Application of electro-Fenton process as alternative for degradation of Novacron Blue dye

•Electro-Fenton reduces color and COD from Novacron Blue synthetic wastewater.•Optimum electro-Fenton conditions were achieved at 400 mA of current, pH 3, temperature of 25 °C and [Fe2+] = 1.0 µM.•Electro-Fenton process produces enough hydroxyl radicals to reduce quickly not only the dye, but also generated by-products.

The electrochemical removal of a synthetic solution containing 190 mg L−1 of Novacron Blue (NB) dye has been studied by electro-Fenton process using a carbon felt gas-diffusion O2 cathode to produce in situ hydrogen peroxide by oxygen reduction. The effect of operating conditions (Fe2+ concentration, applied current and pH solution on the efficiency of the process) was investigated. Results clearly showed that NB and their products may be effectively degraded by the •OH radicals produced by the reaction between the Fe2+ ions and the in situ electrogenerated H2O2 at carbon felt gas-diffusion O2 cathode. After 4 h of electrolysis, chemical oxygen demand (COD) removal was only 34% when no ferrous ions were added to the solutions, while the presence of ferrous ion greatly improved COD removal to more than 90%, depending on operating conditions. Spectrophotometric analysis indicated that the discoloration of the solution occurs in all operating conditions, while gas chromatographic/mass spectrometry analysis confirmed the degradation of NB dye via identification of the principal intermediates formed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide