Soil electro-remediation is a technique that allows the removal of organic and inorganic compounds [1-4]. Changes in the soil matrix during application of the electric field affects desorption and/or absorption, and even the mobilization process of pollutants [5].

Changes caused by the potential gradient in a model soil (sodium bentonite) and the results of pH and contaminant transport of a model designed in Visual Basic were compared to evaluate the process of electro-migration which was simulated through the transport number.

When we compared the behavior of the model soil with a Vertisol soil, the parameters evaluated throughout the cell were: pH, electrical conductivity and z potential. The behavior between the model soil and the Versitol type soil pH is similar in the area near the anode where there is a decrease in pH attributed to the generation of H⁺ and the cathode pH was slightly increased by the presence of ^–OH (Figure 1).

However, the behaviors of the electrical conductivity and z potential are not similar due to the presence of organic matter, microorganisms and the diversity of ions contained in the Versitol type soil. The observed changes in these parameters promote the removal of pollutants. In the case of Vertisol type soil the observed changes in the soil matrix are minimal, which is an advantage of electro-remediation in comparison of another treatments of soil, as biological and chemical procedures.

References.

[1] K. R. Reddy, Technical challenges to in-situ remediation of polluted sites. Geotech. Geol. Eng., 28(3), 211-221 (2010).

[2] M. Pérez-Corona, A. Corona, E. D. Beltrán, J. Cárdenas and E. Bustos, Evaluation of IrO₂ – Ta₂O₅|Ti electrodes during the electroremediation of hydrocarbon – contaminated soil. Sustain. Environ. Res., 23 (4), 279 – 284 (2013).

[3] A. Medel, D. Patiño, E. Méndez, Y. Meas, L. Godínez, J. Manríquez, F. Rodríguez, A. Rodríguez and E. Bustos, Novel electrokinetic remediation system – boron doped diamond (EKR-BDD) process for the destruction of polyaromatic hydrocarbons (PAHs) in liquid phase. Environ. Engin. Manag. J., 14 (4) 879 – 886 (2015).

[4] I. Robles, M. J. Lozano, S. Solís, G. Hernández, M. V. Paz, M. G. Olvera and E. Bustos, Electrokinetic treatment of mercury – polluted soil facilitated by ethylenediaminetetraacetic acid coupled with a reactor with a permeable reactive barrier of iron to recover mercury (II) from wáter. Electrochimica Acta 181, 68 – 72 (2015).

[5] I. Robles, E. Bustos and J. Lakatos, Comparison of the sorption behavior of mercury (II) on inorganic, organic and biomass substrates in the presence of different counter-ions. Sustain. Environ. Res., 25 (5), 255- 260 (2015).