Sequential Process of Electro-Oxidation Followed by UV Photolysis (EO/UV) as a Simple Advanced Oxidation Process

Abstract

A sequential process of electro-oxidation followed by UV photolysis (EO/UV) was proposed as a simple advanced oxidation process. A boron-doped diamond (BDD) anode was used for electrolysis. A series of experiments revealed that the EO/UV significantly enhanced 1,4-dioxane degradation rate against single electro-oxidation and single UV photolysis. In the EO/UV of tap water, reactive radicals produced through UV photolysis of electrochemically generated ozone and free chlorine contributed to 28–53% of 1,4-dioxane degradation and the rest of the contribution was occupied by anodic oxidation. Indirect and direct ozone reactions did not take part in the 1,4-dioxane degradation. The energy efficiency of EO/UV was superior to that of single electro-oxidation at a higher current density and was stable in the electrolytic current range tested. Consequently, EO/UV was more effective in the rapid removal of 1,4-dioxane under an unsteady pollutant loading than the single electro-oxidation.