Removal of methyl orange from aqueous solutions by magnetic maghemite/chitosan nanocomposite films: Adsorption kinetics and equilibrium

Magnetic maghemite (?-Fe2O3)/chitosan nanocomposite films were prepared by solution casting method and characterized by Fourier transform infrared spectra, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction. Batch adsorption experiments were carried out utilizing the composite films to adsorb a typical azo dye, i.e., methyl orange (MO) from aqueous solutions. The effects of adsorbent dosage, solution pH, coexisting anions, and temperature were studied. Adsorption kinetic was verified by pseudo-first-order and pseudo-second-order kinetic models. Results indicated that the rate of dye adsorption followed pseudo-second-order kinetic model for the initial dye concentration range studied. MO adsorption onto magnetic ?-Fe2O3/chitosan composite films was better described by Langmuir isotherm. Thermodynamic studies showed that MO adsorption was exothermic and spontaneous in nature. Because magnetic maghemite/chitosan nanocomposite films could be recovered conveniently and possessed of excellent adsorptive property, it can be developed as an economical and alternative adsorbent to decolorize or treat dye wastewater. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012