Removal of metal ions from aqueous solutions by chitosan-g-itaconic acid/hydrophilic nanoclay nanocomposites

Abstract

In this work, chitosan-g-itaconic acid copolymer nanocomposites containing nanoclay (1-5%, weight ratio) were synthesized using cerium (IV) ammonium nitrate as initiator. The optimum reaction conditions were identified as chitosan/itaconic acid monomer weight ratio of 3/9 and initiator concentration of 0.003 mol/L. These reaction conditions were used as preparation of chitosan-g-itaconic acid copolymer nanocomposites. XRD analysis and grafting percentage determination were used for characterization of nanocomposites. XRD patterns of nanocomposites indicate that clay sheets are exfoliated. Grafting percentages of chitosan-g-itaconic acid copolymers were determined as about 30%. Chitosan-g-itaconic acid nanocomposites were used for the removal of heavy metal ions from aqueous solutions. The results showed that the second-order kinetic model was suitable for the adsorption of Cu(II) and Pb(II) onto chitosan-g-itaconic acid nanocomposites. The equilibrium adsorption data have been evaluated using Langmuir, Freundlich, Temkin, Dubinin-Raduskevich and Redlich-Peterson models. Langmuir isotherm model (Type 1) and Redlich-Peterson isotherms are the best-fit models for the adsorption process in this study.