CuO-doped Ce for catalytic wet peroxide oxidation degradation of quinoline wastewater under wide pH conditions

Abstract This study aimed to treat toxic and refractory organic wastewater, and to address the limitations of Fenton method in treating organic wastewater, that the active components are easy to lose and usually operate at the pH value of 2 ∼ 3. In the present study, CuCe oxide catalyst was produced through citric acid-assisted complexation. Besides, the structural stability and catalytic wet peroxide oxidation (CWPO) performance of the catalyst after 5 times of application were delved into by characterization. The effects of catalyst dosage and pH on quinoline removal were ascertained, while the reusability of the catalyst was explored. Moreover, the variations of pH, hydroxyl radical concentration and UV–Vis spectra in the reaction system were analyzed. The possible degradation pathway and the catalytic mechanism were also discussed. As suggested from the results, the catalyst exhibited high catalytic activity, structural stability and pH adaptability; it also had high CWPO performance for quinoline at the pH from 3.8 to 10.5, and the pH value need not be regulated. Under optimal conditions, 98.1% of quinoline and 86.1% of total organic carbon (TOC) were removed. In the CWPO process of quinoline, the ·OH attacked the nitrogen ring and the benzene ring in sequence.