Ion exchange membranes enhance the electrokinetic in situ chemical oxidation of PAH-contaminated soil

Hongting Xu; Yue Song; Long Cang; Dongmei Zhou

doi:10.1016/j.jhazmat.2019.121042

Ion exchange membranes enhance the electrokinetic in situ chemical oxidation of PAH-contaminated soil

J Hazard Mater. 2020 Jan 15:382:121042. doi: 10.1016/j.jhazmat.2019.121042. Epub 2019 Aug 19.

Authors

Hongting Xu¹, Yue Song², Long Cang³, Dongmei Zhou²

Affiliations

¹ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
³ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: canglong@issas.ac.cn.

PMID: 31450203
DOI: 10.1016/j.jhazmat.2019.121042

Abstract

Electrokinetic in situ chemical oxidation (EK-ISCO) could be used to remediate inorganic/organic-contaminated soil. Oxidizing agents were effectively delivered to the contaminated zones through electromigration and the electroosmosis. However, the cathode may react with oxidants, which would reduce the oxidative effect and lead to low contaminant removal rates. In this study, ion-exchange membranes (IEMs) enhanced EK-ISCO was used to remediate polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. IEMs were installed between the electrode compartment and the soil compartment. The results showed that the IEMs could effectively control pH and the oxidation-reduction potential (ORP) changes in the soil column. Placing a cation-exchange membrane (CEM) at the cathode prevented the S₂O₈^2- from contacting the cathode and reduced the oxidative loss effect, which meant that PAH removal efficiency significantly improved (from 33.1% to 87.1%). Furthermore, there were minimal changes to the soil properties. Maintaining the soil at a low pH also improved the PAH removal efficiency (93.1%), but the physicochemical properties of the soil significantly changed and a large amount of power was consumed (2015 kWh t^-1). This study indicated that placing a CEM at the cathode improved remediation efficiency, and reduced power consumption and the adverse effects on soil properties during EK-ISCO.

Keywords: Electrokinetic remediation; Ion-exchange membrane; Migration; PAHs; Persulfate.

Publication types

Research Support, Non-U.S. Gov't