Efficient activation of peroxymonosulfate for trichloroethylene degradation by cobalt ferrites anchored on CeO2 surfaces: Radical to non-radical pathway shift

Abstract

This research investigates the unique configuration of cobalt ferrite (Co1.5Fe1.5O4) anchored onto the surface of cerium dioxide (CeO2), which effectively activates peroxymonosulfate (PMS) to degrade trichloroethylene (TCE). Co1.5Fe1.5O4-CeO2/PMS was able to completely degrade 5 mg/L of TCE by comparison between PMS and the components of the prepared composites. In addition, the Co1.5Fe1.5O4-CeO2/PMS system was highly adaptable to pH and aqueous substrates. Quenching experiments combined with ESR spectroscopy results demonstrated that ·OH, SO4·-, O2·-, and 1O2 in the system play an important role in degrading TCE. The Co1.5Fe1.5O4-CeO2/PMS system can maintain 90% degradation efficiency for various pollutants (TCE, carbon tetrachloride (CT), dichloromethane (DCM), 2,4-dichlorophenoxyacetic acid (2,4-D)) as well as the actual wastewater, and the multiple cycling experiments have verified that the Co1.5Fe1.5O4-CeO2/PMS has a good stability. XPS comparisons before and after the reaction revealed that cobalt ferrite exhibited a unique transition from the radical pathway to the non-radical pathway during TCE degradation after the introduction of CeO2. This pathway shift can be attributed to the synergistic interaction between cobalt ferrite and CeO2, which adjusts the electronic structure, facilitates the activation of PMS, and generates more reactive oxygen species to decompose TCE. This research offers valuable insights into the design of efficient advanced oxidation catalysts for the removal of organic pollutants from water and the optimization of degradation pathways.