Preparation of CuO/γAl2O3 catalyst for degradation of azo dyes (reactive brilliant red X–3B): An optimization study

Wastewater from the printing and dyeing industries has become one of the critical concerns for remediation by water treatment due to its refractory and toxic characteristics. In this paper, CuO/γ-Al2O3 catalyst with excellent reuse properties was synthesized, which could be used for catalytic wet peroxide oxidation method (CWPO) to degrade reactive brilliant red X–3B. The preparation and reaction conditions of the catalyst were optimized with the decolorization efficiency and stability of the catalyst as measuring indexes. The results showed that the optimal conditions for CuO/γ-Al2O3 synthesis were: roasting temperature of 450 °C, roasting time of 4 h, and Cu loading of 5 wt%. Single-factor experiments and orthogonal experiments indicated that 0.39 mol/L H2O2, 5.50 g/L catalyst, initial pH of 8, and 2.50 h of reaction time were the best reaction conditions to degrade 0.30 g/L reactive brilliant red X–3B with CuO/γ-Al2O3. Under the optimal reaction conditions, the CuO/γ-Al2O3 showed effective reusability. After degradation of the dye wastewater repeatedly 11 times, the dye decolorization efficiency was 90.72%, and the amount of Cu2+ leached was below 0.90 mg/L. This study is an important reference, significant for the treatment of dye wastewater, and could be informative for the sustainable development of future catalysts.