Seawater to Drinking Water

A UK based team of researchers has devised a graphene based sieve capable of removing salt from seawater. This is the type of thing that could help millions around the world get access to clean drinking water.

It has up to this point been difficult to produce graphene based barriers on an industrial  scale. Scientists from the University of Manchester have shown they have solved some of the challenges by using a graphene oxide.

This graphene is characterized as single layer of carbon atoms arranged in a hexagonal lattice. It has extraordinary tensile strength and electrical conductivity.

Current methods of production can be difficult and costly. The new method of production means graphene oxide can be produced in the lab by simple oxidation. Now they can make this single layer of graphene , the challenge becomes making this layer permeable. Hole sizes can not be bigger than one nanometre or the salts go through. Graphene oxide membranes have proven successful in sieving out small nano particles, organic molecules ,and even large salts. However up until now they could not be used to filter out common salts as the holes required were to small. Previous study has shown the graphene swells when placed in water, allowing smaller salts to flow through. Now by placing an epoxy resin on either side of the graphene sheet, the expansion is stopped.

Water molecules can pass through individually, but sodium chloride can not. In fact the speed of water passing through is quite fast, therefore it is ideal for desalinization.

By 2025 the UN expects 14% of the world’s population will be facing water scarcity. Products like this are going to be required. the science of this product has now been proven, questions of durability still need to be answered.

The ultimate goal is to be able to produce potable water from seawater or waste water with minimal energy input.

 

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