Selective Permeation of Water through Angstrom‐Channel Graphene Membranes for Bioethanol Concentration

Abstract

Graphene-based laminate membranes have been theoretically predicted to selectively transport ethanol from ethanol-water solution while blocking water. Here, we report robust angstromchannel graphene membranes (ACGMs) fabricated by intercalating carbon sheets derived from chitosan into thermally-reduced graphene oxide (GO) sheets. ACGMs with robust and continuous slitshaped pores (an average pore size of 3.9 Å) were investigated for the dehydration of ethanol. Surprisingly, only water permeates through ACGMs in the presence of aqueous ethanol solution. For the water-ethanol mixture containing 90 wt.% ethanol, water can selectively permeate through ACGMs with a water flux of 63.8 ± 3.2 kg m -2 h -1 at 20 °C and 389.1±19.4 kg m -2 h -1 at 60 °C, which are over two orders of magnitude higher than those of conventional pervaporation membranes. This means that ACGMs can effectively operate at room temperature. Moreover, the ethanol can be fast concentrated to high purity (up to 99.9 wt.%). Therefore, ACGMs are very promising for production of bioethanol with high efficiency, thus improving its process sustainability.

Thin-Film Composite Membrane Prepared by Interfacial Polymerization on the Integrated ZIF-L Nanosheets Interface for Pervaporation Dehydration

“…Similar to the influence of the ethanol content in the feed, the partial water flux rather than the flux of ethanol increases significantly with the increase of the operating temperature from 30 to 60 °C. A possible explanation from the literature , is that this is due to the increased driving forces across the membranes and the enhanced mobilities of permeating molecules in the membrane matrix at a higher operational temperature. Meanwhile, the normalized membrane permeance decreases and the selectivity also decreases from Figure d.…”

Two-Dimensional-Material Membranes: Manipulating the Transport Pathway for Molecular Separation

“…Wang and co-workers proposed the coassembly of GO nanosheets and the polymer, followed by reduction and carbonization, contributing to the tunable subnanometer pores in ultrathin graphene membranes . The as-fabricated intercalated graphene membranes exhibited ultrafast water evaporation in the desalination process and extraordinary pervaporation dehydration performance for ethanol/water mixtures . Seo et al fabricated CVD graphene membranes for water desalination via a membrane distillation process .…”

Comprehensive analysis on anomalous phenomenon of ethanol‐soluble poly(vinyl butyral) membrane for ethanol recovery via pervaporation

“…[1][2][3][4] Generally, PV membranes for the separation of ethanol aqueous solutions can be divided into water-and ethanolpermselective membranes, which preferentially permeate water and ethanol, respectively. [5][6][7] Many studies have concentrated on developing water-permselective PV membranes, [8][9][10] which are beneficial to separate mixtures with high-concentration ethanol. Nevertheless, for ethanol recovery from low-concentration aqueous solution, hydrophobic polymers are identified as the most prospective PV membrane materials on account of their ethanol perm-selectivity and lower energy costs.…”

“…Membrane‐based pervaporation (PV) technology has become one of the most promising processes for ethanol/water mixtures separation due to its low energy requirement and environment‐friendly characteristics 1–4 . Generally, PV membranes for the separation of ethanol aqueous solutions can be divided into water‐ and ethanol‐permselective membranes, which preferentially permeate water and ethanol, respectively 5–7 . Many studies have concentrated on developing water‐permselective PV membranes, 8–10 which are beneficial to separate mixtures with high‐concentration ethanol.…”