MODELING INFINITE DILUTION ACTIVITY-COEFFICIENTS OF ENVIRONMENTAL-POLLUTANTS IN WATER USING CONFORMAL SOLUTION THEORY

The fate of organic pollutants in the environment and in wastewater tr eatment processes is commonly modeled using a Henry's law constant app roach. By definition, Henry's law constant is the product of a compoun d's vapor pressure and infinite dilution activity coefficient. For man y organic compounds in water solution, the infinite dilution activity coefficients are very large and are not adequately modeled by conventi onal methods such as UNIFAC. In this work, infinite dilution activity coefficients were determined for phenol, pyridine, aniline, p-toluidin e, and o-toluidine in water by differential ebulliometry. An equation rigorously derived from conformal solution theory and van der Waals on e-fluid mixing rules was used to model the temperature dependency of t he infinite dilution activity coefficients. No corrections other than the introduction of two adjustable parameters were incorporated into t he model to account for the strong interactions between molecules. Rel ationships derived from corresponding states theory were used to relat e molecular parameters for size and energy interaction to the critical properties. Arithmetic mean combining rules and geometric mean combin ing rules were used to calculate size and interaction parameters, resp ectively.