Researchers at the University of Texas at Austin say they’ve created a device that can generate clean and safe drinking water using just sunlight and a cheap gel.
Published in Nature Nanotechnology, the system uses combined gel-polymer hybrid materials known as hydrogels to purify water. With solar-absorbing and hydrophilic properties, meaning they are attracted to water, the team says this can produce clean water from any source – even the Dead Sea.
“We have essentially rewritten the entire approach to conventional solar water evaporation,” said team leader Guihua Yu, one of the study’s co-authors, in a statement.
The solar vapor generator developed by the team uses the Sun’s energy to power the evaporation of water. It sits on the top of a container of contaminated water, and when placed in sunlight, released vapor is stored. By using nanostructured gels, the team says their method of desalination is cheaper than others as it can run on natural sunlight.
To test out their technology, the team used water samples from the Dead Sea, which is rich in salt. They said it passed “with flying colors.” They were able to reduce the levels of salt to meet acceptable drinking standards outlined by the World Health Organization (WHO).
“Our outdoor tests showed daily distilled water production up to 25 liters per square meter, enough for household needs and even disaster areas,” added Yu.
“Better still, the hydrogels can easily be retrofitted to replace the core components in most existing solar desalination systems, thereby eliminating the need for a complete overhaul of desalination systems already in use.”
According to the United Nations, more people die every year from drinking unsafe water than they do in war. By 2050, they note that one in four people could have limited access to fresh water, so finding solutions is key. At the moment that number is about one in nine.
The researchers hope that their method can be commercialized, and bring clean water to more corners of the globe as natural supplies lessen. While there are other solutions, they can be expensive and complex. This one seems to be particularly simple and cheap.
“Solar energy, as the most sustainable heat source to potentially power distillation, is widely considered to be a great alternative for water desalination,” said Fei Zhao, the study’s lead author.