Effect of electroosmotic and hydraulic flow on the desalination of soils

• Published in: Journal of applied electrochemistry 2024, Vol.54 (8), p.1685-1698
• Main Authors: Akram, S., Imran, M., Ashraf, S., Akram, A., Kamran, K., Ishaq, M., Hussain, A. A., Abbas, J. K., Ajaj, Y., Habila, M. A.
• Format: Article
• Language: English
• Subjects: Accumulation; Anions; Cations; Chemistry; Chemistry and Materials Science; Contaminants; Electric potential; Electrochemistry; Electromigration; Ferrous ions; Heavy metals; Hydraulics; Industrial Chemistry/Chemical Engineering; Lead; Physical Chemistry; Research Article; Soil contamination; Voltage; Water consumption
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-023-02062-z

This study examines the effect of electroosmotic (EO) and hydraulic flow on the removal of heavy metal (Pb 2+ , total Cr, and Fe 2+ ) and salt (K + and Clˉ) ions from artificially contaminated soil. For this purpose, the vertical electrokinetic (VEK) and hydraulic setups with wet sponges are introduced to reduce water consumption and avoid the accumulation of contaminants near the soil surface. In this study, during VEK experiments, different continuous and pulsed voltage gradients (i.e., 0.5, 1, and 2 V cm −1 ) are applied across the contaminated soil via iron mesh electrodes for 48 h, while during the hydraulic experiment, no voltage gradient is applied. The outcomes revealed that EO and hydraulic flow were directed downward from the top of the soil column, while EO flow was higher for a relatively higher voltage gradient. Therefore, the removal of cations (Pb 2+ and K + ) was higher than anions (total Cr and Clˉ) due to the effect of electromigration and EO flow. In contrast, under relatively low continuous and pulsed voltage gradient, the removal of anions was higher than cations due to electromigration and diffusion. In addition, during the hydraulic experiment, the removal of ions was comparatively lower than in all VEK experiments due to the low hydraulic flux. However, the accumulation of Fe 2+ ions in soil increased with the intensity of voltage gradient due to the corrosion of anode during all VEK experiments, except in the case of the hydraulic experiment where no voltage gradient was applied and the removal efficiency of Fe 2+ ions was 21%. Graphical abstract