Method for Measuring the Temperature Dependence of the Henry's Law Constant of Selected Polycyclic Aromatic Hydrocarbons

The Henry's Law Constant (HLC) is an important thermodynamic constant needed to model air-water exchange of contaminants such as polycyclic aromatic hydrocarbons (PAHs). However, few direct HLC measurements have been reported for PAHs. A gas-stripping apparatus was constructed to allow gaseous and dissolved phase PAH concentrations to be measured over time. HLC was calculated by two methods: measuring PAH loss in the dissolved phase over time and dividing the instantaneous air by dissolved phase concentrations. Both methods yielded similar HLC values that were comparable to the range of HLCs reported in the literature.