Inactivation of Escherichia coli on immobilized TiO 2 using fluorescent light
Abstract
There are many circumstances where it is necessary or desirable to remove or to kill microorganisms found on surfaces. In this paper, we present evidence of the photocatalytic inactivation of Escherichia coli (ATCC8739) cells deposited on TiO 2 loaded membrane filters during irradiation with fluorescent light. The TiO 2 selected was the photocatalyst PC105, with loadings ranging from 520 to 15,590 mg m ‑2. Irradiation was produced by eight 8 W lamps with visible light, and UV (290–400 nm) at 0.05–0.12 W m ‑2 intensity. E. coli inactivation as a function of time was monitored for up to 120 min. In the presence of fluorescent light, the inactivation rate of E. coli increased with a decrease in the TiO 2 loading, giving the best results at 520 mg m ‑2 loading, with complete inactivation achieved after 2 h of exposure. TiO 2 loading higher than 6236 mg m ‑2 resulted in decreased inactivation. SEM images of photocatalyst and bacteria show that increasing the particle contact with the bacteria enhanced the disinfection process. Thus excess TiO 2 did not enhance the antibacterial effect, once maximum cell–photocatalyst contact had been achieved.
- Publication:
-
Journal of Photochemistry and Photobiology A: Chemistry
- Pub Date:
- January 2009
- DOI:
- 10.1016/j.jphotochem.2008.11.005
- Bibcode:
- 2009JPPA..202...92C
- Keywords:
-
- Photocatalysis;
- TiO <SUB loc="post">2</SUB>;
- UV inactivation;
- E. coli;
- Fluorescent light