Experimental Research on Organic Dye Removal from Polluted Water using the Oxidation Method

Electrochemical, biological, adsorption, and oxidative methods can be applied for the treatment of synthetic wastewater containing methyl orange (MO). In this study, MO was catalytically oxidised using ferrous sulphate (FeSO₄) and hydrogen peroxide (H₂O₂). The effects of reagent concentrations, initial dye concentration, contact time, and pH on treatment efficiency were investigated, and the optimal process conditions were identified. FeSO₄ and H₂O₂ are cost-effective and environmentally benign reagents: excess hydrogen peroxide decomposes into water, while the small amount of iron introduced does not significantly impair the quality of the treated effluent. The results showed that increasing the FeSO₄ concentration from 0.02 % to 2.00 % enhanced the removal efficiency of C-MO from 81.5 % to 98.7 %, as the higher availability of Fe²⁺ ions accelerates the formation of HO^● radicals. Increasing the H₂O₂ concentration from 0.6 % to 24 % raised the efficiency from 81.1 % to 94.5 %, and the highest degradation efficiency was achieved at pH 2.00 - 3.00, confirming that optimal Fenton reaction performance occurs under mildly acidic conditions. Investigation of the initial dye concentration revealed that the efficiency ranged from 80.4 % to 89.1 % when the dye concentration increased from 50 mg/L to 750 mg/L, while the reduction at higher concentrations indicates an insufficient amount of HO^● radicals. Contact time studies showed that the efficiency increased from 39.8 % to 97.1 %, with the optimal reaction time being 2 hours. Overall, the findings demonstrate that the Fenton process is a highly effective method for the degradation of azo dyes and holds strong potential for application in wastewater treatment systems.