Graphene oxide membranes show exceptional molecular permeation properties, with promise for many applications1,2,3,4,5. 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 salts4,6. The cutoff is determined by the interlayer spacing (d) of ∼13.5 Å, typical for graphene oxide laminates that swell in water2,4. 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.
This is a preview of subscription content
Subscribe to Nature+
Get immediate online access to the entire Nature family of 50+ journals
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Nair, R. R., Wu, H. A., Jayaram, P. N., Grigorieva, I. V. & Geim, A. K. Unimpeded permeation of water through helium-leak-tight graphene-based membranes. Science 335, 442–444 (2012).
Sun, P. Z., Wang, K. L. & Zhu, H. W. Recent developments in graphene-based membranes: structure, mass-transport mechanism and potential applications. Adv. Mater. 28, 2287–2310 (2016).
Liu, G. P., Jin, W. Q. & Xu, N. P. Graphene-based membranes. Chem. Soc. Rev. 44, 5016–5030 (2015).
Joshi, R. K. et al. Precise and ultrafast molecular sieving through graphene oxide membranes. Science 343, 752–754 (2014).
Akbari, A. et al. Large-area graphene-based nanofiltration membranes by shear alignment of discotic nematic liquid crystals of graphene oxide. Nat. Commun. 7, 10891 (2016).
Tansel, B. Significance of thermodynamic and physical characteristics on permeation of ions during membrane separation: hydrated radius, hydration free energy and viscous effects. Sep. Purif. Technol. 86, 119–126 (2012).
O'Hern, S. C. et al. Selective ionic transport through tunable subnanometer pores in single-layer graphene membranes. Nano Lett. 14, 1234–1241 (2014).
Rollings, R. C., Kuan, A. T. & Golovchenko, J. A. Ion selectivity of graphene nanopores. Nat. Commun. 7, 11408 (2016).
Jain, T. et al. Heterogeneous sub-continuum ionic transport in statistically isolated graphene nanopores. Nat. Nanotech. 10, 1053–1057 (2015).
Surwade, S. P. et al. Water desalination using nanoporous single-layer graphene. Nat. Nanotech. 10, 459–464 (2015).
Cohen-Tanugi, D. & Grossman, J. C. Water desalination across nanoporous graphene. Nano Lett. 12, 3602–3608 (2012).
Wang, L. D. et al. Molecular valves for controlling gas phase transport made from discrete ångström-sized pores in graphene. Nat. Nanotech. 10, 785–790 (2015).
Werber, J. R., Osuji, C. O. & Elimelech, M. Materials for next-generation desalination and water purification membranes. Nat. Rev. Mater. 1, 16018 (2016).
Sahu, S., Ventra, M. D. & Zwolak, M. Dehydration as a universal mechanism for ion selectivity in graphene and other atomically thin pores. Preprint at http://arXiv.org/abs/1605.03134 (2016).
Richards, L. A., Schafer, A. I., Richards, B. S. & Corry, B. The importance of dehydration in determining ion transport in narrow pores. Small 8, 1701–1709 (2012).
Thomas, M., Corry, B. & Hilder, T. A. What have we learnt about the mechanisms of rapid water transport, ion rejection and selectivity in nanopores from molecular simulation? Small 10, 1453–1465 (2014).
Song, C. & Corry, B. Intrinsic ion selectivity of narrow hydrophobic pores. J. Phys. Chem. B 113, 7642–7649 (2009).
Williams, C. D. & Carbone, P. Selective removal of technetium from water using graphene oxide membranes. Environ. Sci. Technol. 50, 3875–3881 (2016).
Feng, J. et al. Observation of ionic Coulomb blockade in nanopores. Nat. Mater. 15, 850–855 (2016).
Cohen-Tanugi, D., McGovern, R. K., Dave, S. H., Lienhard, J. H. & Grossman, J. C. Quantifying the potential of ultra-permeable membranes for water desalination. Energy Environ. Sci. 7, 1134–1141 (2014).
