Synthesis, characterization, and application of SrTiO3 via metallic Ag modification in the inactivation of Enterococcus sp. in wastewater

Wastewater reclamation is crucial due to increasing demand and climate change, and disinfection is a key step in the process. However, traditional disinfectants like chlorination produce harmful by-products, prompting the exploration of alternatives such as Advanced Oxidation Processes (AOPs). Peroxymonosulfate (PMS) has emerged as a promising oxidant, especially when combined with heterogeneous catalysts at low concentrations. One example is the development of new nanostructured materials like SrTiO₃, enhanced by silver nanoparticle (Ag) doping. This study focuses on the synthesis, characterization, and testing of SrTiO₃@Ag for wastewater disinfection, targeting Enterococcus sp., and examining factors such as solar radiation, PMS concentration, and the key species involved in the treatment. In the study, the SrTiO₃@Ag material exhibited limited photocatalytic activity under solar radiation at low concentrations, but this was improved by combining it with low concentrations of PMS, leading to the complete elimination of Enterococcus sp. in 45 min. However, adding solar radiation to the SrTiO₃@Ag/PMS process had an antagonistic effect, increasing the reaction time. Bacterial elimination likely results from a synergistic mechanism involving the antibacterial properties of Ag nanoparticles, the generation of sulfate radicals from PMS, and electron transfer processes enhanced by light-induced plasmon resonance. Oxidizing radicals and electron transfer are the main contributors to bacterial inactivation.