Abstract
Magnetic chitosan grafted with Schiff's base polymer (M-Schiff's-Chit) was prepared as a green sorbent starting from shrimp peels for the effective removal of hexavalent chromium. Chitosan extraction involved three main stages as preconditioning, demineralization deproteinization and deacetylation. The grafting process is confirmed by elemental analysis, Fourier transform infrared spectroscopy. Adsorption experiments were carried out in batch sorption mode to investigate the effect of pH, contact time, sorbent dose, concentration of Cr(VI) and evaluating the thermodynamics. Sorption kinetics are effectively modeled using the pseudo-second order rate equation while Langmuir equation successfully fits sorption isotherms. The sorption is endothermic, spontaneous and entropic. Chromate desorption can be successfully performed with 2 M of NaCl in 0.5 M NaOH and the sorbent can be recycled for at least three sorption/desorption cycles without significant loss in sorption/desorption performances. Furthermore, the environmentally friendly and low-cost M-Schiff's-Chit could be applied as an effective sorbent to remediate Cr(VI) contamination from tannery effluent.