The influence of zero-valent iron on the photodegradation ozonation of di-2-ethylhexyl phthalate in aqueous solution

Abstract

In this study, the effect of nano zero-valent iron (NZVI) or Fe0 on photolysis ozonation (UV/O3) degradation of di-2-ethylhexyl phthalate (DEHP) was investigated. Applied pH, ozone dosage, NZVI dosage, reaction time, and initial concentration of DEHP were the parameters investigated under UV/O3/Fe0 process. The possible dominant mechanisms of DEHP degradation were also discussed. The degradation rate of DEHP gradually decreased with the increase in initial pH from 2 to 11 and increasing ozone dosage. When compared with other doses of NZVI, an NZVI dose of 200 mg/L was found to be more effective. Ozone dosage had little influence on the removal of DEHP. The reaction time of 15 min and initial DEHP concentration of 5 mg/L were optimum conditions in the combined process of UV/O3/Fe0. A comparison of the reaction orders of kinetic studies showed that DEHP degradation is in accordance with pseudo-second-order reaction. At the optimum conditions, the reaction time of 15 min, the major by-products of the oxidation process were phthalic acid and ethyl 5-phenyl-2-penten-4-ynoate. The NZVI photodegradation ozonation technology was capable of efficiently removing DEHP from water solutions.