Measurement of Henry's law constant as function of temperature and salinity for the low temperature range

Abstract

EPICS technique (Equilibrium Partitioning In Closed Systems) was further developed to study the gas-water equilibrium partitioning (Henry's law) of C 1 and C 2 organochlorines and monocyclic aromatic hydrocarbons in the low temperature range. Using this technique Henry's law constant was measured for 13 volatile organic compounds (VOCs) at the temperature range from 2 up to 25°C, and for salt concentrations from 0.0 up to 35.0 ppt (parts per thousand, kg m −3). The data obtained at 25°C, which could be compared, fit well with literature data. A double linear regression was made with Henry's law constant H as a function of the temperature and salinity. This relationship confirmed theoretical considerations. A comparison between H-values obtained for natural sea water and for artificial sea water were in most cases not significantly different, while the few significant differences did not seem to have a systematic deviation. This implies that for marine environments salinity and temperature are the main determining factors for Henry's law constants of VOCs and are sufficient to describe them.