Water filter from wood cellulose offers portable, eco-friendly purification

Clean water is, unfortunately, not guaranteed for anyone. In some countries, people have to make due with polluted water or travel long distances to find clean water. Water purification methods can be expensive or leave traces of harmful chemicals behind. Researchers from the KTH Royal Institute in Sweden, the makers of transparent wood, have developed a bacteria-trapping material from wood cellulose, which kills bacteria without releasing toxins.

The filter combines the wood cellulose with a positively charged polymer, trapping bacteria by attracting and binding them to the material surface. The positively-charged polymer attracts bacteria and viruses which are negatively charged. The bacteria are then stuck to the surface and cannot break free or reproduce, ultimately dying.

The aim of the project is proving a portable filtering system that does not need electricity. The bacteria are trapped only using gravity as the water runs through the filter, and no toxic chemicals are leached into the water.

A major advantage of the treating method is that bacteria cannot develop any resistance to the positively charged polymers, unlike many disinfectants. After use, the filter can safely be burned.

Aside from being a water filter, which is currently being tested, the material shows promise for bandages, plasters, and packaging that kills bacteria.

Photos: KTH Royal Institute of Technology (via