Amorphous Cu-Mn hopcalite as novel Fenton-like catalyst for H2O2-activated degradation of tetracycline at circumneutral pH

Cu-Mn hopcalite, as conventional catalyst showing potential in many chemical reactions, have been rarely researched for their applications in H2O2-activated Fenton-like reactions for decomposition of refractory pollutants. In this work, an amorphous Cu-Mn hopcalite catalyst (CMO-200) was prepared by simple calcination of their precursors at 200 °C. At circumneutral pH, CMO-200 behaved more efficiently than several commercial manganese oxides, CuO, Fe2O3, as well as its crystalline analogues in catalytic degradation of tetracycline (TC) with H2O2 as oxidant. The excellent performance can be kept without remarkable loss during its 6 cycles of reuse. Singlet oxygen, superoxide anion radical and hydroxyl radical were found to be active species for the degradation reaction. The amorphous structure, high contents of chemically adsorbed oxygen, Cu+ and Mn4+ species are speculated as the reasons for its high catalytic performance.