Mixed-matrix ZIF-loaded membranes for effective separation of bio-butanol from fermentation broth

Mixed matrix composite membranes offer superior performance for separation of alcohols from fermentation broth. In this study bio-butanol (Butanol) is recovered from Acetone: Butanol: Ethanol (ABE) fermentation broth using ZIF-71 -PDMS-PVDF membranes. The significance of this work is the supported PVDF layer that was prepared using a dual coagulation bath to increase the surface roughness and contact angle. The addition of hydrophobic ZIF-71 particles into the matrix increases their thermal stability, hydrophobicity, and strength of the membrane. The synthesized membranes exhibited higher hydrophobic characteristic with a contact angle of around 120°. The Pervaporation efficiency of these membranes was analyzed by various experimental parameters such as ZIF loading, permeate pressure, feed temperature, and stirring speed. The membrane interaction parameters were calculated using Flory Huggins and Flory-Rehner equations. The membrane performance was also assessed by Maxwell-Stefan model fitting along with the evaluation of the friction coefficient. The butanol flux (50 g/m2h) was estimated using mathematical modeling and compared with the experimental results (120 g/m2h). The studies inferred that the models are well-fitted for butanol extraction which implies the penetrant-penetrant interaction is lower than penetrant-membrane interactions. A comparison of the present study with literature is well-defined to scale-up the process at an industrial level. [Display omitted] •Synthesis of ZIF 71-loaded PDMS mixed matrix membranes for pervaporative separation of bio-butanol.•Preparation of hydrophobic PVDF substrate layer using dual coagulation bath with ZIF-PDMS dense layer.•Achievement of higher flux and selectivity with the robust and flexible membranes.•Estimation of average diffusion coefficients, in MMMs for BuOH-Water system.