Removal of Heavy Metals and Radionuclides from Soils Using Cationic Surfactant Flushing

Background/Need: At some heavy industrial sites and DOE nuclear weapon manufacture and
test sites, high concentrations of heavy metals and radionuclides in soils impose potential threat to groundwater. Soils with large surface areas and high cation exchange capacities may accumulate significant amounts of heavy metals and radionuclides, requiring eventual soil excavation and ex situ extraction of the heavy metals and radionuclides. Cesium and lead are two relatively common contaminants that are particularly difficult to extract from clay and oxide fractions of soils. Thus a search for an inexpensive, yet effective method, to remove heavy metals from soil
becomes more imminent.

Objectives: The objectives of this research are to test the heavy metal removal efficiency using long chain cationic surfactants and to study the influence of surfactant chain length of several quaternary ammonium surfactants, the initial surfactant concentration, the initial heavy metal loading and initial solution pH and ionic strength on Pb and Cs removal from kaolinite and illite at batch scale, and then to conduct column leaching experiments to verify the batch results at different initial Pb and Cs loading.