Photocatalytic disinfection of escherichia coli over titanium (IV) oxide supported on Hβ zeolite

Abstract

Photocatalytic bactericidal activity of TiO2, and supported over HY, Hβ, HZSM-5 and SiO2-Al2O3 systems were investigated by taking Escherichia coli as a water pathogenic bacterial pollutant indicator. TiO2 of 0.75 g/L was the optimum concentration for higher bactericidal activity. Among HY, Hβ, HZSM-5 and SiO 2-Al2O3 supports, Hβ supported system showed highest bacterial adsorption. This may be due to high surface area of Hβ compared to others and its hydrophobic nature of zeolite that attracts the organic bacterial pollutants than the binary SiO2-Al 2O3. Different loading of TiO2, ranging from 2 to 15 wt.% supported on Hβ zeolite samples are evaluated for dark adsorption measurements and photocatalytic bactericidal activity studies. Increasing the TiO2 percentages onto zeolite support resulted decrease of bacterial adsorption. It is observed that 5 wt.% of TiO 2/Hβ system exhibited high photocatalytic bactericidal activity compared to other catalysts. This higher bactericidal activity over 5 wt.% of TiO2/Hβ in comparison with TiO2 alone is due to the greater adsorption of bacteria and optimum dispersion of TiO2 on Hβ zeolite facilitating higher OH• radical formation and attack of Escherichia coli bacteria. © 2008 Springer Science+Business Media, LLC.