Transition metal-substituted magnetite as an innovative adsorbent and heterogeneous catalyst for wastewater treatment

Abstract

Iron oxides are conventionally used as adsorbent and/or heterogeneous catalyst because of their abundance, easy magnetically separation, affordability, and applicability in broad pH range. This is especially reported for magnetite due to the presence of Fe2+ cations in its structure. However, the pure magnetite has lower adsorption capacity and degradation rate in Fenton reaction, which led to the introduction of transition metal-substituted magnetite (TMSM). This section gives an overview on the adsorption potential and Fenton catalysis performance of various transition metal-substituted magnetite samples. This recently introduced group is produced with incorporation of appropriately identified transition metal/ metals into the naturally available magnetite with simple synthesis method. TMSM has showed a great capacity for treating polluted water bodies using physical and chemical processes. A combination of factors affects the activity: the increased adsorption capacity of the samples evidenced by larger surface area, the participation of thermodynamically favorable redox pairs in regeneration of Fe2+ and •OH radical generation, and the presence of oxygen vacancies serving as active sites on the surface of TMSM. Nevertheless, there is a need for further understanding and expansion of this class of adsorbents and heterogeneous catalysts.