Degradation of antibiotics in multi-component systems with novel ternary AgBr/Ag3PO4@natural hematite heterojunction photocatalyst under simulated solar light.

Abatement of antibiotics from aquatic systems is of great importance but remains a challenge. Herein, we prepared ternary AgBr/Ag3PO4@natural hematite (AgBr/Ag3PO4@NH) heterojunction composite via a simple route for the photocatalytic degradation of antibiotic pollutants. By adjusting the dose of Ag species, four products with different Ag content (denoted as Ag0.5BrPFe, Ag1BrPFe, Ag1.5BrPFe, and Ag2BrPFe) were developed. Among them, Ag1.5BrPFe exhibited the best photocatalytic activity. Four antibiotics (i.e. ciprofloxacin (CIP), norfloxacin (NOR), sulfadiazine (SDZ), and tetracycline (TTC)) could be degraded with synthesized Ag1.5BrPFe in multi-component systems. Water matrix indexes including solution pH, coexisting anions, humic acids exhibited distinct effects on the degradation process. The results revealed that the degradation process was accelerated at acidic conditions while depressed at basic conditions. Superoxide radical and hole were detected by in situ electron spin resonance technique and played the dominant roles. The degradation pathway TTC was tentatively established followed with the identification of the degradation intermediates and computational analysis. This work would shed light on the photocatalytic degradation mechanism of organic pollutants by the AgBr/Ag3PO4@NH composite.