Electrochemical advanced oxidation processes: an efficient degradation method for the complete removal of Acid Blue 40

Abstract Degradation of Acid Blue 40 (AB40) anthraquinone dye by electrochemical treatment was examined using a dimensionally stable anode (DSA) and stainless-steel cathodes as electrode materials, with NaCl as supporting electrolyte and current density of 50 and 100 mA cm -2 . To confirm if the electrolytic process was efficient in removing initial color and organic matter of the AB40 solution, spectrophotometric, chemical oxygen demand (COD) and biochemical oxygen demand (BOD 5 ) analysis were performed. COD removal kinects were studied to evaluate the velocity rate of the reaction. Also, chloroform analysis was realized using a GC-MS to verify if it was generated during the process. Bioassays with Artemia salina , Saccharomyces cerevisiae and Lactuca sativa were performed to verify if the process reduced the initial toxicity. The electrolytic treatment presented itself as a remarkable process degrading almost completely 96.96% of the color in 10 minutes of treatment, using of current density of 50 mA cm -2 . The AB40 solution became more degradable presenting an increase in the biodegradability index. A chloroform formation was observed with current density of 50 mA cm -2 , however, it presented concentrations below the EPA-USA regulations. Bioassays presented low toxicity for the treated solutions. The electrolytic treatment was shown to be highly effective for degradation of AB40 dye solution and DSA electrodes showed remarkable catalytic activity with applied current. It has environmental compatibility with low-cost and durable electrodes. In addition, it was observed high energy efficiency, no requirement for large quantities of chemicals and the process presented safety under soft conditions.