New biomass hydrogel technology extracts drinkable water from the air

Forward-looking: Researchers at the University of Texas at Austin have developed a novel method using natural materials to extract drinkable water from the air. Their “molecularly functionalized biomass hydrogels” system transforms organic matter – such as food scraps, branches, and seashells – into a highly efficient water-absorbing substance.

The system combines specially engineered sorbents (materials that absorb liquids) with mild heat and can generate significant amounts of potable water, even in arid conditions. During field tests, the team demonstrated an impressive yield of 14.19 liters (3.75 gallons) of clean water per day per kilogram of sorbent – far surpassing the typical 1 to 5 liters achieved by most existing sorbents.

“This opens up an entirely new way to think about sustainable water collection, marking a big step towards practical water harvesting systems for households and small community scale,” said Professor Guihua Yu, who led the research team.

The innovation lies in the team’s approach to designing sorbents. Instead of selecting specific materials for specific functions, their general molecular strategy enables the conversion of almost any biomass into an efficient water harvester. This method offers several advantages over traditional synthetic sorbents, including biodegradability, scalability, and minimal energy requirements for water release.

The heart of this technology is a two-step molecular engineering process that imbues biomass-based polysaccharides with hygroscopic and thermoresponsive properties. It allows the system to effectively capture and release water from the air using commonly available natural materials.

This water-generating system is part of Professor Yu’s ongoing efforts to tackle global clean water access issues. His previous work includes developing hydrogel technologies for hyper-arid conditions and an injectable water filtration system.

Looking ahead, the research team is working on scaling up production and developing real-world applications for commercialization. Potential uses include portable water harvesters, self-sustaining irrigation systems, and emergency drinking water devices.

Graduate researcher Yaxuan Zhao notes that since they can fabricate this hydrogel from widely available biomass and design it to operate with minimal energy input, it has strong potential for large-scale production and deployment in off-grid communities, emergency relief efforts, and decentralized water systems.

While scalability appears promising, the researchers will likely encounter challenges in developing a solution that remains efficient and practical outside the lab. For instance, maintaining the high efficiency observed in lab conditions – 14.19 liters of water per kilogram of sorbent daily – could be problematic when scaling up to larger systems, as environmental factors may impact performance.

Additionally, rainwater harvesting systems in urban areas require regular infrastructure maintenance and upgrades. For example, in Indian cities like Chennai and Hyderabad, neglect of rainwater harvesting systems has led to their deterioration and reduced effectiveness.