Cobalt (0/II) incorporated N-doped porous carbon as effective heterogeneous peroxymonosulfate catalyst for quinclorac degradation

A cobalt(0/II)-incorporated N-doped porous carbon (Co/NC) catalyst was prepared via one-step thermal decomposition of ethylene-diamine tetra-acetic acid and a Co salt. Fine Co nanoparticles composed of metallic and oxidized Co species were formed and well dispersed in the graphene-like film-type N-doped carbon support. The Co species played a dominant role in peroxymonosulfate (PMS) activation to generate sulfate and hydroxyl radicals. The N-doped porous carbon synergistically affected the catalytic performance by enhancing electronic transfer. The resulting Co/NC was a highly efficient heterogeneous catalyst for PMS activation and enabled considerably enhanced quinclorac (QNC) degradation. Typically, 93% QNC (50 mg L-1) removal was achieved with 0.08 g L-1 Co/NC and 20 mmol L-1 PMS. The QNC degradation kinetic data fitted a pseudo-first-order kinetic model well, with a correlation coefficient (R2) higher than 0.99. Investigation of the reaction mechanism suggested that hydroxyl (HO) and sulfate (SO4-) radicals were the predominant active species in the Co/NCPMS system and QNC degradation mainly involved dehydroxylation and substitution of OH for COOH. This Co/NC catalyst is promising for use in advanced oxidation processes for the removal of persistent organic pollutants.