Quaternized chitosan/montmorillonite nanocomposite resin and its adsorption behavior

Chitosan was intercalated into a layer of montmorillonite to obtain a chitosan/montmorillonite nanocomposite. The chitosan/montmorillonite nanocomposite resin was prepared via inverse suspension method. Finally, a novel quaternized chitosan/montmorillonite nanocomposite resin was fabricated using the nanocomposite resin as raw material and 2,3-epoxypropyltrimethyl ammonium chloride as quaternized ammonium modifier. The structure and the morphology of chitosan/montmorillonite nanocomposite and quaternized chitosan/montmorillonite nanocomposite resin were characterized by X-ray diffractometry, transmission electron microscopy, Fourier transform-infrared spectroscopy, scanning electron microscopy and confocal laser-scanning microscopy. The results show that the quaternized chitosan/montmorillonite nanocomposite resin possessed smooth surface, regularly spherical shape, dense structure and good dispersibility in water, with average diameter of 14-113 mu m. The low swelling behavior of quaternized chitosan/montmorillonite nanocomposite resin was helpful to its use in column packing. The adsorption results on methyl orange revealed that the quaternized chitosan/montmorillonite nanocomposite resin exhibited stronger adsorption capacity in comparison with quaternized chitosan resin without montmorillonite, and the adsorption capacity increased along with the increasing amount of montmorillonite. The maximum adsorption capacity of quaternized chitosan/montmorillonite nanocomposite resin was 478.5 mg g(-1) and the adsorption behavior could be well described by the Langmuir and Freundlich adsorption isotherm model. Therefore, this study may provide a considerable and prospective material in the field of wastewater treatment.