Enhanced quinoline degradation by persulfate-assisted photocatalytic process with WO3-CuFe2O4 Z-scheme system: Properties and mechanism

Quinoline is a kind of organic pollutant difficult to be biodegraded, for which the photocatalysis technology is a commonly used removal method, but the degradation performance still needs to be improved. In this work, the WO3-CuFe2O4 Z-scheme system was constructed, and the persulfate (PS)-assisted photocatalytic degradation of quinoline with WO3-CuFe2O4 by adding persulfate in the photocatalytic systems was studied. The effects of different systems and key parameters such as catalyst dosage, PS concentration and initial pH value on the degradation efficiency of quinoline were investigated. With the addition of persulfate, the degradation efficiency of quinoline increased from 24.3% to 100% in 150 min, under the condition of [PS] = 3 mmol/L, [catalyst] = 3 g/L, temperature = 25 +/- 2 degrees C, and pH = 9. And the WO3-CuFe2O4 catalyst showed excellent reusability according to the result of 5-cycle repeated experiment. The possible degradation mechanism was studied by the quenching test and the identification of intermediates and products, which indicated the degradation of quinoline in WO3-CuFe2O4/VIS/PS system was realized via denitrification, dehydrogenation, hydroxylation and ring breaking processes.