Optimum emulsion liquid membranes stabilized by non-Newtonian conversion in Taylor–Couette flow
The use of Taylor–Couette flow for extraction by emulsion liquid membranes has been characterized. In particular, the rate limiting step for the extraction of a weak acid (benzoic) in an aqueous continuous phase to a strong base (NaOH) in the encapsulated internal phase has been attributed to a surf...
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Veröffentlicht in: | Chemical engineering science 2004-12, Vol.59 (24), p.5725-5734 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The use of Taylor–Couette flow for extraction by emulsion liquid membranes has been characterized. In particular, the rate limiting step for the extraction of a weak acid (benzoic) in an aqueous continuous phase to a strong base (NaOH) in the encapsulated internal phase has been attributed to a surfactant resistance. Numerical and analytical solutions are developed to characterize the mass transfer at Biot numbers
Bi
<
10
. It is demonstrated for fixed droplet composition that a single curve exists for all
N
for the extent of extraction by stretching the time coordinate by a function of the rotation rate
∝
N
1.2
that is proportional to the globule external area per unit total volume. Moreover, the leakage rate is shown to increase as
t
0.6
and to be proportional to
N
0.75
, the Kolmogoroff eddy velocity. Comparison with stirred tank data demonstrates that greater droplet stability exists for Taylor–Couette flow. |
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ISSN: | 0009-2509 1873-4405 |
DOI: | 10.1016/j.ces.2004.06.015 |