Efficient peroxymonosulfate activation by MOFs derived cobalt-carbon composite for nonradical degradation of ciprofloxacin via Co(IV) = O

The catalytic activity of metal-organic frameworks (MOFs) derived materials can be enhanced by regulation of the exposed active sites of metal centres. Herein, various MOFs were used as precursors to prepare cobalt-carbon composites (Co@C) by pyrolysis. The resultant Co@C-1 showed the best catalytic activity towards peroxymonosulfate (PMS) by efficient removing 100 % of ciprofloxacin (CIP, 10 mg L-1) within 30 min, with a rate constant of 0.240 min- 1. Nonradical pathway via Co(IV) = O species rather than the radical (SO4 center dot- and .OH) pathway was the dominant way to remove CIP in the Co@C-1/PMS system. The toxicity of main intermediate products was evaluated and the possible degradation pathways of CIP were proposed, as well as the activation mechanism of PMS activated by Co@C. This study provides a universal way to regulate the exposed active sites of catalysts derived from MOFs, and enhances our comprehension on the PMS activation mechanism by cobaltbased catalysts.