Sorbents zeolite molecular sieves

R. M. Barrer, Zeolites and Clay Minerals as Sorbents and Molecular Sieves , p. 174, Academic Press, London and New York (1978). 

R. M. Barrer, in Zeolites and Clay Minerals as Sorbents and Molecular Sieves, Academic Press, London, 1978 F. Asinger, Die Petrolchemische Industrie, Akademie-Verlag, Berlin, 1971, pp. 73-95 K. Lindner, Seife-Ole-Fette-Wachse 94 81, 110 (1968) E. Guccione, Chem. Eng. 72(9) 104 (1965). 

Barrer RM (1978) Zeolites and clay minerals as sorbents and molecular sieves. Academic Press, London... 

The Brunauer type I is the characteristic shape that arises from uniform micro-porous sorbents such as zeolite molecular sieves. It must be admitted though that there are indeed some deviations from pure Brunauer type I behavior in zeoHtes. From this we derive the concept of the favorable versus an unfavorable isotherm for adsorption. The computation of mass transfer coefficients can be accompHshed through the construction of a multiple mass transfer resistance model. Resistance modehng utilizes the analogy between electrical current flow and transport of molecular species. In electrical current flow voltage difference represents the driving force and current flow represents the transport In mass transport the driving force is typically concentration difference and the flux of the species into the sorbent is resisted by various mechanisms. 

Barter, P. M. Zeolites and Clay Minerals as Sorbents and Molecular Sieves. 

Although a number of books now contain chapters or sections dealing with zeolites, this subject has been the primary focus in very few volumes. The most noteworthy of these is the treatise by D. W. Breck, Zeolite Molecular Sieves, published by Wiley in 1974. The earliest modem ones are the Russian texts on Molecular Sieves and Their Use, published by V. A. Sokolov, N. S. Torocheshnikov, and N. V. Kel tsev in 1964, and S. P. Zhdanov s Chemistry of Zeolites in 1968. Other significant works include the 1976 ACS Monograph on Zeolite Chemistry and Catalysis edited by J. A. Rabo, and the volume on Zeolites and Clay Minerals as Sorbents and Molecular Sieves by R. M. Barrer, published in England in 1978. 

Typical examples of mlcroporous sorbents are molecular sieves and other well-defined zeolites. See fig. 1.36. Characteristically, sorption is, in the pressure range studied, limited to a few layers, hence Isotherms are of the type I category, The authors interpret their data with a variant of the theory presented in sec. 1.5f, starting with an equivalent of [1.5.38] for confined geometries. 

Table 7.1 lists the typical sorbents used their uses as well as strengths and weaknesses. The four major commercial adsorbents are the following zeolite molecular sieves (zms), activated alumina, silica gel, and activated carbon. The surfaces of activated alumina and most molecular-sieve zeolites are hydrophilic, and will preferentially adsorb water over organic molecules. Silicalite, which is a hydrophobic zeolite, is the main exception. Activated carbon, on the other hand, preferentially adsorbs organic and non-polar or weakly polar compounds over water. The surface of silica gel is somewhere in between these limits and has affinity for both water and organics. Detailed information about each of these classes of adsorbents can be found in Refs. [1,4, 6, 7]. 

Three properties have made the zeolites of major importance their ion exchange and ion sieve behaviour their selectivity as sorbents and molecular sieves and their catalytic and shape selective catalytic functions. Some dates of significance in their long history are given, with references, in [ 8]. These dates are given below. 

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