To those uninitiated to the costs of thermal desalination of water, the idea of simply vaporizing water to take out the impurities seems like it would offer a limitless supply of fresh water just by using it on the world’s oceans. However, the energy costs for thermal desalination has been estimated at around 80 megawatt-hours per megaliter of water produced, rendering it too costly for just about everyone except Gulf States rich in oil and desperate for fresh water.
One way around these high-energy costs has been thought to be solar-powered thermal desalination, which can help produce clean water in remote areas and developing countries. However, the solar approach to water desalination is rather limited in the amount of fresh water it can produce and is further hampered by the need for optical concentrators and for thermal insulation, both of which have limited the large-scale use of this approach.
Now researchers at Nanjing University in China have developed a solar absorber material made from graphene oxide that enables a solar approach to desalinating water without the need for solar concentrators and thermal insulation. The result could be a low-cost, portable water desalination solution ideally suited for developing countries and remote areas.