Simultaneous studies on kinetics, bio-adsorption behaviour of chitosan grafted thin film nanohydrogel for removal of hazardous metal ion from water

Abstract

Abstract Natural biodegradable chitosan (CS) based thin film nanogels (TNG)s were developed and optimized in order to obtain films possessing the optimal functional properties (biodegradabiity, nontoxicity and bioadhesion) to be applied for heavy metal ion removal from aqueous systems. The grafting of 2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) onto CS via redox initiator system of ammonium persulfate (APS) and complex catalyst CuSO4/glycine (1:1) in the presence of foaming agent sorbitol was designed. The CS-g-P(HEMA-co-AA)/nano-CaO, a novel thin film was prepared from the combination of CS-g-P (HEMA-co-AA) copolymers with the modified snail shell, nano-CaO as a nanofiller, then the so prepared CS-g-P(HEMA-co-AA)/nano-CaO nanogel thin film is used to encapsulate active toxic heavy metal ions in water systems. Characterization of TNGs was done by FT-IR, XRD, TGA, FESEM. In addition, their kinetic isotherms with proper kinetic model at optimum pH were studied. The Langmuir and the Langmuir-Freundlich adsorption isotherm models obtained by the UV spectrophotometer were applied to describe the isotherm parameter for Cr (VI) adsorption by TNG. So the TNGs are potentially suitable for use as superadsorbents exhibiting good biodegradability and are cost-effective for their better commercialization and industrialization as well.