The kinetics of the oxidative decolorization of amaranth with KBrO3 acidified by H2SO4 was followed up by monitoring the decrease of the
absorbance of amaranth at max = 520 nm. The reaction was carried out under pseudo-first-order conditions. The concentration of BrO3
- was
ca 300 greater than that of amaranth. The rate of reaction increased with increasing concentration of H2SO4 and BrO3
-
, while amaranth had
no effect on the rate of reaction. The effects of the ions, Cl-
, Brand SO4
-- were investigated and the reaction rate increased with increasing
concentrations of chloride and bromide while it decreased with increasing concentration of SO4
--. A reaction mechanism has been proposed.
Key words: Amaranth Red; decolorization; kinetics; bromate.
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