Cobalt doped graphitic carbon nitride as an effective catalyst for peracetic acid to degrade sulfamethoxazole

In this study, cobalt doped graphitic carbon nitride (CoCN) was prepared and applied as a catalyst to activate peracetic acid (PAA) for sulfamethoxazole (SMX) degradation at neutral pH. PAA could be efficiently activated by CoCN resulting in the efficient degradation of SMX. Characterization results of fresh and used CoCN suggested that cobalt was successfully doped in graphitic carbon nitride (g-C 3 N 4 ) through chemical bonding (CoN bond) and the surface cobalt species in CoCN ( i.e. , &z.tbd;Co( ii ) and &z.tbd;Co( iii )) were the main activators for PAA. Organic radicals ( i.e. , CH 3 C(O)O&z.rad; and CH 3 C(O)OO&z.rad;) were proved to be the dominant reactive species for SMX removal in the CoCN/PAA system by radical scavenging experiments. The increase of cobalt doping content, PAA dosage or CoCN dosage could accelerate SMX degradation and the neutral condition was highly favorable to SMX removal in CoCN/PAA system. CoCN exhibited a good stability and reusability for PAA activation in degrading SMX. Four possible degradation pathways of SMX ( i.e. , hydroxylation, nitration, bond cleavage and coupling reaction) were proposed in the CoCN/PAA system according to eight identified transformation products. An efficient advanced oxidation process (AOP) for sulfamethoxazole (SMX) removal: peracetic acid activated with cobalt doped graphitic carbon nitride.