Carbonized ZIF-8 incorporated mixed matrix membrane for stable ABE recovery from fermentation broth

Abstract

Recently, zeolitic imidazolate framework-8 (ZIF-8) has been recognized as one of the most potential doping particles for pervaporation separation of organics because of its unique pore structure and high surface area. However, in this work, ZIF-8-based mixed matrix membrane (MMM) was found to have poor stability in separating acetone-butanol-ethanol (ABE) fermentation broth due to the organic acids caused the degradation of ZIF-8 framework. To improve the stability of ZIF-8-based MMM in practical application, ZIF-8-derived nanoporous carbon (ZNC) was prepared via direct carbonization and used to replace ZIF-8 in MMM. Results indicated the acid-stability, specific surface area and pore volume of ZNC were all remarkably improved compared with those of ZIF-8. The ZNC-based MMM showed high hydrophobicity and good compatibility between particles and polymer. More attractively, during 100 h of continuous operation for ABE recovery from fermentation broth, ZNC incorporated MMM exhibited a stable performance with an average total flux of 1870 g m−2 h−1 and a n-butanol separation factor of 20.