Application of electrokinetic soil flushing to four herbicides: A comparison

• EKSF can remediate soils polluted with ionic and non-ionic herbicides.
• Herbicides can be mobilized towards the electrodes by electromigration.
• Herbicides can be transported towards the cathode by electroosmotic dragging.
• Volatilization has a great importance and should be accounted in large processes.
• After 15 d long treatment, more than 80% of pesticide is removed.

In this work, four bench-scale plants containing soil spiked with four herbicides (2,4-Dichlorophenoxyacetic acid (2,4-D), oxyfluorfen, chlorsulfuron and atrazine) undergo treatment consisting of an electrokinetic soil flushing (EKSF). Results clearly demonstrate that efficiency of EKSF depends on the chemical characteristic of the pesticide used. The amount of pesticide collected in the anode well is more significant than that collected in the cathode wells, indicating that the electromigration is much more important than drainage by electro-osmotic flux for this application. After 15 d of treatment, the 2,4-D is the pesticide most efficiently removed (95% of removal), while chlorsulfuron is the pesticide more resilient to the treatment. Additionally, volatilization was found to be a process of the major significance in the application of electrokinetic techniques to soil polluted with herbicides and because of that it should always be taken into account in the future design of full-scale processes.

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