Comparison of solar TiO 2 photocatalysis and solar photo-Fenton for treatment of pesticides industry wastewater: Operational conditions, kinetics, and costs

Solar photo-Fenton and solar TiO2 photocatalysis processes were investigated for degradation of pesticides from real industrial wastewater. Chlorpyrifos, lambda-cyhalothrin, and diazinon were the major contaminants found in the wastewater. The effect of initial pH, chemical dosing, and irradiation time on the removal efficiency of pesticides and chemical oxygen demand (COD) were assessed. The maximum removal of COD by photo-Fenton process was 90.7%, while by TiO2 photocatalysis was 79.6%. Moreover, the photo-Fenton process was more efficient for degradation of pesticides fractions. Employing of H2O2 in photocatalysis process (UV/H2O2/TiO2) improved the removal of COD (84%) and the degradation of pesticides. The kinetic study showed that the degradation of pesticides fractions follows pseudo-first-order pattern. Amortization and operating costs of full scale solar oxidation plant were estimated. The estimated costs for photocatalysis and photo-Fenton processes were 8.69 and 5.2 €/m3, respectively.