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Liquid membrane transport and separation of Zn 2+ and Cd 2+ from sulfate media using organophosphorus acids as mobile carriers
Author(s) -
Juang RueyShin,
Kao HsiangChien,
Wu WenHsin
Publication year - 2004
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.950
Subject(s) - phosphoric acid , chemistry , stoichiometry , membrane , extraction (chemistry) , aqueous solution , diffusion , mass transfer , metal , facilitated diffusion , liquid–liquid extraction , inorganic chemistry , chemical equilibrium , analytical chemistry (journal) , sulfate , solvent , chromatography , thermodynamics , organic chemistry , biochemistry , physics
The transport and separation of Zn 2+ and Cd 2+ from binary sulfate solutions in a supported liquid membrane using di(2‐ethylhexyl)phosphoric acid (D2EHPA) and 2‐ethylhexylphosphonic acid mono‐2‐ethylhexyl ester (PC88A) as mobile carriers was studied. Batch solvent extraction experiments were conducted to obtain the reaction stoichiometries. Experiments were performed at different metal concentrations (1.4–14.5 mol m −3 ), metal concentration ratios (0.4–9.2), pH (2–5), and carrier concentrations (0.1–0.6 mol dm −3 ). A mass transfer model was proposed that considers diffusion in the aqueous feed and strip stagnant layers, and within the membrane. The interfacial reactions were assumed to approach equilibrium instantaneously. It was shown that the proposed model was applicable for binary Zn 2+ /Cd 2+ systems (standard deviation, 5%). The larger separation factors of Zn 2+ over Cd 2+ with PC88A than D2EHPA under equilibrium (batch solvent extraction) and non‐equilibrium (liquid membrane) conditions were also evaluated and discussed. Copyright © 2003 Society of Chemical Industry