Refractory petrochemical wastewater treatment by K2S2O8 assisted photocatalysis

The K₂S₂O₈ assisted photocatalytic system was applied for treating refractory petrochemical wastewater. Co-TiO₂/zeolite catalyst synthesized by sol-gel method was demonstrated to possess a good activity towards mineralization of the refractory petrochemical wastewater in the K₂S₂O₈ assisted photocatalytic system. Orthogonal design was employed to optimize the reaction parameters, according to the results, K₂S₂O₈ dosage was the most prominent impact factor. More experiments were conducted to further enhance the COD removal efficiency. In consideration of both efficiency and costs, the petrochemical wastewater was treated in the K₂S₂O₈ assisted photocatalytic system at pH 4, K₂S₂O₈ dosage 2.03 g/L, catalyst amount 250 g/L with irradiation by 1 lamp and aeration. The COD removal efficiency reached up to 93.4% with a rate constant of 1.14 × 10⁻² per min, and Co-TiO₂/zeolite showed a good stability towards the K₂S₂O₈ assisted photocatalytic degradation of petrochemical wastewater.