Ozone decolorization of mixed-dye solutions in a gas-induced reactor

Ozone decolorization of several mixed two- and three-dye solutions was stud ied using a newly developed gas-induced reactor. Decolorization kinetics of the mixed-dye solutions, the ozone utilization rate, and chemical oxygen d emand (COD) elimination during decolorization were all examined. In the kin etic study, the method of absorption of dye solution during ozonation was u sed with mixed two-dye solutions. For more complicated mixed three-dye solu tions, the method of the American Dye Manufacturers Institute. (New York) f or determining decolorization kinetics was adopted. Overall, pseudo-first-o rder kinetics can be used to describe the behavior of mixed-dye solutions d uring decolorization; however, two-stage decolorization kinetics occur in c ertain mixed three-dye solutions. Using the gas-induced reactor, a greater than 90% ozone utilization rate was obtained before 90% decolorization was reached. The elimination of COD was approximately 33% before 96% decoloriza tion.