Determination of Henry's law constants of organics in dilute aqueous solutions

Abstract

Accurate knowledge of Henry's law constants, H, or air/water partitioning coefficients are required to predict the behavior of organic compounds in the environment. In particular, when the compounds are relatively volatile and exhibit low solubility in water, air stripping may be a viable method for above-ground treatment. Henry's law constants of 15 volatile organic compounds in dilute aqueous solutions were measured by the procedure of equilibrium partitioning in a closed system. The method is based upon the measurement of the headspace concentration by gas chromatography. The compounds investigated included six halogenated hydrocarbons, four aromatic hydrocarbons, and five alkanes. The measurements were made at three temperatures between 25 and 45 C. The measured Henry's law constants compared well with the literature data of some liquids. The temperature dependence of Henry's law constant was also studied from the van't Hoff relation.