Photocatalytic Removal of Triethyl Phosphate from Aqueous Solutions Using Zinc Oxide Nanoparticles

Triethyl phosphate (TEP) is one of the most important organophosphate pollutants, used as an industrial catalyst, a polymer resin modifier, an intermediate in the synthesis of pesticides (and other chemicals), and a peroxide stabilizer. The photocatalytic process is based on the irradiation of a semi-conductor compound with ultra-violet lights and subsequent production of high-energy hydroxyl radicals. In this study, the removal of TEP from aqueous solutions was investigated, using photocatalytic oxidation process. Photocatalytic removal of TEP by zinc oxide nanoparticles was studied using a batch reactor, equipped with a UVC lamp at room temperature (25 °C). Parameters affecting the removal of TEP including zinc oxide concentration (700-1200 mg/L), pH (3-10), initial concentration of TEP (30-80 mg/L), and contact time (30-180 min) were investigated. The results showed that the maximum removal rate of TEP is obtained at pH=7, initial concentration of 40 mg/L, nanoparticle dosage of 1200 mg/L, and contact time of three hours. This study showed that organophosphates can be almost completely removed from water in a short time by using photochemical oxidation.