Texas researchers turn food scraps into machine that pulls water from air

Researchers at the University of Texas at Austin have developed a new class of hydrogels from natural biomass that can capture moisture from the air and release it as clean water using mild heat. The study, published in the peer-reviewed journal Advanced Materials by Weixin Guan, Yaxuan Zhao, Chuxin Lei, Yuyang Wang, Kai Wu and Guihua Yu, describes a molecular engineering strategy that converts polysaccharides such as cellulose, starch and chitosan into water-absorbing materials.

The cellulose-based hydrogel produced up to 14.19 kg of water per kg of sorbent per day in outdoor tests using electrical heating. Conventional sorbents typically yield 1, 5 litres per kg per day, according to the university. The material captured 0.86, 1.32 grams of water per gram at 15, 30% relative humidity and released 95% of it at 60°C. The approach aims to enable portable water harvesters and decentralised systems in areas without conventional water infrastructure, using inexpensive and renewable feedstocks like food scraps, branches and seashells.