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Membrane selectivity
Author(s) -
Wills G. B.,
Lightfoot E. N.
Publication year - 1961
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.690070221
Subject(s) - nernst equation , membrane , electrolyte , flux (metallurgy) , diffusion , planck , yield (engineering) , chemistry , scope (computer science) , mechanics , thermodynamics , statistical physics , physics , computer science , electrode , biochemistry , organic chemistry , quantum mechanics , programming language
Previous investigators have developed general integrations of the Nernst‐Planck flux equations to predict the behavior of ion exchange membranes in forced diffusion cells. These results are also applicable to stagnant liquid films, since this latter case can be considered as a membrane with a vanishingly small concentration of fixed charges ( 1 ). However these general integrations yield results of considerable complexity, and even the analysis of a specific system becomes a problem of some scope. This paper is based upon a much less general integration which proceeds by a straightforward manipulation of the Nernst‐Planck flux equations for the special case of a single one‐to‐one electrolyte. The results are used to predict the behavior of a system consisting of a membrane with a stagnant film of liquid on either side. To further facilitate understanding the initial results are further simplified by assuming certain specific systems and then constructing plots showing the membrane efficiency in terms of readily interpreted, commonly encountered variables such as thicknesses, currents, and concentrations.