TY - JOUR
T1 - Application of emulsion liquid membranes to recover cobalt ions from a dual-component sulphate solution containing nickel ions
AU - Kasaini, Henry
AU - Nakashio, Fumiyuki
AU - Goto, Masahiro
N1 - Funding Information:
This work was supported by Monbusho Scholarship Grant to one of the authors (HK). Special thanks go to Dr. Geoff Stevens of University of Melbourne, Australia for the valuable discussion on Interfacial Reactions in Liquid Emulsions. Also profound gratitude is expressed to Daihachi for kindly supplying PC-88A extractant.
Copyright:
Copyright 2004 Elsevier Science B.V., Amsterdam. All rights reserved.
PY - 1998/8/5
Y1 - 1998/8/5
N2 - Emulsion liquid membranes (ELMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) have been applied to recover cobalt II ions from a dilute sulphate solution containing equal amounts of nickel II ions (0.16 g/l). We focused on the study to develop an effective technique to recover cobalt as a target metal. It is found that polyamine (PX 100) membranes allow better permeation rates of cobalt ions than sorbitan monooleate (Span 80) membranes. The separation factor (β(Co/Ni)) in polyamine membranes averaged 70 at a carrier concentration of 12 mol/m3 and feed solution pH 5.5. The permeation rate of Co II was found to increase proportionately with feed pH while for Ni II it decreased substantially at pH above 5.5 indicative of slower interfacial reaction rate. We found that short contact time (4-6 min) of feed solution and emulsion improved separation factor (β(Co/Ni)) at feed pH above 5.5 and also minimized chances of emulsion break up. We have also observed that Span 80 membranes are hydrolyzed readily in a moderate acidic sulphate solution (pH 4.0-5.5) to form viscous gels. Results have shown that excess carrier [(HR)2] affects the stability of emulsion and thus the separation factor. The critical ratio of carrier to emulsifier [(HR)2]/[C(sf)] was found to be approximately 0.5. This paper concludes with a discussion on the prospects of ELM system in practical use.
AB - Emulsion liquid membranes (ELMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) have been applied to recover cobalt II ions from a dilute sulphate solution containing equal amounts of nickel II ions (0.16 g/l). We focused on the study to develop an effective technique to recover cobalt as a target metal. It is found that polyamine (PX 100) membranes allow better permeation rates of cobalt ions than sorbitan monooleate (Span 80) membranes. The separation factor (β(Co/Ni)) in polyamine membranes averaged 70 at a carrier concentration of 12 mol/m3 and feed solution pH 5.5. The permeation rate of Co II was found to increase proportionately with feed pH while for Ni II it decreased substantially at pH above 5.5 indicative of slower interfacial reaction rate. We found that short contact time (4-6 min) of feed solution and emulsion improved separation factor (β(Co/Ni)) at feed pH above 5.5 and also minimized chances of emulsion break up. We have also observed that Span 80 membranes are hydrolyzed readily in a moderate acidic sulphate solution (pH 4.0-5.5) to form viscous gels. Results have shown that excess carrier [(HR)2] affects the stability of emulsion and thus the separation factor. The critical ratio of carrier to emulsifier [(HR)2]/[C(sf)] was found to be approximately 0.5. This paper concludes with a discussion on the prospects of ELM system in practical use.
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U2 - 10.1016/S0376-7388(98)00105-7
DO - 10.1016/S0376-7388(98)00105-7
M3 - Article
AN - SCOPUS:0032486816
VL - 146
SP - 159
EP - 168
JO - Journal of Membrane Science
JF - Journal of Membrane Science
SN - 0376-7388
IS - 2
ER -