Multiblock Copolymer Grafting for Butanol Biofuel Recovery by a Sustainable Membrane Process

• Published in: ACS applied materials & interfaces Vol. 8; no. 25; pp. 16262 - 16272
• Main Authors: Vijay Kumar, Shankarayya, Arnal-Herault, Carole, Wang, Miao, Babin, Jérôme, Jonquieres, Anne
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 29-06-2016; Washington, D.C. : American Chemical Society
• Subjects: Chemical Sciences; Organic chemistry; Polymers; membranes; pervaporation membrane process; grafted copolymer materials; butanol; structure−property relationships; biofuel
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b01900

Biobutanol is an attractive renewable biofuel mainly obtained by the acetone–butanol–ethanol (ABE) fermentation process. Nevertheless, the alcohol concentration has to be limited to a maximum of 2 wt % in ABE fermentation broths to avoid butanol toxicity to the microorganisms. The pervaporation (PV) membrane process is a key sustainable technology for butanol recovery in these challenging conditions. In this work, the grafting of azido-polydimethylsiloxane (PDMS-N3) onto a PDMS-based multiblock copolymer containing alkyne side groups led to a series of original membrane materials with increasing PDMS contents from 50 to 71 wt %. Their membrane properties were assessed for butanol recovery by pervaporation from a model aqueous solution containing 2 wt % of n-butanol at 50 °C. The membrane flux J 50μm for a reference thickness of 50 μm strongly increased from 84 to 192 g/h m2 with increasing PDMS content for free-standing dense membranes with thicknesses in the range of 38–95 μm. At the same time, the intrinsic butanol permeability increased from 1.47 to 4.68 kg μm/h m2 kPa and the permeate butanol content was also strongly improved from 38 to 53 wt %, corresponding to high and very high membrane separation factors of 30 and 55, respectively. Therefore, the new grafted copolymer materials strongly overcame the common permeability/selectivity trade-off for butanol recovery by a sustainable membrane process.