Transformation of houttuynia cordata into a surface-loaded cobalt/biocarbon activated peroxymonosulfate for degradation of chlortetracycline

Peroxymonosulfate (PMS) has attracted great interest over the past few years owing to its great capacity and versatility for the breakdown of developing antibiotic contaminants. It is under intensive investigation for its potential for alternative advanced oxidation processes (AOPs) in wastewater treatment. In this study, we used activated cobalt-doped carbon as a new and excellent metal catalyst to activate PMS. The synthesis of novel Co3O4@C-900 hybrids with numerous active interfaces and superior surface electron transfer was achieved. Co3O4@C-900 and carbon matrix mixed evenly to create a stable catalytic structure. The Co3O4@C-900 structure equipped them with enhanced catalytic efficacy, thus decreasing environmental harm during actual Chlortetracycline (CTC) degradation. The CTC removal rate reached 100% within 10 min, exhibiting outstanding stability and high efficiency of Co3O4@C-900 hybrids. Additionally, we elucidated the PMS activation mechanism by Co3O4@C-900 via electron paramagnetic resonance (EPR) spectroscopy, radical quenching studies, and characterization analyses. Free radical quenching experiments and EPR spectroscopy revealed that the degradation of CTC by the Co3O4@C-900 PMS system was a concomitant process of free-radical and non-radical reactions. The free-radical reactions were based on the activation of PMS by Co3O4@C-900 to generate O2-, SO4- and OH, whereas the non-radical reactions were based on the activation of PMS by C to generate the active species 1O2. Therefore, this study presents Co3O4@C-900 as a promising candidate for PMS activation and also demonstrates a novel mechanism of CTC degradation.