Efficient removal of levofloxacin from different water matrices via simultaneous adsorption and photocatalysis using a magnetic Ag3PO4/rGO/CoFe2O4 catalyst

Abstract

A magnetic Ag3PO4/rGO/CoFe2O4 ternary catalyst was firstly prepared and used for removing levofloxacin (LVF) from different water matrices via simultaneous adsorption and photocatalysis. Compared with Ag3PO4 and Ag3PO4/CoFe2O4, Ag3PO4/rGO/CoFe2O4 shows a superior adsorption-photocatalysis performance for LVF elimination since rGO component not only improves the adsorption ability but also enhances the charge separation efficiency of the catalyst. About 90.7% of LVF in distilled water (10 mg/L) was removed by the ternary catalyst after adsorption for 0.5 h and photocatalysis for 1.0 h, and the removal of LVF performed well in the pH range of 3.51–9.47. Singlet oxygen (1O2) was the major reactive oxygen species for LVF degradation in Ag3PO4/rGO/CoFe2O4 system under visible light, as confirmed by the quenching experiments and ESR study. Based on the detected intermediates in the photocatalytic process, the possible LVF degradation pathways were well-established. As-synthesized Ag3PO4/rGO/CoFe2O4 can also efficiently remove LVF from the different real water matrices (river water, lake water and secondary effluent) via simultaneous adsorption and photocatalysis. Moreover, magnetic Ag3PO4/rGO/CoFe2O4 can be easily recovered and effectively reused for the removal of LVF in actual water bodies.