Crystallization of iron oxide nanotubes by anodization and their relation to photocatalytic properties
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Date
2018-06
Authors
Norahasyima Ramli
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Abstract
Cr(VI) is heavy metal of high toxicity and has been classified as human carcinogen. Cr(VI)
enters into environment from sources such as manufacturing industries of leather and
tanning alloys and steel, rubber and more importantly textile industries which utilizes
Cr(VI) as pigments and dyes. This study is on the applicability of nanostructured porous
iron oxide for the removal of Cr(VI) from aqueous solution. The nanostructured iron
oxide anodic films were synthesized by direct anodic oxidation technique of carbon steel
and then annealed for crystallization of iron oxide. After annealing, α-Fe2O3 formed was
characterized by Field Emission Scanning Electron Microscope (FESEM) and X-Ray
Diffraction (XRD) for morphologies and phases studies respectively. The parameters
experimented were anodization time, effect of voltage and effect of percentage volume
of H2O in ethylene glycol used in electrolyte. A mixture of nanoporous, nanosheet and
nanowires was observed from these experiments. The nanosheets formed as
interconnected nanosheets arrays cell with cell width varies from 26.5 nm to 66.2 nm.
Nanoporous structure were formed at 10 minutes anodization time, with 3 ml H2O and 50
V. Nanosheets with mixtures of nanowire were formed. Nanoporous and interconnected
nanosheets arrays of iron oxide were used as photocatalysts to reduce Cr(VI) under
sunlight. The reduction percentage of Cr(VI) at pH 2 was the fastest after one hour of
exposure to sunlight.