acrylonitrile on the resin surface was a controllable living polymerization, and the binding amount of tetrazoles on the resin surface and adsorption capacity of the resins could be adjusted by the polymerization time. The adsorption of three metal ions was mainly regarded as chemical adsorption based on the coordinating effect by analyzing the relationship between adsorption capacity with the solution pH, adsorption isotherm and adsorption kinetics. At the polymerization time of 10 h, the maximum sorption capacities of Pb(II), Ni(II) and Cd(II) were 1. 57, 1. 68 and 1. 92 mmol/g, respectively. Ten adsorption-desorption cycles demonstrated that the resin possessed high recycling efficiency and stability and was suitable for efficient removal of metal ions from aqueous solution.