An Indian origin scientist and his team of researchers from Washington University in St. Louis have developed a material that can filter out dirt in water with "Veritable wonder material" graphene oxide sheets, using sunlight without any battery.
The graphene oxide sheet is a good conductor of heat and electricity that can work wonders to treat dirty and contaminated water, said Srikanth Singamaneni, one of the team of researchers. “We hope that for countries where there is ample sunlight, such as India, you’ll be able to take some dirty water, evaporate it using our material, and collect fresh water.”
The team has developed a graphene-based biofoam sheet that can be laid on dirty and salted water and left to the sunlight. Once it is exposed to heat from the sunlight, the bacteria-produced cellulose and graphene oxide form a bi-layered biofoam to convert filthy water into drinkable.
Giving credit to the novel design, he said, “You have a bi-layered structure with light-absorbing graphene oxide filled nanocellulose at the top and pristine nanocellulose at the bottom. When you suspend this entire thing on water, the water is actually able to reach the top surface where evaporation happens,” Singamaneni said.
The sunlight on top of it produces heat because of the graphene oxide, but the heat dissipation to the bulk water underneath is minimized by the nanocellulose layer, without wasting the heat. Here the researchers have confined the heat to the top layer where the evaporation actually happens, explained Srikanth.
The cellulose below the bioform acts as a sponge and then evaporates at the top most layer leaving behind suspended residue or salts. The fresh water condenses on the top layer and it can be drawn off for drinking.