Mn-MOFs-derived Mn2O3 as an effective peroxymonosulfate activator for the degradation of organics in water

In this work, Mn2O3 synthesized from Mn-MIL-100 was used as an efficient PMS activator for Rhodamine B (RhB) removal in water. The materials were characterized by XRD, FITR, SEM, EDX, and BET analyses. Results showed that the prepared Mn2O3 had better PMS activation efficiency than Mn2+, Mn3O4, MnO2, and commercial Mn2O3. In RhB removal, the highest RhB degradation and COD removal efficiencies reached 98.2 and 72.15, respectively, after 70 min at the conditions of 10 mgRhB/L, 500 mgPMS/L, 400 mgMn2O3/L, pH 7, and 30 °C. Radical quenching tests showed that the sulfate radicals played a major role in the degradation of RhB. The decomposition of RhB followed pseudo-first-order kinetics (R2 > 0.99) with an activation energy of 34.94 kJ/mol. The effect of anion on RhB decomposition was in the order of SO42−< NO3−< Cl−<HCO3−<HPO42−<CO32−. RhB degradation efficiency remained at 86.74 after 5 cycles of reuse. These results suggest a potential application of PMS activation by Mn2O3 in the treatment of non—or hard-biodegradable wastewater. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.