New Technology Combines Sun and Sea to Make Clean Water

Water is essential to all life as we know it. Even on a planet like Earth that is covered in water, as many as 780 million people lack access to it. For too many people, this can be a life or death situation. More lack access to proper sanitation and, as a consequence, more children, under the age of five, die every year from diarrheal diseases than malaria, TB, and HIV/AIDS combined. Scientists have been looking for years at ways to turn salt water to clean, fresh, potable water. Now, they may have found a way to use a new thin carbon material to do just this. This water can then be put into water tanks with potable water tank linings to make it available to those who need it.

Scientists have been able to talk about one square meter of the material and lay it out on seawater to generate about 1.45 liters of fresh, clean, potable water in 60 minutes. This is according to research that was published recently in the publication, Proceedings of the National Academy of Science. This means that a film of this size can put out enough water to supply an entire family with the water they need to stay healthy. Experts say that people should aim for drinking 1.2 liters of clean water each day.

The research into this technology has been done primarily at Nanjing University in China. Scientists there took graphene, which takes sheets comprised of carbon atoms that are arranged in a honeycomb pattern. This pattern allows the material to absorb light from the sun. When spread out over seawater, it is able to convert more than 94% of the energy from the rays of the sun to produce a water vapor from the heat from that energy. The temperature of the material can go from 13 degree Celsius (55.5 degrees Fahrenheit) to 32 degrees Celsius (89.6 degrees Fahrenheit) in under 60 seconds.

In the past, scientists have tried to use graphene to desalinate water but the process was never efficient enough to make sense to try on a larger scale. One issue they faced was a problem with heat retention. The heat from the sun would dissipate immediately when it contacted the cold ocean water. This problem was taken care of by Professor Zhu Jia, who headed up the effort. Using a protective plastic foam layer, the team was able to help the graphene hold on to the heat.

The new apparatus using tubes to transport the water to the graphene. When the evaporation and heat join forces the cold water up. This process can be used to generate large amounts of water that can be stored in tanks with potable water tank linings or other containment products.

These apparatuses are foldable, lightweight, and easy for people who are settling a new area, camping, and can be used to mass produce clean potable water. It is easy to use in containers with potable water tank linings.

This material has been tested by scientists using water with differing levels of salinity. They went to different areas to check. The Red Sea and the North Sea are examples of their testing areas. After testing the graphene in these different areas, they discovered that they could see the production of water vapor for long periods of time with no decrease in the performance level. There was some salt that settled on the surface but that was taken away by the ebbing of the water.

While there has been no price tag attached to the new technology using this graphene, work is being conducted to make this technology available at a low cost. More research is going to be undertaken to see how it would work outside of the laboratory and how it can withstand harsh conditions such as harsh winds and rain.

While potable water may currently be more scarce than people would like, this technology may make it possible to take saltwater and make it into potable water that can be stored and moved in tanks with potable water tank lining. Adding this water to units with tank liners for water systems can bring needed water to people who need it.

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