Tannery Dye Wastewater Treatment in Batch and Once through Continuous Mode by Electro-Oxidation Using MMO Electrode

Abstract

Treatment of tannery wastewater is challenging because dye concentrations in tannery wastewater are typically lower than any other chemical compound, but their high molar extinction coefficients result in waste streams with heavy coloration even at very low concentrations. In the present work, treatment of Acid Black 210 dye wastewater in batch and once through continuous mode by electro-oxidation through novel Mix Metal Oxide Ti/TiO2-RuO2-IrO2 electrode was explored. The effects of parameters were studied in a laboratory scale to observe the effects on color removal, degradation, and energy consumption efficiency. A response surface methodology with a full factorial BBD model was used for designing and optimizing responses. Multi-response optimization with a desirability function was used to optimize the multiple responses. Optimum conditions for 500 ppm Acid Black 210 dye were achieved at a current intensity of 1.6 A, pH of 6.48, and treatment time of 35 min. The BBD model efficiently interacts between optimizing variables, and its prediction matched the experiment results. At the optimum condition, a once-through continuous setup was run for the flow rates ranging from 5–30 ml min−1. The intermediates formed during the treatment process were analyzed through GC-MS. TOC removal, COD removal, and toxicity bioassay of the sample was also done for disposability analysis.