Photocatalytic disinfection of Escherichia coli over titanium (IV) oxide supported on H beta zeolite

Abstract

Photocatalytic bactericidal activity of TiO(2), and supported over HY, H beta, 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, H beta, HZSM-5 and SiO(2)-Al(2)O(3) supports, H beta supported system showed highest bacterial adsorption. This may be due to high surface area of H beta 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 H beta 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)/H beta system exhibited high photocatalytic bactericidal activity compared to other catalysts. This higher bactericidal activity over 5 wt.% of TiO(2)/H beta in comparison with TiO(2) alone is due to the greater adsorption of bacteria and optimum dispersion of TiO(2) on H beta zeolite facilitating higher OH(center dot) radical formation and attack of Escherichia coli bacteria.