Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process

Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O-2 in the sparged ozone generator effluent (O-2 and O-3 gas mixture) to H2O2. The electro-generated H2O2 then react with sparged O-3 to yield aqueous (OH)-O-center dot, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as (OH)-O-center dot probe, the pseudo-steady concentration of (OH)-O-center dot was determined to be similar to 0.744 x 10(-9) mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher (OH)-O-center dot concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g(-1) TOCremoved. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only similar to 6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g(-1) TOCremoved, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane wastewater. (C) 2015 Elsevier B.V. All rights reserved.