次亜塩素酸ナトリウム漂白における臭化ナトリウム添加の影響

概要

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Effective bleaching conditions of sodium hypochlorite (NaClO) aqueous solution with the addition of sodium bromide (NaBr) have been investigated by using cotton fabric and cellulose film dyed with direct dye (C. I. Direct Blue 78). Bleaching efficiency has been examined by using reflectance and absorbance at a wavelength of 608 nm for fabric and film, respectively. The main results obtained are summarized as follows: 1) At room temperature, bleaching efficiency increased remarkably by adding ca. 0.1% NaBr content in dyed fabric and 0.005% NaBr in dyed film. 2) By UV spectra analyses, maximum absorption shifted from 293 to 330 nm with the addition of NaBr to NaClO aqueous solution, which would suggest the formation of NaBrO by the following reaction. NaClO + NaBr→NaBrO + NaCl 3) Effective bleaching was observed in NaClO/NaBr solution at pH 10, but bleaching efficiency decreased in alkalin solution to more than pH 11, probably due to the prevention of the formation of NaBrO. 4) Using dyed cotton fabrics having the same bleaching efficiency, the diminution ratio of tensile strength of the fabrics bleached by using NaClO/NaBr was smaller than that by heat bleaching.
社団法人日本家政学会の論文
1999-06-15