Effect analysis of copper and brass electrodes on the electroosmotic flow in high saline soil

Abstract

Salinity affects greatly cultivated land by reducing its fertility; also it can lead to potential damages to substructures or even conduct to a collapse in the long run by changing soil geotechnical properties. Electrokinetic technology (EKR) is a promising technique for removing salinity from low-permeability soils. For these, it is essential to study the parameters that govern electro osmotic permeability in order to predict effectiveness and optimize electrokinetic treatment. This work concerns the application of the (EKR) method on the saline-sodic soil of the Bordjias plain located in the south-western region of Mostaganem (Algeria). Due to the semi-arid climate prevailing in this region, vast tracts of land are currently being lost due to salinization. The efficiency of this method is studied by the variation of the electric voltage gradient (0.375, 0.50, and 0.625 V/cm) surface and the electrode materials (brass and copper) on electro-osmotic permeability and electrical energy consumption. The results showed that increasing the electric voltage gradient had no effect on the intensity of electrolysis reactions, which did not change beyond a specific limit, and did not increase the electroosmotic flow; but it generated more electric current than the admissible current for copper electrodes, causing corrosion, unlike brass electrodes, which resisted significantly. For the same electric voltage gradient, brass electrodes resisted longer and resulted in a higher flow rate than copper. Maximum electroosmotic flow was recorded at 0.5 (V/cm) voltage gradient for both material electrodes, but the highest volume of flow evacuated was recorded for EKB2 (brass) (GR2) tests. The coefficient of electroosmotic permeability is inversely proportional to the electrical gradient in contrast to the electrical energy consumption which is also influenced by the type of electrode material used. This implies that an increased voltage gradient results in higher current and energy consumption. The study revealed no significant difference in energy consumption between brass and copper materials in terms of value; however, the Brass exhibits greater durability compared to copper materials. The conducted tests lead to the conclusion that the efficiency of the process can be achieved at a lower applied voltage, using a brass electrode for soils with high salinity concentrations. Consequently, an appropriate electric voltage gradient needs to be determined to achieve efficient electroosmotic treatment while effectively reducing the corresponding energy consumption.