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Background Bioethanol as a renewable energy resource plays an important role in alleviating energy crisis and environmental protection. Pervaporation has achieved increasing attention because of its potential to be a useful way to separate ethanol from the biomass fermentation process. Results This overview of ethanol separation via pervaporation primarily concentrates on transport mechanisms, fabrication methods, and membrane materials. The research and development of polymeric, inorganic, and mixed matrix membranes are reviewed from the perspective of membrane materials as well as modification methods. The recovery performance of the existing pervaporation membranes for ethanol solutions is compared, and the approaches to further improve the pervaporation performance are also discussed. Conclusions Overall, exploring the possibility and limitation of the separation performance of PV membranes for ethanol extraction is a long-standing topic. Collectively, the quest is to break the trade-off between membrane permeability and selectivity. Based on the facilitated transport mechanism, further exploration of ethanol-selective membranes may focus on constructing a well-designed microstructure, providing active sites for facilitating the fast transport of ethanol molecules, hence achieving both high selectivity and permeability simultaneously. Finally, it is expected that more and more successful research could be realized into commercial products and this separation process will be deployed in industrial practices in the near future. Graphical abstract

This study has shown, for the first time, the promise of tree bark biochar as fillers for improving selectivity index and separation flux of polydimethylsiloxane (PDMS) pervaporation membranes for ethanol/water separation.

In this work, polydimethylsiloxane (PDMS) polymeric membranes were fabricated by incorporating fumed silica nanoparticles which were functionalized with two silane coupling agents—NH2(CH2)3Si(OC2H5)3(APTS) and NH2(CH2)2NH(CH2)3Si(OC2H5)3(TSED)—for selective removal of ethanol from aqueous solutions via pervaporation. It was demonstrated that large agglomerates were not observed indicating the uniform distribution of modified silica throughout the PDMS matrices. It is noted that the ethanol diffusivity and the water contact angles were both increased remarkably, being beneficial to the preferential permeation of ethanol through the membranes. The pervaporation results showed that the addition of the two types of modified silica nanoparticles dramatically enhanced both the permeability and selectivity of hybrid membranes. Compared to APTS, silica modified by TSED at the concentration of 4 wt. % resulted in the optimum pervaporation membranes with the maximum separation factor of 12.09 and the corresponding permeation flux of approximately 234.0 g·m−2·h−1in a binary aqueous mixture at 40°C containing 10 wt. % ethanol. The observation will benefit the choice of coupling agents to improve the compatibility between hydrophilic fillers and hydrophobic polymers in preparing mixed matrix membranes.

We fabricated novel composite membranes composed of a polymer of intrinsic microporosity (PIM‐1) and carbon black (CB) nanoparticles functionalized with the silane coupling agent aminopropyl triethoxysilane to recover butanol from aqueous solutions by pervaporation (PV). Scanning electron microscopy showed that the composite membranes were dense and defect free and had good adhesion with substrates. Compared with the those of pristine PIM‐1 membranes, the water contact angles of the composite membranes increased from around 86° to more than 90°; this confirmed the improvement of the hydrophobicity. The swelling degree of the 6 wt % CB‐filled PIM‐1 membranes dropped 23%; this indicated an increase in the swelling resistance. Furthermore, the PV results show experimentally that the incorporation of the functionalized CBs into the PIM‐1 matrix considerably improved both the permeability and selectivity to butanol. At a 4 wt % CB content, the optimum separation performance, with a separation factor of 19.7 and a permeation flux of 1116 g m−2 h−1, was achieved in an aqueous solution containing 5 wt % butanol at 30°C. It was noteworthy that the as‐fabricated membranes exhibited a good separation stability. This is a step forward in terms of continuous butanol production with hybrid membranes in fermentation processes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46912.

For a polymeric blend containing powder additive, quantitative analysis of its mechanical performances with interfacial tension methodology is generally a difficult work because it needs at least two groups of consistent and comparable surface tension data, either for the polymer matrix or for the powder additive, to calculate their interfacial tension. In this article, to quantitatively analyze the effect of interfacial tension on the impact strength of acrylonitrile-butadiene-styrene/flame retardants (ABS/FR) blends, the surface tension components (STC) of three organic flame retardant powders, FR-245 (2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5 triazine), decabromodiphenyl oxide, and charringefoaming agent were measured through the combination of contact angle (CA) and inverse gas chromatography technique. The relationship of the STC measured from CA between ABS resin and its homopolymer components (polyacrylonitrile, polybutadiene, and polystyrene) was also researched. Then, the interfacial tension between the three FR and ABS was calculated. It was found that the impact strength of the ABS/FR blends decreased almost linearly with the increase of the interfacial tension, and the linear correlation degree reached a very high value, 0.9969.