CO₂ separation and capture technologies are of great significance for reducing the greenhouse effect. MOF-based membrane separation technology is promising for CO₂ separation and capture. Researchers found that adding MOFs nanoparticles into the polymer matrix to form mixed matrix membranes (MMMs) can greatly enhance the CO₂ permeability. However, the microscope mechanism of this phenomenon is still unclear. In this study, the molecular simulation method was conducted to explore the microscopic interaction of two typical MOFs, UiO-66 and ZIF-8, in Pebax-2533 polymer matrix. To achieve a more accurate simulation of the mixed matrix membrane, different force fields were compared, and a MMM molecular model of MOF particles surrounded with polymer chains was established. CO₂ adsorption and diffusion in MOF-based mixed matrix membranes was calculated and compared with that in polymer matrix. The properties such as polymer rigidity, fractional free volume (FFV), pore size distribution (PSD) were calculated to evaluate the influence of MOF particles on the polymer matrix. The new molecular model and simulation method proposed in this paper can provide a new path for studying the microscopic mechanism of gas separation by MMMs.
 

CO2 separation, Metal-organic framework, Mixed matrix membrane, Molecular simulation