Mn-doped Fe₂O₃/diatomite granular composite as an efficient Fenton catalyst for rapid degradation of an organic dye in solution

This investigation reports the synthesis and evaluation of a novel and improved diatomite modified with Fe–Mn binary oxide (DT-FeMn) Fenton catalysis for photochemical reactions in aqueous media. The catalyst was prepared by a co-precipitation process and found to be highly efficient for the photocatalytic degradation Rhodamine B (RhB). In comparison with the iron trioxide coating on diatomite (DT-Fe), the nanoparticles on the surface of the DT-FeMn contained multiple active sites. Experimental results indicated that there was a synergy between the Fe and Mn in the Fe–Mn binary oxide, which was the most important factor for the improved catalytic oxidation performance. The stability and reusability of the composite coating of the catalyst were also investigated by comparing the photocatalytic performance and the loss of Fe³⁺ ions. It was found that the synergy between the components of the Fe–Mn binary oxide coating enhanced the stability of Fe³⁺ ions, which prevented the loss of the Fe³⁺ ions. A maximum of 99.1% RhB was degraded after 80 min. This work might provide a novel Fenton material for pollutants removal in the presence of H₂O₂ to alleviate environmental pollution.