Physical characterization and microscopic studies of porites species form Sabah
Physical characterization of Porites species from Sabah have been studied by using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Fourier Transform Raman Spectroscopy (FT-Raman) and Scanning Electron Microscopy (SEM). The purpose of this research is to study physical cha...
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| Format: | Thesis |
| Language: | English |
| Published: |
2008
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/19697/1/Physical%20characterization%20and%20microscopic.pdf |
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| Summary: | Physical characterization of Porites species from Sabah have been studied by using
X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Fourier
Transform Raman Spectroscopy (FT-Raman) and Scanning Electron Microscopy
(SEM). The purpose of this research is to study physical characteristic of 3 powder
particle sizes; ≤38, ≤53, and ≤106 µm of Porites species. Porites skeletons used in
these studies were Porites australiensis, Porites cylindrica, Porites lutea, Porites
lichen, Porites digitata, Porites nigrescens, Porites rus, Porites annae and Porites sp.
It was found that crystallinity is increased from Porites lutea (lowest crystallinity) to
Porites cylindrica (highest crystallinity). Low value of FWHM indicates that the
crystals are defect free and periodically arranged while high value of FWHM indicates
that the crystals are randomly arranged or have low degrees of periodicity. Crystallite
sizes were found to be In the range of 1007.781-1706.040 A and Porites species are
belonged to two groups (smaller and larger crystallite sizes respectively). It is found
that all Porites species exhibit orthorhombic crystal structures. From the values of
Ml, Porites species are categorized into two groups; the first group shows high
values of Ml with biogenic aragonite cell constant while the second group shows
high values of Ml with synthetic aragonite cell constants. It can be concluded that
species with high value of M 1 has peak data profiles which are compatible with the
fitted cell constants. FTIR spectra show the variations In the V1, V2, V3 and V4 bands
strength as a function of particle size. Each band decreases in strength with
decreasing particle sizes for all species. The size of particulate matter will affect the
strength of absorptions because electromagnetic radiation will interact with
particulate matter differently for different particle sizes as the ratio of surface to
volume scattering changes. FT-Raman spectra show the effect of particle size on the
wavenumber and Intensity of carbonate symmetric stretching mode, V1 bands. It is
found that the Intensity of V₁ band decreases with decreasing particle size. These
changes In the wavenumber of Raman bands with particle size are inherent
properties of individual minerals. From morphological study, corallites distribution of
Porites species can be divided into even and uneven. SEM at low magnification
(100X) shows fine structures of Intact coral skeletons. SEM at high magnification
(2000X) however shows broken and fragmented rod-shaped aragonite crystals of
some Porites species due to the effects of grinding process. In conclusion, there are
significant differences of physical characteristic between these three particle sizes of
Porites powder samples. |
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