Researchers have developed a device that uses solar energy to create drinking water from seawater in an efficient manner.
Scientists from the University of Waterloo have created an innovative and energy-saving device that extracts drinking water from seawater, primarily using the process of solar-powered evaporation.
Desalination is crucial for various coastal and island countries facing shortages of fresh water, particularly as population growth and global water use are rising rapidly. According to the UN World Water Development Report 2024, approximately 2.2 billion individuals globally lack access to clean water, highlighting the urgent demand for new methods to produce fresh water.
Traditional desalination methods often involve forcing seawater through membranes to remove salt, but this approach requires a lot of energy. Additionally, salt tends to build up on the membrane surfaces, which limits water flow and decreases efficiency. Consequently, these systems need regular upkeep and cannot run continuously.
In response to this issue, the researchers at Waterloo looked to nature for solutions, designing a device that mimics the way trees move water from their roots to their leaves. This new technology allows for ongoing desalination without extensive maintenance requirements.
“We drew our inspiration from observing nature’s self-sustaining systems and how water evaporates and condenses naturally,” said Dr. Michael Tam, a professor at Waterloo’s Department of Chemical Engineering.
“Our engineered system encourages water evaporation, carries it to the top, and condenses it in a closed-loop process, effectively stopping salt from building up and maintaining device efficiency.”
This innovative device harnesses solar energy, converting about 93 percent of sunlight into usable energy—a fivefold improvement over existing desalination systems. It can also yield around 20 liters of fresh water per square meter, matching the daily amount recommended by the World Health Organization for basic drinking and hygiene needs.
The research team, including PhD students Eva Wang and Weinan Zhao, constructed the device using coated nickel foam embedded with a conductive polymer and thermoresponsive pollen particles. This design captures sunlight across a wide range of the solar spectrum, turning it into heat. A layer of saltwater on the polymer heats up and rises, mimicking how water is drawn through tree capillaries.
As water evaporates, the leftover salt settles at the bottom of the device, functioning like a backwash system in a swimming pool, preventing water blockage and ensuring uninterrupted operation.
Dr. Yuning Li, also from the Waterloo Department of Chemical Engineering, assisted the team in harnessing solar energy for the project by using a solar tester to evaluate the device’s light absorption capabilities.
“This new device is not only efficient but also portable, making it particularly suitable for remote areas with limited access to fresh water,” Li stated. “This technology provides a sustainable approach to the growing water crisis.”
Moving forward, the researchers at Waterloo aim to construct a prototype that can be tested on the sea to evaluate its performance at a larger scale.
“If the results are successful, this technology could sustainably deliver fresh water to coastal communities and support multiple UN Sustainable Development Goals, including those related to health, water access, poverty reduction, and responsible consumption,” Tam noted.
