Scientists Have Invented a Graphene-Based Sieve That Turns Seawater Into Drinking Water

Coal and Related Carbon Resources / Lignite, Graphite, Graphene, & Carbon Uses

Date posted: 04/04/17

Fiona MacDonald reports that researchers in the UK have achieved a major turning point in the quest for efficient desalination by announcing the invention of a graphene-oxide membrane that sieves salt out of seawater. There are already several major desalination plants around the world using polymer-based membranes to filter out salt, but the process is still largely inefficient and expensive, so finding a way to make it quicker, cheaper, and easier is a huge goal for researchers. Thanks to climate change, seawater is something there will plenty of in the future, Greenland coastal ice caps which have already passed the point of no return are predicted to increase sea levels by around 3.8 cm (1.5 inches) by 2100, and if the entire Greenland Ice Sheet melts, future generations will be facing oceans up to 7.3 meters (24 feet) higher. But at the same time, clean drinking water is still incredibly hard to come by in many parts of the world. The UN predicts that by 2025, 14% of the world population will encounter water scarcity. And many of those countries will not be able to afford large-scale desalination plants. The researchers are now hoping that the graphene-based sieve might be as effective as large plants on the small scale, so it would be easier to roll out. Graphene oxide is also a lot easier and cheaper to make in the lab than single-layers of graphene, which means the technology will be affordable and easy to produce. The selective separation of water molecules from ions by physical restriction of interlayer spacing opens the door to the synthesis of inexpensive membranes for desalination, Ram Devanathan from the Pacific Northwest National Laboratory, who was not involved in the UK research, wrote in an accompanying Nature News and Views article. The ultimate goal is to create a filtration device that will produce potable water from seawater or wastewater with minimal energy input.