Portal de Periódicos da CAPES

Chloride ion effects on the aqueous oxidation of So2

1983; Elsevier BV; Volume: 17; Issue: 3 Linguagem: Inglês

10.1016/0004-6981(83)90135-x

1878-2442

A.G. Clarke, M. Radojević,

Electrochemical Analysis and Applications

A survey of electrolyte effects on the oxidation rate of sodium sulphite solutions has been carried out covering Na+, K+, NH4+, Ca2+, SO2−4, HCO3−, NO3−, F−, Cl− and Br− up to 0.1 M concentration. No significant cation effects were revealed but significant anion catalysis by Cl− and Br− was found. The levels at which the reaction rate was affected were above 10−3 M. For solutions of water containing 10−5−10−4 M sulphite the reaction rate constant was found to be first order in SO2−3 and half-order in H+consistent with previous workers. For chloride solutions the results are best represented as −d[s(IV)]dt∝[S(IV)]2[Cl−]1.3[H+]−0.5pH 3−7. Possible mechanisms involving either ClO− ions or Cl atoms are discussed. Liquid aerosols or droplets in the environment which contain significant chloride levels will show a greater ability to oxidize adsorbed sulphur dioxide than pure water droplets.