Deshmukh, A., Yip, N. Y., Lin, S. H. & Elimelech, M. Desalination by forward osmosis: identifying performance limiting parameters through module-scale modeling. J. Membr. Sci. 491, 159–167 (2015).
Das, R., Ali, M. E., Abd Hamid, S. B., Ramakrishna, S. & Chowdhury, Z. Z. Carbon nanotube membranes for water purification: a bright future in water desalination. Desalination 336, 97–109 (2014).
Dreyer, D. R., Park, S., Bielawski, C. W. & Ruoff, R. S. The chemistry of graphene oxide. Chem. Soc. Rev. 39, 228–240 (2010).
Wilson, N. R. et al. Graphene oxide: structural analysis and application as a highly transparent support for electron microscopy. ACS Nano 3, 2547–2556 (2009).
Loh, K. P., Bao, Q., Eda, G. & Chhowalla, M. Graphene oxide as a chemically tunable platform for optical applications. Nat. Chem. 2, 1015–1024 (2010).
Liu, H. Y., Wang, H. T. & Zhang, X. W. Facile fabrication of freestanding ultrathin reduced graphene oxide membranes for water purification. Adv. Mater. 27, 249–254 (2015).
Sun, P. Z. et al. Highly efficient quasi-static water desalination using monolayer graphene oxide/titania hybrid laminates. NPG Asia Mater. 7, e162 (2015).
Hu, M. & Mi, B. X. Enabling graphene oxide nanosheets as water separation membranes. Environ. Sci. Technol. 47, 3715–3723 (2013).
Hung, W. S. et al. Cross-linking with diamine monomers to prepare composite graphene oxide-framework membranes with varying d-spacing. Chem. Mater. 26, 2983–2990 (2014).
Zhang, Y., Zhang, S. & Chung, T. S. Nanometric graphene oxide framework membranes with enhanced heavy metal removal via nanofiltration. Environ. Sci. Technol. 49, 10235–10242 (2015).
Greenspan, L. Humidity fixed-points of binary saturated aqueous-solutions. J. Res. Natl Bur. Stand. Sect. A 81, 89–96 (1977).
Rezania, B., Severin, N., Talyzin, A. V. & Rabe, J. P. Hydration of bilayered graphene oxide. Nano Lett. 14, 3993–3998 (2014).
Radha, B. et al. Molecular transport through capillaries made with atomic-scale precision. Nature 538, 222–225 (2016).
Tissandier, M. D. et al. The proton's absolute aqueous enthalpy and Gibbs free energy of solvation from cluster ion solvation data. J. Phys. Chem. A 102, 7787–7794 (1998).
Chekli, L . et al. A comprehensive review of hybrid forward osmosis systems: performance, applications and future prospects. J. Membr. Sci. 497, 430–449 (2016).
Rockland, L. B. Saturated salt solutions for static control of relative humidity between 5° and 40° C. Anal. Chem. 32, 1375–1376 (1960).
This work was supported by the Royal Society and the Engineering and Physical Sciences Research Council, UK (EP/K016946/1 and EP/M506436/1). K.G. acknowledges Marie Curie International Incoming Fellowship. K.S.V. and R.R.N. acknowledge support from BGT Materials Limited.
The authors declare no competing financial interests.
About this article
Cite this article
Abraham, J., Vasu, K., Williams, C. et al. Tunable sieving of ions using graphene oxide membranes. Nature Nanotech 12, 546–550 (2017). https://doi.org/10.1038/nnano.2017.21
Effects of channel size, wall wettability, and electric field strength on ion removal from water in nanochannels
Scientific Reports (2022)
Nature Reviews Physics (2022)
Random interstratification in hydrated graphene oxide membranes and implications for seawater desalination
Nature Nanotechnology (2022)
Nature Materials (2022)
Nature Communications (2022)