Sorption of Chlorobenzene Vapors on Styrene−Divinylbenzene Polymer

Headspace gas chromatography was used to measure sorption equilibra between XAD-2, a styrene−divinylbenzene copolymer, and gaseous 1,2-dichlorobenzene (1,2-DiCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) and hexachlorobenzene (HCB) at temperatures above 40 °C. From the measurements, the sorption isotherms were constructed for the systems 1,2-DiCB/XAD-2, 1,2,4,5-TeCB/XAD-2, and HCB/XAD-2. It is shown that (a) capillary condensation within the mesopore structure of XAD-2 occurs at higher partial pressures; (b) the equilibrium data at relatively low partial pressures can be fitted to Freundlich isotherms; and (c) the sorption isotherms for the three compounds of interest are linear at very low partial pressures. Sorption coefficients at low partial pressures and 20 °C, extrapolated from the slopes of the linear isotherms obtained in the temperature range 90 °C to 130 °C, were (1.2 × 10 -6, 1.5 × 10 -5, and 1.6 × 10 -2 ) mol·m -2 ·Pa -1 for 1,2-DiCB/XAD-2, 1,2,4,5-TeCB/XAD-2, and HCB/XAD-2, respectively. This is in good agreement with values predicted using empirical models proposed in the literature.