Sorption of nonionic surfactants on soil

Experiments in batch soil/aqueous systems were conducted to evaluate the important physical-chemical factors determining the sorption of nonionic surfactants onto natural soil. An understanding of this is valuable to the application of nonionic surfactants for soil washing and enhanced subsurface remediation. Sorption data were found to follow a Langmuir type isotherm reaching a saturation maximum over 10000 mg l(-1) solution concentration of surfactant. The hydrophilic ethylene oxide portion of nonionic surfactants plays a more important role in determining the extent of sorption by soils than the hydrophobic hydrocarbon chain portion. Sorption capacity of nonionic surfactants for soils appears to be related to the mineralogical composition of the soil surface, soil organic carbon content, ionic strength and solution pH.