Mechanism of preferential CO2 permeation of amine-containing polymeric membrane
March 5-10, 2017
H2 is industrially produced by steam reforming and following water-gas shift reaction of light hydrocarbons in Japan. This process emits CO2 but can be carbon-free, if CO2 in the off-gas is separated over H2 after H2 purification by pressure-swing adsorption. We have developed polymeric membranes containing various amines including poly(amidoamine)s (PAMAMs) for preferential CO2 permeation over H2. [1-4]. The PAMAM immobilized membranes show excellent CO2 separation properties in the separation. However, the CO2 permeability of the polymeric membranes should be elevated for implementation of the membrane, for example, from 5 (current) to 30 GPU in CO2 capture at on-site H2 station. Recently, we found that alkanolamines, such as (2-aminoethyl)ethanolamine (AEEA), exhibit higher CO2 separation properties than PAMAM in the same polymeric matrices. Hydroxyl group adjacent to amino group forms hydrogen bonding to CO2 in the interaction between amine and CO2, which reduces the interaction and/or dissociation energy to facilitate CO2 diffusion in the membrane. In this presentation, immobilization of various alkanolamines in poly(vinyl alcohol) (PVA) matrix was studied to formulate polymeric membranes, and the CO2 separation performance was examined. The mechanism of preferential CO2 permeation of the amine-containing PVA membranes will be discussed.
PVA aqueous solution was blended with alkanolamines by various weight ratios. The resulting solution was cast onto a plastic dish. A self-standing and transparent membrane was obtained after evaporating the solvent. The membrane morphology was characterized by XRD, SAXS, SEM, NMR, and DSC. The CO2 separation over H2 was performed under various operation conditions, and the CO2 separation performance was determined by gas chromatography.
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Mai Yoshizawa, "Mechanism of preferential CO2 permeation of amine-containing polymeric membrane" in "Separations Technology IX: New Frontiers in Media, Techniques, and Technologies", Kamalesh K. Sirkar, New Jersey Institute of Technology, USA Steven M. Crame, Rensselaer Polytechnic Institute, USA João G. Crespo, LAQV-Requimte, FCT-Universidade Nova de Lisboa, Caparica, Portugal Marco Mazzotti, ETH Zurich, Switzerland Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/separations_technology_ix/10