Metal-Organic Framework (MOFs)-Derived Carbon Nanotubes (CNT) Intercalated into Ultrathin Polyamide Selective Layers to Improve Ethanol Purification Performance

With the growing severity of the energy crisis, the development of renewable and clean energy sources that can replace fossil fuels has become a hot research topic. Biofuel ethanol, mainly derived from biomass through processes like saccharification and fermentation, with a volume concentration of over 99% anhydrous ethanol, has emerged as a promising alternative energy source due to its natural abundance and non-toxic properties. Utilizing membrane separation technology to purify ethanol offers a more efficient alternative to traditional distillation techniques, significantly reducing overall production costs. The selective layer for the membrane is prepared through interfacial polymerization using d-sorbitol (DST) and trimesoyl chloride (TMC). DST is chosen for its higher number of hydroxyl groups, which provide a denser separation layer with the thickness less than 100 nm. Its linear structure reacts well with TMC, enhancing crosslinking and improving separation performance. Metal-organic framework (MOFs)-derived carbon nanotubes (CNTs) are a novel carbon material with the diameter of 10 nm obtained by high-temperature calcination of ZIF-67. During the pyrolysis process, there is no aggregation, and embedding MOFs-derived CNTs in the thin-film nanocomposite (TFN) membrane selective layer can create mass transport channels to increase the TFN membrane's flux without compromising separation efficiency.<br/>Therefore, post-treatment using MOFs-derived CNT intercalated into ultrathin polyamide selective layers can further enhance the flux and keeping a stable separation efficiency of TFN membranes with a stable performance over a long period of time.