Investigation of the Efficiency of ZnO Photocatalyst in the Removal of p-Nitrophenol from Contaminated Water

In the present study, photocatalytic removal of p-nitrophenol has been carried out in the presence of ZnO by using a batch reactor with a UV-C lamp (15 W). The effects of applied ZnO concentration and UV light intensity have been studied. The increase of initial pollutant concentration decreases the removal rate, and the results indicate that the apparent reaction rate constant in the UV/ZnO process is a function of ZnO concentration. The kinetics of removal follow pseudo- first order. The influence of pollutant assisting chemicals such as NaCl, NaHCO3 and Na2CO3 on photocatalytic removal has been investigated. Addition of these chemicals reduces the removal rate. HPLC results showed that some intermediates appeared in the reaction course and were removed with increasing irradiation time. Therefore the results reveal that the mineralization of (p-NP) at optimum condition occurs and COD reduction of 80.0 % takes place after 150 min of irradiation.