Effects of cathode materials on the oxychlorides generation laws in the DSA electrooxidation system and performance assessment of COD removal
The Direct Solar Airflow(DSA)electrooxidation system,employed for the electrochemical oxidation of chlorine-rich wastewater,yields oxychlorides as byproducts.This can lead to an overestimation of Chemical Oxygen Demand(COD)removal efficiency and a misleading impression of compliant effluent.This study investigates the influence of oxychloride formation in the DSA electrooxidation system on COD and Total Organic Carbon(TOC)determination when utilizing various cathodes.After 180 minutes of treatment at a current density of 40 mA·cm-2,TOC removal was largely consistent across different cathodes.However,the apparent COD removal followed the order Ti(94％),stainless steel(86％),and Cu/Zn cathode(74％),corresponding to the production of oxychlorides;notably,the Ti cathode produced more Chlorine Dioxide(ClOx-)as byproducts.Oxychloride oxide production can be significantly mitigated using a Cu/Zn cathode with robust reducing capabilities and increasing the content of organic phenol.The removal of oxychlorides(ClO-and ClO3-)via sulfite reduction resulted in a decrease in COD removal efficiency to similar levels,suggesting a masking effect of chloroxylate ions on COD determination.In control experiments,it was observed that ClO3 interfered more significantly with COD determination than ClO-.By examining the generation of oxychlorides under DSA electrooxidation systems with different cathodes and their interference with COD removal performance determination,a convenient,green,and effective control strategy was introduced,providing a novel method for accurately evaluating COD removal performance of electrooxidation systems.
NETL
NSTL
万方数据
