New Technology Turns a Sunny Day into Safe Water


clean water, photocatalyst		clean water, photocatalyst
More than 2 billion people worldwide live without access to safe, clean water. As the problem is exacerbated by climate change, scientists have come up with a new solution using sunlight, a plentiful resource. Manolo Guijarro/Getty Images

Clean water. It's something most of us take for granted. We turn on a faucet and don't give a second thought that the water coming out of it for cooking, cleaning and drinking is pure and safe. For many around the world, however, this can be a risky assumption. The supply of healthy water can't keep up with the demands of increasing populations, as well as the effects of climate change. But scientists are developing a technology that can help address this crisis using something we do have plenty of: sunlight.

The United Nations says more than 2 billion people are without ready access to safe, clean water for drinking and for sanitation — a basic human right declared by the U.N. General Assembly in 2010. And 1 million people die each year from diseases related to unsafe water and hygiene. Add to this the dual demands of more agriculture and more energy that more people create, as well as the changing weather patterns that are increasingly common, and the pressures for a safe and stable water supply only continue to increase.

This is why the findings of researchers in the scientific journal Chem, published Feb. 7, 2019, are so important, and so exciting. Using a photocatalyst — a material that chemically changes in the presence of light — of graphitic carbon nitride (g-C3N4) in very thin sheets, scientists have quickly eliminated nearly 100 percent of disease-causing bacteria, including E. coli, in tests conducted on 2.64 gallons (10 liters) of water. That's enough drinking water for four people for one day.

Similar to the way a magnet can attract metal, these sheets attract electrons that then form compounds with the oxygen present, such as hydrogen peroxide, to rid the water of harmful bacteria. While using a photocatalyst and sunlight to purify water is not new, previous methods required metals that left behind their own pollutants, or took much longer to complete the process.

Ramping up production for large-scale purification is still in development, but this method is encouraging as an additional means of securing safe water for a growing population. It's time to see the future of clean water in a whole new light.