g-C3N4 supported tungsten single atom induced persulfate activation to achieve efficient degradation of sulfadiazine in water

Advanced oxidation processes using persulfate (PS) have proven effective in degrading organic pollutants in water. The key to these processes is the development of catalysts that efficiently activate PS. Single-atom catalysts (SACs), where individual metal atoms are dispersed on a solid support, offer superior catalytic activity compared to traditional metal catalysts and hold great promise. In this study, we synthesized a tungsten-based SAC (W-SA-g-C 3 N 4 ) by anchoring tungsten onto graphite-like carbon nitride (g-C 3 N 4 ) for sulfadiazine (SDZ) degradation in water. The results showed that single-atom tungsten was mainly incorporated into the g-C 3 N 4 in the W 6 + state, which created more active sites for PS activation and enhanced electron migration. More than 92.3% of SDZ was decomposed within 60 min in the W-SA-g-C 3 N 4 /PS system, and appropriate catalyst dosage and solution pH favored SDZ decomposition processes. The presence of Cl − , SO 4 2− , and NO 3 − had slight impacts on SDZ degradation efficiency, and over 85% of ciprofloxacin, norfloxacin, and oxytetracycline could also be removed in the W-SA-g-C 3 N 4 /PS system. Radical scavenger and EPR experiments identified 1 O 2 and •O 2 − as key species in SDZ degradation. The SDZ degradation processes mainly involved the fragmentation of the benzene ring and associated clusters. Additionally, the catalyst exhibited excellent stability and recyclability. Download: Download high-res image (344KB) Download: Download full-size image