Ozone Decolorization of Mixed‐Dye Solutions in a Gas‐Induced Reactor

Abstract

Ozone decolorization of several mixed two‐ and three‐dye solutions was studied using a newly developed gas‐induced reactor. Decolorization kinetics of the mixed‐dye solutions, the ozone utilization rate, and chemical oxygen demand (COD) elimination during decolorization were all examined. In the kinetic study, the method of absorption of dye solution during ozonation was used with mixed two‐dye solutions. For more complicated mixed three‐dye solutions, the method of the American Dye Manufacturers Institute (New York) for determining decolorization kinetics was adopted. Overall, pseudo‐first‐order kinetics can be used to describe the behavior of mixed‐dye solutions during decolorization; however, two‐stage decolorization kinetics occur in certain mixed three‐dye solutions. Using the gasinduced reactor, a greater than 90% ozone utilization rate was obtained before 90% decolorization was reached. The elimination of COD was approximately 33% before 96% decolorization.