Photocatalytic Removal of Escherichia Coli by ZnO Activated by Ultraviolet-C Light from

Background and objectives: There is a great interest in photocatalyticoxidation of contaminants, using ZnO, in recent years. The main objectiveof this research was to study photocatalytic disinfection of E. coli bacteriaas water microbial pollution index, using nanoparticles of ZnO and a UVlamp in a batch reactor.Material and Methods: In this study, the contaminated water sample wasprepared through adding 102 and 103 E. coli bacteria per ml of raw water.The contaminated water entered the photocatalytic oxidation reactor andremoval efficiency of E. coli bacteria in different conditions were studied,including pH (5.5, 7, and 9), time (10, 20, 30, 40, 50 and 60 mins), dose ofnano particles ZnO (0.2,0.4,0.8 and 1 gr/l), number of bacterium (102 and103 per milliliter) and voltage of UV-C lamp, 27 volts. Characterizations ofZnO nano particles were determined using scanning electron microscopeequipped with Energy Dispersive X-ray Analysis (EDX) system and X-raydiffraction (XRD) method.Results: Photocatalytic process efficiency is enhanced by increasingreaction time and dose of nano particles ZnO in the presence of UV lampirradiation. The results show that the best conditions for removal of 102 and103 bacteria per milliliter are obtained from condition including pH of 7,reaction time of 30 mins, 0.8 gr/l doses of nano particles ZnO and 27-volt-UV lamp.Conclusion: The results indicate that the increase of reaction time anddose of nano particles ZnO, in the presence of radiation UV lamp, have themost significant effect on photocatalytic efficiency. Based on the results,photocatalytic can be promising method for removal of E. coli bacteriumfrom drinking water.Keywords: Photocatalytic, E. coli, irradiation UV, ZnO nanoparticles,Aqueous Solution