In many parts, the world access to clean water is a significant challenge. Often the way that water is purified for drinking is by simply boiling the water. Scientists have found a new solar-based water purification method that is much more effective at reducing contaminants than boiling the water alone. The new method comes from researchers at the University of Rochester and uses sunlight.
The team says that sunlight is a resource that anyone can access and can be used to evaporate and purify contaminated water with greater than 100% efficiency. The method uses femtosecond laser pulses that etch the surface of a regular sheet of aluminum into a super wicking, super energy absorbing material. When the aluminum plate is placed in water at an angle facing the sun, the surface draws a thin layer of water upwards over the metal surface.
The material can retain nearly 100% of the energy it absorbs from the sun to quickly heat the water. Simultaneously it’s able to change the intermolecular bonds of the water, significantly increasing the efficiency of the evaporation process. The scientists say using sunlight to boil the water has long been a recognized way to eliminate microbial pathogens and reduce deaths from diarrheal infections. However, boiling water doesn’t remove heavy metals and other contaminants.
Lab experiments showed that the new method reduces the presence of all common contaminants such as detergent, dyes, urine, heavy metals, and glycerin the safe levels for drinking. The new process avoids the inefficiencies of other methods, and it’s straightforward to clean by simply spraying it. The most significant advantage is the panels can be continuously adjusted to face the sun to maximize energy absorption directly.
The project was supported by the builder Melinda Gates Foundation, the National Science Foundation, and the US Army Research Office. It’s unclear when the process might go into commercial applications.