Projects per year
Abstract
Graphene oxide membranes show exceptional molecular permeation properties, with promise for many applications. However, their use in ion sieving and desalination technologies is limited by a permeation cutoff of ∼9 Å (ref. 4), which is larger than the diameters of hydrated ions of common salts. The cutoff is determined by the interlayer spacing (d) of ∼13.5 Å, typical for graphene oxide laminates that swell in water. Achieving smaller d for the laminates immersed in water has proved to be a challenge. Here, we describe how to control d by physical confinement and achieve accurate and tunable ion sieving. Membranes with d from ∼9.8 Å to 6.4 Å are demonstrated, providing a sieve size smaller than the diameters of hydrated ions. In this regime, ion permeation is found to be thermally activated with energy barriers of ∼10–100 kJ mol–1 depending on d. Importantly, permeation rates decrease exponentially with decreasing sieve size but water transport is weakly affected (by a factor of <2). The latter is attributed to a low barrier for the entry of water molecules and large slip lengths inside graphene capillaries. Building on these findings, we demonstrate a simple scalable method to obtain graphene-based membranes with limited swelling, which exhibit 97% rejection for NaCl.
Original language | English |
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Pages (from-to) | 546-550 |
Journal | Nature Nanotechnology |
Volume | 12 |
DOIs | |
Publication status | Published - 3 Apr 2017 |
Research Beacons, Institutes and Platforms
- National Graphene Institute
Fingerprint
Dive into the research topics of 'Tunable Sieving of Ions Using Graphene Oxide Membranes'. Together they form a unique fingerprint.Projects
- 1 Finished
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Graphene-based membranes
Budd, P., Carbone, P., Casiraghi, C., Grieve, B., Haigh, S., Holmes, S., Jivkov, A., Kinloch, I., Raveendran Nair, R., Schroeder, S., Siperstein, F. & Vijayaraghavan, A.
1/07/13 → 30/06/18
Project: Research
Press/Media
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SKY NEWS: Scientists create graphene 'sieve' to turn seawater into drinking water
4/04/17
1 item of Media coverage
Press/Media: Research
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