MXene-regulated non-radical dominated degradation of binary sulfadiazine and sulfamethoxazole in semi-coke supported MXene/persulfate system

Sulfadiazine (SDZ) and sulfamethoxazole (SMX) are typical sulfonamide drugs that may pose potential risks to aquatic environment and organisms. Here, a small amount of MXene was introduced into an industrial waste semi-coke (SC) to prepare SC supported MXene (SC-MXene) heterogeneous catalyst for activating persulfate (PS) to degrade SDZ and SMX simultaneously. At SC to MXene ratio of 20:1, pH=7.0, T=30 °C, 0.20g/L SC-MXene and 0.50g/L PS, the developed SC-MXene/PS system had the degradation efficiency of 99.8% for SDZ and 99.9% for SMX within 120min. Furthermore, this system was able to efficiently degrade the target pollutants over a wide pH range of 3-9, with the degradation process being significantly promoted in the presence of Cl- and HCO3-. Compared with SC/PS system dominated by free radicals, SC-MXene/PS system was mainly controlled by non-radical 1O2 and electron transfer process, and thus was less susceptible to external factors and more conducive to the treatment of multiple antibiotics in real wastewaters. Compared to other relevant studies on MXene, this study demonstrates the unique role of MXene as an effective modifier for carbon-based catalysts, achieving a low-cost transformation of PS activation from free radical to non-radical pathways, and offering a promising option for the design of high-performance carbon-based catalysts in a non-radical dominated role via MXene regulation.