Ultrasound-assisted synthesized BiFeO3 as FeOH+ promoted peroxymonosulfate activator for highly efficient degradation of tetracycline

A multiferroic BiFeO3 (BFO) catalyst was fabricated through a mild one-pot hydrothermal process with a bath-ultrasound assisted dissolution of Fe(NO3)3·9H2O for 30 min. X-ray photoemission spectroscopy revealed that the BFO (BFO-u) catalyst with US assisted dissolution of Fe(NO3)3·9H2O in the synthetic process exhibited high Fe2+ and OH− levels, which could be explained to be Fe3+ + H2O → ) ) ) Fe2+ + H+ + •OH. As a result, BFO-u catalyst activated potassium peroxymonosulfate (PMS) efficiently for degrading tetracycline hydrochloride. In particular, visible-light assisted activation of PMS over BFO-u catalyst exhibited the highest degradation rate constant, at 0.352 min−1. Species-trapping experiments revealed that the presence of PMS promoted the generation of •OH, •O2− and 1O2 that all participated in degrading TCH, in which 1O2 was primarily contributed to the degradation. Also, BFO-u catalyst was stable and recyclable and thus suitable for practical applications.