Characteristics of removal of hydrophobic organic carbons from sand/mulch using nonionic surfactants

Shehdeh W. Jodeh

It has been known that surfactants are able to improve the mass-transfer of hydrophobic pollutants from the solid or nonaqueous liquid phase into the aqueous phase by decreasing the interfacial tension and by accumulating hydrophobic compounds in micelles. Micelles are often characterized according to their size and shape. These geometric properties depend on both the chemical structure of the surfactant and the concentration and the nature of the aqueous environment. The adsorption of the surfactant to solid surfaces can lower the concentration of free surfactant in aqueous solutions. If the degree of adsorption is high, then the surfactant concentration can drop below the CMC (critical micelle concentration), rendering the surfactant solution unable to solubilize. Therefore, the amount of surfactant mass that will sorb should be accounted for when selecting the injection concentration. In this study, a nonionic surfactant, Triton X-100, was used to study the sorption characteristics of soil organic content. The surface tension is used to calculate this kind of sorption. The results indicated that when the concentration of surfactant was lower than the CMC, the amount of surfactant sorbed on soil increased with the increasing surfactant concentration, and the surfactant sorption characteristics of the uncontaminated soil can be modelled by the Freundlich isotherm. For the contaminated soils, the amount of surfactant sorbed was higher than that for the uncontaminated soils.

Key words: contaminant, isotherm sorption, supernatant, surface tension

Land Contamination & Reclamation, 17 (2), 245-254 (2009)

DOI 10.2462/09670513.875

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Article code 875