NUS scientists have developed a new zinc-based, water-absorbing hydrogel that harvest water directly from the humid air above water surfaces.
According to the scientists, the gel-like material is over eight times more absorbent than commercial drying agents.
Moreover, it requires only natural sunlight to harvest water from the water-saturated hydrogel.
“Due to the hot climate in Singapore, about 45 million cubic meters of water is lost from reservoirs through evaporation each year,” explains Assistant Professor Swee-Ching Tan.
“Our hydrogel can convert moisture present in humid air to water without the need for any external energy input.”
“By harnessing the moisture-rich air that is commonly found above water surfaces, we can collect water, which would otherwise be lost to the environment, for different uses.”
According to the scientists, conventional drying agents like silica gel and calcium chloride can only absorb small amounts of water.
Extracting water from these agents would require energy intensive processes and high temperatures.
NUS’ hydrogel on the other hand absorbs water more than four times its original weight.
According to the scientists, when used repeatedly over multiple absorption-desorption cycles within a day, the amount of water it collects can reach up to 14 times per kg of hydrogel used.
The novel hydrogel releases water at a relatively lower temperature of between 45 and 50 degrees Celsius, which can be achieved easily with the team’s setup.
Moreover, while most commercially available drying agents are only suitable for single use, the NUS-developed hydrogel maintains its absorption capability even after 1,000 absorption-desorption cycles.
Tan contends that their invention can be scaled up considerably to function as a floating water-capturing farm.
This approach could benefit rural communities where access to clean water remains a challenge, which in a way helps mitigate the global water crisis.
Image and content: National University of Singapore (NUS)