Structure and Catalytic Performance of Aluminum-Based Ozone Catalysts Prepared by a Direct Mixing Method

Ozonation catalysis has attracted considerable attention for the treatment of refractory organic wastewater due to its efficient generation of reactive oxygen species (ROS). However, conventional catalyst preparation methods often suffer from drawbacks such as the production of metal-containing waste effluents. In this study, flash calcined alumina (FCA) was employed as a support to synthesize four ozonation catalysts (γ-Al, Cu-Al, Fe-Al, and Ce-Al) via a direct solid-state mixing method with CuO, Fe₂O₃, and CeO₂. The structural properties and oxalic acid degradation performance of these catalysts were systematically investigated. The catalytic activity followed the order: Cu-Al > Ce-Al > Fe-Al >> γ-Al, with Cu-Al achieving a degradation efficiency of 90%. The superior performance of Cu-Al is attributed to the optimal dispersion of CuO on the support, along with the efficient Cu²⁺/Cu⁺ redox cycle that promotes continuous ·OH generation. In contrast, the Ce⁴⁺/Ce³⁺ redox pair exhibits higher reversibility than Fe³⁺/Fe²⁺, resulting in better catalytic activity of Ce-Al. Moreover, FCA mixing method eliminates repeated calcination steps and avoids the generation of metal-containing waste, while significantly reducing energy consumption, cost, and carbon emissions.