H2O2 assisted BiVO4@Ag2O to effectively degrade doxycycline under visible light

Doxycycline (DC) is an antibiotic that exists in the environment and urgently needs to be effectively removed. Herein, the light/BiVO 4 @Ag 2 O/H 2 O 2 system and light/BiVO 4 @Ag 2 O system were constructed to achieve effective degradation of DC. Under the same degradation conditions, the efficiency and mechanism of two systems on DC degradation were compared. The results showed that the removal rate of DC in light/BiVO 4 @Ag 2 O/H 2 O 2 system was better than that in light/BiVO 4 @Ag 2 O system. The optimal pH ranges were 3.5–9.5 and 7.5–9.5 for light/BiVO 4 @Ag 2 O/H 2 O 2 and light/BiVO 4 @Ag 2 O systems, respectively. The optimal water temperatures were both 35 °C in two systems. The optimal BiVO 4 @Ag 2 O dosages were both 182 mg/L. The Cl − , SO 4 2 - and BrO 3 - had promoting effects on DC removal, while NO 3 - and PO 4 3 - had inhibitory effects on DC removal. The capture experiment showed that h + , ·O 2 − and ·OH existed in two degradation systems, among which h + played an important role. Analysis of degradation intermediates showed that the proportion of smaller molecules in light/BiVO 4 @Ag 2 O/H 2 O 2 visible light system was higher than that in light/BiVO 4 @Ag 2 O visible light system, indicating that oxidation active substances were more easily produced in light/BiVO 4 @Ag 2 O/H 2 O 2 system.