LIQUID-LIQUID, EXTRACTION FOR SURFACTANT-CONTAMINANT SEPARATION AND SURFACTANT REUSE

Liquid-liquid extraction was investigated for use with surfactant enha nced subsurface remediation. A surfactant liquid-liquid extraction mod el (SLLEM) was developed for batch equilibrium conditions based on con taminant partitioning between micellar, water, and solvent phases. The accuracy of this fundamental model was corroborated with experimental results (using naphthalene and phenanthrene as contaminants and squal ane as the extracting solvent). The SLLEM model was then expanded to n onequilibrium conditions. The effectiveness of this nonequilibrium mod el was corroborated with experimental results from continuous flow hol low fiber membrane systems. The validated models were used to conduct a sensitivity analysis evaluating the effects of surfactants on the re moval of the contaminants in liquid-liquid extraction systems. In addi tion, liquid-liquid extraction is compared to air stripping for surfac tant-contaminant separation. Finally, conclusions are drawn as to the impact of surfactants on liquid-liquid extraction processes, and the s ignificance of these impacts on the optimization of surfactant-enhance d subsurface remediation.