Incorporating Zwitterionic Graphene Oxides into Sodium Alginate Membrane for Efficient Water/Alcohol Separation

Abstract

For the selective water-permeation across dense membrane, constructing continuous pathways with high-density ionic groups are of critical significance for the preferential sorption and diffusion of water molecules. In this study, zwitterionic graphene oxides (PSBMA@GO) nanosheets were prepared and incorporated into sodium alginate (SA) membrane for efficient water permeation and water/alcohol separation. The two-dimensional GO provides continuous pathway, while the high-density zwitterionic groups on GO confer electrostatic interaction sites with water molecules, leading to high water affinity and ethanol repellency. The simultaneous optimization of the physical and chemical structures of water transport pathway on zwitterionic GO surface endows the membrane with high-efficiency water permeation. Using dehydration of water/alcohol mixture as the model system, the nanohybrid membranes incorporating PSBMA@GO exhibit much higher separation performance than the SA membrane and the nanohybrid membrane utilizing unmodified GO as filler (with the optimal permeation flux of 2140 g m(-2) h(-1), and separation factor of 1370). The study indicates the great application potential of zwitterionic graphene materials in dense water-permeation membranes and provides a facile approach to constructing efficient water transport pathway in membrane.

Novel Mixed Matrix Sodium Alginate–Fullerenol Membranes: Development, Characterization, and Study in Pervaporation Dehydration of Isopropanol

“…It was shown that rGO-filled (1.6 wt %) membranes exhibited improved separation factor (1566) and an unusual change in permeation flux (1.7 kg/(m 2 h)) in pervaporation dehydration of 90 wt % ethanol aqueous solution at 76 • C. In [48], graphene oxide quantum dots (GOQDs) were used as a modifier to develop a novel nanocomposite SA membrane for ethanol dehydration. The obtained nanocomposite membrane possessed improved permeation flux (2.4 kg/(m 2 h)), which was increased by 60% compared with the pristine SA membrane and 1152 separation factor in pervaporation dehydration of 90 wt % ethanol aqueous solution at 77 • C. The authors in [49] developed a SA membrane for efficient water permeation and water/alcohol separation by the incorporation of zwitterionic graphene oxides (PSBMA@GO) nanosheets into the polymer matrix. The MMMs with PSBMA@GO (2.5 wt %) exhibited much higher separation performance (2.1 kg/(m 2 h) permeation flux and 1370 separation factor in the pervaporation of 90 wt % ethanol aqueous solution at 77 • C) compared with membranes based on pure SA and on a composite with unmodified GO.…”

Polymeric Nanocomposite Membranes for Next Generation Pervaporation Process: Strategies, Challenges and Future Prospects

“…The membrane demonstrated a water permeability of 0.198 mg m −1 h −1 KPa −1 and a water-IPA molar selectivity of 6726 which was 35 times higher than that of the pristine- co -polyimide [ 180 ]. The Zwitterionic graphene oxide was incorporated into SA for efficient water-alcohol separation [ 181 ]. The GO surface was further modified with methylnicotinamide chloride (MNA) for oil-water separation [ 182 ] that improved the interaction between the nanosheets and the sulfonated polyphenylenesulfone (sPPSU) polymer.…”

Pervaporation dehydration of bio-fuel (n-butanol) by dry thermal treatment membrane

“…Graphene has received wide attention by the researchers' because of its derivative graphene oxide (GO). GO enhances the permeation factor of PEI polymer due to hydrophilic properties of the filler [22][23][24][25][26] like the presence of rich oxygen groups such as hydroxyl, carboxyl, carbonyl and epoxide groups. These rich oxygen groups exhibit polar properties [27,28].…”