LaRuO3 perovskites as effective and reusable heterogeneous catalysts to activate peroxymonosulfate for carbamazepine degradation

Abstract

Sulfate radical-based technologies have been frequently applied to degrade pharmaceutical and personal care products (PPCPs). Metal-based catalysts have shown great potential for activating persulfate (PS) and peroxymonosulfate (PMS) to degrade PPCPs. In this study, a Ru-based perovskite (ARuO3, A = La, Ba, Ce, Sr) was synthesized by the sol–gel method and used as a catalyst to activate PMS for the degradation of carbamazepine (CBZ). Results demonstrated that the A-site cations had a significant influence on the catalytic performance of the perovskite, and the degradation efficiency of CBZ in descending order for different Ru-based perovskites was as follows: La > Ba > Sr > Ce. LaRuO3 was selected as the optimal catalyst for CBZ degradation. LaRuO3 efficiently activated PMS to degrade CBZ in a neutral environment. The reaction rate constant had a positive linear correlation with the concentration of PMS in a range between 0.1 mM and 0.5 mM. ESR analysis and radical quenching experiments confirmed the existence of 1O2, •OH, and SO4•− in the LaRuO3/PMS system, and SO4•− played the most significant role in decomposing CBZ. The recycling experiment and XPS spectra suggested the stability of LaRuO3.