Chemically Enhanced Sunlight for Killing Bacteria
| Autor: | D. W. Goswami, S. S. Block, V. P. Seng |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Aqueous solution
biology Renewable Energy Sustainability and the Environment business.industry Photodissociation technology industry and agriculture Energy Engineering and Power Technology chemistry.chemical_element Photochemistry medicine.disease_cause biology.organism_classification Catalysis chemistry.chemical_compound Optics chemistry Titanium dioxide medicine Water treatment business Ultraviolet Bacteria Titanium |
| Zdroj: | Journal of Solar Energy Engineering. 119:85-91 |
| ISSN: | 1528-8986 0199-6231 |
| Popis: | Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO{sub 2}) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that effect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was detected. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO{sub 2} does not affect the bacteria. However, several common bacteria were killed in just a few minutes on solar exposure in the presence of TiO{sub 2}. Whereas without TiO{sub 2} it took more than an hour to destroy them. A concentration of 0.01 percent TiO{sub 2} was most effective in killing bacteria and tenfold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. An alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO{sub 2} particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO{sub 2}.more » This suggests that TiO{sub 2} served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves shows that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn`t greatly increase the rate of the kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased.« less |
| Databáze: | OpenAIRE |
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