Surfactant solubilization of hydrophobic compounds in soil and water

Publisher Website
Google Scholar
Abstract
Reductions in the apparent soil-water partition coefficients (Kd *) for 28 polychlorinated biphenyls (PCBs) caused by the surfactant sodium dodecylsulphate (SDS) in the aqueous phase were studied. Above the critical micelle concentration (CMC) of the surfactant, Kd * was reduced by 2–3 orders of magnitude, but even far below CMC at environmentally relevant surfactant concentrations significant reductions in Kd * were observed. The plot of the soil-water partition coefficient (Kd) divided by Kd * versus the concentration of SDS allowed for the calculation of monomer (Kmn oc) and micellar (Kmc oc) surfactant-water partition coefficients normalized to organic carbon for each PCB congener. Kmn oc values were comparable with published values for the partition of PCBs between natural dissolved organic matter and lake water. Kmc oc values were up to 30 times higher than Kmn oc values and comparable with published octanol-water distribution coefficients. The findings of the present study underline the potential of surfactants at concentrations below their CMC to mobilize otherwise strongly bound hydrophobic compounds in soil-water systems.
Keywords