Determining the Henry's volatility coefficient of nitrosamines in CO2 capture solvents

Fundamental properties of nitrosamines, such as their Henry's law constants, are needed to accurately predict the gas-phase partitioning and mitigate emissions of these volatile compounds from operating CO2 capture systems. In this work, the Henry's volatility coefficient of several environmentally relevant nitrosamines were experimentally obtained from water, from a concentrated amine solution and from a CO2 loaded amine solution using a static headspace solid phase microextraction and gas chromatography mass spectrometry method. The dimensionless Henry's volatility coefficients of N-nitrosodimethylamine and N-nitrosodiethylamine were found to be range of 0.001-0.1 at CO2 absorber exit temperatures from 25 to 55 degrees C. A linear temperature dependency of the Henry's volatility coefficient for these nitrosamines was observed. CO2 loading in the amine solvent increases the Henry's volatility coefficient of the more non-polar nitrosamine while it decreased the Henry's volatility coefficient of the more polar nitrosamine. Similar to parent amines, the polarity of the individual nitrosamines plays a key role in its Henry's volatility coefficients and gas phase partitioning from concentrated amine solutions.