Preparation of Chitosan/Bone Char/$$\hbox {Fe}_{3}\hbox {O}_{4}$$Fe3O4 Nanocomposite for Adsorption of Hexavalent Chromium in Aquatic Environments

Abstract

In this study, magnetic chitosan/bone char/\(\hbox {Fe}_{3}\hbox {O}_{4}\) nanocomposite (MCB–\(\hbox {Fe}_{3}\hbox {O}_{4}\) nanocomposite) was prepared and utilized as an adsorbent for the removal of Cr(VI) from aqueous environments. The effects of influencing parameters such as initial concentration of Cr(VI), adsorbent dose, initial pH, mixing rate, salinity and the existing of competing organic compounds on the adsorption of Cr(VI) were investigated. According to the obtained results, the adsorption process followed the pseudo-first-order kinetic model and Langmuir adsorption isotherm model. Decreasing initial pH from 11 to 2 resulted in increasing the removal efficiency (%) from 24.94 to 88.60%, respectively. Also, the efficiency (%) of Cr(VI) removal increased from 33.73 to 98.81% when the dose of adsorbent rose from 0.25 to 4.0 g/L, respectively. The presence of ethanol and humic acid in solution resulted in decreasing the removal efficiency (%) of Cr(VI) ions.