Stop disinfectants: a green material removes almost all the bacteria in the water, making it drinkable for 4 people in just one hour. The experiment, conducted by researchers from the University of Technology Sydney (Australia), opens the door to more eco-friendly water purification methods.
Stop disinfectants: a green material removes almost all of the bacteria in the water, obtaining a quantity drinking enough for 4 people in just one hour. The experiment, conducted by researchers from the University of Technology Sydney (Australia), opens the door to much more eco-friendly water purification methods.
This new material is a thin photocatalyst layer based on carbon and nitrogen, that is, it releases electrons when illuminated, generating chemicals that can kill microbes. It is not a substance that occurs in nature, because it has been modified by scientists with suitable chemical groups containing oxygen (ketones and acids), in order to carry out the disinfecting action in the light.
A not very new mechanism, that of using light to purify water: to cite an example, a study by the Johns Hopkins University School of Medicine found that adding lime juice to water and exposing it to sunlight can effectively purify it. Some other methods use metals that filter out toxic substances. Others are not metallic, but are less efficient because they do not release electrons very easily.
The method of the University of Technology Sydney is instead particularly innovative because the chemical groups linked to the initial layer are able to "attract" the electrons towards the edges (with a mechanism that in chemistry is called inductive, due to the strong electronegativity oxygen, which tends to attract electrons to itself).
The experiment really has killed almost 100% of the bacteria contained in a 50-milliliter water sample, including E. coli, and did so much faster than in the past. The "classic" non-metallic photocatalysts, in fact, which take more than an hour to achieve what this material did in 30 minutes.
"Our goal was to develop an efficient way of using sunlight to produce water in less advanced or remote areas of the world without a central supply of clean water - explains Guoxiu Wang, who led the research - since the composition of carbon and nitrogen should make the material inexpensive ”.
In fact, millions of people around the world consume water from unsafe sources every day. A 2016 Unicef report specifically reported how 663 million inhabitants of the planet draw water from unhealthy sources and about 2,4 billion (four out of ten inhabitants) live in hygienic conditions incompatible with safety and health.
Will this technology solve the problem? It's still too early to tell and has currently only been tested in the lab, but the researchers intend to work with engineers to make the design suitable for commercial use. We will have news in the future, hopefully not too far away.
The work was published in Chem.
Read also:
- Drink potable water thanks to the energy of the sun
- PureMadi and MadiDrops, natural filters from the earth to purify water in thirsty countries
Roberta de carolis
