Removal of methylene blue by polyacrylamide-g-chitosan Fe۳O۴ nanocomposite: characterization and adsorption studies

In this study, the magnetic adsorbent was applied for the removal of cationic methylene blue dye (MB) from aqueous solution. Fe۳O۴ nanoparticles were prepared by alkaline precipitation using ferric and ferrous chloride as pre-cursor and coated with polyacrylamide- graft- chitosan (PAM-g-CS). The phase formation and crystalline nature were confirmed by Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The X-ray diffraction results showed that nanoparticles have well crystallized structure with average particle size of ۱۰ nm. VSM analysis for Fe۳O۴ and PAM-g-CS/ Fe۳O۴ particles at room temperature revealed a super paramagnetic behavior with high saturation magnetization and no remnant magnetization. The FTIR spectrum confirmed the coating of PAM-g-CS on the surface of Fe۳O۴ nanoparticles. Adsorption of methyl blue (MB) onto adsorbent was investigated with respect to pH (۳,۷,۹), adsorption time and initial MB concentration (۲۰-۱۲۰ mg/l). The adsorption isotherm at the optimum pH ۷, were fitted by Langmuir and Freundlich isothermal models where the equilibrium adsorption data were well described by the Freundlich isotherm. Results highlight the potential of PAM-g-CS/ Fe۳O۴ application as an adsorbent for water contaminated by MB dye.