Electrofenton process based on Iron electrodes for the removal of Ponceau ۴R from aqueous solutions

The dye compounds could be hazardous to human’s health. Ponceau ۴R known as Acid Red ۱۸ or E۱۲۴ is a water-soluble azo dye with acidic group that widely used in the food industry and drug products. Due to its disadvantage on human health, the removal of Ponceau ۴R from wastewaters is important before its entrace to the environment [۱]. The aim of this study was to remove Ponceau ۴R by electrofenton process using iron electrodes from aqueous solutions. In the electrofenton process, the continuous electrogeneration of H۲O۲ is achieved by O۲ reduction in the presence of dissolved Fe۲+ by different reduction processes [۱]. For electrofenton process, a glass reactor with a total volume of ۹۰۰ mL containing two iron electrodes (۶۳ × ۸۰ × ۲ mm) was used. This set up was connected to a power supply. The effect of five effective parameters such as applied voltage (۵, ۱۰, ۱۵, ۲۰ V), ionic strength (۰, ۰.۰۵, ۰.۱, ۰.۲ M), dye concentration (۵۰, ۱۰۰, ۲۰۰, ۲۵۰ mg L-۱), pH of solution (۲, ۳, ۴, ۶) and percentage of H۲O۲ (۱۰, ۲۰, ۲۵ ,۳۰ %) were investigated in four levels and optimized by Taguchi orthogonal array design method (OA۱۶). The residual concentrations of Ponceau ۴R after electrofenton process was spectrophotometrically determined (۵۰۵ nm) in the time range of ۰-۹۰ min with time intervals of ۱۰ min and the removal efficiencies were obtained. Based on the results, the optimum conditions were obtained as pH: ۴, voltage: ۲۰ V, H۲O۲: ۲۵%, salt concentration (Na۲SO۴): ۰.۰۵ M and the initial concentration of dye: ۵۰ mg L-۱. Under the optimum conditions about ۱۰۰ % of Ponceau ۴R was removed during ۲۰ min.The results confirmed the eclectrofenton process is able to remove Ponceau ۴R with maximum efficiency at a short time.