Preparation of magnetic chitosan/Fe-Zr nanoparticles for the removal of heavy metals from aqueous solution

Copper and hexavalent chromium are heavy metals that are harmful to human health. Natural adsorbent chitosan, due to its considerable properties such as the presence of functional groups of –NH2 and -OH, non-toxicity, low cost, and biocompatibility, has gained much attention in pollutant removal. Therefore, in the present study, adsorption of chromium (VI) and copper (II) ions was conducted in a batch system using magnetic chitosan/Fe-Zr nanoparticles. In addition, the effect of different variables such as contact time, pH, adsorbent dose, initial concentration of heavy metals, and temperature were investigated. The results of the present study indicated that the highest efficiency in removal of chromium (VI) and copper (II) in pH of 4 were 99.52% and 97.72%, respectively. Moreover, adding 0.4 g of the composite at concentration of 5 mg/l can result in up to 97.43% removal of copper (II) and adding 1 g of this composite at the same concentration can result in more than 91% removal of chromium (VI). In addition, it was concluded that increasing the density of the heavy metals did not have a remarkable effect on the removal efficiency. The equilibrium related to adsorbent capacity and the amounts of nanoparticles were obtained using the plots of Langmuir and Freundlich adsorption isotherms for chromium (VI) and copper (II), respectively. The studied adsorbent had a high level of efficiency in the removal of heavy metals from aqueous solutions.