Electrokinetic techniques are characterized by the use of a DC current for the removal of contaminants from porous materials. The method can be applied for several purposes, such as the recuperation of soil contaminated by heavy metals or organic compounds, the desalination of construction materials and the prevention of the reinforced concrete corrosion. The electrical energy applied in an electrokinetic process produces electrochemical reactions at the electrodes. Different electrode processes can occur. When considering inert electrodes in aqueous solutions, the reduction of water at the cathode is usually the dominant in the process. On the other hand, the electrode processes at the anode depend on the ions present in its vicinity. Oxidation of water and chloride are typically assumed to be the most common processes taking place. Electrons produced in the electrode processes are transported from the anode to the cathode through the closed electrical circuit of the cell. In the solution, the electrical current is carried by the ions, which move towards the electrode with different charge. Therefore, different authors have studied the system using the circuit theory. Assuming that it is possible to study the region limited by the electrodes as a one-dimensional problem, the system consisting of electrolyte, electrodes, conductors and power supply can be considered as an electrical circuit connected in series. According to the Ohm’s law, the voltage and the electrical current would be related to the conductivity of the media. This conductivity will vary as the electrokinetic process proceeds. For a better control of the electrokinetic process, a constant difference of voltage or a constant current density between the electrodes is typically used. Most authors argued that fixing the current density results in more efficient electrokinetic experiments with less operative problems. Nevertheless, in long term treatments, maintaining a constant current density can be difficult due to limitations of the power supply.
|Publication status||Published - 2010|
|Event||Conference on Electrochemical Science and Technology - Technical University of Denmark, Kgs. Lyngby, Denmark|
Duration: 30 Sep 2010 → 1 Oct 2010
|Conference||Conference on Electrochemical Science and Technology|
|Location||Technical University of Denmark|
|Period||30/09/2010 → 01/10/2010|