Heavy metal ions removal from water using a smart polyurethane/acrylic hybrid

Abstract

Heavy metal contamination is certainly one of the most serious environmental problems today. In the present work, polymer films with pH-responsive properties were used for the removal of heavy metals from aqueous solution. These polymers were prepared using different amounts of 2-(diethylamino)ethyl methacrylate (DEA), and a polyurethane based on isophorone diisocyanate (PU) to obtain pH-responsive hybrid films of PU/DEA. Equilibrium sorption characteristics of Cu2+ and Zn2+ on polymer films were evaluated through batch studies. Hybrid systems were characterized by using FTIR, UV–Visible and microscopy techniques. The effect of pH, initial metal ion concentration and hybrid film composition on the extent of sorption were investigated. Maximum removal of Cu2+ and Zn2+ in hybrid systems was at pH 4.0, for 250 mg/L initial concentration of each ion, and for the hybrid system with more proportion of DEA (50 wt. %). Polymer systems showed greater selectivity for Zn2+ than for Cu2+, and the equilibrium sorption data were satisfactorily fitted to Langmuir sorption isotherm model. Characterization techniques revealed that functional groups of DEA, in hybrid systems, are the main sorption sites for the metal ions.