| 1038 Effect of Domestic Water-Purifiers on Fluoridated Water | ||
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T. TANAKA, T. SATO, and K. YAEGAKI, Nippon Dental University, Tokyo, Japan Objective: Activated carbon filters and hollow fiber film filters are used as domestic water purifiers. Further fluoride ion (F-) supplements were suggested, as F- absorption by the filters was reported. Therefore F- adsorption by the filters was examined in this research with determining F- concentrations in both water and filters. Material and Methods: A water purifier equipped with the activated carbon filters, the hollow fiber film filters (PF-CB-S and KIF227, Organo, Tokyo) and water pump (MDG-M2S100N, Iwaki, Tokyo) was developed to standardize the conditions of the experiments. The sample solutions were made of the mixture of distilled water or tap water with NaF at various F- concentrations (0.1-10 mg/L). Each solution was examined at before and after each filter. The solution was passed through the filters at constant flow rate. F- concentration was determined with using F- electrode. Also, F- concentrations absorbed into the filters were determined with both phyrohydrolysis method and flow-injection analysis. Results: F- adsorption was not found in the hollow fiber film filter at any F- concentration. When the solution of 0.8mgF/L was examined with using the activated carbon filter, F- adsorption was found till 210 L passing through the filter. Similar results were found at other concentration. However, when the NaF solutions made of tap water were examined, F- adsorption was disappeared after 8L passing through the filter. F- concentrations in the activated carbon filters were found to be 230ppm or less, whereas F- was not found in the fresh filters. Conclusions: The hollow fiber film filter did not absorb F-. The activated carbon filter absorbed F- in purified water and reduced its concentrations, but its effects on F- concentrations in tap water were very limited and very quickly disappeared. Hence, further F- supplement is not required, even if these domestic filters were utilized. | ||
| Seq #118 - Caries, Erosion, De/remineralization 3:30 PM-4:45 PM, Thursday, March 22, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
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