Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods

Fan, Guangping; Cang, Long; Gomes, Helena I.; Zhou, Dongmei

Abstract

Persulfate-based in-situ chemical oxidation (ISCO) for the remediation of organic polluted soils has gained much interest in last decade. However, the transportation of persulfate in low-permeability soil is very low, which limits its efficiency in degrading soil pollutants. Additionally, the oxidation-reduction process of persulfate with organic contaminants takes place slowly, while, the reaction will be greatly accelerated by the production of more powerful radicals once it is activated. Electrokinetic remediation (EK) is a good way for transporting persulfate in low-permeability soil. In this study, different activation methods, using zero-valent iron, citric acid chelated Fe²⁺, iron electrode, alkaline pH and peroxide, were evaluated to enhance the activity of persulfate delivered by EK. All the activators and the persulfate were added in the anolyte. The results indicated that zero-valent iron, alkaline, and peroxide enhanced the transportation of persulfate at the first stage of EK test, and the longest delivery distance reached sections S4 or S5 (near the cathode) on the 6th day. The addition of activators accelerated decomposition of persulfate, which resulted in the decreasing soil pH. The mass of persulfate delivered into the soil declined with the continuous decomposition of persulfate by activation. The removal efficiency of PCBs in soil followed the order of alkaline activation > peroxide activation > citric acid chelated Fe²⁺ activation > zero-valent iron activation > without activation > iron electrode activation, and the values were 40.5%, 35.6%, 34.1%, 32.4%, 30.8% and 30.5%, respectively. The activation effect was highly dependent on the ratio of activator and persulfate.

Citation

Fan, G., Cang, L., Gomes, H. I., & Zhou, D. (2016). Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods. Chemosphere, 144, 138-147. https://doi.org/10.1016/j.chemosphere.2015.08.074

• Journal Article Type: Article
• Acceptance Date: Aug 24, 2015
• Online Publication Date: Sep 5, 2015
• Publication Date: Feb 1, 2016
• Deposit Date: Sep 23, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: Chemosphere
• Print ISSN: 0045-6535
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 144
• Pages: 138-147
• DOI: https://doi.org/10.1016/j.chemosphere.2015.08.074
• Keywords: Polychlorinated biphenyls (PCBs), Soil remediation, Electrokinetics, Persulphate activation
• Public URL: https://hull-repository.worktribe.com/output/379246
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0045653515300746
• Additional Information: Authors' accepted manuscript of article published in: Chemosphere, 2015, v.144
• Contract Date: Nov 23, 2017