To harvest fresh water out of vapour in air, researchers take inspiration from spider webs, beetles
Ontario, Canada: A group of scientists is developing cutting-edge technology to capture water vapour in the air and turn it into liquid.
Professor Michael Tam of the University of Waterloo and his PhD pupils Yi Wang and Weinan Zhao have created sponges or membranes with a large surface area that continuously absorb moisture from their environment.
Fresh water is traditionally gathered from rivers, lakes, groundwater, and oceans (after treatment) for human consumption. Due to the severe problem of freshwater scarcity, Dr Tam is now researching technologies that are inspired by nature to capture water from alternate sources.
“A spider’s web is an engineering marvel,” said Tam, a University Research Chair in the field of functional colloids and sustainable nanomaterials. “Water is efficiently captured by the web. The spider doesn’t need to go to the river to drink, as it traps moisture from the air.”
Similarly, Namib desert beetles have no easy access to water but acquire water from thin air by leaning into the wind to capture droplets of water from the fog with their textured body armour. This allows the moisture to collect and drip into their mouths.
Tam and his research group are engaged in biomimetic surface engineering for sustainable water harvesting. One technology Tam is designing is called atmospheric water harvesting. To mimic the beetle’s unique surface structure, Tam’s research group is designing a similar surface structure using a cellulose-stabilized wax emulsion to fabricate surfaces that attract tiny water droplets while swiftly releasing larger ones.
Tam is working with net zero carbon materials, such as natural and plant-based materials, to develop sustainable technologies. His research group is developing technologies that capture and repel water droplets by harnessing the power of interfacial science and nanotechnology. He has successfully developed superhydrophobic and waterproof paper. He is also engineering a smart and tunable surface that captures water from the air and dehumidifies it with minimal energy consumption.
The next step is to develop a scalable process to engineer such surfaces.
Solar evaporation systems directly harvest solar energy, absorbing water and generating fresh collectible vapour through evaporation. Unique mushroom structures inspired the smart biomimetic structural designs for solar evaporation.
The proposed freshwater generation systems are inexpensive, energy-efficient, and environmentally friendly.
In a recent publication in Nature Water, Tam and his team discuss several promising new water collection and purification technologies.
