Radical-induced destruction of diethyl phthalate in aqueous solution: kinetics, spectral properties, and degradation efficiencies studies

Abstract

In this work, the reactions of ∙OH, eaq−, and SO4∙− with diethyl phthalate (DEP) were investigated in aqueous solution by pulse radiolysis, and degradation efficiencies of DEP with ∙OH and eaq− were evaluated in water using steady-state radiolysis as well. The absolute rate constants of ∙OH, eaq−, and SO4∙− with DEP were determined as 2.3 × 109, 1.0 × 1010, and 1.0 × 108 M−1 s−1, respectively. The degradation efficiencies for the ∙OH and eaq− reactions were 81 and 33 %, respectively. Transient absorption spectra were observed for the intermediate radicals produced by ∙OH, eaq−, and SO4∙− reactions. The results suggested that eaq− transferred to the ester group, resulting in the formation of DEP radical anions. In contrast, ∙OH and SO4∙− added predominantly to the aromatic ring of DEP, forming the corresponding ∙OH adducts. The fundamental mechanistic parameters and degradation efficiencies derived from these results were significant for evaluations and applications of advanced oxidation processes.