2D Laminar Membranes for Selective Water and Ion Transport

Abstract

energy storage and conversion devices, [26][27][28] as outlined in recent reviews (Figure 1, left). [29] Behind these applications lie a fundamental question: how water and ion transport are controlled in the laminar structure to obtain desired selectivity. A comprehensive summary of structure-transport relation is thereby imperative to understand and optimize membrane selective performance, but is so far lacking. In such context, our review aims to fill this gap by discussing: 1) how 2D materials with specific physicochemical features are assembled into laminar membranes; 2) most importantly, how membrane structure, and its response to external impacts, can tune mass transport (herein, water and ions); 3) how these transport mechanisms translate into selectivity in applications, and into future design of high-performance laminar membranes. Unsolved problems and emerging challenges around these topics are then concluded. We note that the knowledge summarized here can also, at least partly, assist the understanding of the selective gas, liquid, and micromolecule transport through laminar membranes, which are gaining considerable attention as well. [30][31][32] Transition Metal Carbides and/or Nitrides (MXene): MXene nanosheets are etched and delaminated from parent bulk MAX to M n+1 X n T x (e.g., Ti 3 C 2 T x ), and have thus several atom sublayers. [39] While M and X are early transition metal

Ultrathin water-stable metal-organic framework membranes for ion separation

“…Nevertheless, most nanoporous membranes are usually thick at micrometer scale and are formed by discrete channels, hampering membrane permeability (9,10). Recently, two-dimensional (2D) materials, such as graphene oxide (GO), reduced GO, MoS 2 , etc., have recently emerged as building blocks for membrane synthesis (11)(12)(13). These 2D nanosheets have constructed a new class of membranes with an ultrathin thickness, in which the interlayer space between adjacent nanosheets acts as selective nanochannels for ion sieving (14).…”

Functionalizing graphene oxide framework membranes with sulfonic acid groups for superior aqueous mixture separation

“…S3 †), which may be caused by the presence of SSA in the filtrating mixture with the effect of regulating the stacking manner of the GO nanosheets. 29,30 A cross-sectional view of the GOF-SSA membrane is displayed in Fig. 2b, which reveals that the horizontally stacked nanosheets were compactly assembled onto the nylon substrate.…”

Ion Transport in Nanofluidic Devices for Energy Harvesting

“…58 Afterward, many different graphene-related membranes or graphene-composited membranes were explored to extract energy from salinity gradient. 8,59 A typical example of GOMs is reported by Guo and co-authors. 53 By coupling one pair of oppositely charged GOMs in a three-compartment electrochemical cell, they realized the output power density of 0.77 W/m 2 by mixing 0.5 M NaCl artificial seawater and 0.01 M NaCl river water, as well as a high series voltage up to 2.7 V by tandem GOM-NRED stacks.…”