Introduction and demonstration of a novel Pb(II)-imprinted polymeric membrane with high selectivity and reusability for treatment of lead contaminated water.

Lead contaminant in water has become an issue of great concern due to its high toxicity and easy accumulation in human body. In this study, a novel Pb(II)-imprinted polyvinyl alcohol (PVA)/polyacrylic acid (PAA) membrane (Pb-IM) was prepared based on semi-interpenetrating polymer network for selective lead removal. The chemical stability and lead adsorption performance of the Pb-IM were evaluated. The results revealed that the Pb-IM exhibited high adsorption capacity of 1.003mmol/g for lead, fast adsorption equilibrium within 1.5h, and the adsorption process obeyed Langmuir isotherm model and intraparticle pore diffusion model. The Pb-IM retained high adsorption of lead in the presence of competitive factor, i.e. cadmium. In comparison with non-imprinted PVA/PAA membrane, the Pb-IM possessed a much higher selectivity toward lead versus cadmium, with selectivity coefficient of 70.7. Furthermore, the Pb-IM displayed a high reusability for lead uptake and could maintain 96.32% of the adsorption capacity of virgin Pb-IM after six adsorption/desorption cycles. The FTIR and XPS analyses indicated that carboxyl groups in PAA and hydroxyl groups in PVA were mainly associated with the lead adsorption. Finally, the stability study showed that Pb-IM was quite stable and suitable for water treatment. It can be concluded that the Pb-IM can be provided as a powerful material for the selective removal of lead from aqueous solution.