Abstract
Experimental isotherms describing the adsorption of pure N2, CH4 and CO in AlPO4-11, AlPO4-17, and AlPO4-18 were determined using the volumetric method at 40°C and at 23°C (AlPO4-11 only) over a pressure range up to 123 kPa, and subsequently fitted with the Langmuir or Freundlich equations, as well as the Flory-Huggins Vacancy Solution Theory equation. The capacities for the adsorbates investigated were found to depend on the geometry of the sieve pore size, as well as the molecular dimensions and the polority of the adsorbate involved. At 40°C and over the investigated pressure range, AlPO4-11 and AlPO4-17 adsorbed pure CH4 in the highest amounts, while AlPO4-18 had a slightly higher capacity for pure CO.
The model parameters obtained by fitting the experimental pure-component isotherms permitted the prediction of binary adsorption information for the CO−N2, CH4−CO, and CH4−N2 gas mixtures at 101.3 kPa total pressure, using the Extended Langmuir Model, the Ideal Adsorbed Solution Theory, and/or the Flory-Huggins Vacancy Solution Theory for mixtures. An explanation of the behaviour predicted by each model for each adsorption system is attempted.
Similar content being viewed by others
References
Bennett, J.M., W.J. Dytrych, J.J. Pluth, J.W. Richardson, Jr., and J.V. Smith, “Structural Features of Aluminophosphate Materials with Al/P=1,”Zeolites,6, 349–359 (1986).
Breck, D.W.,Zeolite, Molecular Sieves: Structure, Chemistry and Use, John Wiley & Sons, New York, Inc., 1974.
Broughton, D.B., “Adsorption Isotherms for Binary Gas Mixtures,”Ind. Eng. Chem.,40(8), 1506–1508 (1948).
Cochran, T.W., R.L. Kabel, and R.P. Danner “Vacancy Solution Theory of Adsorption Using Flory-Huggins Activity Coefficient Equations,”AIChE Journal,31(2), 268–277 (1985).
Graham, D., “Adsorption, Equilibria” inAdsorption, Ion Exchange and Dialysis, AIChE Chemical Engineering Progress Symposium Series,55(24), 17–23 (1959).
Grillet, Y., P.L. Llewellyn, H. Reichert, J.P. Coulomb N. Pellenq, and J. Rouquerol, “Confinement in Micropores and Enthalpies of Physisorption,” inCharacterization of Porous Solids III J. Rouquerol et al. (Eds.), Studies in Surface Science and Catalysis, Elsevier, Amsterdam, Vol. 87, pp. 525–534, 1994.
Innes, W.B. and H.H. Rowley, “Adsorption Isotherms of Mixed Vapors of Carbon Tetrachloride and Methanol on Activated Charcoal at 25°C,”J. Phys. Coll. Chem.,51, 1154–1171 (1947).
Innes, W.B., R.B. Olney, and H.H. Rowley, “Adsorption Isotherms of Mixed Vapors of Benzene and Methanol on Activated Charcoal at 25°C,”J. Phys. Coll. Chem.,55, 1324–1334 (1951).
Kemball, C., E.C., Rideal, and E.A. Guggenheim, “Thermodynamics of Monolayers,rrdTrans. Faraday Soc.,44, 948–954 (1948).
Langmuir, I., “Adsorption of Gases on Plane Surfaces of Glass, Mica and Platinum,”J. Am. Chem. Soc.,40, 1361–1403 (1918).
Lillerud, K.P. and D. Akporiaye, “Systematic Relationships Between the Structures of CHA, AEI and KFI,” inZeolites and Related Microporous Materials: State of the Art 1994, J. Weitkamp et al. (Eds.),Studies in Surface Science and Catalysis, Elsevier, Amsterdam, Vol. 84, pp. 543–550 (1994).
Markham, E.C. and A.F. Benton, “The Adsorption of Gas Mixtures by Silica,”J. Am. Chem. Soc.,53, 497–507 (1931).
Martens, J.A. and P.A. Jacobs, “Crystalline Microporous Phosphates: a Family of Versatile Catalysts and Adsorbents,” inAdvanced Zeolite Science and Applications, Studies in Surface Science and Catalysis, Elsevier, Amsterdam, Vol. 85, pp. 653–685, 1994.
Meier, W.M. and D.H. Olson,Atlas of Zeolite Structure Types, 3rd. rev. ed., Butterworth-heinemann, London, 1992.
Myers, A.L. and J.M. Prausnitz, “Thermodynamics of Mixed-Gas Adsorption,”A.I.Ch.E.J.,11(1), 121–127 (1965).
Rudolf, P.R. and C.E. Crowder, “Structure Refinement and Water Location in the Very Large-Pore Molecular Sieve VPI-5 by X-ray Rietveld Techniques,”Zeolites,10, 163 (1990).
Ruthven, D.M.,Principles of Adsorption and Adsorption Processes, John Wiley & Sons, New York, 1984.
Simmen, A., L.B. McCusker, Ch. Baerlocher, and W.M. Meier, “The Structure Determination and Rietveld Refinement of the Aluminophosphate AlPO4-18,”Zeolites,11, 654–661 (1991).
Stelmack, P., “Adsorption of N2, CO, CH4, and Binary Mixtures of these Gases in Zeolite, 5A, Clinoptilotite, and AlPO4-11 Molecular Sieves,” B.A.Sc. Thesis, University of Ottawa, Ottawa, 1994.
Suzuki, M.,Adsorption Engineering, Kodansha Ltd., Tokyo, and Elsevier Science Publishers B.V., Amsterdam, 1990.
Szostak, R.,Handbook of Molecular Sieves, Van Nostrand Reinhold, New York, 1992.
Theocharis, C.R. and M.R. Gelsthorpe, “Modified Aluminophosphate Microporous Solids,” inCharacterization of Porous Solids, K.K. Unger et al. (Eds.), Elsevier Science Publishers B.V., Amsterdam, 1988.
Valenzuela, D.P. and A.L. Myers,Adsorption Equilibrium Data Handbook, Prentice-Hall Advanced Reference Series, Prentice-Hall, Englewood Cliffs, New Jersey, 1989.
Wilson, S.T., “Synthesis of AlPO4-Based Molecular Sieves,” inIntroduction to Zeolite Science and Practice, Studies in Surface Science and Catalysis, H. van Bekkum, E.M. Flanigen, and J.C. Hansen (Eds.), Elsevier, Amsterdam, Vol. 58, pp. 137–151, 1991.
Yang, R.T.,Gas Separation by Adsorption Processes, Butterworth Publishers, Mass. U.S.A., 1987.
Zeldowitsh, J., “On the Theory of the Freundlich Adsorption Isotherm,”Acta Physicochim, U.R.S.S.,1(6), 961–973 (1935).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Predescu, L., Tezel, F.H. & Chopra, S. Adsorption of nitrogen, methane, carbon monoxide, and their binary mixtures on aluminophosphate molecular sieves. Adsorption 3, 7–25 (1997). https://doi.org/10.1007/BF01133003
Issue Date:
DOI: https://doi.org/10.1007/BF01133003