A three-electrode column for Pd-catalytic oxidation of TCE in groundwater with automatic pH-regulation and resistance to reduced sulfur compound foiling

WATER RESEARCH

卷:47

Article

Yuan, Songhu^1,2  Chen, Mingjie³  Mao, Xuhui²  Alshawabkeh, Akram N.² 

[1] China Univ Geosci, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Peoples R China

[2] Northeastern Univ, Dept Civil & Environm Engn, Boston, MA 02115 USA

[3] Lawrence Livermore Natl Lab, Atmospher Earth & Energy Div, Livermore, CA 94550 USA

关键词: Pd;    Electrolytic;    TCE;    Groundwater remediation;    Reduced sulfur compounds;   

DOI  :  10.1016/j.watres.2012.10.009

来源: Elsevier

【 摘 要 】

A hybrid electrolysis and Pd-catalytic oxidation process is evaluated for degradation of trichloroethylene (TCE) in groundwater. A three-electrode, one anode and two cathodes, column is employed to automatically develop a low pH condition in the Pd vicinity and a neutral effluent. Simulated groundwater containing up to 5 mM bicarbonate can be acidified to below pH 4 in the Pd vicinity using a total of 60 mA with 20 mA passing through the third electrode. By packing 2 g of Pd/Al2O3 pellets in the developed acidic region, the column efficiency for TCE oxidation in simulated groundwater (5.3 mg/L TCE) increases from 44 to 59 and 68% with increasing Fe(II) concentration from 0 to 5 and 10 mg/L, respectively. Different from Pd-catalytic hydrodechlorination under reducing conditions, this hybrid electrolysis and Pd-catalytic oxidation process is advantageous in controlling the fouling caused by reduced sulfur compounds (RSCs) because the in situ generated reactive oxidizing species, i.e., O-2, H2O2 and center dot OH, can oxidize RSCs to some extent. In particular, sulfite at concentrations less than 1 mM even greatly increases TCE oxidation by the production of SO4 center dot-, a strong oxidizing radical, and more center dot OH. (C) 2012 Elsevier Ltd. All rights reserved.

【 授权许可】

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