Preparation of poly(vinylalcohol)/poly(acrylamide-co-vinyl imidazole)/-Fe2O3 semi-IPN nanocomposite and their application for removal of heavy metal ions from water

A series of magnetic semi-interpenetrating polymer network (semi-IPN) hydrogels was prepared in one-stage strategy composed of linear poly(vinyl alcohol) (PVA) chains and magnetic -Fe2O3 nanoparticles entrapped within the cross-linked poly(acrylamide-co-vinylimidazole) (poly(AAm-co-VI)) network. The influence of PVA, weight ratio of AAm:VI, -Fe2O3, and MBA on the swelling properties of the obtained nanocomposite hydrogels was evaluated. The prepared magnetic semi-IPN hydrogels were fully characterized and used as absorbent for removal of Pb(II) and Cd(II) from water. Factors that influence the metal ion adsorption such as solution pH, contact time, initial metal ion concentration, and temperature were studied in details. The experimental results were reliably described by Langmuir adsorption isotherms. The adsorption capacity of semi-IPN nanocomposite for Pb(II) and Cd(II) were175.80 and 149.76mgg(-1), respectively. The kinetic experimental data indicated that the chemical sorption is the rate-determining step. According to thermodynamic studies, Pb(II) and Cd(II) adsorption on the hydrogels was endothermic and also chemical in nature. The prepared magnetic PVA/poly(AAm-co-VI) semi-IPN hydrogels could be employed as efficient and low-cost adsorbents of heavy metal ions from water. Copyright (c) 2016 John Wiley & Sons, Ltd.