Removal of Neutral Red Dye via Electro-Fenton Process: A Response Surface Methodology Modeling

Recycling wastewater for industries and providing future security for humans and the environment are important issues that need to be concerned. In this study, electro-Fenton (EF) process using graphite electrodes as cathode and anode and its application in removing neutral red (NR) dye using response surface methodology (RSM) was examined. Ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), temperature programmed desorption (TPD), total organic carbon (TOC), and gas chromatography–mass spectrometry (GC-MS) analysis were performed to analyze the degradation of the NR and characterization of the nanocatalysts. The effects of operational parameters such as applied current, amount of catalyst, initial NR concentration, reaction time, and pH on the decolorization efficiency of the NR were examined. The results showed that in the applied current of 200 mA, the amount of Fe 2+ 2%, the initial NR concentration of 40 mg/L, and pH = 3 during 40 min of reaction time, the maximum decolorization efficiency value was 85.88% at homogenous EF, and 90.32% and 92.44% at heterogeneous EF using HZC and FeZC nanocatalysts, respectively. The results of the experimental part were compared by predictions via Minitab 16 software. The correlation coefficient found between the experimental and the model results was 99.7%. Graphical abstract