If you’ve heard about graphene, you’ve probably heard about all its wonderful claims but you are unlikely to have heard about any practical uses for the material. How about graphene as a ‘selective membrane for filtration and nano-pore sensing’?

It’s just a fancy colander. We use one in our daily lives to separate one thing from another – keep the pasta in the colander and drain the water away. This is what we are essentially trying to do with graphene, take a mixture and put it through our colander to filter out certain things. The advantage here being that graphene is only one atom thick and the holes in the material are incredibly small.

So what’re we trying to filter through this thin, flexible and invisible material? The ultimate aim is to filter out the salt from sea water, this would allow us to achieve desalination turning sea water into safe drinking water. We’re not quite there yet though, for now we are trying to learn more about graphene as a filter by separating parts of salt from water. In order to do this we are having to tweak some parameters – thickness, material coating and hole size.

Drawing parallels with a colander once more, changing the hole size will dictate what you can keep separate from the water – too large and the pasta will fall through, too small and the filtering takes a long time. Similarly, the thickness will affect how sturdy the filter is and finally the coating will affect if things stick to the material – think Teflon in your frying pan. Tuning these parameters whilst keeping our membrane as thin as possible would open up many possibilities from desalination to making the holes large enough to allow us to detect and measure DNA and other
molecules. It is certainly a challenge but we hope that, one day, we can get it just right.

Mustafa Calgar

NanoDTC  PhD Associate 2017

Read more: keyserlab.org / muscaglar.com