Preparation of microporous polyamide networks for carbon dioxide capture and nanofiltration

For the first time, microporous polyamide networks have been synthesized via the interfacial polymerization of piperazine and acyl chloride monomers containing tetrahedral carbon and silicon cores. These polyamides, with Brunauer–Emmett–Teller surface area between 488 and 584 m2 g−1, show a CO2 uptake of up to 9.81 wt% and a CO2/N2 selectivity of up to 51 at 1 bar and 273 K, suggesting their great potential in the area of carbon capture and storage applications. We have developed the interfacial polymerization on the surface of the porous polyacrylonitrile substrate, resulting in the formation of ultrathin microporous membranes with thicknesses of about 100 nm. These nanofiltration (NF) membranes exhibited an attractive water flux of 82.8 L m−2 h−1 at 0.4 MPa and a high CaCl2 (500 mg/L) rejection of 93.3%. These NF membranes follow the salt rejection sequence of CaCl2 > NaCl > Na2SO4, demonstrating the positively charged character of these membranes.