The catalyst derived from the sulfurized Co-doped metal–organic framework (MOF) for peroxymonosulfate (PMS) activation and its application to pollutant removal

Abstract

The applications of metal–organic framework (MOF) in advanced oxidation processes (AOPs) for pollutant removal have attracted extensive attention. The new catalyst derived from MOFs for the application in AOPs has not yet been well investigated. In the current study, a highly efficient and stable catalyst for the peroxymonosulfate (PMS) activation was fabricated. The catalyst was derived from the sulfurized Co-doped MOF (S-Co-MOF) calcined at different temperature (300–600 ℃). In the optimal conditions, the pollutant removal efficiency could reach almost 100 % within 7 min, and the reaction rate constant (k) was 57 times higher than that in the reaction system containing the catalyst derived from the non-sulfurized Co-MOF. The remarkable improvement of catalytic performance of the catalyst was attributed to its reduced charge transfer resistance (Rct) and the predominant existence of Co(II), which were resulted by the sulfurization and Co doping. In addition, the effects of PMS concentration, catalytic dose and coexisting ions on the pollutant degradation were investigated. Furthermore, the results of the quenching experiments and the electron paramagnetic resonance (EPR) tests showed that the generated SO4•- radical during the PMS activation process played key role in pollutant degradation. The OH• and 1O2 were the products of the hydrolysis process of SO4•-. Besides, the formed O2•- was noticed to be an important precursor for the 1O2 generation. The newly fabricated catalyst for PMS activation could give insight into the SO4•- based AOPs applied in wastewater treatment.