Singlet oxygen dominant-activation by hollow structural cobalt-based MOF/peroxymonosulfate system for micropollutant...

Despite the keen interest in potentially using the metal-organic framework (MOF) in advanced oxidation processes (AOPs), their application for environmental abatement and the corresponding degradation mechanisms have remained largely elusive. This study explores the use of cobalt-based MOF (CoMOF) for peroxymonosulfate (PMS) activation to remove tetracycline (TC) from water resources. Under optimal conditions, the given catalytic system could achieve a TC removal of 83.3%. Radical quenching tests and EPR analysis revealed that SO₄•-, HO•, •O₂^-, and ¹O₂ could participate in the catalytic degradation, but the discernible removal mechanism was mainly ascribed to the nonradical pathway induced by ¹O₂. At only 5 mg/L of CoMOF, the performance of the catalytic system was superior to that of PMS alone for different types of micropollutants. The CoMOF/PMS system could also reliably deal with typical anions in water, such as Cl^-, SO₄^2-, HCO₃^-, and PO₄^3-. The MOF catalyst could last for four cycles with a minor decrease in reactivity of ∼30%. However, the removal performance decreased markedly when aromatic natural organic matter (NOM) were present in the water bodies, and the effectiveness was lower in alkaline or acidic environments. Our work offers insights into the catalytic degradation of CoMOF/PMS applied in contaminated water remediation and serves as a baseline for fabricating an efficient MOF with enhanced catalytic performance and stability.