To determine the amount of volatile organic compounds that are released from wastewater treatment facilities, equilibrium data are needed. For environmental applications in which dilute concentrations occur, the equilibrium data are usually expressed as Henry's Law Constants (HLC's).
Although a plethora of values for HLC's can be found, most values are determined only at 25° C. Henry's Law Constants have been calculated for nineteen selected VOC's from experimentally determined activity coefficients at infinite dilution and from extrapolated
vapor-liquid equilibrium data. These data are all taken from the literature. The compounds studied include homologous series of alcohols, acids, aldehydes, and selected aromatics and ketones. The log of the HLC was empirically fit as a function of the reciprocal temperature, analogous to the
relationship for several thermodynamic properties. The experimentally determined values of HLC's are correlated for each compound from 20 to 100° C. The developed correlations provide the best available values of HLC's over the temperature range 20° C to
100° C. Of the compounds analyzed, approximately 84% were found to have a nonlinear correlation of 0.90 or greater. Many of the values reported by the EPA differ significantly from the correlated values determined in this project. Henry's Law Constants estimated by
UNIFAC, the Pierotti Method, and several solubility methods were compared with the experimentally determined values. UNIFAC was found to provide the best estimation of the HLC's. Solubility estimation methods gave only order of magnitude values. None of the estimation methods were satisfactory
for the two aromatics studied.
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