Study of the evaporation of pollutant liquids under the influence of surfactants

Abstract

Abstract In the present work, reversed‐flow gas chromatography (RF‐GC) is utilized for the study of the evaporation of volatile liquids. Evaporation rates and the respective diffusion coefficients are determined for the evaporation of ethanol and 1,1,1‐trichloroethane in nitrogen, at 306.2 K. The precision (>99.5%) and accuracy of the method, as well as the uncertainty of the determined parameters, ascertain the potential of the presented methodology. The experimentally obtained evaporation rates have units of velocity, and for high volatility compounds their values are identified with the liquid film mass‐transfer coefficients. The latter compare successfully to available literature values, further ascertaining the validity of the presented methodology. The variation of the evaporation rates of ethanol and 1,1,1‐trichloroethane, in the presence of various amounts of Triton X‐100, indicates that different, but in any case high amounts of surfactant are required for the drastic retardation of the vaporization rate. The reduction of the evaporation rate can be attributed either to the formation of densely packed surface monolayers or to the formation of an insoluble monolayer. © 2006 American Institute of Chemical Engineers AIChE J, 2006