Intensified Biobutanol Recovery by using Zeolites with Complementary Selectivity

Area of Science:

• Chemical Engineering
• Materials Science
• Separation Science

Background:

• Biobutanol production via acetone-butanol-ethanol (ABE) fermentation is crucial for sustainable energy.
• Efficient separation of biobutanol from complex fermentation media remains a significant challenge.
• Existing liquid-phase separation methods often suffer from low efficiency and high energy consumption.

Purpose of the Study:

• To develop and evaluate a vapor-phase adsorptive recovery process for biobutanol.
• To investigate the use of shape-selective zeolites for enhanced separation of biobutanol from ABE mixtures.
• To optimize the process for high purity and recovery of biobutanol.

Main Methods:

• Preparation and characterization of all-silica zeolites with CHA and LTA topologies.
• Adsorption isotherm and breakthrough experiments using single-component and multi-component systems.
• Density Functional Theory (DFT) simulations to understand molecular interactions.
• Investigation of process parameters including humidity, pressure, and zeolite combinations.

Main Results:

• All-silica CHA and LTA zeolites exhibited opposite selectivities, with CHA favoring ethanol and LTA favoring butanol.
• Zeolite molecular sieving properties effectively removed acetone from the mixture.
• A sequential adsorption process using LTA and CHA zeolites achieved 99.7 mol% butanol purity with high recovery.
• DFT simulations provided insights into the molecular mechanisms governing separation.

Conclusions:

• Vapor-phase adsorptive recovery using tailored zeolites is a highly effective method for biobutanol separation.
• The combination of LTA and CHA zeolites offers a synergistic approach for achieving high-purity biobutanol.
• This process presents a promising alternative to conventional separation techniques for ABE fermentation products.