Construction and Characterization of MOF-Nanosheet Based Mixed Matrix Membranes with Two-Dimensional Nano-Confined Molecular Transport Pathways
Final Report Abstract
In this project, we successfully prepared a series of Zn2(bim)3 nanosheets modified with different functional groups: (1) Using octadecylamine as the intercalating agent, the aminomodified Zn2(bim)3 nanosheets were prepared by the top-down method (2) The hydroxymethyl-modified Zn2(bim)3 nanosheets are prepared in situ by the bottom-up method. According to the characterization results, it can be known that the surfactant ODA-assisted intercalation can realize the efficient peeling of the amino-modified layered Zn2(bim)3 material. By adding glycidyl methacrylate (GMA) monomer to the stripped nanosheet dispersion for insitu polymerization, the epoxy group of GMA will react with the amino group on the octadecylamine (ODA) between the layers to connect successively, and at the same time, the double bond of GMA is polymerized and solidified in situ to prepare a mixed matrix membrane with high nano-sheet dispersion in one step. The hydrogen permeation flux is 4.2×10^-10 mol · m^-2 · s^-1 · Pa^-1, and the H2/CO2 selectivity is 4.8. The low separation selectivity of the mixed matrix membrane may be due to the poor compatibility of the nanosheets with the polymer, resulting in non-selective interface defects; the low permeability of the mixed matrix membrane is mainly due to the intrinsic poor permeability of the polymer itself. It is possible to prepare mixed matrix membranes with high separation selectivity and high permeability by screening suitable polymeric substrates or functionally modifying polymers. Optimized synthesis can obtain hydroxymethyl-modified Zn2(bim)3 nanosheets with a thickness of about 30 nm. The hydroxymethyl-modified Zn2(bim)3 nanosheets membrane was successfully prepared on the porous alumina support by the drip coating method. The membrane has good CO2/N2 separation performance, the CO2 permeance is 6×10^-9 mol·m^-2 · s^-1 · Pa^-1, and the separation coefficient is 14. Under the condition of 3wt% water vapor, the separation performance of the membrane is improved, the CO2 permeance is 1×10^-9 mol · m^-2 · s^-1 · Pa^-1, and the selectivity is 29. Overall, the separation membrane has good CO2 permeance, CO2/N2 separation performance and stability.
Publications
- Functionalized ZIF-7/Pebax 2533 mixed matrix membranes for CO2/N2 separation, Microporous Mesoporous Mater. 297 (2020) 110030
J. Gao, H.Z. Mao, H. Jin, C. Chen, A. Feldhoff, Y.S. Li
(See online at https://doi.org/10.1016/j.micromeso.2020.110030) - Ultrafast semi-solid processing of highly durable ZIF-8 membranes for propylene/propane separation, Angew. Chem. Int. Ed. 59 (2020) 21909-21914
Q. Ma, K. Mo, S.S. Gao, Y.F. Xie, J.Z. Wang, H. Jin, A. Feldhoff, S.T. Xu, J. Lin, Y.S. Li
(See online at https://doi.org/10.1002/anie.202008943)
