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1631036 
Journal Article 
Dehydration of isopropanol and its comparison with dehydration of butanol isomers from thermodynamic and molecular aspects 
Qiao, XY; Chung, TS; Guo, WF; Matsuura, T; Teoh, MM 
2005 
Yes 
Journal of Membrane Science
ISSN: 0376-7388 
252 
1-2 
37-49 
WOS:000228850700005 
By examining the dehydration of aqueous isopropanol (IPA)
systems using two Sulzer commercially available polyvinyl alcohol (PVA)/polyacrylonitrile (PAN)
membranes which were prepared from different cross-linking agents, we have (1) investigated the
membrane performance from the standpoints of flux versus permeance and separation factor versus
selectivity plots and (2) determined the effects of membrane properties such as degrees of
cross-linking and hydrophilicity on water and IPA flux and permeance and their separation factor
and membrane selectivity. PERVAP 2201 has higher degrees of cross-linking and chain packing than
PERVAP 2510, while PERVAP 2510 has stronger hydrophilicity than PERVAP 2201. For PERVAP 2510,
water permeance increases sharply with feed water concentration, but shows little dependence on
temperature. For PERVAP 2201, water permeance shows flat relationship with feed water
concentration, but increases with increasing temperature. Both IPA flux and permeance increase
with increasing feed water concentration and their relationship with feed water content can be
mathematically explained. It is noticed that the separation factor versus feed water content
plots may mislead the analysis of water influence on membrane performance and exaggerate the
plasticization phenomenon. Coupled transport has been observed between IPA and water. However,
the degree of coupled transport is dependent on the membrane properties, such as the degree of
cross-linking, affinity to water and structure responses on temperature rise. Compared with the
dehydration of butanol systems, we found that the degree of coupled transport follows the order
of 1-butanol > 2-butanol > IPA > tert-butanol. After examining many physicochemical properties of
penetrants and membrane materials, it is concluded that the molecular linearity (or the aspect
ratio) of penetrant molecules and their solubility parameters (as well as polarity parameter)
determine the magnitude of coupled transport, while the effects of other physicochemical
properties seem to be not so important if coupled transports become dominant in the dehydration
process. (c) 2004 Elsevier B.V. All rights reserved. 
pervaporation; isopropanol; butanol isomers; dehydration; permeance; selectivity