Removal of a reactive textile dye by CaO2-based oxidation process

The adoption of environmentally friendly practices in removing textile dye-containing wastewater through advanced oxidation processes is crucial for ecological and environmental health. Calcium peroxide (CaO2) stands out as an environmentally friendly oxidant with potent oxidizing capabilities. Examining CaO2's potential in oxidizing textile dyes in wastewater can advance the proliferation of eco-friendly treatment methods. This study investigates the efficacy of Direct-CaO2, UV/CaO2, Fe2+/CaO2, and UV/Fe2+/CaO2 processes in oxidizing RB222 textile dye. Optimal conditions for these processes were determined, revealing CaO2 dosage as the most influential independent variable. At a pH of 10 and with 1.0 g CaO2 dosage, CaO2 and UV/CaO2 processes achieved color removal efficiencies of 79.80% (180 min) and 90.40% (120 min), respectively, for 100 mg/L RB222. The optimum pH and Fe2+/CaO2 ratio for Fe2+/CaO2 and UV/Fe2+/CaO2 processes were determined as 2.50 and 0.40, respectively. Under these conditions, Fe2+/CaO2 achieved complete color removal in 40 minutes with 0.125 g CaO2, while UV/Fe2+/CaO2 accomplished the same in 10 minutes with 0.0625 g CaO2. Anions such as Cl-, SO42-, and PO43- were found to have adverse effects on RB222 oxidation. Thermodynamic analyses indicated that oxidation reactions were endothermic across all processes. Studies utilizing CaO2 demonstrated its high potential for RB222 removal. These findings are expected to significantly benefit the treatment of dye-containing wastewater, offering an effective and environmentally friendly approach. Keywords: Textile Dye, CaO2, Oxidation