Visible-light-driven photocatalytic inactivation of Escherichia coli by titanium dioxide anchored on natural pyrite

Resumen

Escherichia coli (E. coli) is a human fecal pathogen and a current serious threat to health. In recent years, photocatalysis has been postulated to be an efficient technology for the disinfection of different types of aqueous matrices. This research focuses on the study of the efficacy of TiO2 anchored in natural pyrite (TiO2NP) in the elimination of E. coli. TiO2NP was successfully prepared and characterized by FTIR, SEM-EDS, and XRD analysis. The effect of operational parameters includes pH, catalyst dosage, catalyst ratio, light intensity, ultraviolet (UV) radiation, aeration, inorganic ions, and organic matter on bacteria inactivation. The result showed that the result showed effective photocatalytic inactivation of E. coli at natural water pH (6.5–8.5). The findings revealed that aeration and UVA accelerate Kmax 0.094 min−1 and 0.139 min−1, respectively. The increase in bacteria density and inorganic matter decreased Kmax 0.14 min−1 and 0.03 min−1, respectively. The inhibiting effect of inorganic ions was obtained as F− > Ca2+ > NO3− > SO42− > Cl−. The effect of the type of catalyst was obtained as TiO2NP > NP > TiO2. However, TiO2 causes •OH generation in the photocatalytic disinfection process, and E. coli inactivation. This study confirmed that TiO2NP is capable of successfully inactivating E. coli in aquatic environments.