Multicomponent vapor sorption on active carbon by combined microgravimetry and dynamic sampling mass spectrometry

Combined gravimetric and dynamic sampling mass spectrometry methods have been developed for the direct measurement of multicomponent vapor sorption on microporous materials. This method combines the gravimetric method for determination of the kinetics and equilibria of total adsorption, and mass spectrometry for the analysis of each adsorbate component during temperature programmed desorption. Mass spectrometry was also used for the determination of the adsorptive gas-phase concentrations during adsorption. Results are presented for adsorption of water/n-octane and water/n-butane on active carbon BAX950 using helium as the carrier gas. Marked differences were observed in the amount of water vapor adsorbed in the presence of n-butane compared with static water vapor and water vapor in helium. The dynamics of adsorption and desorption resulting from competitive adsorption have been investigated. The kinetics are compared with data for single component adsorption of static vapors and flowing vapors in helium. The results are discussed in terms of the diffusion processes and adsorption mechanism.