Impact of Enhancement with Calcium Chloride Solution on the Electrolysis and Electro-Osmosis Mechanisms of Clayey Solis in Electrokinetics Process

Electrokinetics is known as a common method for improvement of soil engineering properties and contaminant removal from soils. In carbonated soils due to the soil buffering capacity, the acid front does not form through the soil sample. Therefore, the soil improvement usually caused by hydrogen ion effect will not occur. Consequently, a reduction in electrokinetics efficiency happens. One of the methods to overcome this problem is the application of enhancement methods. In this paper the influence of enhancement by the use of calcium chloride solution on two mechanisms of electrolysis and electro osmosis in electrokinetics remediation of carbonated clay is experimentally investigated. For this purpose, an un enhancement and enhance electrokinetics process with 0.2, and 0.5 molar concentrations of calcium chloride has been applied on  carbonated natural clay  samples. The calcium chloride solutions were added to anode reservoir. The achieved results of this paper indicate that due to the noticeable percentages of carbonate calcium in soil sample, not only the pH of soil in electrokinetics process has not decrease, but also because of alkaline condition of soil sample due to the presence of calcium carbonate and calcium chloride solution, the pH of soil has increased. Furthermore, in enhancement electrokinetics with calcium chloride, the presence of calcium ions and an increase in electro migration process have caused an increase in efficiency of electro osmosis. For this reason, the volumetric flow rate of enhanced electrokinetics experiments with 0.5 molar calcium chloride has been almost 250% more than that of for un-enhanced experiments.