In an environment as parched as the desert, a superabsorbent hydrogel developed by scientists has demonstrated an impressive capacity to draw vast amounts of water from the atmosphere. This could potentially resolve the long-standing issue of unequal water resource distribution.
As environmental conditions shift and climate change intensifies, the strain on global water and energy resources is escalating. According to UNICEF, almost two-thirds of the world’s population endure extreme water scarcity for a minimum of one month each year.
While searching for innovative moisture-capturing materials, the team at MIT zeroed in on “hygroscopic hydrogels”. These are hydrogels capable of collecting atmospheric humidity. Though beneficial in a variety of environmental situations, the hydrogels must achieve high efficiency, low cost, sustainability, and scalability to be commercially viable.
The hydrogel recently developed by the Massachusetts Institute of Technology exhibits a greatly enhanced capacity for absorbing water vapour, even in desert conditions. This was achieved by introducing the salt “lithium chloride” to the hydrogel. Capable of absorbing over ten times its mass in water, lithium chloride is secured by the hydrogel.
According to the study’s lead author, Gustav Graeber, this approach synergistically combines the best features of both components: the hydrogel’s ability to store large amounts of water and the salt’s ability to trap vast amounts of water vapour.
To test the impact of varying concentrations, the research team infused the hydrogel disk with lithium chloride salt solution of different concentrations, weighing it daily to monitor the amount of salt incorporated. After a 30-day immersion period, the researchers found that the hydrogel had absorbed 24 grams of salt per gram.
The team also evaluated the new hydrogel under various humidity conditions, discovering that it could absorb water without leakage at humidity levels of 30%, 50%, and 70%. Even in environments with humidity lower than 30%—similar to desert nights—the hydrogel was able to draw 1.79 grams of water per gram of material, a 15% increase over previously tested hydrogels. This can then be heated and condensed to collect pure water.
Given the significant temperature fluctuations in desert climates—ranging from scorching heat to sub-zero cold—the team pointed out that a material capable of generating water in such conditions would be highly valuable. The researchers’ forthcoming challenge lies in accelerating the water absorption process.