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Wastewater containing volatile organic compounds (VOCs) is generated in various industrial processes and is seriously harmful to the natural environment and human health. Its treatment has become extremely important due to increasing environment concerns. Here, a high permeable membrane for fast and high-efficient VOCs removal from aqueous solutions by pervaporation is reported. The as-prepared PIM-1 membrane allows ultrafast permeation of VOCs and exhibits excellent VOCs selectivity, particularly for ethyl acetate, dimethyl ether, and acetonitrile. Typically, the PIM-1 membrane exhibits an ultrahigh flux and separation factor of 39.5 kg μm m−2 h−1 and 189, respectively, in the pervaporation of 1.0 mol% aqueous ethyl acetate solution. Furthermore, the solubility-diffusion mechanism is revealed in the pervaporation of 10 kinds of 1.0 mol% VOCs solutions. It is found that the pervaporation performance is affected directly by physicochemical properties of VOCs. Moreover, effects of feed composition and temperature on the pervaporation are studied in details. © 2015 American Institute of Chemical Engineers AIChE J, 62: 842-851, 2016 [ABSTRACT FROM AUTHOR]

Polymers of intrinsic microporosity (PIMs) are attractive materials and have drawn increasing attention in separation membranes. Here carboxy groups are introduced to improve hydrophilicity of the PIMs membranes for pervaporation dehydration of ethylene glycol (EG). The resulting carboxylated PIM–1 (cPIM–1) membranes have adjustable carboxylation degree of up to 0.94. Carboxylation produces many small diffusion channels and greatly improves the membrane hydrophilicity that increases linearly with the carboxylation degree. The membranes show excellent pervaporation performances that depend on the membrane hydrophilicity. The fluxes and permeance greatly increase and likewise the separation factor and water selectivity linearly increase with the hydrophilicity. Compared with other membranes, the cPIM–1 membranes show the high flux. Typically, the cPIM–1 membrane with the carboxylation degree of 0.94 has a total permeation flux of 13.68 kg μm m −2 h −1 and separation factor of 75.92 in the dehydration of the 80 wt% EG mixture at 30 °C. The cPIM–1 presents a wide application in the pervaporation dehydration of organics. [ABSTRACT FROM AUTHOR]

Ethylene glycol (EG) is an essential chemical and forms mixtures with water or methanol in the production processes. Its purification is imperative in the production of pure EG from its water/methanol mixtures. Conventionally, distillation is employed in this separation process at the expense of massive energy consumption. Here water/methanol-EG mixtures are separated by the highly permeable PIM-1 membrane via pervaporation to produce the pure EG product. PIM-1 is one of most representative polymers of intrinsic microporosity (PIMs) that are attractive membrane materials. The overall separation performances for water/methanol-EG mixtures are investigated systematically. The membrane shows good separation performances as well as high purifying efficiency. Typically, the membrane has a high flux of 10.40 kg µm m-2 h-1 and separation factor of 24.2 in the pervaporation of methanol (18.50 wt %)-EG mixtures at 30 °C. In addition, effects of feed composition and temperature are investigated respectively on the separation performances. The flux and separation factor increases simultaneously with the water/methanol content in feed, whereas the separation factor decreases with increasing feed temperature for the methanol-EG mixture and the opposite for the water-EG mixture. The PIM-1 membrane shows a great potential in the EG purification industries. [ABSTRACT FROM AUTHOR]

Novel polymer–MOF nanocomposite membranes are prepared via the incorporation of ZIF-8 nanocrystals into cardo polyetherketone (PEK-c) for pervaporation separation of water/methanol/MTBE ternary mixtures. The ZIF-8 nanocrystals with 20–40 nm size are synthesized for preparing membranes. The resulting membranes have ZIF-8 nanocrystals dispersed homogeneously and embedded in the membrane matrix with adjustable ZIF-8 loading of up to 20 wt%. Moreover, the membranes have homogeneous microstructure, good thermal and mechanical stabilities. They show favorable pervaporation performances for separation of the water/methanol/MTBE mixtures. The incorporation of ZIF-8 greatly enhances the permeation flux. At the low ZIF-8 loading, the water selectivity increases and the total separation factor is very high and greater than 1.97 × 10 4 . Typically, the membrane with 4 wt% ZIF-8 has the total flux of 1.48 kg μm m −2 h −1 , water and total separation factor of 181 and 1.97 × 10 4 respectively. The newly developed nanocomposite membranes have a great potential in high-efficient purification of MTBE. [ABSTRACT FROM AUTHOR]