A novel isophorone wastewater treatment technology-wet electrocatalytic oxidation and its degradation mechanism study

Abstract

How to solve the poisoning and loss of catalysts in catalytic wet air oxidation (CWAO) process remains a great challenge. In this work, an electric field was introduced into wet air oxidation (WAO) process for the efficient degradation of isophorone (IP) wastewater for the first time, named as wet electrocatalytic oxidation (WEO) process. Different composite electrodes including Ti/PbO2, Ti/Pt, Ti/Ru-Ir and Ti/Ir-Ta electrode were selected as the anodes of WEO technique and the results showed that the total organic carbon (TOC) removal via WEO process with PbO2 anode (89.56 %) was much higher than CWAO equipped with noble metal catalyst (Ru/TiZrO4, 75.0 %). Additionally, the current efficiency of WEO process was 85.6 %, which was significantly better than that of EO process (12.1 %). A response surface methodology was applied to elucidate the effects of reaction conditions on IP degradation. Analysis of response surface model showed TOC removal were markedly affected (p ≤ 0.01) by the reaction time (t), temperature (T), current density (ID), T2 and ID2, and also determined (p ≤ 0.05) by the interactions of T with t and ID respectively. In addition, a synergistic effect was proved to take place in WEO process with synergistic effect factor f of 1.2 at optimized conditions. As an advanced wastewater treatment technology, WEO integrates the advantages of both electro-catalytic oxidation (EO) and WAO.