Effluent Disinfection of Real Wastewater by Ag–TiO₂ Nanoparticles Photocatalysis

Currently pathogen microorganisms, presents in wastewater, are more resistant to conventional disinfection process, due to its constant change induced for the antibiotic for human diseases. One of the new options for the pathogen microorganisms is the heterogeneous photocatalysis, which has been used for remove microorganism, but never in real wastewater effluent. This paper shown the synthesis of Ag–TiO₂ nanoparticles, its physical characterization was carried out by TEM, SEM, S-BET, XPS and band gap measurement by UV-vis spectroscopy showing that Ag–TiO₂ are spherical particles with sizes around 50 nm with 1 and 10 %w of Ag, and a significant decrease in the band gap. The disinfection system was illuminated using the solar radiation of a spring day at Querétaro, Mexico, in lapses from 11:00 am to 03:00 pm; the microbiological tests were performed according to the Official Mexican Norm (NOM-003-SEMARNAT-1996), the results shows that after 3 hours of solar photocatalysis disinfection process the material 1 %w Ag–TiO₂ at 0.2 gL⁻¹, removes the fecal and total coliform microorganisms from effluent, leaving Enterobacter, Escherichia, Citrobacter, Salmonella and Klebsiella microorganisms alive due to its capability of reactivation.