Use of alkaline earth dodecylsulfates for purification of soil materials from polycyclic aromatic hydrocarbon (PAH) contamination. Recycling of the surfactants and the water

Sodium dodecylsulfate solutions contaminated with polycyclic aromatic hydro carbons (PAH), e.g. pyrene, were purified by addition of calcium or barium salt solution and precipitation of the corresponding calcium or barium dode cylsulfate. The precipitates were cleaned up using several organic solvents . Regeneration of sodium dodecylsulfate from the calcium dodecylsulfate pre cipitate was possible by solving the substance in an ethanol/water mixture (1:1) and precipitation of calcium hydroxide using sodium hydroxide as a pr ecipitating agent. It was shown, that the calcium dodecylsulfate can be use d directly as a tenside in a hot water solution or in an ethanol/water mixt ure. An extraction procedure could be developed, to remove the PAH contamin ations quantitatively from the tenside solutions and concentrate them to sm all quantities by distillation of the organic solvents. It was demonstrated , that closed cycles of reagents in low need of energy are possible. The pr ocedure was tested at a perylene contaminated kaolin sample.