Over the past decade, advanced oxidation process based on the heterogeneous activation of peroxymonosulfate (PMS) has become increasingly popular for degradation of organic contaminants in aquatic systems. Perovskite oxides are promising materials with diverse applications, especially as PMS activator. In this study, a series of (LSMO) perovskites (x= 0.0, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45) were synthesized using the modified sol-gel method and their potential application as PMS activator for tetracycline (TC) degradation was investigated. It was figured out that strontium doping significantly enhances the catalytic performance of LaMnO3, and (LSMO0.25) exhibited the highest efficiency as PMS activator for TC degradation. Iodometric titration and X-ray photoelectron spectroscopy (XPS) analyses revealed that, the catalytic performance can be attributed to Mn3+ ions in perovskite structure acting as intrinsic catalytic sites, with improving activity by increasing the ratio of Mn4+/Mn3+ redox pairs likely participating in PMS activation. Additionally, the abundance of oxygen vacancies, which were induced by introducing Sr ions in LMO structure, played a pivotal role in promoting the formation of singlet oxygen (). Chemical quenching experiments revealed the both radical and non-radical reactions involved in TC degradation. Moreover, the study explored the impact of various experimental parameters such as LSMO dosage, PMS content, TC concentration, and initial pH on TC degradation. Furthermore, the coexistence of inorganic anions in TC degradation process was investigated. It was found that, the and ions had a minor effect on the TC removal, while, and ions substantially hindered TC elimination. The obtained results revealed LSMO0.25 perovskite with enhanced oxidation state of manganese ions and high oxygen vacancy holds great promise for advanced oxidation applications.
