The foam can be made into huge sheets at a low cost.
Using graphene oxide sheets, engineers at Washington University have figured out a novel way to turn dirty water into drinkable water.
Detailing their paper in the journal Advanced Materials, the new approach combines graphene oxide with bacteria-produced cellulose to form a bi-layered biofoam.
“The process is extremely simple,” Srikanth Singamaneni, associate professor of mechanical engineering and materials science, said in a press release.
“The beauty is that the nanoscale cellulose fiber network produced by bacteria has excellent ability to move the water from the bulk to the evaporative surface while minimizing the heat coming down, and the entire thing is produced in one shot.”
Basically, the cellulose at the bottom of the biofoam acts like a sponge and draws water up to the graphene oxide. Then, rapid evaporation occurs, and the clean water can be collected from the top of the sheet.
Interestingly, the process in which the biofoam is formed works in the same way an oyster makes a pearl — bacteria forms layers of nanocellulose fibers, and then the graphene oxide flakes become embedded in the fibers.
Another benefit of the biofoam is that it’s extremely light and inexpensive to make.
“Cellulose can be produced on a massive scale,” Singamaneni says, “and graphene oxide is extremely cheap—people can produce tons, truly tons, of it. Both materials going into this are highly scalable. So one can imagine making huge sheets of the biofoam.”
According to the researchers, the properties of the synthesized foam material have characteristics that enhance solar energy harvesting, rendering it more effective at destroying the bacteria and contaminants in the water.
“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,” Singamaneni notes.
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