Efficient Catalytic Ozonation of 1H-Benzotriazole by Floating FeCe@fly Ash Cenosphere: Performance and Mechanism

Developing a highly efficient, stable, and economical heterogeneous ozone (O₃) catalyst is still a challenge. Herein, a floating fly ash cenosphere supported FeCe bimetallic catalyst (FeCe@FAC) was successfully synthesized and was analyzed by multiple characterization techniques. FeCe@FAC exhibits excellent catalytic ozonation for 1 H-benzotriazole (BTA), O₃ (0.12 g/min) removes 100% of BTA (0.1 mM) and 44.43% of mineralization efficiency is obtained, which is much higher than individual metal-doped FAC/O₃ and O₃ systems within 15 min at pH 7.0. EPR and quenching experiments confirm that hydroxyl radical (•OH), superoxide (O₂^•−), and singlet oxygen (¹O₂) are the primary active oxidizing species, making a significant responsible for the degradation of BTA. Moreover, the presence of coexisting substances such as Cl⁻, SO₄²⁻, and NO₃⁻ (10 mM) shows no significant effect on the removal of BTA in the FeCe@FAC/O₃ system. However, humic acid (HA) slightly inhibits BTA removal, primarily due to the competition between HA (10 mg/L) and BTA for active free radicals. However, HCO₃⁻ greatly enhances the degradation of BTA as it could increase the solution pH. Also, FeCe@FAC exhibits an excellent stability for BTA oxidation in five consecutive cycles. As a result, FeCe@FAC has a promising application in the treatment of wastewater.