Removal of Cu2+ and Pb2+ Ions Using CMC Based Thermoresponsive Nanocomposite Hydrogel

Abstract

In this study, carboxymethylcellulose (CMC) based thermoresponsive nanocomposite hydrogel was synthesized for the removal of Cu2+ and Pb2+ ions from aqueous solutions. To prepare nanocomposite hydrogel, graft copolymerization of N-isopropyl acrylamide (NIPAm) and acrylic acid (AA) onto CMC was carried out in Na-montmorillonite (MMT)/water suspension media and ammonium persulfate (APS) used as initiator. The chemical structures of hydrogels were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction spectroscopy (XRD). Lower critical solution temperature (LCST), pH responsivity, swelling, and deswelling properties of the hydrogels were also examined. In addition competitive and non-competitive removal of Cu2+ and Pb2+ studies were carried out. According to heavy metal sorption studies results, removal capacities of nanocomposite hydrogel for both metal ions were found to be higher than those of pure hydrogel. The analyzed adsorption data showed that the adsorption process of Cu2+ and Pb2+ could be explained by pseudo-second order kinetic model. Moreover, according to competitive sorption studies, it is found to be that both hydrogels are more selective to Cu2+ ion rather than Pb2+.