Effect of electric field intensity on energy consumption and removal efficiency of chromium ions from salt-affected clayey soils

This study investigates the effect of electric field intensity on electroosmosis and the effects of potential distribution, current and pH on the removal of total Cr, Na + , Clˉ and K + ions from salt-effected clayey soils. During electrokinetic experiments, DC electric field intensities varying from 0.5 to 2 Vcm − 1 were applied across the artificially contaminated soil samples for 48 hours. The results depict that the electric field intensity directly influences the electroosmotic flow and electromigration of ionic species presented in the pore solution of the specimens. The maximum removal of total Cr (~ 71%), Na + (~ 91%), Cl ˉ (~ 65%) and K + (~ 63%) was achieved at 2 Vcm − 1 due to the electromigration and initially higher electroosmotic flow (i.e., 69 ml). However, the higher electric field intensity resulted in enhanced electric energy consumption (i.e., 218.6 kWhr-m − 3 ) and the production of more aggressive acidic and alkaline environments across the electrodes. Thus, the migration of ions and electroosmosis were inhibited due to the higher potential drop caused by the collusion of pH fronts. Moreover, under an electric field intensity of 2 Vcm − 1 , the electrical conductivity of soil reduced from 5.2 to 1.29 dS m − 1 .