SINGLE-COMPONENT AND MIXTURE SOLUBILITIES OF HEXACHLOROBENZENE AND PENTACHLOROPHENOL IN SUPERCRITICAL CARBON-DIOXIDE

Mixture solubilities are of particular importance when considering sup ercritical processes for separation of multicomponent mixtures and ext raction of mixtures from solid matrixes, such as cleaning of spent ads orbents or remediation of contaminated soils. An investigation of the solubility limits of two priority pollutants, hexachlorobenzene and pe ntachlorophenol, was performed using a novel solubility apparatus. Mix ture solubilities were found to decrease substantially in the case of hexachlorobenzene. A thermodynamic model employing the Wong-Sandler mi xing rules was used for prediction of the solubility data. This model was shown to work better than the traditional van der Waals quadratic mixing rule for the binary systems and correlated well with measured p entachlorophenol partial molar volumes.