Potential of Vetiver grass for the phytoremediation of a real multi-contaminated soil, assisted by electrokinetic

Phytoremediation assisted by electrokinetic is a potential technology for remediation of contaminated soil, but little is known about its application on real contaminated soils. This study aims to evaluate the Vetiver grass application on the electro-phytoremediation of a real contaminated soil around a metal smelter factory. Different types of the electric field (AC-DC), voltage gradient (1-2V/cm), saturation and unsaturation condition, and Eh-pH variation were investigated for Vetiver electro-phytoremediation performance. Vetiver grass had been grown for 21 days. Then three different voltage gradients (1, 2DCV/cm and 2ACV/cm) were applied for 8 h/d across the soil domain for the next 21 days in comparison with a control cell without electric field (PR). The results showed that despite the AC current application which induced small changes, the application of DC current significantly changed the Eh-pH values. The maximum accumulation of extractable metals in Vetiver grass occurred in 2DCV/cm that shows approximately 50% increase in comparison with the AC and PR cells. The presence of contaminants poisons the Vetiver in all cells and all plants under 2DCV/cm dried out at the end of the experiment. Despite the significant reduction of heavy metals, there was no noticeable phytoextraction due to the application of DC current. Therefore, DC current can be used for phytoremediation through phytostabilization. However, the overall metals uptake in plants shoots under AC treatment with BCF>1 was much higher than the PR and DC treatment. Considering the translocation rate and plants health, if the AC current is applied in a long treatment time, it could have better results in electro-phytoremediation of the Vetiver grass through phytoextraction process. However, the maximum removal of heavy metals was in the cathode part of the cell under 2DCV/cm that shows 65% improvement in comparison with the PR cell. (C) 2019 Elsevier Ltd. All rights reserved.