Preparation of Mn2O3/MIL-100(Fe) composite and its mechanism for enhancing the photocatalytic removal of rhodamine B in water

Abstract

In this study, Mn₂O₃/MIL-100(Fe) composite was successfully synthesized by the hydrothermal method and applied for photocatalytic removal of rhodamine B (RhB) in water. The physical and chemical properties of the synthesized materials were characterized by XRD, FTIR, SEM, UV-visible, and BET analyses. Experimental results showed a great enhancement in the photocatalytic ability of the Mn₂O₃/MIL-100(Fe) composite as compared to individual Mn₂O₃ or MIL-100(Fe) under visible light and persulfate activation. The affecting factors such as pH, photocatalyst dose, RhB concentration, and Na₂S₂O₈ concentration were investigated to find out the best conditions for efficient photocatalysis. By conducting a radical quenching test, all radicals of HO˙, SO₄˙⁻, ¹O₂, and O₂˙⁻ were found to be important in photocatalytic decomposition. The mechanism was proposed for the enhancement of photocatalytic RhB removal via band potential calculation, charge separation, surface redox reaction, and key reactive oxidation species. With its durability, reusability, and high efficiency, the Mn₂O₃/MIL-100(Fe) composite emerges as a potential photocatalyst working under visible light for application in wastewater treatment.