Dehydration of C₂–C₄ alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

Abstract

The dehydration of alcohol/water mixtures using pervaporation membranes requires less energy than is required by conventional separation technologies. In this paper, we report electrostatically enhanced graphene oxide (GO) membranes for the highly efficient pervaporation dehydration of C 2 -C 4 alcohol/water mixtures. Positively charged molecules were introduced as the interlayer of negatively charged GO layers via layer-by-layer assembly, thereby creating an electrostatic attraction that drives the assembly of GO nanosheets into ordered interlayer channels. The effects of the feed temperature, water concentration, and continuous operation on the membrane transport behavior were systematically investigated. In the dehydration of 90 wt% alcohol/water mixtures at 70 C, the membrane exhibited ethanol/water, isopropanol/water, and n-butanol/water fluxes of 2.35, 2.98, and 4.69 kg/(m 2 hr), respectively, as well as separation factors for the same mixtures of 3,390, 5,790, and 4,680, respectively. This excellent alcohol/water dehydration performance outperforms those of state-of-the-art polymeric membranes and GO-based membranes.

Poly(vinyl alcohol)/ZSM-5 zeolite mixed matrix membranes for pervaporation dehydration of ethanol and n-propanol

“…In the meantime, the same polarity sequence was reported for the three alcohols [ 33 ], leading to different affinities within PVA-based membranes and different pervaporation results as discussed above. Unsurprisingly, similar dependency of dehydration performances on molecular size for some alcohol solutions have been reported recently [ 34 – 37 ]. For example, the dewatering separation factor of UiO-66-filled polyimide membranes was reported to decline in the sequence of ETA < IPA < n-butanol [ 34 ] or methanol < ETA < IPA [ 35 ], while the pervaporation flux followed the opposite sequence.…”

Insights into High Li+/Mg2+ Separation Performance Using a PEI-Grafted Graphene Oxide Membrane

“…The GO−PEI suspension which showed deeper color and good dispersion was further measured by the zeta potential, as shown in Figure 1b. The GO suspension always kept negatively charged due to the ionization of oxygencontaining functional groups on the surface of GO nanosheets, 42,43 while the GO−PEI suspension was positively charged in solutions with different pH values. Owing to the abundant positively charged amino groups on the PEI molecular chain, part of them neutralized the negative potential of GO nanosheets, and the remaining part was exposed to the resolution environment, leading to the surface of GO−PEI nanosheets positively charged.…”

Design, Development, and Outlook of Superwettability Membranes in Oil/Water Emulsions Separation

“…Currently, the main method used to separate the miscible organic solvent‐water is the synergistic effect of pore size screening and pervaporation. [ 235–239 ] Jin and co‐workers (2021) constructed spherical polyelectrolyte brush (SPB) structures, and then combined with graphene oxide laminates to prepare a high‐performance alcohol‐water separation membrane ( Figure ). [ 235 ] Inserting the SPB structure into the GO nanosheets can effectively solve the problems existing in the graphene membranes.…”