Waste-derived MCM-41 as dual-functional support for cobalt ferrite: Performance as peroxymonosulfate activator for ciprofloxacin decontamination

Abstract

Herein, a series of CoFe2O4 decorated on waste-derived Mobil Composition of Matter No. 41 (MCM-41) was developed. Incorporation of MCM-41 as a support for CoFe2O4 (CFMCM) provides dual functionality to disperse the catalyst and adsorb leached metal, leading to remarkable performance and stability. The CFMCM was used as a peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) removal indicating that CFMCM with 11 wt% CoFe2O4 (CFMCM-11) had the highest performance (kapp = 0.17 min−1). Increasing the catalyst loading and PMS dosage contributed positively to the CIP degradation. The catalyst can be reused at least 3 times without significant metal leaching (<35 µg/L) showing that it is stable. Analysis of the dominant reactive species using scavengers revealed that SO4•− was the major reactive species while HO• played a minor role. The SO4•− and HO• were generated from the redox transition between Co2+/Co3+ and Fe2+/Fe3+. Based on the intermediates identified, the CIP degradation pathways consisting of piperazine ring oxidation, and decarboxylation reactions were proposed. Overall, this study shows that the waste-derived materials can be integrated as part of the strategy to develop catalysts for environmental applications.