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

Date of Publication

2001

Document Type

Master's Thesis

Degree Name

Master of Science in Chemistry

Subject Categories

Chemistry

College

College of Science

Department/Unit

Chemistry

Thesis Adviser

Elaine Tolentino

Defense Panel Chair

Jaime Raul O. Janairo

Defense Panel Member

Julita Robles
Christine Binag

Abstract/Summary

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 XRD pattern shows peaks that are characteristic of pure akaganeite-system. Based on its TGA (thermogravimetric analyses) profile, its thermal stability is reported at 255 degrees Centigrade and at 402 degrees Centigrade, a new phase is formed which is hematite-magnetite based on its XRD pattern. The SEM result shows a needle-like morphology that is a characteristic feature of a tunnel structure.Another successful route in producing akaganeite-type material is via transformation of a layered, lepidocrocite-type material precursor referred to as 1-FeOx-L2. Although this tunnel material has a lower thermal stability which is at 195 degrees Centigrade, its XRD pattern shows a relatively pure akaganeite-type material. It has also a needle-like morphology based on its scanning electron microscopy (SEM).

Abstract Format

html

Language

English

Format

Print

Accession Number

TG03279

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

105 numb. leaves ; 28 cm.

Keywords

Iron oxides--Magnetic properties; Chemistry; Physical and theoretical; Chemical structure

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