Electrokinetics chemical oxidation/reduction

Yang GCC (2009) Electrokinetic-chemical oxidation/ reduction. In Reddy KR, Cameselle C (eds) Electrochemical remediation technologies for polluted soils, sediments and groundwater. Wiley, Hoboken, pp 439-471... 

Despite the relatively good results found in literature for soil contaminated with TCE, the removal and elimination of COCs requires enhanced electrokinetic technologies. They comprise the use of solubilizing agents such as cosolvents, surfactants, or cyclodextrins. The other possible alternative for the removal of COCs from soil implies the combination of electrokinetic with other remediation techniques such as chemical and electrochemical oxidation/reduction, permeable reactive barriers, electrolytic barriers, and electric heating. 

The treatment methods for remediation of energetic materials from soils are divided on in situ and ex situ biological (bioremediation, phytoremediation, composting), in situ and ex situ physico-chemical (adsorption, oxidation, electrokinetic separation, extraction, solidification, reduction, soil washing), in situ and ex situ thermal (pyrolysis, desorption) [1]. Among the above described... 

The above inequality lists the major players in the action of an electrokinetic barrier. Whether diffusion is important will depend very much on the timescale (Fig. 16.3). For the movement of contaminants through sands, it may be that diffusion can be neglected initially. The movement of chemicals in a solution by diffusion can be quite slow compared with other processes. The distance moved is proportional to the square root of twice the diffusion coefficient times the time taken. For example, for a molecule with a free diffusion coefficient of 10 m /s, the distance moved in Is is about 40/rm in 1 day, about 1.3cm in 1 week, about 3.4cm and in 1 year, about 25 cm. So, for a first approximation, we can perhaps neglect diffusion. However, for long-term protection, for example, of a landfill, diffusion would of course have to be considered. Adsorption, biodegradation, and reduction-oxidation are also not included in this simple approach. 

---