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Title: Ion sieving and desalination: Energy penalty for excess baggage

Here, more than a billion people do not have access to clean water globally and millions of people die every year from water borne diseases. Human activity has resulted in depletion of groundwater, seawater intrusion in coastal aquifers, pollution of water resources, ecological damage, and resultant threats to the world’s freshwater, food supply, security, and prosperity. To address this challenge, there is a pressing need to produce clean water from seawater, brackish groundwater, and waste water. Current desalination methods are energy intensive and produce adverse environmental impact. At the same time, energy production consumes large quantities of water and creates waste water that needs to be treated with further energy input. Water treatment with membranes that separate water molecules from ions, pathogens and pollutants has been proposed as an energy-efficient solution to the fresh water crisis. Recently, membranes based on carbon nanotubes, graphene and graphene oxide (GO) have garnered considerable interest for their potential in desalination. Of these, GO membranes hold the promise of inexpensive production on a large scale but swell when immersed in water. The swollen membrane allows not only water molecules but also ions, such as Na + and Mg 2+, to pass through. Abraham and coworkersmore » show that the interlayer spacing in a GO laminar membrane can be tuned to a certain value and then fixed by physically restraining the membrane from swelling. When the authors reduced the spacing systematically in steps from 9.8 Å to 7.4 Å, the ion permeation rate was reduced by two orders of magnitude while the water permeation rate was only halved.« less
Authors:
 [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Report Number(s):
PNNL-SA-124040
Journal ID: ISSN 1748-3387
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Nature Nanotechnology
Additional Journal Information:
Journal Volume: 12; Journal Issue: 6; Journal ID: ISSN 1748-3387
Publisher:
Nature Publishing Group
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE; graphene oxide; desalination; membrane
OSTI Identifier:
1363990