Magnetic chitosan grafted (alkyl acrylate) composite particles: Synthesis, characterization and evaluation as adsorbents

Abstract

An efficient process for preparing a series of magnetic chitosan grafted (alkyl acrylate) composite particles as novel adsorbent materials has been proposed. Magnetite nanoparticles (Fe3O4) were produced by co-precipitation. Modified chitosan (CSg) bearing surface vinyl groups was synthesized by glycidyl methacrylate coupling in acidic aqueous solution through an epoxide ring opening mechanism. The magnetic chitosan grafted (alkyl acrylate) composites were prepared by radical copolymerization of butyl acrylate (BA), butyl methacrylate (BMA) or hexyl acrylate (HA) with ethylene glycol dimethacrylate (EGDMA) onto the modified chitosan vinyl groups, with addition of magnetite nanoparticles in suspension. The prepared particles were characterized by TEM, SEM, XRD, VSM and FTIR. Adsorption batch experiments on the newly synthesized composites were conducted using Ni(II) ions in aqueous solutions. The variables that influence the sorption capacity, namely the solution pH, initial metal ion concentration, sorbent mass, adsorption time and temperature have been investigated. The adsorption kinetics was analyzed by fitting the data into the following models: pseudo-first-order, pseudo-second-order and intraparticle diffusion. The Langmuir, Freundlich and Dubinin–Radushkevich models were used to fit the adsorption isotherms. The proven high stability and recovery capacity of the composite particles suggest their potential use for Ni(II) ions removal from wastewater by using magnetically aided adsorption technology.