Comparative study of dye solution treatment by electro-fenton process using carbon paper and carbon paper modified with carbon nanotubes as cathode

The Electro-Fenton (EF) process was used for decolorization of an anthraquinone dye, Reactive Blue 69 (RB69) and a real textile wastewater. Hydrogen peroxide was electro-generated by reduction of dissolved oxygen in acidic solution. Carbon paper (CP) and carbon paper modified with carbon nanotubes (CP-CNT) were used as the cathode and a Pt sheet was used as the anode electrode. Hydrogen peroxide was continuously generated by the two-electron reduction of dissolved oxygen at cathode electrode while Fe³⁺ was added to the solution. The results indicated that the decolorization efficiency using CP-CNT cathode was higher than that of CP electrode. The effect of operational parameters such as applied current density, initial pH and electrolyte type was studied in an attempt to reach the higher dye removal efficiency. The results of COD measurements indicated that EF with CP-CNT led to 73% degradation after 300 min of electrolysis time. Also, for real textile wastewater containing reactive dyes, the results of COD measurements indicated that EF process caused 75% reduction after 420 min electrolysis time.