Structure-Transport Relationships of Water-Organic Solvent Co-transport in Carbon Molecular Sieve (CMS) Membranes.

Autor: Yoon YH; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Ren Y; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Sarswat A; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Kim S; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Lively RP; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Jazyk: angličtina
Zdroj: Industrial & engineering chemistry research [Ind Eng Chem Res] 2023 Oct 30; Vol. 62 (44), pp. 18647-18661. Date of Electronic Publication: 2023 Oct 30 (Print Publication: 2023).
DOI: 10.1021/acs.iecr.3c02519
Abstrakt: We explore the effects of the carbon molecular sieve (CMS) microstructure on the separation performance and transport mechanism of water-organic mixtures. Specifically, we utilize PIM-1 dense films and integrally skinned asymmetric hollow fiber membranes as polymer precursors for the CMS materials. The PIM-1 membranes were pyrolyzed under several different pyrolysis atmospheres (argon, carbon dioxide, and diluted hydrogen gas) and at multiple pyrolysis temperatures. Detailed gas physisorption measurements reveal that membranes pyrolyzed under 4% H 2 and CO 2 had broadened ultramicropore distributions (pore diameter <7 Å) compared to Ar pyrolysis, and pyrolysis under CO 2 increased ultramicropore volume and broadened micropore distributions at increased pyrolysis temperatures. Gravimetric water and p -xylene sorption and diffusion measurements reveal that the PIM-1-derived CMS materials are more hydrophilic than other CMS materials that have been previously studied, which leads to sorption-diffusion estimations showing water-selective permeation. Water permeation in the vapor phase, pervaporation, and liquid-phase hydraulic permeation reveal that the isobaric permeation modes (vapor permeation and pervaporation) are reasonably well predicted by the sorption-diffusion model, whereas the hydraulic permeation mode is significantly underpredicted (>250×). Conversely, the permeation of p -xylene is well predicted by the sorption-diffusion model in all cases. The collection of pore size analysis, vapor sorption and diffusion, and permeation in different modalities creates a picture of a combined transport mechanism in which water-under high transmembrane pressures-permeates via a Poiseuille-style mechanism, whereas p -xylene solutes in the mixture permeate via sorption-diffusion.
Competing Interests: The authors declare no competing financial interest.
(© 2023 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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