Highly CO2‑Selective Membranes Composed of Quaternary Ammonium Functionalized Silica Nanoparticles

The ever-growing concerns regarding climate change have intensified the focus on carbon dioxide (CO2) separation and capture techniques, recognizing CO2 as a crucial factor in global warming. Among various technologies, membrane separation has been identified as a promising method due to its high separation efficiency. However, optimizing both permeance and selectivity in CO2 separation membranes poses a substantial challenge. This study introduces a novel high-performance CO2 separation membrane, constructed with core–shell quaternary ammonium functionalized silica nanoparticles (CS-QSNPs) and poly­(vinylpyrrolidone) (PVP), classified as a mixed matrix membrane. CS-QSNPs were synthesized using a sol–gel method, employing tetraethyl orthosilicate and trimethyl­[3-(trimethoxysilyl)­propyl]­ammonium chloride, exhibiting an impressive compatibility with PVP. The surface quaternary ammonium groups of CS-QSNPs exhibited a pronounced affinity for CO2, which contributed to enhanced CO2 solubility in the membrane, thus facilitating CO2 transport pathways. The resulting membrane demonstrated a remarkable CO2/N2 selectivity of 140 and a CO2 permeance of 69 gas permeation units. This breakthrough in CO2 separation membrane technology holds significant promise for industrial applications, particularly in the domain of CO2 capture and separation. The robust, cost-effective approach, aligned with the objectives of environmental protection and sustainability, makes this research a valuable contribution to the field of harmful materials’ management.