Amino-decorated organosilica membranes for highly permeable CO₂ capture

Membrane-based separation technologies are considered an effective process for the capture of CO₂ due to advantages such as high levels of energy efficiency with inexpensive levels of investment. It remains challenging, however, to develop a membrane with high levels of both permeance and selectivity with the ability to capture CO₂ in a highly efficient manner. Herein, we report amino-decorated organosilica membranes that are based on a facile and effective co-polymerization strategy that uses bis(triethoxysilyl)acetylene (BTESA) and (3-aminopropyl) triethoxysilane (APTES) precursors. This co-polymerization strategy simultaneously endows the resultant membranes with a controlled pore size and enhanced CO₂-philic properties that have significantly improved CO₂ separation performance. These composite membranes display CO₂ permeance that ranges from 2550–3230 GPU and a range for CO₂/N₂ selectivity of 31–42 in the separation of CO₂/N₂ mixtures, which outperforms most state-of-the-art membranes and exceeds the target for post-combustion CO₂ capture operations. A satisfying performance was achieved with a CO₂ permeance of 8 ✕ 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ (2390 GPU) and CO₂/CH₄ selectivity of 70. The present study highlights an elegant decoration strategy for the production of membranes with ultrahigh CO₂ capture capacities, which can also be extended to other organosilica precursors for target-oriented separations by varying the bridged or side-chain groups.