A new solar powered technology absorbs moisture from the air and returns it as clean water.
University of Texas engineers used hydrogels, gel-polymer hybrid materials that act as “super sponges” and release water when heated.
Fei Zhao, co-author of the technique, said: “We have developed a completely passive system where all you need to do is leave the hydrogel outside and it will collect water.
“The collected water will remain stored in the hydrogel until you expose it to sunlight. After about five minutes under natural sunlight, the water releases.”
The hydrogel is composed of hygroscopic polypyrrole chloride and enabled by the molecular level integration of hygroscopic and hydrophilicity?switchable polymers.
But the fundamental design principle to prepare materials that can convert the water vapour in the air to collectible liquid water is still mostly unknown, the research team said in their paper, published in Advanced Materials.
The team built on a previous iteration of their solar-powered water purification system, unveiled last year, which lacked the ability to harvest water from the air.
Yu and his team have filed a patent for their new version of the technology, which works in dry and humid weather conditions and avoids intensive energy consumption.
The system can produce enough water to meet the daily needs of an average household – prototype tests showed daily water production of up to 50 litres, per 1 kilogram of hydrogel.
The method has potential in small, portable and inexpensive filtration systems for poverty-stricken areas, disaster situations or developing nations with restricted access to clean drinking water.
Globally, at least 2 billion people use a contaminated drinking water source, according to the UN, Contaminated drinking water is estimated to cause 502,000 diarrhoeal deaths each year.