Crosslinked chitosan oligosaccharide-based binary and ternary blends for the removal of Cu(II) ions

Copper is one of the toxic heavy metal, it has to be eliminated from the polluted environment. Thus, the present work was aimed to prepare glutaraldehyde crosslinked chitosan oligosaccharide (COS)-based binary and ternary blend using carboxymethyl starch (CMS) and kaolin clay (KC) and applied as a sorbent for copper(II) ions to overcome excessive heavy metal pollution. Initially, the binary and ternary blends are prepared using sol–gel method and then examined for its formation and suitability for adsorption using FTIR, XRD, BET, Zeta potential and SEM studies. The prepared COS/CMS and COS/CMS/KC blends demonstrated outstanding adsorption properties for the arrest of Cu 2+ ion. The adsorption efficiency of the prepared binary and ternary blends was examined through batch mode, and the experimental data were fitted with Langmuir and Freundlich isotherm models and kinetic models. The obtained results revealed that the Langmuir model showed better fit for binary blend and for ternary blend Freundlich isotherm model showed better fit through the highest R 2 values. The maximum adsorption capacity was 98.91 mg/g and 132.45 mg/g for binary and ternary blends, respectively. Graphic abstract