Preparation of magnetic activated carbon-chitosan nanocomposite for crystal violet adsorption

Magnetic, cheap and versatile adsorbents were developed for crystal violet (CV) adsorption in this study. These adsorbents are magnetic activated carbon (AC-Fe3O4) and chitosan grafted magnetic activated carbon (Chitosan-AC-Fe3O4). Fe3O4 and chitosan were also used for adsorption. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), zeta potential analysis and Fourier transform infrared spectroscopy (FTIR) methods were used for characterization of adsorbents. Adsorption parameters for CV were investigated. Raw chitosan and Fe3O4 were also used for CV adsorption to compare the results of composites. The chosen adsorption parameters are amount of adsorbent, contact time, initial CV concentration, and temperature. The equilibrium period was observed to be very short for chitosan and Fe3O4 nanoparticles. The adsorption efficiencies of these adsorbents are very low. AC-Fe3O4 and AC-Fe3O4-Chitosan nanoparticles reached equilibrium at 80 min. The all adsorbent-CV systems followed pseudo second-order kinetic model. AC-Fe3O4 and AC-Fe3O4-Chitosan composites suited non-linear Freundlich isotherm for all temperatures (298, 308 and 318 K). Regeneration of adsorbents was also investigated. 1 M of acetic acid and 0.1 M of NaOH solutions were tested. Acetic acid solution desorbed CV better than NaOH solution at 6 hours.