Liquid Metal Organic Frameworks Based Mixed Matrix Membranes For Efficient Bioethanol Separation

Abstract

Liquid Metal Organic Frameworks Based Mixed Matrix Membranes For Efficient Bioethanol Separation By Amna Kasuri This dissertation investigates the enhancement of ethanol-water separation using novel mixed matrix membranes (MMMs) incorporating metal-organic frameworks (MOFs). ZIF-90, a well-known MOF, is utilized for its exceptional pore properties, and its outer surface is innovatively functionalized with carbenes to create a porous liquid (PL) form. This functionalization aims to prevent particle agglomeration, a common challenge in MOFs' application in MMMs, thus facilitating higher selectivity and efficiency. The research is structured in two main parts. Initially, the MMMs are synthesized by embedding the carbene-functionalized ZIF-90 PL into a polydimethylsiloxane (PDMS) matrix. This composite membrane is then applied in the pervaporation process for ethanol-water separation. The novel use of ZIF-90 in a PL state is proposed to enable defect-free membrane synthesis with high filler loading, enhancing the process's efficiency. In the second part, a composite of ZIF-90 with Deep Eutectic Solvents (DESs) is developed through in-situ formation within the MOF pores. The resultant ZIF-90-DES composite is incorporated into PDMS to form another set of MMMs. These membranes are expected to further improve the pervaporation performance due to the synergetic effect of MOF pores and DES properties. Extensive characterization of the prepared membranes highlights their effectiveness in ethanol dehydration via pervaporation. The PL-based MMMs demonstrate a significant performance with a total flux of 3.86 kg/m2.hr and a separation factor of 29.3 at 60 °C, with a filler loading of up to 45 wt.%. The ZIF-90-DES composite MMMs also show promising results, achieving a flux of 2.83 kg/m2.h and a separation factor of 24.3. These findings underscore the potential of using MOF-based composites in MMMs for efficient ethanol-water separation, paving the way for advanced applications in catalysis and gas separation.