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Separation of binary mixtures of carbon dioxide and methane through sulfonated polycarbonate membranes
Author(s) -
Sridhar S.,
Aminabhavi Tejraj M.,
Ramakrishna M.
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24628
Subject(s) - permeation , membrane , polycarbonate , selectivity , thermal stability , chemistry , permeability (electromagnetism) , chemical engineering , nuclear chemistry , polymer chemistry , analytical chemistry (journal) , chromatography , organic chemistry , biochemistry , engineering , catalysis
Polycarbonate (PC) was sulfonated to varying degrees using acetyl sulfate. FTIR and NMR experiments were carried out to confirm sulfonation. The membranes were characterized by DSC and TGA to assess thermal stability. Ion exchange capacity (IEC) and degree of sulfonation (DS) were determined and their effect on permeation of CO 2 and CH 4 gases was investigated. Free volume fractions (FVF) of the membranes were found to decrease from 0.31 to 0.19 as the DS increased from 0 to 39.4%. Single gas permeation studies revealed that sulfonated PC exhibited higher selectivities than unmodified PC at reduced permeability. For a DS of 14.4%, sulfonated PC exhibited a selectivity of 36.1, which was 1.7 times that of unmodified PC, whereas the permeability dropped from 8.4 to 4.7 Barrers. In case of binary CO 2 /CH 4 mixture permeation through PC membrane of the same DS, an increase in CO 2 feed concentration from 5 to 40 mol % produced an increase in permeability from 0.24 to 2.0 Barrers and a rise in selectivity from 11.7 to 27.2 at constant feed pressure (20 bar) and temperature (30°C). A rise in the feed pressure from 5 to 30 bar at a constant feed composition of 5% CO 2 resulted in a reduction in permeability from 0.38 to 0.2 Barrers and selectivity from 15.6 to 10.2. Sulfonated PC was found to be a promising candidate for separation of CO 2 from CH 4 . © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007