Article abstract


Nature Nanotechnology 5, 297 - 301 (2010)
Published online: 21 March 2010 | Corrected online: 3 July 2013 | doi:10.1038/nnano.2010.34



There is a Corrigendum (August 2013) associated with this Article.

Subject terms: Nanofluidics | Nanosensors and other devices

Direct seawater desalination by ion concentration polarization

Sung Jae Kim1, Sung Hee Ko2, Kwan Hyoung Kang2 & Jongyoon Han1,3


A shortage of fresh water is one of the acute challenges facing the world today. An energy-efficient approach to converting sea water into fresh water could be of substantial benefit, but current desalination methods require high power consumption and operating costs or large-scale infrastructures, which make them difficult to implement in resource-limited settings or in disaster scenarios. Here, we report a process for converting sea water (salinity ~500 mM or ~30,000 mg l−1) to fresh water (salinity <10 mM or <600 mg l−1) in which a continuous stream of sea water is divided into desalted and concentrated streams by ion concentration polarization, a phenomenon that occurs when an ion current is passed through ion-selective membranes. During operation, both salts and larger particles (cells, viruses and microorganisms) are pushed away from the membrane (a nanochannel or nanoporous membrane), which significantly reduces the possibility of membrane fouling and salt accumulation, thus avoiding two problems that plague other membrane filtration methods. To implement this approach, a simple microfluidic device was fabricated and shown to be capable of continuous desalination of sea water (~99% salt rejection at 50% recovery rate) at a power consumption of less than 3.5 Wh l−1, which is comparable to current state-of-the-art systems. Rather than competing with larger desalination plants, the method could be used to make small- or medium-scale systems, with the possibility of battery-powered operation.

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  1. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
  2. Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyojadong, Gyeongbuk, 790-784, Korea
  3. Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

Correspondence to: Jongyoon Han1,3 e-mail: jyhan@mit.edu

* In this Article, we measured the electrical current necessary to run the desalination process (Supplementary Information Fig. 3) and reported that the power efficiency of the method was around 3.5 Wh l−1. We have subsequently been unable to reproduce this power efficiency and now believe that our electrical current measurements were wrong. The efficiency of our device is likely to be significantly worse than originally stated. This is because the device has long channels running from the reservoirs to the ion concentration polarization (ICP) zone, and although only a minimal amount of power is required to move ions around the ICP zone, these channels consume a considerable amount of power. Therefore, Supplementary Information Fig. 3, the quoted power efficiency of the device and our discussion surrounding this value in the original paper are not valid. This error does not affect the other results in the Article, and in particular our conclusion that ICP can be used to desalinate sea water.

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