preparation of a novel magnetic nanocomposite hydrogel based on carboxymethyl chitosan for the adsorption of crystal violet as cationic dye

The novel magnetic carboxymethyl chitosan/poly (acrylic amide) hydrogel (m-cmc-pamh) was prepared using magnetic montmorillonite (m-mmt) and characterized by fourier transform infrared spectroscopy (ft-ir), transmission electron microscopy (tem), scanning electron microscopy (sem), x-ray diffraction (xrd) and vibrating sample magnetometry (vsm) techniques. results showed that m-cmc-pamh has been prepared successfully properties without damaging the crystal structure of fe3o4. adsorption capacity of crystal violet (cv) on the m-cmc-pamh was 72.4 mg/g. the cv adsorption well described by the pseudo-second-order kinetics and langmuir isotherm equations. the positive value of the enthalpy change δh° (23.5 kj/mol) showed that the adsorption was endothermic and physical in nature. the value of gibbs free energy change δg° was found to be -9.7 kj/mol at 295 k for m-cmc-pamh, which shows spontaneity of the cv adsorption. so, m-cmc-pamh can be used as a low-cost alternative to other adsorbents for the removal of dyes from aqueous solutions.