Macroscopic Salt Rejection through Electrostatically Gated Nanoporous Graphene

Wyss, Roman M.; Tian, Tian; Yazda, Khadija; Park, Hyung Gyu; Shih, Chih‐Jen

doi:10.1021/acs.nanolett.9b02579

Cited by 23 publications

(15 citation statements)

References 42 publications

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“…Nanoporous graphene supported on PET shows an ion rectification effect due to the presence of conical nanopores as a result of asymmetric etching [64][65][66][67][68]. Applying an external potential and gating the graphene the ion selectivity can even be tuned [69].…”

Section: Ion Transport Through Graphene Nanoporesmentioning

confidence: 99%

Graphene Nanopores

Löthman¹

2021

Nanopores

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Graphene is a two-dimensional, atomic thin, usually impermeable nanomaterial with astonishing electrical, magnetic and mechanical properties and can therefore at its own right be found in applications as sensors, energy storage or reinforcement in composite materials. By introducing nanoscale pores graphene alter and extend its properties beyond permeability. Graphene then resembles a nanoporous sensor, a nanoporous, atomic thin membrane which opens up for such varied applications such as water purification, industrial waste water treatment, mineral recovery, analytical chemistry separation, molecular size exclusion and supramolecular separations. Due to its nanoscopic size it can serve as nanofilters for ion separation even at ultralow nano- or picomolar concentrations. It is an obvious choice for DNA translocation, reading of the sequence of nucleotides in a DNA molecule, and other single molecular analyses as well for biomedical nanoscopic devices since dimensions of conventional membranes does not suffice in those applications. Even though graphene nanopores are known to be unstable against filling by carbon adatoms they can be stabilized by dangling bond bridging via impurity or foreign atoms resulting in a robust nanoporous material. Finally, graphene’s already exceptional electronic properties, its charge carriers exhibit an unusual high mobility and ballistic transport even at 300 K, can be made even more favorable by the presence of nanopores; the semimetallic graphene turns into a semiconductor. In the pores, semiconductor bands with an energy gap of one electron volt coexist with localized states. This may enable applications such as nanoscopic transistors.

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Section: Ion Transport Through Graphene Nanoporesmentioning

confidence: 99%

Graphene Nanopores

Löthman¹

2021

Nanopores

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“…The gating effect may allow more tailorable and efficient molecular sieving through vertical nanochannels. [139][140][141] Although the tunable physicochemical properties of 2D materials offer opportunities to exploit all these effects fully, different types of organic solvents usually complicate such an investigation. Unlike separation in water, where water is the only solvent of interest, organic solvent separation can involve a multitude of solvents with very different properties.…”

Section: Mechanisms Of Molecular Transport and Sieving Capacitymentioning

confidence: 99%

“…The gating effect may allow more tailorable and efficient molecular sieving through vertical nanochannels. [ 139–141 ]…”

Section: Challenges and Outlookmentioning

confidence: 99%

2D Material Based Advanced Membranes for Separations in Organic Solvents

Sui

Yuan

et al. 2020

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2D materials have shown high potentials for fabricating next‐generation membranes. To date, extensive studies have focused on the applications of 2D material membranes in gas and aqueous media. Recently, compelling opportunities emerge for 2D material membranes in separation applications in organic solvents because of their unique properties, such as ultrathin mono‐ to few‐layers, outstanding chemical resistance toward organic solvents. Hence, this review aims to provide a timely overview of the current state‐of‐the‐art of 2D material membranes focusing on their applications in organic solvent separations. 2D material membranes fabricated using graphene materials and a few representative nongraphene‐based 2D materials, including covalent organic frameworks and MXenes, are summarized. The key membrane design strategies and their effects on separation performances in organic solvents are also examined. Last, several perspectives are provided in terms of the critical challenges for 2D material membranes, including standardization of membrane performance evaluation, improving understandings of separation mechanisms, managing the trade‐off of permeability and selectivity, issues related to application versatility, long‐term stability, and fabrication scalability. This review will provide a useful guide for researchers in creating novel 2D material membranes for advancing new separation techniques in organic solvents.

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“…Even a very weak ozone etching creates 3.8 Å size pores in graphene and allows to pass Na + and Cl − ions electrodynamically. Still, it is not yet known how electrodynamics overcomes dehydration energy and passes ions, but according to a recent report by Wyss and Tian et al, the applied electric field interacts with the passing ions by adjusting the Coulomb capacity of graphene [41]. These reports provide hints on how difficult it is to fabricate nanometer-sized pores in graphene, obtain sufficient information about its size, and apply it to ion separation or selective ion permeation.…”

Section: Ion Transport Through Graphene Nanoporesmentioning

confidence: 99%

Architecture and mass transport properties of graphene-based membranes

2020

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A recently rising question of the applicability of two-dimensional (2D) materials to membranes of enhanced performance in water technology is drawing attention increasingly. At the center of the attention lies graphene, an atom-thick 2D material, for its readiness and manufacturability. This review presents an overview of recent research activities focused on the fundamental mass transport phenomena of two feasible membrane architectures from graphene. If one could perforate pores in a pristine impermeable graphene sheet with dimensional accuracy, the perforated 2D orifice would show unrivaled permeation of gases and liquids due to the 0D atomic barrier. If possibly endowed with selectivity, the porous graphene orifice would avail potentially for membrane separation processes. For example, it is noteworthy that results of molecular dynamics simulations and several early experiments have exhibited the potential use of the ultrathin permeable graphene layer having sub-nanometer-sized pores for a water desalination membrane. The other membrane design is obtainable by random stacking of moderately oxidized graphene platelets. This lamellar architecture suggests the possibility of water treatment and desalination membranes because of subnanometric interlayer spacing between two adjacent graphene sheets. The unique structure and mass transport phenomena could enlist these graphene membrane architectures as extraordinary membrane material effective to various applications of membrane technology including water treatment. Graphic abstract

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Macroscopic Salt Rejection through Electrostatically Gated Nanoporous Graphene

Cited by 23 publications

References 42 publications

Graphene Nanopores

Graphene Nanopores

2D Material Based Advanced Membranes for Separations in Organic Solvents

Architecture and mass transport properties of graphene-based membranes

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