Zeolite MFI adsorbent for recovery of butanol from ABE fermentation broths produced from an inexpensive black liquor-derived hydrolyzate

Abrar Faisal,Jonas Hedlund,Ming Zhou,Mattias Grahn

doi:10.1007/s13399-018-0315-9

Abstract

In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.

Highlights

Black liquor is generated in pulp mills and mainly contains pulping chemicals, lignin, and degraded hemicellulose
Other groups studied recovery of butanol from model ABE solutions using KA-1 and polymeric resins with good outcome [23, 24]. Most of these studies focused on recovery of butanol and other valuable compounds like butyric acid, etc. from model solutions and very little attention was given to recovery from real fermentation broths
In the present work, we demonstrate that high-silica MFI zeolite shows high adsorption selectivity for butanol against the other main compounds present in real fermentation broths and that the adsorbent is seemingly insensitive to the presence of phenolic compounds in the fermentation broth

Summary

Introduction

Black liquor is generated in pulp mills and mainly contains pulping chemicals, lignin, and degraded hemicellulose. As zeolite MFI is a stable material and strightforward to synthesize in its hydrophobic (high Si/Al ratio) form at relatively low cost, it is one of the most studied materials for recovering butanol from dilute aqueous solutions Another key challenge for commercialization of the ABE process is the ability to yield high productivity and selectivity starting from inexpensive raw materials. In this respect, the carbohydrates, mainly in the form of hemicellulose, found in the black liquor constitute such an inexpensive source of substrate for the microorganisms. We for the first time present data on the recovery of butanol and butyric acid from real ABE fermentation broths prepared from a black liquor hydrolyzate using a high-silica MFI zeolite adsorbent

Methods

Results

Conclusion