Membrane assisted processing of acetone, butanol, and ethanol (ABE) aqueous streams

https://doi.org/10.1016/j.cep.2021.108462Get rights and content
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Highlights

  • Commercial membranes evaluated for recovery and dehydration of ABE aqueous mixture.

  • Pervap™4060 displayed the best performance among hydrophobic membranes assessed.

  • Modified silica hydrophilic membrane presented excellent dewatering properties.

  • Liquid-liquid separation of ABE aqueous mixture enhanced the process efficiency.

  • Comprehensive concept of ABE broth downstream processing using membranes proposed.

Abstract

Downstream processing of ABE fermentation broth is challenging issue. In this work, results of the application of both hydrophobic and hydrophilic commercial membranes during the pervaporation of ABE aqueous mixtures were investigated and presented. Hydrophobic pervaporation experiments were performed using ABE-water mixtures containing 0–5 wt% of organics in feed, using commercial membranes: POMS, PEBAX, and Pervap™4060. Separation factor and Pervaporation Separation Index were employed to discuss hydrophobic pervaporation results. Pervap™4060 membrane revealed the best separation performance in the removal of ABE components from diluted aqueous mixtures mimicking the fermentation broth, resulting in two-phase permeate containing ca. 34 wt% of organics. The subsequent liquid-liquid phase separation resulted in the organic phase containing 62 wt% of ABE. Hydrophilic pervaporation experiments were performed in contact with ABE-water system initially comprising 38 wt% of water applying both the Pervap™4100 PVA based polymeric membrane and modified silica ceramic one. Application of hydrophilic membranes allowed for the complete dewatering of ABE-water mixtures. Eventually, the combination of membrane separation processes (microfiltration, hydrophobic pervaporation, hydrophobic thermopervaporation, membrane distillation, and hydrophilic pervaporation) enhanced by the liquid-liquid phase separation was suggested for the recovery and dehydration of ABE aqueous mixture.

Keywords

Hydrophobic and hydrophilic pervaporation
ABE - acetone, butanol, ethanol
Recovery of ABE from aqueous mixtures
Dehydration of ABE aqueous mixture
Liquid-liquid phase separation

Abbreviations

A
membrane area [m2]
ABE
acetone-butanol-ethanol
AcO
acetone
BuOH
butanol
EtOH
ethanol
Ji
permeate flux of component i [g m−2 h−1]
Jt
total permeate flux [g m−2 h−1]
m
mass of permeate collected over given period of time
MD
membrane distillation
MF
microfiltration
PDMS
poly(dimethylsiloxane)
PEBA
poly(ether block amide)
PMS
poly(methylsilane)
PTMSP
poly[1-(trimethylsilyl)-1-propyne]
PV
pervaporation
PVA
poly(vinyl alcohol)
S
selectivity [-]
TPV
thermopervaporation
UF
ultrafiltration
Yi
weight fraction of component i in permeate [-]
β
separation factor [-]
Δmi
mas of permeate [g]
Δt
time of the permeate collection [h]

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