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Water Desalination Using Graphene Possible - Motivation For Chemical Engineers?

Question asked by Ankita Katdare in #Coffee Room on Jul 2, 2012
Ankita Katdare
Ankita Katdare · Jul 2, 2012
Rank A1 - PRO
With fresh water resources exhausting and seawater desalination being vey expensive, new ways had to be found. And MIT researchers are just at it. They have figured out that sheets of graphene perforated with precisely sized holes can be used in desalination systems for a lot less expense than the current methods. Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering in MIT’s Department of Materials Science and Engineering along with the graduate student David Cohen-Tanugi added other elements to the material to cause the edges of these holes to chemically interact with water molecules. So, either they repel them or attract them. They found out that methods like chemical etching and self-assembling systems are suitable to make precise holes in graphene.

[​IMG]
When water molecules (red and white) and sodium and chlorine ions (green and purple) in saltwater, on the right, encounter a sheet of graphene (pale blue, center) perforated by holes of the right size, the water passes through (left side), but the sodium and chlorine of the salt are blocked.Graphic: David Cohen-Tanugi

For those of you know about 'reverse osmosis' - the process that uses membranes to filter the salt from the water, must have read that it requires extremely high pressure and thus great energy usage. But, graphene, the wonder material, which is a lot thinner can operate at much lower pressure and can fetch us fresh water at a very lower cost. And though manufacturing of the very precise pore structures is going to be difficult on a large scale, the predictions about graphene are exciting enough to motivate chemical engineers to perform more detailed analyses of water desalination with these types of materials.

Here's a video that explains the new process -

<iframe src="https://www.youtube.com/embed/k5Tjy_90WBU" frameborder="0" width="640" height="360"></iframe>
<div>You may check the paper describing the new process in the journal <em>Nano Letters by </em>MIT.</div>
<div></div> Posted in: #Coffee Room

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