A novel magnetically separable γ-Fe2O3/crosslinked chitosan adsorbent: Preparation, characterization and adsorption application for removal of hazardous azo dye

A novel magnetically separable adsorbent, namely magnetic gamma-Fe2O3/crosslinked chitosan composites (M gamma-Fe2O3/CSCs), was prepared by miroemulsion process and characterized by XRD, FT-IR, TGA, DSC, SEM and VSM. Adsorption of methyl orange (MO), used as a model pollutant, from aqueous solution on M gamma-Fe2O3/CSCs was investigated. Characterization results indicated that magnetic gamma-Fe2O3 nanoparticles have been introduced in M gamma-Fe2O3/CSCs and kept intrinsic magnetic properties. The saturated magnetization (sigma(s)) of M gamma-Fe2O3/CSCs can be expediently adjusted by changing additive dosage of Fe2O3. Adsorption results showed that both nanocomposite adsorbents with weight ratio of gamma-Fe2O3 to chitosan of 1:10 and 2:5 exhibited higher adsorption capacities and attained adsorption equilibriums in shorter time compared with crosslinked chitosan. After adsorption, M gamma-Fe2O3/CSCs were effectively separated from reaction solution in 10 s by applying an adscititious magnetic field. Adsorption kinetics of MO on 1:10 M gamma-Fe2O3/CSCs followed the pseudo-second-order kinetic model. Effects of both initial pH and adsorbent dosage on the adsorption of MO were remarkable in experimental conditions. (c) 2010 Elsevier B.V. All rights reserved.