Adsorption of Brilliant Green from Aqueous Solutions onto Crosslinked Chitosan Graft Copolymers

Abstract

In this study, graft copolymerization of itaconic acid (IA) and crotonic acid (CA) onto the crosslinked chitosan beads were carried out using ammonium persulfate as initiator. Grafted chitosan beads were characterized by FT-IR analysis and grafting percentage determination. Grafting efficiency and add-on percentages values of grafted chitosan beads were determined as 23-29 and 32-47%, respectively. Then, equilibrium isotherms and kinetics of brilliant green adsorption onto grafted chitosan beads were investigated. The results indicated that the pseudo-second-order kinetic model fitted better than the data obtained from pseudo-first-order model for the adsorption of brilliant green onto grafted chitosan beads. The fit of data for brilliant green (BG) adsorption onto grafted chitosan beads suggested that the Langmuir model gave closer fittings than the Freundlich model. The preparation of crosslinked chitosan beads grafted with IA or CA and their potential use as an adsorbent for removal of cationic dye (brilliant green) from aqueous solutions was studied. The results propose that the adsorption process might be chemical adsorption and seems to follow Langmuir and Freundlich isotherms with better fitting of Langmuir isotherm with experimental data. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.