The Determination Of Low Concentration Chlorine Dioxide In Water And Several Oscillatory Reaction Systems Relating To Chlorine Dioxide

This paper reports the determination of low concentration chlorine dioxide in water by spectrophotometry and several oscillatory reaction systems relating to chlorine dioxide.The low concentration of chlorine dioxide in water can be determined by spectrophotometry based on the chlorine dioxide can decolor and oxidize xylenol orange and chlorophenol red. The concentration of chlorine dioxide can be determined accurately and precisely by the standard working curve of absorbance at certain wavenumber to the concentration of chlorine dioxide. The linearity of standard working curve is better when the concentration of chlorine dioxide is above 0.05⁰.25mg/L for using xylenol orange, 0.10⁰.50 mg/L for using chlorophenol red. This method can be used to measure the concentration of chlorine dioxide in drinking water at lower concentration. This paper also investigated the interference factors of ClO₂^-, and ClO₃^- to influence the determination of chlorine dioxide.The appearance of the oscillation depends critically on the pH for the ClO₂—I₂-Ethyl acetoacetate (EAA) chemical oscillatory reaction system in a closed system by determining the absorbance of I₃^- with reaction time at 280nm. The pH value is 2.2 — 3.8 at this experimental condition. The initial concentration of ethyl acetoacetate, chlorine dioxide, and iodine has great influence to the oscillatory reaction system at 280nm in H₂SO₄ medium. The oscillation phenomenon appears as long as the reactants are mixed. There is not preoscillatory or induction period. The oscillation phenomenon can also occur at 350nm. The oscillation phenomenon is more distinctness by adding starch in the ClO₂^I₂^EAA chemical oscillatory reaction system at 581nm in H2SO4 medium. In addition, the absorbance levels off instead of increasing rapidly in no adding starch condition when the oscillatory reaction ceased.In the ClO₂^- — I^-(?)EAA chemical oscillatory reaction system, the oscillation phenomenon can be observed by adding starch at 468nm and 581nm. The changing law is similar each other at the two wavenumbers. There is preoscillatory or induction period. The oscillation phenomenon is more distinctness at 581nm than 468nm at the same condition. The oscillation phenomenon can also occur at 299nm. The oscillation phenomenon can occur at 350nm when starch is not added. The initial concentration of...