A simple potential-theory model for predicting mixed-gas adsorption

Abstract

The Dubinin-Astakhov equation, which is based on the micropore volume filling theory, is extended to mixed-gas adsorption by using the concept of maximum available pore volume. The proposed model requires only single-gas data for predicting mixed-gas adsorption; no additional equation, such as the Lewis relationship, is needed. The proposed model is not iterative, and the calculation involved is extremely simple. The model has been tested against experimental data for 16 binary mixture systems involving a wide variety of adsorbents and a wide range of pressures, with satisfactory results. It also compares favorably or equally satisfactorily with the ideal adsorbed solution theory, the Grant-Manes model, and an extension of the DA equation proposed by Bering et al. However, all three of these methods require iterative (numerical) computation.

Multicomponent adsorption of biogas compositions containing CO2, CH4 and N2 on Maxsorb and Cu-BTC using extended Langmuir and Doong–Yang models

“…where, the maximum available micropore volume of the ith component is expressed as a reduced limiting micropore volume (Doong and Yang 1988;Rege et al 2001). In Eq.…”

“…Additionally, if the partial pressure of one of the components approaches its saturation pressure and the limiting adsorption volume of the one component is smaller than that of the other, the calculated volume of adsorbed components can be negative. In this case, the problem can be circumvented, as suggested by the authors (Doong and Yang 1988), by using the average limiting volume (V 0 ) and recalculating the values of RT/e, where e is the characteristic energy of adsorption and n the pore heterogeneity parameter, by fitting the single-gas data. Both the ELM and DYM are simple in their implementation in a sense that they use the fitted parameters from corresponding pure gas isotherms: a set of affinity coefficients for each component and the maximum adsorbed amount of component for ELM and gas partial pressure, saturation pressure, micropore volume, the characteristic energy and pore heterogeneity parameter for DYM, in order predict the adsorbed amounts of every component in the gas mixture.…”

“…Both the ELM and DYM are simple in their implementation in a sense that they use the fitted parameters from corresponding pure gas isotherms: a set of affinity coefficients for each component and the maximum adsorbed amount of component for ELM and gas partial pressure, saturation pressure, micropore volume, the characteristic energy and pore heterogeneity parameter for DYM, in order predict the adsorbed amounts of every component in the gas mixture. In the past, these models have been shown to yield good predictions of the adsorption process for different mixtures on a wide range of microporous sorbents (Doong and Yang 1988;Hamon et al 2009;Hamon et al 2010). …”

Review and comparisons of D/R models of equilibrium adsorption of binary mixtures of organic vapors on activated carbons

“…Table 1 equations for estimating molar volumes above normal boiling points [19]. Since one goal of our work is to predict adsorption capacities of components of a wide variety of liquid mixtures using a minimum amount of input da@ which must be readily available, in this paper we choose to use pure liquid molar volumes (20 -25 'C), even for components of adsorbed mixtures.…”

Multicomponent adsorption equilibrium: Henry's law limit for pore‐filling models

“…Most of these models are based on the Polanyi potential theory (Lewis et al, 1950a;Grant and Manes, 1966;Dubinin, 1975;Mehta and Danner, 1985;Doong and Yang, 1988). A recent model is instead based on an Antoine-type equation (Hacskaylo and LeVan, 1985).…”