DETERMINATION OF AIR-WATER HENRYS LAW CONSTANTS FOR HYDROPHOBIC POLLUTANTS

A novel system is described for the determination of Henry's law constants (H) for hydrophobic compounds between air and water with an accuracy of about 5%. The method involves measurement of the compound concentration in only the water phase while being stripped isothermally from solution at a known gas flow rate. Determinations of H were made for benzene, toluene, ethylbenzene, chlorobenzene, naphthalene, biphenyl, and phenanthrene, and agreement with available literature data was satisfactory. Since, if any two of the three quantities H, vapor pressure, and aqueous solubility are known, the third may be calculated, it is suggested that the method may be useful for obtaining accurate solubility and vapor pressure data or for verifying existing data. The method may be suitable for elucidating the extent of sorption of volatilizing compounds in aqueous environments and quantifying the role of sorption in reducing volatilization rates. © 1979, American Chemical Society. All rights reserved.