Determination of the Efficiency of Fenton-Like Process in the Presence of Zero-Valent Catalyst: Reactive Dye Degradation

In this study, the removability of azo group Reactive Red 2 (RR2) dye from aqueous solution was investigated in the presence of zero-valent iron with a Fenton-like process based on color and Chemical Oxygen Demand (COD) parameters. The effects of pH, zero-valent iron, and hydrogen peroxide (H2O2) concentrations on color and COD removal were investigated. The optimum color and COD removal conditions were determined as pH 3, ZVI = 0.1g/L, and H2O2 = 150mg/L. Under optimum conditions, at initial RR2 values of 10, 30, 50, 70, 100, 150, and 200 mg/L, color removal ranged from 100% to 95%, and COD removal ranged from 97.98% to 65.67%. The increase in RR2 concentration has a negative effect, mainly on COD removal. Kinetic evaluations were made by examining the efficiency of the process against time at different dyestuff concentrations at a constant temperature of 20οC under the most suitable process conditions for both color and COD removal. Pseudo-first-order, pseudo-second-order, and Behnajady-Modirshahla-Ghanbery kinetic models were applied to the color and COD removal results. At concentrations of 100, 150, 200 mg/L RR2, in the BMG model, the coefficient of determination for color was calculated in the range of 0.9984-1, while for COD it was determined in the range of 0.9935-0.9987. The results from kinetic calculations showed that the Fenton-like reaction fits the Behnajady-Modirshahla-Ghanbery model. This process can be considered a feasible advanced oxidation process, particularly for color removal, as it is inexpensive, easily accessible, and environmentally friendly.