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Continuous‐flow electrodialysis of acetate, butyrate, and chloride: A correlating equation
Author(s) -
Schrodt J. Thomas,
Yonikas Patrick J.,
Grieves Robert B.
Publication year - 1969
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450470418
Subject(s) - mole fraction , electrodialysis , chemistry , membrane , chloride , concentration polarization , thermal diffusivity , analytical chemistry (journal) , chromatography , thermodynamics , biochemistry , organic chemistry , physics
An experimental investigation is presented of the electrodialysis of acetate or butyrate with chloride, in a continuous‐flow unit with a membrane area of 50 cm. 2 separating a test cell pair. The effects on the transport of the individual anions are established of several independent variables, including membrane type, organic specie, mole fraction of organic in the feed, and current density. Polarization is evident at a current density of 8 ma./cm. 2 A semi‐empirical equation is developed and, utilizing the experimental data, the equation yields the cell constant and the ratio of the diffusivity of each anion to the film thickness. The equation, relating the purification factor (ratio of feed and effluent concentrations) and the key independent variables, may be utilized to correlate and extend a rather limited number of data points for other chemical systems in other continuous‐flow units. For both membranes, both organic species, and over a wide range of feed mole fractions and current densities, the mole fraction of an anion transported across the membrane can be related to the feed mole fraction by a simple power relation, indicating a convenient way of expressing membrane selectivity.