Zeolite-like performance for xylene isomer purification using polymer-derived carbon membranes

Significance Xylenes are essential feedstocks for manufacturing packaging materials, versatile chemicals, industrial solvents, etc. The purification of xylene isomers is one of the most important yet energy-intensive organic mixture separations in the chemical industry. We achieved the separation of xylene isomers using carbon molecular sieve (CMS) membranes derived from a spirobifluorene-based polymer of intrinsic microporosity (PIM-SBF), which could potentially reduce the energy consumption, carbon emissions, and equipment footprint. CMS membranes are solvent- and temperature-resistant materials that can withstand high transmembrane pressures when fabricated into the form of hollow fibers. The new CMS membrane produced here shows competitive performance with state-of-the-art zeolites under high xylene loadings, and its development has provided fundamental insight and guidance into the manipulation of CMS pore structure.