Synthesis and activity of FeAPO-5 molecular sieve for catalytic oxidation of phenol in aqueous solution

Iron-substituted aluminophosphate molecular sieves (FeAPO-5) were synthesized by hydrothermal crystallization and characterized with XRD, SEM, FT-IR and UV-Vis techniques. The results showed that the synthesized samples had good crystallinity and uniform grain. From the obtained characterization results, it could be concluded that both the framework and extra-framework Fe species were together present in the FeAPO-5 samples, and most iron ion was incorporated into the AlPO₄-5 framework. FeAPO-5 as a heterogeneous catalyst is effective for catalytic oxidation of phenol in aqueous solutions with H₂O₂ as oxidant. The best results (99.0% phenol conversion, 77.8% total organic carbon) after 240 min at 80°C were obtained with phenol initial concentration 200 mg·L^-1, H₂O₂ initial concentration 1200 mg·L^-1 and pH5.0. Meanwhile, inductively coupled plasma (ICP) spectrometry results indicated that the concentration of leaching-off Fe³⁺ in the solution was very little and the FeAPO-5 molecular sieves was stable in the process of catalytic oxidation of phenol in aqueous solutions.