For much of the world facing water shortages, a beacon of hope may be on the horizon: the ability to easily turn hot air into drinking water. For the past few years, researchers at the University of Texas at Austin have focused on moisture in the air as a potential source of drinking water for residents in drought-stricken areas. In new research published in the Proceedings of the National Academy of Sciences, they have achieved a major breakthrough in their efforts to create drinking water from thin air: a molecularly engineered hydrogel can create clean water using only the energy of sunlight.
Researchers at the University of Texas have created a hydrogel that uses sunlight to create drinkable water from the air. The technology creates highly efficient microgels that could potentially provide an economical, portable solution to global water shortages. The picture above shows a water sample collected using gel. Source: University of Texas at Austin
Producing water using solar energy
Researchers were able to use solar energy to extract water from the atmosphere and make it drinkable at temperatures as low as 40 degrees Celsius, which coincides with summer weather in Texas and other parts of the world. This means that, one day, people in places with excessive heat and little access to clean water can simply place a device outside and it will produce water for them with no extra effort.
"With our new hydrogel, we're not just pulling water out of thin air. We're doing it very quickly and without using much energy," said Guihua Yu, professor of materials science and engineering in the Cockrell School of Engineering's Walker Department of Mechanical Engineering and the Texas Materials Research Institute. "What's really attractive about our hydrogel is how it releases water. Think of a hot Texas summer -- we can take advantage of the natural rise and fall in temperatures without having to turn on a heater."
Depending on humidity conditions, the device can produce 3.5 to 7 kilograms of water per kilogram of gel material.
An important feature of this research is that the hydrogel can accommodate microscopic particles called "microgels." These microgels could increase speed and efficiency, bringing such devices closer to reality. By converting hydrogels into tiny particles, ultrafast water capture and release can be achieved. This provides a new, highly efficient adsorbent that can significantly increase water production through multiple cycles per day.
Researchers are making more improvements to the technology in hopes of turning it into a commercial product. One area of focus is optimizing the engineering design of the microgels to further increase efficiency.
Scaling up is an important next step. The researchers aim to translate their findings into a practical, scalable solution that can be used globally as a low-cost, portable method of producing clean drinking water. This could be life-changing in countries such as Ethiopia, where nearly 60% of the population lacks access to basic clean drinking water.
"Our ultimate goal in developing this device is to make it accessible to people around the world who need quick and continuous access to clean drinking water, especially in arid areas," said Zhao Yaxuan, a graduate student in the laboratory.
The team is working on other versions of the device made from organic materials, which would make mass production cheaper. In the transition to more commercially viable designs, there are also challenges in scaling up moisture absorber production and maintaining durability over the life of the product. The focus of the research also includes how to make the device portable and suitable for various application scenarios.
This project is funded by the Welch Foundation's Norman Hackerman Award in Chemical Research and the Camille Dreyfus Teacher-Scholar Award.