Enhanced Stability of Abundant Amorphous Iron (III) oxide Grafted AlSBA-15 as Highly Efficient Heterogeneous Fenton Catalyst for the Destruction of Phenol

24 wt% of iron has been successfully grafted as amorphous iron oxide over mesoporous channels of SBA-15 and 10 wt% alumina coated SBA-15 (AlSBA-15) using selective extraction deposition (SED) technique. The synthesized materials have been characterized using XRD, N-2 adsorption studies, SEM-EDS, Al-27 MAS NMR, XPS, H-2-TPR, and HR-TEM techniques. Al-27 MAS NMR and XPS characterization results revealed that iron has been preferentially grafted over alumina. The increased binding energy of the Fe2p electron (XPS) in the 24wt %Fe/AlSBA-15 confirms the existence of strong donor-acceptor interaction between grafted iron oxide and an alumina support. In TPR studies, unlike silica support, AlSBA-15 tuned the reduction property of various grafted oxidic iron species, which is evidenced by shifting of iron reduction peak to a high temperature of 436 degrees C. In the destruction of 200 ppm of phenol 24wt %Fe/AlSBA-15 catalyst demonstrated 100% phenol conversion and 86% TOC removal with 0.4 ppm (0.1%) iron leaching within 30 minutes of reaction. 24wt %Fe/SBA-15 catalyst also exhibited similar performance however, leaching of iron was found to be up to 20 ppm (8%). The 24wt %Fe/AlSBA-15 catalyst was recycled successfully five times without loss in the catalytic activity and stability.