The new wood-based filter has, in laboratory studies, good bacterial retentive properties meaning that it can produce purified water of a low microbial cell count. The filter has been developed by technologists from the KTH Royal Institute of Technology.
The filter has been manufactured from wood cellulose, in the form of antibacterial fibers, together with a positively-charged polymer. This is created by the wood fibers being dunked into a polymer solution. The positive charge functions to trap bacteria (which are negatively charged) from samples of water passed through the matrix. Once attached the natural antibacterial properties of the wood kill the bound organisms. The polymer can trap bacteria in the order of several thousands. Once trapped, the bacteria, including harmful pathogens, become trapped to the material surface.
The filter was developed by Professor Monica Ek and her team. One of the team members, Anna Ottenhall discussed the project further: “The great idea is that we are trapping the bacteria and removing them from the water by our positively-charged filter. The bacteria trapping material does not leach any toxic chemicals into the water, as many other on-site purification methods do.”
A key advantage with the filter, in relation to bacterial removal and bacterial kill, is that the organisms cannot become resistant to the material (unlike the case with antimicrobial drug substances). Once used the filter can be disposed of in a relatively ‘green’ way by burning. The material contains no toxic substances.
It is hoped the filter can be used in places where there is no infrastructure or clean water supply. The bacterial trapping principles behind the filter could also be used for medical aids, such as bandages and plasters.
The KTH Royal Institute of Technology who developed the filter are experimenting with other wood-based technologies. These include transparent wood; batteries made from wood that can be squished; and a polystyrene alternative made from wood
