A new device uses sunlight to turn dirty water into drinking water
March 22 has been chosen by the United Nations as World Water Day - a day for people to look back at the importance of the most precious resource on Earth. Water is a resource that occupies about three-fourths of the Earth's surface, but only about 2.5% of that is clean water that can be used. Many scientists have devised various solutions to help create clean drinking water.
Researchers at the University of Texas, USA are developing an equipment capable of producing clean drinking water from most polluted water or seawater, even from the Dead Sea. A solar-powered system combined with hydrogel-absorbing light to purify water by distillation - Science Alert reported on April 6.
Distillation and desalination techniques are commonly used in soft drink production. However, existing distillation technologies such as multi-stage distillation and multi-effects distillation are costly, because they consume a lot of energy and require modern infrastructure.
The new technology uses only solar energy to volatilize water and remove impurities.
According to Fei Zhao, a member of the research team, the new technology uses only solar energy to evaporate water and remove impurities. This method is way simpler and more cost-saving.
"Water desalination through distillation is a common method for mass production of freshwater. However, current distillation technologies, such as multi-stage flash and multi-effect distillation, require significant infrastructures and are quite energy-intensive," said Zhao. "Solar energy, as the most sustainable heat source to potentially power distillation, is widely considered to be a great alternative for water desalination."
Solar water filters are made from hydrogel material with light absorbing properties. The nanostructure of the hydrogel helps make more use of the sun's energy without optical devices that concentrate the light, thereby accelerating the evaporation. Afterwards, the steam is handled, condensed into clean water and placed in a container.
The team tested the water samples from the Dead Sea with salinity of about 34% (10 times the salinity of conventional seawater). Water after filtration meets the drinking water standards of the World Health Organization and the United States Environmental Protection Agency (EPA).
It is estimated that about one-ninth of the world's population now lives in poor conditions withy no safe drinking water sources near their homes. This solar energy filter opens up the opportunity to save tens of thousands of people each year as a result of using polluted water.
The study was published in the journal Nature Nanotechnology. Scientists say that more time is needed to be able to apply new technology in real life.
By: Lily Haney