Document Type : Original Article

Authors

• Mansour Sarafraz ¹
• Mohsen Khosravi ²
• Gholamreza Bonyadinejad ¹
• Afshin Ebrahimi ³
• Seyed Mahmood Taghavi-Shahri ⁴

¹ Department of Environmental Health Engineering, Student Research Center, School of Health, Isfahan University of Medical Sciences (IUMS), Isfahan, Iran

² Department of Nanotechnology, University of Isfahan, Isfahan, Iran

³ Environment Research Center, Research Institute for Primordial Prevention of Non-communicable Disease, IUMS, Isfahan, Iran and Department of Environmental Health Engineering, School of Health, IUMS, Isfahan, Iran

⁴ Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran

Abstract

Aims: The aim of this study was decolorization of the synthetic aqueous solution of the acid orange 10 (AO10) dye on Ti/SnO ₂ -Sb anode using the response surface methodology based on central composite design. Materials and Methods: The Ti/SnO ₂ -Sb electrode was prepared using the standard thermal decomposition method and three variables: Current density (CD), pH, and supporting electrolyte concentration were assessed. The dye decoloration was monitored spectrophotometrically by measuring the absorbance of the remaining dye at the maximum absorption wavelength (λ _max ) of 475 nm on a ultraviolet-visible spectrophotometer. To measure AO10 mineralization under optimum conditions, chemical oxygen demand (COD) and total organic carbon (TOC) removal also were evaluated. Results: It was found by the model prediction, minimum dye decolorization was 39% (CD = 6 and pH = 7.5) and maximum dye decolorization was 101% (CD = 65 and pH = 2). Thus, the optimum conditions for AO10 decolorization in synthetic dye solution were electrolyte concentration of 75 mM/L, pH of 2, and CD of 65 mA/cm. Under optimum conditions, decolorization of 100 mg/L dye was complete, and 61.3% and 43.9% COD and TOC removal were recorded after 50 min of electrolysis, respectively. Conclusion: High-efficiency electrochemical degradation of AO10 was achieved over Ti/SnO ₂ -Sb anode as a model electrode. It was concluded that the most effective factor for AO10 decolorization was CD. The electrochemical degradation using Ti/SnO ₂ -Sb electrode is a suitable and an environment-friendly method for the degradation of refractory dyes in aqueous solution.

Keywords

• Acid orange 10
• central composite design
• electrochemical degradation
• response surface methodology
• Ti/SnO2-Sb