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

Abstract

In the present study, the electrokinetic technology was coupled with a permeable reactive barrier (PRB), composed of micro-scale Fe to treat a clay soil contaminated by perchloroethylene (PCE). A non-ionic surfactant, Triton X-100, was selected as the solubility enhancing agent. A series of batch tests, having 10-day duration, were carried out to evaluate the fate, transport and removal of PCE. This study also demonstrates the effectiveness of the non-uniform EK/ZVIPRB system for the treatment of the PCE-contaminated, low permeability soils. A bench scale system was used, which contained 400 g of PCE contaminated soil (0.6 g PCE kg−1 soil) and a PRB containing 30 g of iron particles. Seven lab scale tests were conducted using a potential gradient of 1 V cm−1 for studying the influence of different variables like surfactant, the inclusion of PRB in the soil and the effect of polarity reversal. Results showed that the combination of EK and ZVIPRB could enhance the overall removal of PCE from soils by 40 % as compared to EK alone. Among the variables, the surfactant was seen to be essential for the movement of the pollutant through the PRB, and the PCE removal improved significantly on 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 days.