Diazinon is one of organophosphate pesticides which it is classified as a relatively dangerous substance (Class II by WHO). The PANI/g C3N4/ CeO2 nanocomposite was synthesized by in situ polymerization method to determine the efficiency of photocatalytic degradation of diazinon. The photocatalytic activities efficiencies of the supported and unsupported nanocomposites were evaluated using diazinon as a model pollutant. The superior photocatalytic effect of the PANI/g C3N4/CeO2 nanocomposite is attributed to the synergistic effect of PANI and g C3N4/CeO2 which promotes migration efficiency of the photogenerated carriers on the g C3N4/CeO2 nanocomposite interface. The effects of pH, initial diazinon concentration, catalyst load, hydrogen peroxide as well as effect of other organic compound were investigated using photocatalytic degradation of PANI/g C3N4/CeO2. The results obtained indicate the efficient degradation at pH= 6 which extent to 94.08 %, at 10 ppm extent to 88.9%, at 0.1 g/L extent to 97.48 %; were as increasing the concentration of hydrogen peroxide, the percent of degradation of diazinon increased due to the increased reaction between hydrogen peroxide and electron in the conduction band of PANI/g-C3N4/CeO2. Hydrogen peroxide can effectively inhibited electron hole recombination. Therefore hydrogen peroxide is better electron acceptor than dissolved oxygen; it acts as an alternative electron acceptor to oxygen. The effect of different organic compound on the photocatalytic degradation of diazinon; organic compound such as phenol, citric acid, EDTA and oxalic acid were examined, the result indicated that photocatalytic degradation was negatively affected in the presence of all organic compounds.

Keywords: Advanced Oxidation Process, Diazinon, Heterogeneous Photocatalysts, Nanocomposites, Polyaniline.

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