Abstract

In this work we tried to establish the photokilling effect of zinc oxide photocatalyst on some type of bacteria. Photocatalytic disinfection reaction under UV-light in presence of zinc oxide (ZnO) in aqueous solution has been investigated. This method is effective for killing bacillus subtilis, pseudomonas sp. and salmonella bacteria in water. ZnO semiconductor exhibits strong bacterial activity .The aim of this research is to design a new photo bioreactor and its application to sterilize the water from bacteria . Primary experiments have been done to determined the optimum conditions which lead to high killing efficiency of bacteria in aqueous solution . The results showed that the bacterial effect of ZnO under UV- light irradiation on bacterial suspension was much higher than without using ZnO .The photocatalytic reactions were carried out with various ZnO weights. The highest photocatalytic bacillus and salmonella photokilling rate was obtained at 0.3g ZnO weight and at 0.4g for pseudomonas sp. The effect of pH on removal of bacteria was studied and the photocatalytic photokilling of three type of bacteria was obtained at acidic pH .