%0 Journal Article
%T Experimental Study of Closed System in the Chlorine Dioxide-Iodide-Sulfuric Acid Reaction by UV-Vis Spectrophotometric Method
%A Na Li
%A Laishun Shi
%A Xiaomei Wang
%A Fang Guo
%A Chunying Yan
%J International Journal of Analytical Chemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/130102
%X The mole ratio has great influence on ClO2-I£¿-H2SO4 closed reaction system. By changing the initiate concentration of potassium iodide, the curve of absorbance along with the reaction time was obtained at 350£¿nm and 297£¿nm for triiodide ion, and 460£¿nm for iodine. The changing point of the absorbance curve's shape locates at . For the reaction of ClO2-I£¿ in the absence of H2SO4, the curve of absorbance along with the reaction time can be obtained at 350£¿nm for triiodide ion, 460£¿nm for iodine. The mole ratio r is equal to 1.00 is the changing point of the curve's shape no matter at which wavelength to determine the reaction. For the reaction of ClO2-I£¿-H+ in different pH buffer solution, the curve of absorbance along with the reaction time was recorded at 460£¿nm for iodine. When r is greater than 1.00, the transition point of the curve's shape locates at pH 2.0, which is also the point of producing chlorite or chloride for chlorine dioxide at different pH. When r is less than 1.00, the transition point locates at pH 7.0. 1. Introduction The oxidation of iodide by chlorine dioxide was reported by Bray [1], where it was used in the analytical determination of chlorine dioxide. The kinetic study of the reaction between chlorine dioxide and potassium iodide in aqueous solution was investigated by Fukutomi and Gordon [2], where two distinctly different rates were observed in the pH range 5.5¨C8.5. The first reaction corresponds to the rapid formation of the intermediate [ClO2I£¿]. The second corresponds to the decomposition of the intermediate, which results in the formation of and I2. The reaction between iodide ion and chlorite ion exhibits a remarkable variety of kinetic phenomena [3]. Responses to single and periodic pulse perturbations have been studied experimentally and numerically by Dolnik and Epstein [4] for the reaction of chlorine dioxide and iodide ion in a stirred tank reactor. Excitability with transient oscillations was obtained for perturbations by chlorine dioxide or chlorite, while stimulation by iodide produced no excitable response. The dynamical behavior of the chlorine dioxide-iodide reaction has been studied in a system consisting of two continuous flow stirred tank reactors (CSTRs) [5]. By introducing an additional reactant to chlorite-iodide system that can react to regenerate the iodide consumed during each cycle of oscillation, De Kepper et al. [6¨C8] constructed the chlorite-iodate-thiosulfate and the chlorite-iodide-malonic acid (MA) systems, which oscillate in a closed (batch) as well as an open system. The batch oscillation in
%U http://www.hindawi.com/journals/ijac/2011/130102/