Application of the photocatalytic reaction of TiO2 to disinfection and the killing of escherichia coli bacteria

Abstract EN

Photocatalytic disinfection reaction under UV-visible light in presence of oxygen and Titanium dioxide (TiO2) in aqueous solution has been investigated.

This method is effective for killing Escherichia-coli bacteria in water.

TiO2 semiconductor exhibits strong bacterial activity.

The aim of this research is to design a new photobioreactor and its application to sterilize the water from E-coli bacteria. Primary experiments have been done to determined the optimum conditions which lead to high killing efficiency of E-coli bacteria in aqueous solution.

The results showed that the bacterial effect of TiO2 under UV-visible light irradiation on E-coli bacterial suspension was much higher than without using TiO2.

The photocatalytic reactions were carried out with various TiO2 concentrations.

The highest photocatalytic E-coli photokilling rate was obtained at 0.5 mg / ml TiO2 concentration, which is equal to 3.25 x 10-2 CFUs / sec.

This rate was increased to 5.8 x 10-2 CFUs / sec when 10 ppm of hydrogen peroxide was add to E-coli aqueous solution under UV-visible light in presence of oxygen and ideal concentration of TiO2 (0.5mg / ml).

The mechanism of TiO2 illumination to produce oxidizing species and the effect of these species on the bacterial activity in aqueous solution has been suggested.