THE INFLUENCE OF A SURFACTANT ON THE RATE OF PHENANTHRENE MASS-TRANSFER INTO WATER

Polycyclic aromatic hydrocarbons (PAH) are hydrophobic pollutants foun d in contaminated soils at many sites in the U.S. One method proposed to improve remediation of PAH contaminated soil is to add surfactants to help mobilize these and other poorly soluble compounds. Previous wo rk on the effects of surfactants on PAH and other pollutants has focus ed on equilibrium phenomena. The influence of a surfactant on the rate of dissolution of phenanthrene, a model PAH, was determined in this s tudy. Phenanthrene dissolution kinetics depended on the observed mass transfer coefficient and the apparent saturation concentration, both o f which depended on surfactant concentration. A simple two-step mass t ransfer model was developed to describe the relationship between disso lution rate and surfactant concentration. This approach may be useful in estimating effects on mass transfer kinetics for a variety of surfa ctants using data that are either available in the literature or are r eadily measured.