Graphene oxide filter will turn sea water into drinking water

graphene oxide
A graphene membrane. courtesy: The University of Manchester

As the climate is changing and population is increasing, it reduces the modern city’s water supplies. Wealthy modern countries are investing on the projects which are working in the field of desalination technologies, because they know that 70% of our earth contains water and if we are able to filter it, then there will be no water crises at all. Graphene oxide membranes have attracted researchers for new filtration technologies and now they have succeeded of making membranes which can filter the common salt from the sea water. This research will provide clean drinking water for millions of people who struggle to access clean water sources.

Previously, Graphene oxide membranes developed at the National Graphene institute have filtered small nano-particles, organic molecules and even large salts. But it failed to filter the common salts because if graphene oxide immersed in the water, it become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.

The University of Manchester based group have further developed these membranes and found a way to avoid the inflammation of the membrane when exposed to water. The pore size in the membrane can be precisely controlled which can filter common salt out of salty sea water and make it safe to drink.

The common salt dissolved in the sea water, always form a ‘shell’ of water molecules around the salt molecules. This allows the graphene oxide membrane to block the salt from flowing along with the water.

Professor Rahul Nair, at The University of Manchester said: “Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology. This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene oxide based membranes with required sieve sizes.”

Mr. Jijo Abraham and Dr. Vasu Siddeswara Kalangi were the joint-lead authors on the research paper: “The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes.” said Mr. Abraham.

By 2025 the UN expects that 14% of the world’s population will encounter water scarcity. This technology has the potential to revolutionise water filtration across the world.


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