In situ growth of Fe3O4 on montmorillonite surface and its removal of anionic pollutants

Abstract

An environmentally functional material for the efficient removal of anionic pollutants in water was prepared for our study. Montmorillonite (M) was modified by hydrochloric acid (HCl) and cetyltrimethylammonium bromide (CTAB). Fe₃O₄ was grown in situ to prepare modified Fe₃O₄/montmorillonite (AC Fe₃O₄–Mt) composites. The number of hydroxyl sites on the surface of Mt and the surface tension were increased by HCl and CTAB modification, respectively, which enabled higher Fe₃O₄ surface growth, promoting the multi-directional crystallisation of Fe₃O₄ and improving reactivity. The XRD results show that Fe₃O₄ grows on the surface of Mt and has good crystallinity and high purity, meaning that AC Fe₃O₄–Mt is more reactive than Fe₃O₄. When AC Fe₃O₄–Mt is used to remove anionic pollutants in water, the removal effect under the synergistic action of adsorption-redox is significantly improved, and the maximum removable quantities of Cr(VI) and 2-4-dichlorophenol can reach 41.57 mg g⁻¹ and 239.33 mg g⁻¹, respectively. AC Fe₃O₄–Mt is a high efficiency and environmentally functional material with green environmental protection, which can be used in the field of sewage treatment.