Tuning MOF/polymer interfacial pore geometry in mixed matrix membrane for upgrading CO<sub>2</sub> separation performance.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38985866.
- Also identified by DOI 10.1126/sciadv.adk5846 and PMC identifier 11235163.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The current paradigm considers the control of the MOF/polymer interface mostly for achieving a good compatibility between the two components to ensure the fabrication of continuous mixed-matrix metal-organic framework (MMMOF) membranes. Here, we unravel that the interfacial pore shape nanostructure plays a key role for an optimum molecular transport. The prototypical ultrasmall pore AlFFIVE-1-Ni MOF was assembled with the polymer PIM-1 to design a composite with gradually expanding pore from the MOF entrance to the MOF/polymer interfacial region. Concentration gradient-driven molecular dynamics simulations demonstrated that this pore nanostructuring enables an optimum guided path for the gas molecules at the MOF/polymer interface that decisively leads to an acceleration of the molecular transport all along the MMMOF membrane. This numerical prediction resulted in the successful fabrication of a [001]-oriented nanosheets AlFFIVE-1-Ni/PIM-1 MMMOF membrane exhibiting an excellent CO<sub>2</sub> permeability, better than many MMMs, and ideally associated with a sufficiently high CO<sub>2</sub>/CH<sub>4</sub> selectivity that makes this membrane very promising for natural gas/biogas purification.