STUDIES ON PHOTOCATALYTIC DEGRADATION OF E. COLI PRESENT IN DRINKING WATER USING COMMERCIAL, SYNTHESIZED AND DOPED TIO2 AS CATALYST

Abstract

Photocatalytic degradation employing semiconductors as photocatalyst is a promising and attractive method for
the removal of pollutants in wastewater. TiO2 has been identified as the most effective and useful photocatalyst. However,
the applications of TiO2 has been retarded by fast recombination of electron-hole pairs and their wide band gap which
corresponds to the UV light. Therefore, the study with modifying TiO2 in order to reduce the electron-hole
recombination and sensitization towards visible light is one of the current hotspots in the photocatalyst research.
Photocatalytic degradation experiments were carried out using E. coli, UV light was mainly used as photon source. The
proposed study aims at investigating the above mentioned aspects by conducting an in-depth study of E. coli degradation
using commercially available, sol-gel synthesized and doped TiO2. Experimental runs were carried out with varying
inoculum levels of 1 ml/L, 10 ml/L, 20 ml/L and this was fixed at 20 ml/L and also with varying concentrations of
commercially available TiO2 i.e. 0.05 g/L, 0.1 g/L, 0.5 g/L, 0.7g/L, 1 g/L and 2 g/L in 100 ml and 1L total volume where 0.5
g/L was found to be optimum catalyst concentration for which the time taken was 2 h to degrade. Degradation studies
were also conducted with sol-gel synthesized TiO2 and Ag doped TiO2 which took 9 and 6 min respectively for the
optimum 0.5g/L catalyst concentration. Also Ag doped TiO2 was tested under sunlight for which the degradation time
was 30 min.