Electro-Fenton process based on sacrificial Iron electrode for Ponceau 4R removal

Dyes  are common pollutants that are found in industrial wastewater including food, pharmaceutical, and cosmetic industries. This study aimed to degrade Ponceau 4R (P4R) by the electro-Fenton (EF) process based on iron electrodes in the aqueous solutions. For the EF process, a 900 mL glass reactor containing two iron electrodes which connected to a power supply was used. The effects of five experimental variables namely applied voltage (5–20 V), electrolyte concentration (0–0.2 mol L⁻¹ Na₂SO₄), initial P4R concentration (50–250 mg L⁻¹), pH of the solution (2–6), and H₂O₂ content (0.033–0.100 %v/v) were investigated in four levels and optimized by Taguchi method (OA₁₆). The residual concentrations of P4R after the EF process were spectrophotometrically determined at 505 nm in the time range of 0–90 min with time intervals of 10 min and the removal efficiencies were obtained. Based on the results, the optimum conditions were obtained as pH = 3, voltage = 20 V, H₂O₂ = 0.033 % v/v, C _Na2SO4 = 0.1 M and the C_P4R = 50 mg L⁻¹. Under the optimum conditions, about 100% of P4R was removed during 10 min. The energy consumed in the EF process was calculated as 19.82 KWh/m³ during 10 min. The results obtained good removal efficiencies for the degradation of P4R in the real aqueous solutions introducing it as an efficient decolorization method for treatment of P4R polluted waters.