Oxygen vacancy induced peroxymonosulfate activation by Mg-doped Fe2O3 composites for advanced oxidation of organic pollutants

Oxygen vacancy engineering has emerged as an effective approach to improve the performance of catalysts for peroxymonosulfate (PMS) activation. Herein, we report a facile precipitation method followed by calcination to synthesize cost-effective and environmentally friendly magnesium-doped hematite (Mg/Fe2O3) composites. Multiple characterization results reveal that the incorporation of Mg can significantly increase the oxygen vacancies and specific surface area of 5%Mg/Fe2O3, leading to a significantly enhanced performance in degrading Rhodamine B (RhB) through PMS activation. In a typical reaction, almost complete RhB (10 mg/L) removal can be achieved by the activation of PMS (0.2 g/L) using 5%Mg/Fe2O3 (0.5 g/L). Moreover, the as-synthesized catalyst exhibits a broad pH working range (3.96-10.69), high stability, and recyclability. The effects of several parameters (e.g., catalyst amount, PMS dosage, solution pH and temperature, and coexisting inorganic anions) on the removal of RhB in the 5% Mg/Fe2O3/PMS system are investigated. A plausible PMS activation mechanism is proposed, and O-1(2) and O-center dot(2)- are identified as the predominant reactive species in RhB degradation instead of SO4 center dot- and (OH)-O-center dot. This study provides new insights into the development of highly efficient iron-based catalysts and highlights their potential applications in environmental purification. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Oxygen vacancy engineering is an effective approach to improve catalyst performance for peroxymonosulfate (PMS) activation. Here, a cost-effective and environmentally friendly magnesium-doped hematite (Mg/Fe2O3) composite was synthesized, showing enhanced Rhodamine B degradation through PMS activation. The catalyst exhibited wide pH working range, high stability, and recyclability, with O-1(2) and O•(2)- identified as the predominant reactive species in RhB degradation.