Silica/Polyimide Mixed Matrix Membrane for <scp>CO₂</scp>/<scp>CH₄</scp> and <scp>O₂</scp>/<scp>N₂</scp> Gas Separation: A Computational Approach

ABSTRACT Silica‐incorporated polyimide (PI)‐based mixed matrix membranes (MMMs) are emerging as promising candidates for gas separation. However, experimental evaluation of their performance is challenging due to the complex interactions between polymers and fillers and limitations in isolating individual transport mechanisms. This study employs Monte Carlo and molecular dynamics (MD) simulations to investigate the solubility and diffusivity of CO 2 /CH 4 and O 2 /N 2 in silica/6FDA‐ODA PI MMMs with varying silica loadings (0–20 wt%). The mixed gas compositions are chosen to reflect real‐world conditions, as 30% CO 2 in CO 2 /CH 4 mixtures, representative of sour gas in natural reserves, and 21% O 2 in O 2 /N 2 mixtures, mimicking air composition. Results indicate that incorporating 10 wt% silica enhances CO 2 permeability by 270% and CO 2 /CH 4 selectivity by 136% compared to pristine 6FDA‐ODA PI. For O 2 /N 2 separation, an O 2 permeability of 23.59 and selectivity of 3.11 were achieved. These findings align well with the experimental literature, with 0.01%–10.4% deviation. Benchmarking confirms superior permeability over reported membranes, highlighting the potential of silica/6FDA‐ODA PI MMMs for efficient gas separation. This study provides valuable molecular‐level insights, paving the way for the rational design of high‐performance membranes for industrial applications.