Decolorization of C.I. Reactive Yellow 84 in aqueous solution by electrocoagulation enhanced with ozone: influence of operating conditions.

We studied the use of a combination of electrocoagulation (EC) and ozonation for the decolorization of the azo dye, C.I. Reactive Yellow 84 (RY84). The effects of initial dye concentration, initial pH, current density, salt concentration, ozone flow rate, temperature and interelectrode distance on the decolorization of RY84 were investigated. The results showed that a synergistic effect was achieved by combining EC with ozone for the decolorization of RY84. Under the experimental conditions, the decolorization rate increased with an increase in current density. However, the decolorization rate decreased with an increase in initial dye concentration and salt concentration. The interelectrode distance did not substantially affect the decolorization rate. Other operating parameters such as initial pH, ozone flow rate and temperature had both positive and negative effects. Over 97% of the color decay was achieved within 10 min reaction time under reasonable experimental conditions. When the decolorization of RY84 was complete, the efficiency of removal of total organic carbon (TOC) was more than 85%.