Mechanisms of enhanced total organic carbon elimination from oxalic acid solutions by electro-peroxone process

WATER RESEARCH

卷:80

Article

Wang, Huijiao¹  Yuan, Shi¹  Zhan, Juhong^1,2  Wang, Yujue¹  Yu, Gang¹  Deng, Shubo¹  Huang, Jun¹  Wang, Bin¹ 

[1] Tsinghua Univ, Beijing Key Lab Emerging Organ Contaminants Contr, State Key Joint Lab Environm Simulat & Pollut Con, Sch Environm, Beijing 100084, Peoples R China

[2] Kunming Univ Sci & Technol, Fac Environm Sci & Engn, Kunming 650500, Yunnan, Peoples R China

关键词: Advanced oxidation;    Ozone;    Hydrogen peroxide;    Electrocatalytic ozonation;    Electrolysis;   

DOI  :  10.1016/j.watres.2015.05.024

来源: Elsevier

【 摘 要 】

Electro-peroxone (E-peroxone) is a novel electrocatalytic ozonation process that combines ozonation and electrolysis process to enhance pollutant degradation during water and wastewater treatment. This enhancement has been mainly attributed to several mechanisms that increase O-3 transformation to (OH)-O-center dot in the E-peroxone system, e.g., electro-generation of H2O2 from O-2 at a carbon-based cathode and its subsequent peroxone reaction with O-3 to (OH)-O-center dot, electro-reduction of O-3 to (OH)-O-center dot at the cathode, and O-3 decomposition to (OH)-O-center dot at high local pH near the cathode. To get more insight how these mechanisms contribute respectively to the enhancement, this study investigated total organic carbon (TOC) elimination from oxalic acid (OA) solutions by the E-peroxone process. Results show that the E-peroxone process significantly increased TOC elimination rate by 10.2-12.5 times compared with the linear addition of the individual rates of corresponding ozonation and electrolysis process. Kinetic analyses reveal that the electrochemically-driven peroxone reaction is the most important mechanism for the enhanced TOC elimination rate, while the other mechanisms contribute minor to the enhancement by a factor of 1.6-2.5. The results indicate that proper selection of electrodes that can effectively produce H2O2 at the cathode is critical to maximize TOC elimination in the E-peroxone process. (C) 2015 Elsevier Ltd. All rights reserved.

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