Photocatalytic Disinfection of Escherichia coli over Titanium (IV) Oxide Supported on Hβ Zeolite

Photocatalytic bactericidal activity of TiO 2 , and supported over HY, Hβ, HZSM-5 and SiO 2 –Al 2 O 3 systems were investigated by taking Escherichia coli as a water pathogenic bacterial pollutant indicator. TiO 2 of 0.75 g/L was the optimum concentration for higher bactericidal activity. Among HY, Hβ, HZSM-5 and SiO 2 –Al 2 O 3 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 SiO 2 –Al 2 O 3 . Different loading of TiO 2 , ranging from 2 to 15 wt.% supported on Hβ zeolite samples are evaluated for dark adsorption measurements and photocatalytic bactericidal activity studies. Increasing the TiO 2 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 TiO 2 /Hβ in comparison with TiO 2 alone is due to the greater adsorption of bacteria and optimum dispersion of TiO 2 on Hβ zeolite facilitating higher OH • radical formation and attack of Escherichia coli bacteria.