Ti-LaFeO3 perovskite for enhanced tetracycline degradation and disinfection via photo-Fenton reactions: Performance and mechanistic insights

Resumen

The presence of contaminants of emerging concern (CECs) along with pathogenic microorganisms poses a significant environmental and health concern. In this study, Ti-LaFeO3 was investigated for the activation of two oxidants: hydrogen peroxide (H2O2) and peroxymonosulfate (PMS) in presence of solar light towards simultaneous degradation of tetracycline (TC) and disinfection of wastewater. Heterogeneous catalytic wet peroxide oxidation (CWPO), which relies on the catalytic breakdown of H2O2, or more recently PMS, in the presence of metal ions such as typically iron, and photocatalysis, which exploits the redox properties of semiconductors under light irradiation, have both garnered significant attention for their high efficiency and relatively low cost. The effects of solution pH, catalyst and oxidants concentration, were comprehensively investigated. The highest degradation of TC was observed after 120 min in the presence of PMS and solar radiation at alkaline pH and 0.1 g/L Ti-LaFeO3. Furthermore, the impact of common water anions such as chloride, phosphate, carbonate and nitrate, was evaluated on the TC degradation. Last but not least, scavenging tests revealed that hydroxyl and sulfate radicals were the dominant reactive oxygen species (ROS) responsible for the TC degradation in both Solar/Ti-LaFeO3/PMS and Solar/Ti-LaFeO3/H2O2 processes. In general, center dot OH is the most reactive but nonselective species, strongly interacting with tert-butyl alcohol, methanol, and benzoic acid, while 1O2 is the least reactive but highly selective, with NaN3 as its primary scavenger.