Superhydrophilic N,S,O-doped Co/CoO/Co9S8@carbon derived from metal-organic framework for activating peroxymonosulfate to degrade sulfamethoxazole: Performance, mechanism insight and large-scale application

Herein, a N,S,O-doped Co/CoO/Co9S8@carbon hybrid (Co/CoO/Co9S8@NSOC) has been constructed by calcinating a Co-based metal–organic framework (Co-MOF) with 4,4-bipyridine and 2,5-thiophenedicarboxylic acid as linkers. Co/CoO/Co9S8@NSOC exhibited a high and recycled catalytic efficiency for peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX, 20 mg/L) with a reaction rate of 1.31 min−1, which was 5.2 times than that of Co-MOF. The catalytic behavior should be attributed to the rich active sites, lamellar morphology, superhydrophilicity, and magnetism. Furthermore, the Co/CoO/Co9S8@NSOC was immobilized on a filter membrane (CMFM) to adapt to the flowing system, which could recycle 20 times without losing activity. To employ in a large-scale static environment, the Co/CoO/Co9S8@NSOC was loaded on the commercial sponge (CoSPG). In a 50 L water tank, the CoSPG realized to decompose 160 mg/L SMX solution with 37 h and had long-term stability over 10 days. Notably, the PMS cost of treating one ton of wastewater is only $0.34, indicating a huge industrial application value.