In many parts, global access to clean water is a major challenge. Often the way drinking water is purified is simply by boiling the water. Scientists have found a new method of solar-based water purification that is much more effective in reducing pollutants than boiling 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 more than 100% efficiency. The method uses femtosecond laser pulses that etch the surface of a regular sheet of aluminum onto a super absorbent and super energy absorbent material. When the aluminum plate is placed in water at an angle facing the sun, the surface draws a thin layer of water upward onto the metal surface.
The material can retain almost 100% of the energy it absorbs from the sun to quickly heat water. Simultaneously, it can change the intermolecular bonds of water, significantly increasing the efficiency of the evaporation process. Scientists say that using sunlight to boil water has long been a recognized way to kill microbial pathogens and reduce deaths from diarrheal infections. However, boiling water does not remove heavy metals and other contaminants.
Laboratory experiments showed that the new method reduces the presence of all common contaminants, such as detergents, dyes, urine, heavy metals, and glycerin, the safe levels to drink. The new process avoids the inefficiencies of other methods, and is easy to clean simply by spraying. The most significant advantage is that the panels can be continuously adjusted to face the sun to maximize energy absorption directly.
The project was supported by the constructor Melinda Gates Foundation, the National Science Foundation, and the US Army Research Office It is unclear when the process could go into commercial applications.
