화학공학소재연구정보센터
Chemical Engineering Journal, Vol.283, 544-552, 2016
Determination of the gas-to-liquid partitioning coefficients using a new dynamic absorption method (DynAb method)
The determination of partitioning coefficients which describes the behaviour of a pollutant between phases (gas, liquid, solid) is of fundamental importance in different scientific areas (fate and behaviour of pollutants, design of abatement technologies, flavour release). A new and fast method, based on selected ion flow tube mass spectrometry, was developed to determine the gas-to-liquid partitioning coefficients (K-AW) of volatile organic compounds (VOC). By using the dynamic absorption method (DynAb method), a gas stream with a known and constant compound concentration is bubbled through a liquid volume. The outlet gas concentration is continuously measured and results in a breakthrough curve. From the breakthrough curve of the measured gas concentration, K-AW can be calculated. In contrast to the existing dynamic methods, K-AW obtained by DynAb method does not assume equilibrium of the target compound between the liquid and the air bubble leaving the liquid and therefore avoids erroneous evaluation of K-AW. The developed method was applied to determine K-AW for five odorous VOCs (dimethyl sulphide, dimethyl disulphide, 2-methylpropanal, 3-methylbutanal and hexanal). K-AW values can be determined in short time (less than 15 minutes) with a reproducibility of less than 5%. Measured K-AW (mol m(gas)(-3)/mol m(liquid)(-3)) at 25 degrees C are 8.61 +/- 0.20 x 10(-2) for dimethyl sulphide, 5.90 +/- 0.23 x 10(-2) for dimethyl disulphide, 1.27 +/- 0.06 x 10(-2) for 2-methylpropanal, 1.43 +/- 0.05 x 10(-2) for 3-methylbutanal and 1.41 +/- 0.03 x 10(-2) for hexanal. The dependence of the partitioning coefficients on temperature (4 to 25 degrees C) and ammonium sulphate concentration (0 to 300 g L-1) were described by Van't Hoff and Setchenow equations, respectively. (C) 2015 Elsevier B.V. All rights reserved.