Remediation of PCE contaminated clay soil by coupling electrokinetics with zero-valent iron permeable reactive barrier

Abstract

In the present study, electrokinetic technology was coupled with a Permeable Reactive Barrier (PRB) composed of micro-scale Fe to treat a clay soil contaminated by Perchloroethylene (PCE) as a Dense Non-Aqueous Phase Liquid (DNAPL). A nonionic surfactant, Triton X-100, was selected as the solubility enhancing agent. A series of 10 d duration batch tests were carried out in order to evaluate the fate and transport and removal of PCE and to demonstrate the effectiveness of the non-uniform EK/ZVI PRB system for the treatment of PCE-contaminated low permeability soils. A benchscale system was used, which contained 400 g of PCE contaminated soil (0.6g PCE kg-1 soil) and a PRB composed by 30 g iron particles. Seven lab-scale tests were conducted under a potential gradient of 1 V.cm-1 in order to study the influence of different variables: the effect of the surfactant, the effect of the PRB inclusion in the soil and the effect of polarity reversal. Results showed that the combination of EK and ZVI PRB could increase overall DNAPL removal from soils by 40% when compared with EK alone; the surfactant was necessary to move the pollutant trough the PRB, and the DNAPL removal generally increased by reversing the electrode polarity in the EK-PRB test (73% in Anode, 64% in Cathode). The best results showed an 80% PCE removal efficiency after 10 d.

Biostimulation versus bioaugmentation for the electro-bioremediation of 2,4-dichlorophenoxyacetic acid polluted soils

“…For example, reported that the insertion of Pd/Fe PRB caused EOF decrease 1.8 times in an electroremediation process for hexachlorobenzene-polluted soil. Kebria et al (2016) reported similar results in electroremediation of PCE polluted soil by using Fe 0 particles as PRB. On the other hand, same authors reported that coupling a Cu/Fe PRB in electroremediation of hexachlorobenzene-polluted soil caused that EOF increased.…”

Strategies for the electrobioremediation of oxyfluorfen polluted soils

“…Wang et al [13] reported that a Pd/Fe PRB inclusion caused that EOF decreased 1.8 times in an electrokinetic remediation process of hexaclorobenzenepolluted soil. Kebria et al [14] reported similar results. On the contrary, the same authors [15] reported that a Cu/Fe PRB insertion caused that EOF increased, again in an electrokinetic remediation process of hexaclorobenzene-polluted soil.…”

Microbial fuel cell‐enhanced electrokinetic process for remediation of chromium from marine sediments

“…Further, the pH variation in the cathode region was as follows: MEKC 6˃ MEKC 3˃ MEKC 5˃ MEKC 2˃ MEKC 1˃ MEKC 4. In the anode region, an acidic condition was established while the alkaline environment was produced in the cathode region; thus, pH increased in the cathode and decreased in the anode 52,53 . The fall in pH near the anode causes the cationic exchange of hydrogen with the contaminant absorbed on the sediment surface, leads to the release of the contaminant ions.…”