Facile fabrication of magnetic chitosan hydrogel beads and modified by interfacial polymerization method and study of adsorption of cationic/anionic dyes from aqueous solution

Abstract

Dyes are a new type of environmental and water pollution which has caused global concern. Many researchers have been done in order to remove dyes from wastewater based on adsorption. This project describes the preparation of magnetic chitosan hydrogel beads based on chitosan biopolymer, magnetic graphene oxide nanoparticles (GO/Fe3O4), and isophthaloyl chloride for removal of cationic and anionic dyes from aqueous solution. Chitosan hydrogel beads were prepared in the presence of GO/Fe3O4 nanoparticles. GO/Fe3O4 nanoparticles were prepared by the in-situ co-precipitation method. Afterward, amine groups in chitosan/GO/Fe3O4 hydrogel beads reacted with acyl chloride (in isophthaloyl chloride) via interfacial polymerization technique to modify surface of hydrogel beads. The results showed that the kinetic data and adsorption isotherm were best-correlated to the pseudo-second-order model and Langmuir model, respectively. The maximum adsorption capacities of cationic MB and anionic EBT were 289 and 292 mg/g, respectively. Moreover, the mechanism for the adsorption was studied by the fitting of isotherm data by the Dubinin-Radushkevich model showed that happened by the physio-sorption mechanism. The thermodynamic data indicated that the adsorption process was spontaneous, favorable and endothermic.