Enhancing Degradation of Sulfamethoxazole by Layered Double Hydroxide/carbon Nanotubes Catalyst Via Synergistic Effect of Photocatalysis/persulfate Activation

A Co3Mn-LDHs and carbon nanotube (Co3Mn-LDHs/CNT) composite catalyst was constructed for permonosulfate (PMS) activation and degrading sulfamethoxazole (SMX) under Vis light irradiation. The introduction of CNTs into Co3Mn-LDHs facilitate the exciton dissociation and carrier migration, and the e- and h+ were readily separated from Co3Mn-LDHs/CNT in the photocatalysis process, which promoted the production rate of reactive oxygen species (ROS), so the Co3Mn-LDHs + Vis + PMS system exhibited better activity with an SMX degradation ratio of 61.25% than those of Co3Mn-LDHs + Vis system (42.30%) and Co3Mn-LDHs + PMS system (48.30%). After 10 cycles, the degradation rate of SMX only decreased by 7.16%, indicating the good reusability of the Co3Mn-LDHs/CNTs catalyst. The results of electron paramagnetic resonance (EPR) analysis and radical quenching experiments demonstrated that that the SO4 center dot- played crucial role for SMX removal in Co3Mn-LDHs/CNTs + Vis + PMS system, and both e(-) and h(+) made an important contribution to activating PMS to produce ROS. Overall, this work provided an excellent catalyst for photo-assisted PMS activation and suggested the activation mechanism for organic pollutant remediation.