Solar Nanowire-Nanotube Filter May Help Make Drinking Water More Accessible

The World Health Organization reported that at least 1.8 billion people drink water contaminated with feces, and by 2040, a big part of the world will endure water stress due to insufficient resources of drinking water.

As specified in a Tech Xplore report, even at present, clean water is a privilege for many people all over the world.

The United Nations Children's Fund or UNICEF, on the other hand, approximately 1,800 children are dying from diarrhea due to unsafe water supply, which leads to diseases like cholera.

It has turned imperative then that efficient and cost-efficient ways to decontaminate water are developed. This is exactly what a team of researchers led by Laszlo Forro at EPFL has accomplished, with a new water purification filter, combining titanium dioxide, TiO2 nanowires, and carbon nanotubes powered by nothing else but sunlight.

TiO2 Nanowires

Initially, the scientists showed that the TiO2 nanowires by themselves can effectively purify water in the existence of sunlight. Nevertheless, interweaving the nanowires with carbon nanotubes is forming a composite material that's adding an extra layer of decontamination through the pasteurization of water, killing off human pathogens like bacteria and massive viruses.

The idea is that when ultraviolet or UV light, from the visible spectrum of sunlight, is hitting the filter, causing it generates a group of molecules known as Reactive Oxygen Species or ROS. Such molecules include hydrogen peroxide or H202, Oxygen or O2-, and Hydrogen or OH are known to be effective pathogen killers.

Testing the Device with E. Coli

The scientists tested their device with E. Coli bacteria, the so-called "gold-standard" for bacterial survival research, although it should work with other microbial pathogens like Campylobacter jejuni, a common diarrhea-inducing pathogen in the developed nation, Giardia lamblia, a bacterium that's causing the intestinal infection giardiasis, Salmonella, the Cryptosporidium that causes diarrheal cryptosporidiosis, the hepatitis A virus, and Legionella pneumophila that's causing Legionnaire's disease.

The device is remarkably adept when it comes to eliminating all the pathogens from the water and exhibits promising results even prior to the elimination of micropollutants like pesticides, drug residues, and cosmetics, among others, as specified in a similar Inceptive Mind report.

Forro explained, that in close collaboration between biologists, physicists, and chemists, they have developed a very efficient device intended for water purification, which does not require any energy source except sunlight.

The lead researcher added, that their prototype can supply clean drinking water even in remote places to small populations and could be scaled up so easily.

A Great Achievement in Science

It is quite an achievement and an essential side-product of this work is that it has enticed a huge number of talented and motivated students who are concerned about environmental issues for sustainability.

In their research published in the Nature journal partner npj Clean Water, the study authors exhibited a prototype of the filter and made recommendations for further improvements.

The project's lead scientist Endre Horvath said he is convinced that it will create a robust follow-up in versatile scientific communities and hopefully, funding agencies.

Related information about nanotubes boosting solar energy is shown on Seeker's YouTube video below:

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