CO sub(2) separation membranes using ionic liquids in a Nafion matrix

• Published in: Journal of membrane science 2010-11, Vol.363 (1-2), p.72-79
• Main Authors: Yoo, Soondong, Won, Jongok, Kang, Sang Wook, Kang, Yong Soo, Nagase, Shigeru
• Format: Article
• Language: English
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2010.07.013

Nafion composite membranes for CO sub(2) separation with good CO sub(2)/CH sub(4) separation factors were developed using ionic liquids (ILs) and Nafion. Three ionic liquids containing the 1-n-hexyl-3-methylimidazolium ([hmim]) cation with different anions were characterized by the measurement of the CO sub(2) separation performance using supported ionic liquid membranes in a polysulfone asymmetric support. Two different Nafion membrane-containing ILs for CO sub(2) separation membranes were prepared by the adsorption of IL on a dense and electrospun Nafion/polyethyleneoxide composite membrane in order to improve the stability of the liquid membrane. The electrospun Nafion layer containing polyethyleneoxide was prepared by the electrospinning technique in order to affix [hmim][BF sub(4)] (or [hmim][PF sub(6)]) on the porous polysulfone asymmetric support. The ideal CO sub(2)/CH sub(4) separation factor of electrospun Nafion composite membranes with [hmim][BF sub(4)] was consistent with that of [hmim][BF sub(4)]. The ideal CO sub(2)/CH sub(4) separation factor was 26 for the Nafion composite membranes containing both [hmim][BF sub(4)] and [hmim][PF sub(6)] in the dense Nafion layer, implying a change in the microdomain of Nafion in the presence of IL and the facilitation effect of ILs for CO sub(2) separation through the IL-swollen Nafion membrane.