Catalytic ozonation with vanadium oxide-doped TiO2 nanoparticles for the removal of di-2-ethylhexyl phthalate

Among various plastic additives, di-2-ethylhexyl phthalate (DEHP) has been a great concern due to its high leaching potential and harmful effects on both human and the ecosystem. For the effective oxidation and mineralization of DEHP by ozone in the existing TiO2 catalytic processes, the heterogeneous catalyst, vanadium oxide (V2O5)-incorporated TiO2 (V2O5/TiO2), was synthesized. The generation of hydroxyl radicals was promoted by cyclic redox reactions of vanadium atoms in V2O5/TiO2 via the increase of surface oxygen vacancies by the replacement of V5+ species in the lattice of TiO2. The catalytic ozonation in the presence of V2O5/TiO2 exhibited the significantly higher degradation of DEHP with the pseudo-second-order kinetic constant of 1.7 × 105 mM-1min-1 and the removal efficiency of 58.7% after 60 s in 2 mg/L of ozone. The degradation of DEHP was initiated by the shortening of the alkyl-side chain followed by the opening of esterified benzene moieties.