Abstract: Characterization of disinfection process using quaternary ammonium salts grafted cellulose fiber was carried out with E.coli as a model bacteria. A rapid adsorption of E.coli. on the grafted fiber was identified, as indicated by the dramatic reduction of the concentration of viable cells in the suspensions. The adsorption as function of the fiber input indicates the dominating role of the electrostatic interaction between the fiber and E.coli. cell surface. The determination of oxygen uptake rate (OUR) was introduced to characterize the growth of E.coli. on the fiber surface. The adsorption of E.coli. on the fiber surface was observed with scanning electron microscope(SEM), which showed the lysis of cell envelope along with the processing. The results obtained in the present study show that the disinfection process is composed by two steps, in which the first step, i.e., the adsorption of E.coli. on the fiber surface driven by electrostatic interaction, is a fast reaction. While cell lysis, the second step, is a relatively slow reaction. The present study also shows the potential of OUR and SEM as fundamental tools in the development of antibacterial materials.

Key words: Surface contact disinfectant, Quaternary ammonium salts(QAS), E. Coli, Oxygen uptake rate