Crystals that extract water from the air with unprecedented efficiency

Scientists have created a new crystalline material that can extract water from the air without requiring any energy input to function. The efficiency achieved in this way is unprecedented.

The achievement is the work of an international team including, among others, Linfeng Lan, from Jilin University in the Chinese city of Changchun, and Pance Naumov, from New York University in Abu Dhabi, United Arab Emirates. The latter is a university established in the United Arab Emirates by the New York University of the United States.

The Earth’s atmosphere contains a colossal amount of untapped fresh water that is waiting to be collected, provided there is a viable way to extract that moisture from the air and retain and concentrate the resulting water.

The design of the new type of smart crystals, which the researchers named Janus crystals, is inspired by desert plants and animals, which can survive in extreme arid conditions. Desert beetles and lizards, for example, have evolved to develop surface structures on their bodies that have hydrophilic zones and hydrophobic zones and effectively capture moisture from the air. Water is attracted to the hydrophilic zones and droplets accumulate and transport through the hydrophobic zones.

The researchers chose three chemically versatile organic compounds from which they grew elastic organic crystals. They then tested how each of these materials interacted with airborne water, which led to the creation of the new class of water-capturing materials, Janus crystals, which contain hydrophilic and other hydrophobic regions at the surface, some to capture the water and the others to transfer it to a receptacle for collection.

A moment of the research and development work of the new crystals. (Photo: NYU Abu Dhabi)

Desalination is a widely used method to produce drinking water when there are no fresh water sources nearby. However, in addition to requiring the proximity of a sea or salt lake, a process with high energy consumption is necessary to separate the salt dissolved in the salt water. On the other hand, the atmospheric humidity condensation process used by Janus crystals is spontaneous under the normal environmental conditions of each location and can be carried out without energy input, and without the need for liquid water, potentially providing an inexhaustible source of clean water.

Lan, Naumov and their colleagues present the technical details of their new system for extracting water from the air in the academic journal Journal of the American Chemical Society, under the title “Efficient Aerial Water Harvesting with Self-Sensing Dynamic Janus Crystals.” (Fountain: NCYT by Amazings)