Hydrothermal synthesis and characterization of akageneite-type iron oxide octahedral molecular sieves (FeOX-OMS) by direct dissolution and transformation of layered precursor to 2x2 tunnel structure

• Main Authors: Tolentino, Elaine Nicolas, Alfornon, Pamela
• Format: text
• Published: Animo Repository 2002
• Subjects: Molecular sieves—Synthesis; Molecular sieves—Dissolution; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/13357
• Institution: De La Salle University

Iron oxide octahedral molecular sieve with 2x2 tunnel, designated' as FeOx-OMS (2x2) was successfully synthesized through hydrothermal method. FeOx-OMS (2x2) has high degree of purity and higher thermal stability than those of previously reported akaganeite-type materials. The X-ray powder diffraction (XRD) pattern shows peaks that are characteristic of pure akaganeite-system. Based on its TGA profile, it is thermally stable up to 255°C and at 402 °c, a new phase is formed which is a mixture of hematite-magnetite based on its XRD pattern. The SEM result shows a needle-like morphology that is characteristic of a tunnel structure. Another successful route in producing...kaganeite-type material is via transformation of a layered, lepidocrocite-type material precursor referredt o as L-FeOx. Although this tunnel material has a lower thermal stability, which is at 195°C, its XRD pattern shows also a relatively pure akaganeite- type material. It has also a needle-like morphology based on its scanning electron micrograph.