Electro-peroxone degradation of diethyl phthalate: Cathode selection, operational parameters, and degradation mechanisms

Meifang Hou; Yaofei Chu; Xiang Li; Huijiao Wang; Weikun Yao; Gang Yu; Seiichi Murayama; Yujue Wang

doi:10.1016/j.jhazmat.2015.12.054

Electro-peroxone degradation of diethyl phthalate: Cathode selection, operational parameters, and degradation mechanisms

J Hazard Mater. 2016 Dec 5:319:61-8. doi: 10.1016/j.jhazmat.2015.12.054. Epub 2015 Dec 31.

Authors

Meifang Hou¹, Yaofei Chu², Xiang Li³, Huijiao Wang³, Weikun Yao³, Gang Yu³, Seiichi Murayama⁴, Yujue Wang⁵

Affiliations

¹ School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, China.
² School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, China; School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
³ School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
⁴ Power and Industrial Systems R&D Center, Toshiba Corporation, Fuchu-shi, Tokyo, Japan.
⁵ School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084, China. Electronic address: wangyujue@tsinghua.edu.cn.

PMID: 26777107
DOI: 10.1016/j.jhazmat.2015.12.054

Abstract

This study compares the degradation of diethyl phthalate (DEP) by the electro-peroxone (E-peroxone) process with three different carbon-based cathodes, namely, carbon-polytetrafluorethylene (carbon-PTFE), carbon felt, and reticulated vitreous carbon (RVC). Results show that the three cathodes had different electrocatalytic activity for converting sparged O2 to H2O2, which increased in order of carbon felt, RVC, and carbon-PTFE. The in-situ generated H2O2 then reacts with sparged O3 to yield OH, which can in turn oxidize ozone-refractory DEP toward complete mineralization. In general, satisfactory total organic carbon removal yields (76.4-91.8%) could be obtained after 60min of the E-peroxone treatment with the three carbon-based cathodes, and the highest yield was obtained with the carbon-PTFE cathode due to its highest activity for H2O2 generation. In addition, the carbon-PTFE and carbon felt cathodes exhibited excellent stability over six cycles of the E-peroxone treatment of DEP solutions. Based on the intermediates (e.g., monoethyl phthalate, phthalic acid, phenolics, and carboxylic acids) identified by HPLC-UV, plausible reaction pathways were proposed for DEP mineralization by the E-peroxone process. The results of this study indicate that carbon-based cathodes generally have good electrocatalytic activity and stability for application in extended E-peroxone operations to effectively remove phthalates from water.

Keywords: Electrocatalytic ozonation; Electrode; Hydrogen peroxide; Ozone; Phthalates.