Dangerous bacteria and toxic heavy metals can be removed from water by a filtration membrane developed by scientists from the Centre for Energy and Environmental Technologies (CEET) at the Technical University of Ostrava and the Czech Institute for Research and Advanced Technologies (CATRIN) at Palacký University in Olomouc. In addition, it eliminates combined pollution, which poses a serious environmental and health risk, in a single step, without the need for the energy source and chemicals normally used for water disinfection. The membranes can be easily recovered, making this technology a breakthrough solution for affordable and safe drinking water anywhere in the world.
The scientists focused on using commonly available and inexpensive filter membranes, on which they coated the Nobel Prize-winning carbon material graphene with chemical traps for heavy metals and bacteria. In developing the technology, they took inspiration from a process they recently used to develop atomic antibiotics. They presented the new technology to the scientific world in the prestigious journal Chem.
“We used graphene modified with carboxyl groups, which effectively trap heavy metals such as lead and cadmium. In the next layer of the membrane, we used a similar graphene material with manganese ions. These ions have a strong chemical binding to bacteria, which we have already demonstrated in our research on atomic antibiotics,” said the author of the concept, Radek Zbořil, who works at both CATRIN and CEET and runs one of the so-called living laboratories of the REFRESH project.
The filtration membranes developed by Czech scientists are able to operate even on a semi-operational scale, which enables their deployment in practice. “The technology achieves filtration efficiency of over 99.999 percent against a wide range of microorganisms in distilled, tap and river water. In addition, the membranes exhibit a high capacity for heavy metal capture, meeting stringent legislative limits. The whole process is very simple, which allows its use even in areas without access to electricity. The technology is cheap to maintain because the membranes can be easily and efficiently regenerated for reuse,” explained David Panacek, first author of the study, who is now at Imperial College of London.
With its simple design and affordable materials, the new technology appears to be a low-cost alternative to traditional water treatment methods that are complex and energy intensive. In addition, this approach represents a completely new concept in water filter disinfection. Current technologies such as ultrafiltration or nanofiltration rely on small pores in membranes to trap bacteria, but are very costly.
“In our technology, we do not address pore size, but rely on the chemical properties of manganese ions, which bind strongly to bacteria. This technology allows us to effectively remove even problematic strains such as Pseudomonas aeruginosa, known for its ability to form biofilms in pipes and filters. This has huge potential for improving water disinfection in hospitals or food processing plants,” added Milan Kolář from Palacký University’s Faculty of Medicine, who was involved in the research.
Heavy metals enter surface water from industrial production or mining, while bacteria often come from inadequately treated wastewater, agricultural activities and stormwater runoff. Traditional methods for removing these contaminants are technologically challenging and costly. Chemical processes such as ozonation or chlorination are used to remove bacteria, while heavy metals are removed by multi-step methods such as precipitation, flocculation, coagulation and others.
“Combining these demanding processes is technologically and economically very difficult. In developing countries, where there is a lack of funding and adequate infrastructure, combined heavy metal and bacterial pollution is one of the biggest problems in terms of clean water availability. The aim of the research was to simplify the complex water treatment process and develop a cheap technology that can remove both types of pollution in a single step, which has been achieved,” Zbořil added.
The technology could find applications in, for example, treating wastewater in industrial areas, providing drinking water in developing countries, or providing fast and effective solutions in crisis situations such as war or natural disasters where access to electricity is limited.
The research was supported by the REFRESH project of the Operational Programme Just Transformation.
Contact persons:
Radek Zbořil | author of the concept
radek.zboril@vsb.cz| M: 775 733 378
Martina Šaradínová | PR manager of the REFRESH project
martina.saradinova@vsb.cz | M: 705 698 288
Link to article: https://www.sciencedirect.com/science/article/pii/S2451929425003766?via%3Dihub
