28. Surfactants/co-surfactants, solvents/co-solvents

Mobilizing agents such as surfactants and solvents are used to improve the efficiency of soil washing with water. They can be used in situ (injection of the washing solution into the soil to be treated in situ) or ex situ (washing of excavated soil in an appropriate unit).

• Principle

  Mobilizing agents are chemical substances added to soil washing solutions to increase their extraction efficiency (figure 28 ). The use of these additives is only necessary when non-aqueous liquid phases (NAPL) are present.

  The mobilizing agents tested to date are surfactants and organic solvents. The term "co-surfactant" or "co-solvent" is used when several surfactants or solvents are used in the same washing solution....