KINETICS OF PHENANTHRENE DISSOLUTION INTO WATER IN THE PRESENCE OF NONIONIC SURFACTANTS

The apparent liquid saturation concentration of phenanthrene and the o bserved mass transfer coefficient in a completely mixed batch system w ere quantified as a function of surfactant concentration for four comm ercially available nonionic surfactants and two synthetic, nonionic gl ycolipids under development for possible commercial application. A mat hematical model was developed to describe the dissolution process in t he presence of these nonionic surfactants. The model accounts for diff usional transport of phenanthrene in the aqueous phase and transport o f phenanthrene-saturated micelles across the hydrodynamic boundary lay er. For the surfactants investigated and the experimental apparatus us ed, the observed mass transfer coefficients for phenanthrene dissoluti on into water were in the range of 0.01-0.025 cm/min in the presence o f surfactant micelles as compared to 0.1 cm/min without surfactant. Al though surfactants decrease the observed mass transfer coefficient rel ative to water alone, the influence of surfactants on phenanthrene sol ubilization results in an overall increase in phenanthrene dissolution rates.