Water security is a significant problem worldwide, and pulling it out of the atmosphere is becoming a potential solution. Water vapor is always around us in the air, even in dry conditions. Scientists from the National University of Singapore (NUS) have developed a ‘smart’ spongey aerogel that turns airborne water molecules into a drinkable liquid without needing an external power source or having any moving parts.
The aerogel is composed of long snake-like polymers combined with a metal-organic framework (MOF), porous structures with ultra-high surface areas, and highly valued in various research fields for its significant versatility. MOFs could potentially be used in anything from advanced batteries, devices that rapidly detect toxic gases, and alternative rocket fuels. In June 2020, Australian researchers found that the porous material could also absorb CO2 from the atmosphere. And now, we can add collecting freshwater from airborne vapor to that list too!
NUS’s hybrid material offers a chemical structure that continuously and simultaneously attracts and repels water. This means the aerogel can autonomously absorb water molecules from the air, condense them into a liquid form and then release it, similar to a sponge. However, it doesn’t need to be squeezed to release its collected substance like a sponge. While the aerogel doesn’t need sunlight to operate, it does boost its water-repelling abilities and enables it to turn 95% of the collected-vapor into liquid water.
In the laboratory, the NUS researchers demonstrated the material’s continuous operation for up to 1,440 hours, with the water it produced meeting the WHO’s standards for drinkable water. In humid conditions, the team found that 2.2 lb (1 kg) of the material can create as much as 4.5 gallons (17 liters) of water per day. However, the aerogel allegedly weighs almost nothing, so it might require a considerable amount of space to store a collector of that size.
While other scientists have previously developed similar technologies that turn air into drinkable water, NUS’s version is simpler and more promising. It doesn’t require electricity or sunlight to function and involves no moving parts. The NUS researchers are currently looking for commercial partners to advance the development of this water harvesting technology.
Prof. Ho Ghim Wei, who led the research team, concluded:
Given that atmospheric water is continuously replenished by the global hydrological cycle, our invention offers a promising solution for achieving sustainable freshwater production in a variety of climatic conditions, at a minimal energy cost.
The NUS team published their findings on October 16, 2020, in the journal Science Advances.
