Activation of persulfate by CoO nanoparticles loaded on 3D mesoporous carbon nitride (CoO@meso-CN) for the degradation of methylene blue (MB)

A simple and facile synthesis method is developed for the fabrication of CoO loaded ordered mesoporous carbon nitride ([email protected]) composites, at various CoO loadings, and used, for the first time, to activate persulfate (PS) for methylene blue (MB) degradation. The interfacial interaction between the ultrafine CoO nanoparticles, immobilized by high surface area, regular mesopores, and graphitic nature of the meso-CN support can further enhance the catalytic activation of PS for methylene blue (MB) degradation. Among all catalysts studied, the 5-wt% [email protected] exhibits the best catalytic performance with a kobs of 0.264 min−1. High initial pH, especially at pH-11, is more beneficial for PS activation. Furthermore, the [email protected] nanocatalyst is highly stable with a consistently high degree of MB degradation and negligible cobalt leaching for at least 5 consecutive catalytic cycles. Both SO4− and OH are the major reactive species based on results of EPR and quenching experiments. The degradation intermediates of MB are also identified by HPLC/MS/MS and the possible degradation pathway is proposed. Results clearly demonstrate that [email protected] is a promising green catalyst with enormous potential for the remediation of hazardous chemicals using PS.