Surface-Engineered Inorganic Nanoporous Membranes for Vapor and Pervaporative Separations of Water–Ethanol Mixtures†
AbstractSurface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc form) were prepared and studied for both vapor-phase separation and liquid pervaporative separations of water-ethanol mixtures. Superhydrophobic nanoceramic membranes demonstrated more selective permeation of ethanol (relative to water) by cross-flow pervaporation of liquid ethanol–water mixture (10 wt % ethanol feed at 80 °C). In addition, both superhydrophilic and superhydrophobic membranes were tested for the vapor-phase separations of water–ethanol mixtures. Porous inorganic membranes having relatively large nanopores (up to 8-nm) demonstrated good separation selectivity with higher permeation flux through a non-molecular-sieving mechanism. Due to surface-enhanced separation selectivity, larger nanopore-sized membranes (~5–100 nm) can be employed for both pervaporation and vapor phase separations to obtain higher selectivity (e.g., permselectivity for ethanol of 13.9 during pervaporation and a vapor phase separation factor of 1.6), with higher flux due to larger nanopores than the traditional size-exclusion membranes (e.g., inorganic zeolite-based membranes having sub-nanometer pores). The prepared superhydrophobic porous inorganic membranes in this work showed good thermal stability (i.e., the large contact angle remains the same after 300 °C for 4 h) and chemical stability to ethanol, while the silica-textured superhydrophilic surfaced membranes can tolerate even higher temperatures. These surface-engineered metallic/ceramic nanoporous membranes should have better high-temperature tolerance for hot vapor processing than those reported for polymeric membranes. View Full-Text
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Hu, M.Z.; Engtrakul, C.; Bischoff, B.L.; Lu, M.; Alemseghed, M. Surface-Engineered Inorganic Nanoporous Membranes for Vapor and Pervaporative Separations of Water–Ethanol Mixtures. Membranes 2018, 8, 95.
Hu MZ, Engtrakul C, Bischoff BL, Lu M, Alemseghed M. Surface-Engineered Inorganic Nanoporous Membranes for Vapor and Pervaporative Separations of Water–Ethanol Mixtures. Membranes. 2018; 8(4):95.Chicago/Turabian Style
Hu, Michael Z.; Engtrakul, Chaiwat; Bischoff, Brian L.; Lu, Mi; Alemseghed, Mussie. 2018. "Surface-Engineered Inorganic Nanoporous Membranes for Vapor and Pervaporative Separations of Water–Ethanol Mixtures." Membranes 8, no. 4: 95.
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