Use of a surfactant coacervate phase to extract chlorinated aliphatic compounds from water: Extraction of chlorinated ethanes and quantitative comparison to solubilization in micelles

At temperatures above the cloud point, aqueous solutions of nonionic surfac tants separate into a coacervate phase and a dilute phase. The distribution of di-, tri-, and tetrachloroethanes between these phases was shown to inc reasingly favor the coacervate phase as the hydrophobicity (degree of chlor ination) of the solute increases. The solute solubilization equilibrium con stant was shown to be very similar for solubilization into coacervate surfa ctant aggregates compared to micellar solubilization pei aggregated surfact ant molecule for octylphenol polyethoxylate surfactants and to increase wit h increasing temperature and increasing solute hydrophobicity. As temperatu re increases above the cloud point, the partition ratio increases primarily because the concentration of surfactant in the coacervate increases, secon d because the solubilization equilibrium constant in the coacervate surfact ant aggregate increases, and third because the concentration of micellized surfactant (and solubilization therein) in the dilute phase decreases.