Equilibria and activity coefficients for non-ideal adsorbed mixtures from perturbation chromatography

Kabir, Hocine; Grévillot, Georges; Tondeur, Daniel

doi:10.1016/s0009-2509(98)00004-9

Cited by 23 publications

(15 citation statements)

References 8 publications

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“…The activity coefficients in the adsorbed phase then become a function of the spreading pressure. The constitutive equations of the equilibrium are then (Myers and Prausnitz 1965 ;Kabir et al, 1998 ;Do, 1998), the gas phase being assumed perfect :…”

Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

“…P i * (17) 1 1 1 1 1 1 1 1 dp dx p x ; dp dq p q ; dp a is the partial molar surface area of species i, a mixture property. The superscript * refers to single component isotherms and will be explained in more detail below (see for example [Kabir et al, 1998], or the original paper of [Myers and Prausnitz,1965]). q i * is the adsorbed concentration of pure i corresponding to the partial pressure p i = P i *, also obtained from the pure i isotherm.…”

Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

“…Equation 1 6 tion Theory, dx 1 /dp 1 can be calculated analytically [Kabir et al 1998, Appendix] as: may be rewritten in terms of derivatives with respect to p 1 instead of variations:…”

Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

“…18 and 19 follows the same lines as in the ideal case, and has been developed in [Kabir et al, 1998]. Thus only the end result is given here :…”

Section: The Regular-adsorbed-solution Modelmentioning

confidence: 99%

“…As in Myers' approach, the adsorbed phase composition are obtained indirectly. The method partly relies on a detailed thermodynamic analysis developed for chromatographic experiments and presented in a previous publication related to chromatography [Kabir et al, 1998]. In contrast to the Van Ness approach, the thermodynamic equations are treated analytically, and no iterative numerical resolution is needed.…”

Section: Introductionmentioning

confidence: 99%

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Incremental Gravimetry: A Method for Two-Parameter Model Building of Binary Gas Co-Adsorption Equilibria

Tondeur

Bonnot²,

Luo³

2004

Adsorption

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This paper presents and develops a novel methodology to determine thermodynamic parameters of binary gas co-adsorption equilibria at given total pressure, based exclusively on binary gravimetric measurements at this same total pressure, together with single component isotherms. By "Incremental Gravimetry", we designate a procedure in which the adsorbent sample is submitted to increments of composition of a flowing binary gas, and the corresponding increments of weight of the sample at equilibrium are measured. The experimental example is the co-adsorption of methane and carbon dioxide on Norit activated carbon near ambient temperature and pressure.The approach relies on the thermodynamics of non-ideal adsorbed solutions. The experimental methodology is described, the underlying theory is then presented. Compact analytical expressions are established that relate the measured limiting slopes of the incremental gravimetric curves (at infinite dilution of one component in the other) to quantities that derive only from the pure component isotherms, and to the infinite dilution activity coefficients. The latter are then uniquely determined. Classical two-parameter models for the composition dependence of activity coefficients are then implemented to reconstruct the complete binary isotherms and the incremental gravimetric curves. The comparison of the latter with the measured curves permits to test the different models.-1 -

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Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

“…Equation 1 6 tion Theory, dx 1 /dp 1 can be calculated analytically [Kabir et al 1998, Appendix] as: may be rewritten in terms of derivatives with respect to p 1 instead of variations:…”

Section: Thermodynamics Of the Non-ideal Adsorbed Phasementioning

confidence: 99%

“…18 and 19 follows the same lines as in the ideal case, and has been developed in [Kabir et al, 1998]. Thus only the end result is given here :…”

Section: The Regular-adsorbed-solution Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Incremental Gravimetry: A Method for Two-Parameter Model Building of Binary Gas Co-Adsorption Equilibria

Tondeur

Bonnot²,

Luo³

2004

Adsorption

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Adsorption in Simulated Moving Beds

