Nonionic Surfactant Sorption onto Soil

Experiments in batch soil/aqueous systems were conducted to evaluate the sorption onto soil of four nonionic surfactants. At bulk solution surfactant concentration less than the respective critical micelle (aggregate) concentration (CMC or CAC), sorption can be assessed using a surface tension technique and can be characterized with a Freundlich isotherm. At bulk solution surfactant concentrations equal to or greater than the critical concentration, sorption of the micelle-forming surfactants can be assessed by a spectrophotometric technique with an azo dye and had a constant value; sorption of the lamellae-forming surfactant can be assessed by a chemical oxidation technique and, however, appeared to be an increasing function of the surfactant dose.