Catalytic activation of peroxymonosulfate using MnO2@quasi-MOF for singlet oxygen mediated degradation of organic pollutants in water

The properties of metal organic frameworks (MOFs), surface area, porosity, and functionality make them an ideal material for heterogenous catalysis. We developed a MnO2@quasi-MOF (MnO2@q-MOF) catalyst by incorporating MnO2 into a MIL-53 (Fe) structure with reduction of KMnO4 to MnO2 followed by a mild heat treatment at 300 °C. MnO2@q-MOF showed higher exposed metal sites due to thermally induced decarboxylation and higher activity because of in situ MnO2 formation while preserving the porosity and crystalline structure of MIL-53 (Fe). We activated potassium peroxymonosulfate (PMS) using our MnO2@q-MOF catalyst for decomposition of methylene blue and HEPES in water. The MnO2@q-MOF catalyst outperformed both MIL-53 (Fe) and unsupported MnO2 in the degradation of dye and was reusable. The primary mechanism of PMS activation was revealed to be a singlet oxygen (1O2) mediated process.