Adsorption and growth inhibition of bacteria on carbon materials containing zinc oxide Original Research Article

An ion-exchange resin with particle size of 0.5 mm was treated for 24 h by either an aqueous solution of [Zn(NH3)4]2+ complex or 29% aqueous ammonia. The resins treated were carbonized for 10 min in nitrogen gas at 500, 700 and 1000°C to prepare carbons with and without ZnO. The adsorption and the growth inhibition of bacteria on their carbon samples were studied. The adsorbed amount of bacteria on samples without ZnO increased with the increase of carbonization temperature and the amount of carbon powder. The adsorbed amount of Staphylococcus aureus was smaller than that of Escherichia coli. However, it was found that all bacteria in the suspension were adsorbed onto the samples containing ZnO, irrespective of the carbonization temperature and the amount of carbon powder. The antibacterial activity on the carbon samples containing ZnO increased with the increase of the amount of ZnO in samples and decreased with the increase of carbonization temperature. The antibacterial activity for Staphylococcus aureus was found to be stronger than that for Escherichia coli. No activity of the carbon samples without ZnO was observed. The occurrence of antibacterial activity was supposed to be due to the generation of hydrogen peroxide from ZnO in carbon samples.