HENRYS LAW CONSTANTS AND INFINITE DILUTION ACTIVITY-COEFFICIENTS FOR VOLATILE ORGANIC-COMPOUNDS IN WATER BY A VALIDATED BATCH AIR STRIPPINGMETHOD

An improved batch air stripping technique has been developed for the d etermination of Henry's law constants and infinite dilution activity c oefficients-of volatile organic compounds in water. The experimental d esign confirms that the;two fundamental assumptions in batch air strip ping are fulfilled: (i) equilibrium between vapor and dissolved organi c in the top of the stripping column; (ii) homogeneity of the liquid, phase. Various organics:in water, representing a range of Henry's law constants from 5 X 10(3) to 2 x 10(5) kPa, were investigated. When acc urate pure component vapor pressure data are available, accurate infin ite dilution activity coefficients can be calculated from the ratio of the Henry's law constant to the pure component vapor pressure. For ce rtain aqueous systems, the UNIFAC model for hydrophobic compounds stil l fails to give accurate predictions of thermodynamic properties.