Using TiO2-Biocharcoal and TiO2-Diatomite for photodisinfection in washing machine wastewater

Abstract

The photodisinfection process using biomolded semiconductor photocatalysts can inactivate bacteria in wastewater washing machine samples. The comparative study evaluated the photocatalyst material titanium dioxide (TiO2) synthesized with diatomite and biocharcoal biotemplate (TiO2-Biocharcoal and TiO2-Diatomite) in photodisinfection processes using domestic washing machine wastewater samples, the results of bacterial inactivation were above 96%. The efficiency of the photodisinfection process was evaluated by counting the number of colonies of the bacteria. Experiments under LED solar lamps presented similar bacterial inactivation, and a correlation with kinetic models. The kinetic study demonstrated a curved regression, indicating a better fit with the Hom model. A tail at the end of the modeling curve indicates the presence of a high concentration of inactive bacteria in the medium, while a shoulder at the beginning of the curve suggests a heterogeneous sample with a high concentration of gram-positive bacteria. The toxicity tests performed with wastewater samples without light exposure indicated low toxicity for both materials. The study presented promising disinfection results for an accessible and efficient photo-sterilization process of water contaminated with bacteria using abundant solar and renewable energy throughout the national territory.