Amino-decorated organosilica membranes for highly permeable CO2 capture

Abstract

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.