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Diffusion in zeolites containing mixed cations
Author(s) -
Yeh Y. T.,
Yang R. T.
Publication year - 1989
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690351010
Subject(s) - thermal diffusivity , percolation theory , diffusion , chemistry , percolation (cognitive psychology) , adsorption , thermodynamics , zeolite , kinetic energy , organic chemistry , catalysis , conductivity , physics , quantum mechanics , neuroscience , biology
Experimental results are reported for equilibrium adsorption and diffusivities of CH 4 , C 2 H 6 and CO 2 in type A zeolite containing mixed Na and K cations ranging from 0 to 100% in composition, at two temperatures and 1 atm. Two simple theoretical solutions are given for the diffusivity. One is for diffusion with pore (aperture) blocking using the effective medium approximation, which is readily available from the literature on percolation theory. The other is a kinetic solution derived in this work for cavities containing heterogeneous sites, which is a case where the percolation theory is not applicable. The equilibrium adsorption results show that K + has a preference for the aperture (or pore‐blocking) sites (site type II), and these results are interpreted by the bond percolation theory. The diffusivity results are successfully interpreted by the poreblocking theory in zeolites containing less than 25% K + and by the kinetic theory for zeolites with higher K + contents.