SEPARATION OF SOME DYES FROM AQUEOUS-SOLUTIONS BY FLOTATION

Separation of the dyes brilliant green, neutral red, eriochrome black T, and eosin from aqueous solutions by flotation was studied using oleic acid surfactant. Nearly 100% of the investigated dyes could be floated under the optimum conditions. The effect of pH on the flotation efficiency was studied in particular. At pH less-than-or-equal-to 2, 7.5, less-than-or-equal-to 5, and less-than-or-equal-to 6, the maximum flotation was achieved for brilliant green, neutral red, eriochrome black T, and eosin, respectively. The effects of oleic acid and dye concentrations, some ions, and temperature on the floatability were examined. Moreover, the selective separation of some dyes was attempted.