Evaluation of a hybrid advanced oxidation process for removal of pirimicarb insecticide in aqueous media: Statistical optimization and estimation of electrical energy consumption

In this paper, the role of periodate and persulfate as inorganic oxidants were studied in presence of ultraviolet radiation and titanium dioxide nanoparticles as a hybrid advanced oxidation photocatalytic processes for degradation and mineralization of the pirimicarb insecticide in aqueous media. The effects of several factors such as the ultraviolet irradiation, initial oxidant concentration, titanium dioxide nanoparticles dosage, and pH on the process performance were investigated. The process optimization was performed by the central composite design as a tools of response surface methodology for 30 mg L⁻¹ of the insecticide initial concentration at 25°C and 10 min of degradation process. A degradation efficiency of about 86% and 85% have been obtained for the persulfate and periodate processes, respectively, in the optimum conditions. The mineralization efficiency of the process using persulfate and periodate were about 35% and 46% after 60 min, respectively. The kinetic studies show that both processes follow a pseudo-first-order kinetic model and the rate constants were 0.1483 min⁻¹ for the persulfate and 0.1152 min⁻¹ for the periodate process. Generally, it can be concluded that this method is suitable for the degradation and mineralization of toxic aromatic compounds.