Santana

Silva

Azevedo

et al. 2009

Encyclopedia of Industrial Biotechnology

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Chromatographic separation is based on the differential affinity of the components to a surface of solid adsorbent. While the batch or elution chromatography has found the largest number of applications up to now, Simulated Moving Bed (SMB) chromatography as a continuous process is gaining more attention due to its advantages in terms of productivity and eluent consumption. SMB is a multicolumn, continuous adsorption separation process that increases throughput, purity and yield relative to batch chromatography. Designing SMB processes involves, among other tasks, the selection of the number of columns per zone and the proper selection of the flowrates (feed, desorbent, raffinate, extract and recycle) and of the switching times in each cycle of operation. Nowadays, SMB technology has been applied to separation and purification of proteins, enantiomers and sugars. Several advances to improve SMB technology efficiency includes new configurations of equipment designs to provide more degrees of freedom than the classical process and also the implementation of the use of solvent gradient, temperature gradient and of supercritical fluids as eluents. The rise of biotechnological products within the marketplace for pharmaceuticals is but one example of how recent developments in this area are making a major impact.

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Mixed‐gas adsorption

2001

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The prediction of multicomponent adsorption equilibria from single-component data is one of the most challenging and important problems in adsorption. The chief obstacle to progress is a scarcity of accurate and consistent experimental data o®er a wide range of temperature and loading for testing theories. Se®eral binaries and one ternary system ( ) on two types of zeolites silicalite and faujasite were studied in a combination calorimeter-®olumetric apparatus. Acti®ity coefficients and excess functions for enthalpy, free energy, and entropy were extracted from the binary data using a three-constant equation to represent nonidealities. The successful correlation of binary excess functions with pure-component properties for type I isotherms on zeolites is a first step toward predicting multicomponent adsorption from single-gas adsorption and a major ad®ancement o®er the theory of ideal adsorbed solutions. IntroductionThe ability of porous materials to adsorb fluids selectively is the basis of many industrial applications, especially catalysis and the separation and purification of gases and liquids. Industrial applications of adsorption include the recovery of organic solvent vapors, dehydration of gases, separation and purification of hydrogen from steam-methane reformers, separation and purification of air, separation of normal paraffins from branch and cyclic paraffins, production of olefins from Ž olefin and paraffin mixtures, and so on Tien, 1994; Critten-. den and Thomas, 1998; Yang, 1987 . Even though adsorption plays an important role in the gas separation and purification industry, the prediction of multicomponent equilibria is still Ž one of the most challenging problems in adsorption Talu, . .The main problem is a lack of accurate and consistent experimental data for testing theories. Almost no data are available on enthalpy of adsorbed mixtures, although such information is necessary for the modeling of fixed-bed adsorbers. Indirect measurements of mixture heats of adsorption using volumetric or gravimetric methods are possible in principle, but require voluminous data on isobars, isotherms, Ž . and loci of constant composition Sircar, 1985Sircar, , 1991 Experimentally, an isotopic, steady-state kinetic technique Ž was used to calculate mixture heats of adsorption Bajusz et . al., 1998a,b . Other studies have used the isosteric method to Ž measure mixture equilibria Bulow, 1994; Bulow and Shen,¨. 1998; Hampson and Rees, 1993; Rees et al., 1991 . We have described previously a calorimeter for simultaneous measure-Ž ments of mixture equilibria and heats of adsorption Dunne Correspondence concerning this article should be addressed to A. L. Myers.. et al., 1997; Siperstein et al., 1999a . Here, we report activity coefficients, excess free energies, and enthalpies of mixing in the adsorbed phase.The objective of this article is to understand the molecular basis for these deviations from ideality and attempt to predict them on the basis of single-gas properties. Deviations from ideal mixing are exp...

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Equilibria and activity coefficients for non-ideal adsorbed mixtures from perturbation chromatography

Cited by 23 publications

References 8 publications

Incremental Gravimetry: A Method for Two-Parameter Model Building of Binary Gas Co-Adsorption Equilibria

Incremental Gravimetry: A Method for Two-Parameter Model Building of Binary Gas Co-Adsorption Equilibria

Adsorption in Simulated Moving Beds

Mixed‐gas adsorption

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