Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9952607 | Journal of Membrane Science | 2018 | 17 Pages |
Abstract
MOF mixed-matrix membranes (MMMs) are regarded as promising candidates for energy-efficient natural gas purification. This work reports the fabrication of high-performance 6FDA-polyimide MMMs, based on the incorporation of zeolite-like MOF (ZMOF) as fillers, and their associated permeation studies for CO2/CH4 separation. To eliminate micron-sized crystals, a facile repeating sedimentation approach was used to harvest nanocrystals from the as-synthesized bulk ZMOF crystalline powder material. This enables the deployment of ZMOF nanocrystals with relatively uniform dimension and morphology in the polymer matrix. Typical 6FDA-polyimides encompassing distinct diamine moieties (6FDA-DAM, 6FDA-DETDA-DABA or PDMC) were explored as polymer matrices to disclose the transport property matching the hosted ZMOF filler. Mixed-gas permeation measurements revealed that the incorporation of the ZMOF filler affords a concurrent enhancement of the CO2 permeability and the CO2/CH4 selectivity for the three tested 6FDA-polyimides. Particularly, the highly permeable 6FDA-DAM showed a considerably enhanced performance for CO2/CH4 that transcends the 2008 Robeson upper-bound. Detailed analysis of the sorption data and diffusion coefficients suggest that the enhanced transport property in the ZMOF-based MMM is plausibly attributed to the combination of the higher CO2 sorption capacity and selectivity, and favorable gas diffusivity via the CO2-philic framework of ZMOF in moderately confined pores.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
Gongping Liu, Ying Labreche, Valeriya Chernikova, Osama Shekhah, Chen Zhang, Youssef Belmabkhout, Mohamed Eddaoudi, William J. Koros,