The Non-Ideality of the System Benzene + 1,2-Dichloroethane Adsorbed in Microporous Carbons at 293 K

Abstract

In the case of simple vapour mixtures adsorbed by active carbons, the activity coefficients seem to depend essentially on the composition of the adsorbed phase, rather than on the degree of micropore filling. Consequently, the liquid-solid adsorption equilibrium of benzene + 1,2-dichloroethane mixtures has been investigated at 293 K, using a typical active carbon and following earlier work for adsorption from the vapour phase. This system has the advantage that the mixture is ideal in the liquid state, which provides a convenient reference for the study of the adsorbed phase. The activity coefficients, as well as the excess enthalpy of immersion of the carbon into the liquid mixtures, provide information on the modifications in the adsorbed state with respect to the ideal mixture. It is also shown that the introduction of the activity coefficients derived from the solidliquid equilibrium increases considerably the accuracy of the MyersPrausnitz-Dubinin model for the adsorption of the vapour mixtures.

Binary Mixtures of Chlorobenzene and Cyclohexane Vapours Adsorbed under Dynamic and Static Conditions by Activated Carbon Beds

“…Industrial filtration methods require simple and easy predictions. As described in this study, combination of the MPD theory with Dubinin's equation and with the formalism of Myers and Prausnitz (Stoeckli et al 2002) leads to predictions which can be extended over a wide range of pressures and temperatures for an ideal adsorbed state (IAS). The binary mixture c-C 6 H 12 + C 6 H 5 Cl is non-ideal in the liquid phase.…”

“…calculation of ψ without employing activity coefficients.). It is very interesting to observe that the theory developed for static adsorption presented by Stoeckli et al (2002) works successfully for dynamic adsorption systems. The data can be compared with the static adsorption and PSA results presented in Figures 2 and 3.…”

“…In a similar manner, the liquid state (Guggenheim 1967) and the activity coefficients in the adsorbed state can be described by general expressions with a good approximation, as demonstrated by Stoeckli et al (2002).…”

“…As shown by Stoeckli et al (2002), combination of the Myers-Prausnitz-Dubinin theory (MPD) with the activity coefficients of the corresponding solid-liquid equilibrium led to a good correlation between the calculated and experimental mole fractions for the adsorption of binary mixture vapours by microporous solids under static conditions. The present study demonstrates the approach, which is based on an ideal adsorbed state (IAS).…”

“…This approach, recently recognized as the MPD theory, provides a useful basis for the theoretical treatment of adsorption data obtained under static (Stoeckli et al , 2000(Stoeckli et al , 2002 and dynamic conditions, as initially presented by Stoeckli et al (1997Stoeckli et al ( , 2000 both apply to full micropores (θ = 1) and the adsorbed state x a . Using these coefficients, Stoeckli et al (2002) demonstrated a very good agreement between the calculated and experimental mole fractions x a i . The MPD approach was successfully tested by Stoeckli et al (2002) for the binary vapour mixture chlorobenzene + cyclohexane adsorbed by activated carbon U-03 under static conditions.…”