Water is essential to life and amazingly abundant, yet incredibly, less than 3 percent of Earth’s water is drinkable. Even much of that freshwater is bound up in glaciers and ice caps. Water insecurity is a deep-seated, growing problem. However, at Washington University in St. Louis, a team of engineers have come up with a material that may make clean water much more accessible and abundant.
The team’s new device is a biofoam sheet made from two layers: a top layer of graphene oxide and a bottom layer of nanocellulose produced by bacteria. This sheet is lightweight enough to float on top of water. The bottom layer of cellulose acts like a sponge, pulling water up onto the top of the sheet, where the graphene oxide layer collects heat from the sun. Graphene is a material with tremendous thermal conductivity, and it acts to concentrate the solar energy into heat on the upper layer of the biofoam sheet.
This heat evaporates the water on top of the sheet, while the nanocellulose lower layer insulates the body of water from the heat, keeping the heat concentrated where it needs to be instead of dissipating throughout the body of water. As the dirty water evaporates, it leaves dirt and other contaminants behind, and it can then be collected as clean, pure drinkable water.
In addition to using this innovative new material to clean dirty water, scientists are exploring other possible uses, such as desalination to reclaim drinkable water from the oceans. Adding other nanostructured materials to the matrix may allow the sheets to remove other types of contaminants, increasing the supply of potable water worldwide.
If you’re interested in more ways in which people can help to solve environmental problems, see how urban parks are providing crucial environmental benefits to their communities.Whizzco