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Ozonation of azo dye acid black 1 under the suppression effect by chloride ion

2010; Brazilian Chemical Society; Volume: 21; Issue: 3 Linguagem: Inglês

10.1590/s0103-50532010000300009

1678-4790

Alexandre Paprocki, Heldiane Souza dos Santos, Marta E. Hammerschitt, Marçal Pires, Carla M. N. Azevedo,

Advanced oxidation water treatment

The aim of this study is to determine the kinetics of the Acid Black 1 dye by oxidizing action of ozone and to evaluate the influence of chloride ion contamination on the dye degradation. Pseudo-first order kinetics was observed for both decolorization (620 nm) and aromatic structure (321 nm) degradations. A complete color removal was verified in 25 min ([dye]0 = 1.8 × 10-5 mol L-1), while aromatic structures degraded at slower rates. The presence of chloride ion, the principal impurity of the solid dye reagents, influences significantly the ozonation rate (-42%), even at low chloride concentration (5.6 × 10-4 mol L-1). The most probable mechanism for the chloride suppression effect involves a direct reaction between O3 and Cl- generating HOCl, among other by-products. In despite of that, ozonation could be a competitive degradation process for this dye.