TY - JOUR
T1 - CMS membranes from PBI/PI blends
T2 - temperature effect on gas transport and separation performance
AU - Pérez-Francisco, José Manuel
AU - Santiago-García, José Luis
AU - Loría-Bastarrachea, María Isabel
AU - Paul, Donald R.
AU - Freeman, Benny D.
AU - Aguilar-Vega, Manuel
N1 - Funding Information:
J.M.P.F. gratefully acknowledges a scholarship from CONACyT (Mexico's National Council for Science and Technology) under Grant 354777 and the financial support from Tecnol?gico Nacional de M?xico (Grant 537.18-PD). M. Aguilar-Vega is grateful for a fellowship from Fulbright-Garcia-Robles (COMEXUS) for a sabbatical leave at UT Austin. The authors acknowledge Dr. Patricia Quintana for allowing access to The National Laboratory of Nano and Biomaterials (LANNBIO) from CINVESTAV-IPN, Merida Unit, grants FOMIX-YUCATAN 108160 and CONACYT 123913, in which X-ray diffraction analysis was carried out with the technical assistance of M. C. Daniel Aguilar-Trevin?o.
Funding Information:
J.M.P.F. gratefully acknowledges a scholarship from CONACyT (Mexico's National Council for Science and Technology) under Grant 354777 and the financial support from Tecnológico Nacional de México (Grant 537.18-PD ). M. Aguilar-Vega is grateful for a fellowship from Fulbright-Garcia-Robles (COMEXUS) for a sabbatical leave at UT Austin. The authors acknowledge Dr. Patricia Quintana for allowing access to The National Laboratory of Nano and Biomaterials (LANNBIO) from CINVESTAV-IPN, Merida Unit, grants FOMIX-YUCATAN 108160 and CONACYT 123913, in which X-ray diffraction analysis was carried out with the technical assistance of M. C. Daniel Aguilar-Treviño.
Publisher Copyright:
© 2019 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/3/1
Y1 - 2020/3/1
N2 - This study reports pure gas permeability and diffusion coefficients for carbon molecular sieve membranes (CMSM) derived from dense membranes based on blends of a rigid polyimide PI DPPD-IMM (PI) and polybenzimidazole (PBI), PI/PBI, at different concentrations. The permeability, diffusion and selectivity for PI/PBI blend CMS membranes was systematically tested as a function of concentration and temperature. CMS membrane derived from pure PI DPPD-IMM membrane (PI100-600) exhibited the highest permeability coefficients (PHe = 960 Barrer, PCO2 = 503 Barrer) and the highest separation factors (αO2/N2 = 8.3 and αCO2/CH4 = 56.5). Increasing PI concentration in the membranes blend precursors shows a positive effect on CMS membranes permeability, diffusion coefficients and selectivity. These results are attributed to an increase in micropores dimension that was reflected by the emergence of a d-spacing shift from 5.9 Å to 7.1 Å. It was also found that large concentrations of PBI (>50 wt%) in the precursor showed a negative effect on permeability and also in gas pair selectivity for carbon membranes which was attributed to carbazole-type strands densification of the structure. As PI concentration increases in PI/PBI CMS membranes, they present higher entropic selectivity and low energetic selectivity leading to the best permeability/selectivity relationship surpassing 2008 Robeson's upper bound for O2/N2 and CO2/CH4 gas pairs.
AB - This study reports pure gas permeability and diffusion coefficients for carbon molecular sieve membranes (CMSM) derived from dense membranes based on blends of a rigid polyimide PI DPPD-IMM (PI) and polybenzimidazole (PBI), PI/PBI, at different concentrations. The permeability, diffusion and selectivity for PI/PBI blend CMS membranes was systematically tested as a function of concentration and temperature. CMS membrane derived from pure PI DPPD-IMM membrane (PI100-600) exhibited the highest permeability coefficients (PHe = 960 Barrer, PCO2 = 503 Barrer) and the highest separation factors (αO2/N2 = 8.3 and αCO2/CH4 = 56.5). Increasing PI concentration in the membranes blend precursors shows a positive effect on CMS membranes permeability, diffusion coefficients and selectivity. These results are attributed to an increase in micropores dimension that was reflected by the emergence of a d-spacing shift from 5.9 Å to 7.1 Å. It was also found that large concentrations of PBI (>50 wt%) in the precursor showed a negative effect on permeability and also in gas pair selectivity for carbon membranes which was attributed to carbazole-type strands densification of the structure. As PI concentration increases in PI/PBI CMS membranes, they present higher entropic selectivity and low energetic selectivity leading to the best permeability/selectivity relationship surpassing 2008 Robeson's upper bound for O2/N2 and CO2/CH4 gas pairs.
KW - Blend precursors
KW - CMS membrane
KW - Entropic selectivity
KW - Gas separation
KW - Graphenic stuctures
UR - http://www.scopus.com/inward/record.url?scp=85076707597&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2019.117703
DO - 10.1016/j.memsci.2019.117703
M3 - Article
AN - SCOPUS:85076707597
VL - 597
JO - Journal of Membrane Science
JF - Journal of Membrane Science
SN - 0376-7388
M1 - 117703
ER -