Graphene targets water treatment and carbon capture

Carbon filter

Now,Ho Bum Parkat Hanyang University in South Korea and colleagues have demonstrated that a membrane based on graphene and graphene oxide makes an effective filter to separate carbon dioxide from nitrogen gas. The researchers made their membranes by taking an existing porous polymer membrane and either dipping it in a solution of graphene and graphene oxide, or letting the solution drip onto it while it was spinning. By tailoring the exact fabrication method, the researchers could end up with several layers of graphene and graphene oxide that were either loosely or tightly locked together.

Park and colleagues discovered that if the membrane was well-interlocked, and if the gases to be separated had a high water content, the membrane would block the passage of nitrogen but allow through carbon dioxide. The humidity is what allows this separation, according to Park, because it fills the membrane with tiny drops of water through which carbon dioxide -but not nitrogen -could dissolve. The researchers believe this membrane could be used to capture carbon dioxide from certain industrial processes, such as coal burning, and thereby reduce greenhouse emissions.

In a separate development,Miao Yuat the University of South Carolina, US, and colleagues have created a graphene oxide membrane that can separate carbon dioxide from hydrogen, and hydrogen from nitrogen. The researchers believe that their membrane - which they created by vacuum-filtering a dispersion of graphene oxide through a porous support - could find applications in water treatment.

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