The enhanced peroxymonosulfate-assisted photocatalytic degradation of tetracycline under visible light by g-C3N4/Na-BiVO4 heterojunction catalyst and its mechanism

In this study, to enhance the peroxymonosulfate (PMS)-assisted photocatalytic degradation of tetracycline (TC) under visible light over BiVO 4 , g-C 3 N 4 coupling and Na + doping was used to co-modify BiVO 4 to obtain g-C 3 N 4 /Na-BiVO 4 (CN/Na-BiVO 4 ) heterojunction catalyst. The prepared CN/Na-BiVO 4 exhibited the apparently enhanced PMS-assisted photocatalytic TC degradation efficiency and can degrade approximately 98.20% of TC in 40 min, being 3.13 folds of BiVO 4 . The boosted TC degradation over CN/Na-BiVO 4 was ascribed to the Z-scheme heterojunction formation, doped Na + , more V 4+ and oxygen vacancies resulting from Na + doping facilitate the electron-hole pairs migration and separation. Meanwhile, more V 4+ and oxygen vacancies generated in Na-BiVO 4 also promoted the PMS activation . Therefore, a large number of reactive oxygen species (ROSs), including •O 2 − , h + , •OH, SO 4 •− , and 1 O 2 , were produced in CN/Na-BiVO 4 +PMS+Vis system to degrade TC. The mechanism of enhanced PMS-assisted photocatalytic degradation of TC was proposed. This work further highlighted the advantages of the PMS-assisted photocatalytic technology in antibiotics removal and also demonstrated that g-C 3 N 4 coupling and Na doping co-modify BiVO 4 was one effective and feasible method for promoting the PMS-assisted photocatalytic degradation of TC under visible light.