Disinfection of textile materials contaminated with E. coli in liquid carbon dioxide

A new environmental friendly way to disinfect textile materials in liquid carbon dioxide is presented and discussed. As contaminated material, E. coli on cotton fabric is used. Pure liquid carbon dioxide at 20 °C and 70 bar has a slightly disinfecting effect, which is caused by the carbonic acid formed in the presence of the natural moisture content of cotton and in carbon dioxide. On the other side, E. coli can be completely destroyed by wetting the textile with water prior to the treatment in liquid CO2. The same effect is attainable by adding 5 vol.% 2-propanol or Triclosan. Comparative studies in water at 20 °C with 2-propanol and Triclosan demonstrate that generally in liquid carbon dioxide lower concentrations of disinfecting agents are needed. In water the best results are obtained by using 1 vol.% peracetic acid.