January 27, 2012
Researchers Use Graphene To Distill Vodka
According to a new study, membranes based on the material graphene can be used to distill alcohol.
The researchers wrote in the journal Science that they created the membrane from graphene oxide, which is a chemical derivative of graphene.
A University of Manchester academics won the Noble Prize in Physics in 2010 by demonstrating the variety of properties Graphene has.
Graphene oxide is the same graphene sheet, but is randomly covered with other molecules like hydroxyl groups OH. Graphene oxide sheets stack on top of each other and form a laminate.
The laminates the team used in the study are hundreds of times thinner than a human hair, but still are strong, flexible and easy to handle.
When the team sealed off a metal container with the laminate, they said even the most sensitive equipment was unable to detect air or any other gas, including helium.
They found that when water was placed in the container, it evaporated at a normal rate, as if the graphene-oxide membranes were not even there.
The team said the water molecules diffused through the graphene-oxide membranes so quickly that the evaporation rate was the same independently whether the container was sealed or completely open.
"Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules," Dr Rahul Nair, who was leading the experimental work, said in a press release.
"They arrange themselves in one molecule thick sheets of ice which slide along the graphene surface with practically no friction. If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules."
He said that helium gas is hard to stop, but it was unable to penetrated the ultra-thin films the team placed on the metal container.
"At the same time, water evaporates through them unimpeded. Materials cannot behave any stranger," Professor Sir Andre Geim, the leader of the team, said in a press release. "You cannot help wondering what else graphene has in store for us".
The team said that this material could be used in situations where someone needs to remove water from a mixture or a container, while keeping all the other ingredients in.
The researchers also sealed off the container with the graphene oxide laminate while it was filled with vodka.
"Just for a laugh, we sealed a bottle of vodka with our membranes and found that the distilled solution became stronger and stronger with time. Neither of us drinks vodka but it was great fun to do the experiment", adds Dr Nair.
They say they do not envision a use of graphene in distilleries, nor do they see any immediate ideas for applications.
However, Geim said "The properties are so unusual that it is hard to imagine that they cannot find some use in the design of filtration, separation or barrier membranes and for selective removal of water."
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