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

In this study, MnO/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 MnO/MIL-100(Fe) composite as compared to individual MnO or MIL-100(Fe) under visible light and persulfate activation. The affecting factors such as pH, photocatalyst dose, RhB concentration, and NaSO concentration were investigated to find out the best conditions for efficient photocatalysis. By conducting a radical quenching test, all radicals of HO˙, SO˙, O, and O˙ were found to be important in photocatalytic decomposition. The mechanism was proposed for the enhancement of photocatalytic RhB removal band potential calculation, charge separation, surface redox reaction, and key reactive oxidation species. With its durability, reusability, and high efficiency, the MnO/MIL-100(Fe) composite emerges as a potential photocatalyst working under visible light for application in wastewater treatment.