Phase behavior of organic pollutants in supercritical water

Abstract

Methods for analyzing, ranking, and predicting the global phase behavior and possible heterogeneous fluid equilibria in supercritical water-organic pollutant systems are discussed in terms of present-day conceptions of the global phase diagrams of binary mixtures. The phase equilibria of some classes of organic compounds (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzodioxins and furans as well as some pesticides) in supercritical water are studied. Based on found correlations with the partition coefficient of organic substances in immiscible mixtures of octanol and water (KOW), we determine the binary interaction parameter k12 in a one-fluid mixture model. Analytical expressions for predicting the azeotropic states of binary mixtures are derived; the occurrence of azeotropic behavior in aqueous solutions of organic compounds is estimated. Results of calculations of phase equilibria and critical curves for earlier unstudied organic pollutants in supercritical water are described.