Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk
The optical properties of ZnO-SiO2 composite had attracted a lot of attention this past decade. However, the production cost is quite high due to huge amount of high purity silica required in the synthesis process. Thus, alternative method was required especially using waste materials for...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/90574/ http://psasir.upm.edu.my/id/eprint/90574/1/FS%202020%2022%20-%20IR.pdf |
| _version_ | 1848861104804986880 |
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| author | Anuar, Muhammad Fahmi |
| author_facet | Anuar, Muhammad Fahmi |
| author_sort | Anuar, Muhammad Fahmi |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | The optical properties of ZnO-SiO2 composite had attracted a lot of attention this past decade.
However, the production cost is quite high due to huge amount of high purity silica required in the
synthesis process. Thus, alternative method was required especially using waste materials for
example coconut husk. In this research, low cost ZnO-SiO2 composite were prepared by
solid state reaction method using agricultural waste materials: coconut husk. The coconut husk
was subjected to high temperature 500, 600, and 700 ºC to obtain coconut husk ash (CHA). CHA was
then undergone chemical treatment (acid and alkali) as an attempt to increase its
silica content. Thermogravimetry analysis (TGA) was carried out where it shows that most of
the weight degradation of coconut husk during pyrolysis occurs at 221 ºC to 360 ºC. From
X-ray fluorescence (XRF) analysis, the silica content increased from 8-11 % to more than 90 % for
both acid and alkali treatment Moreover, the intensity of X-ray diffraction (XRD) peaks
increased along the increased in temperature between 500 ºC to 700 ºC. The Field emission scanning
electron microscopy (FESEM) images was analysed and showed rod-like structure of the
CHA that was irregular in sizes and become slightly smaller after acid and alkali treatment.
Besides that, broad bands were found by Fourier Transform Infrared spectroscopy (FTIR) at
wavenumber 1066 cm⁻¹, 788 cm⁻¹ and 432 cm⁻¹ which related to Si-O-Si thus confirmed the presence of
silica in CHA. The optical band gap of CHA untreated, acid treated, and alkali treated were 4.05
eV, 4.34 eV and 4.21 eV respectively. Next, ZnO-SiO2 composite were prepared by mixing zinc
oxide (ZnO) powder with silica from CHA with 1:1 ratio by solid state method sintered at 600
ºC-1000 ºC to investigate the effect of sintering temperature on the properties of ZnO-SiO2
composite. First, XRD spectrum showed the zinc silicate was formed at sintering temperature 600oC and the peaks intensity increased along the sintering temperature. The
composite shows well-distinct boundaries of rhombohedral-like particle when
sintered at 1000 ºC that indicates the high crystallinity of the zinc silicate when
sintered. Furthermore, the FTIR results shows the formation of Si-O-Si, ZnO4 and
SiO4 vibration in the composite spectrum becoming narrow and stronger as the
sintering temperature increased. The absorbance intensity of the ZnO-SiO2
composite was observed to decrease with the sintering temperature and the
optical band gap of the composite at room temperature is 3.22 eV. The value
increased to 3.26 eV at 600 ºC and decreasing until 900 ºC before rapidly
increased to 4.05 eV at 1000 ºC. In the nutshell, the CHA has great potential to be
used as silica substitute in preparation of ZnO-SiO2 composite. |
| first_indexed | 2025-11-15T12:55:50Z |
| format | Thesis |
| id | upm-90574 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T12:55:50Z |
| publishDate | 2020 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-905742021-08-18T02:17:11Z http://psasir.upm.edu.my/id/eprint/90574/ Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk Anuar, Muhammad Fahmi The optical properties of ZnO-SiO2 composite had attracted a lot of attention this past decade. However, the production cost is quite high due to huge amount of high purity silica required in the synthesis process. Thus, alternative method was required especially using waste materials for example coconut husk. In this research, low cost ZnO-SiO2 composite were prepared by solid state reaction method using agricultural waste materials: coconut husk. The coconut husk was subjected to high temperature 500, 600, and 700 ºC to obtain coconut husk ash (CHA). CHA was then undergone chemical treatment (acid and alkali) as an attempt to increase its silica content. Thermogravimetry analysis (TGA) was carried out where it shows that most of the weight degradation of coconut husk during pyrolysis occurs at 221 ºC to 360 ºC. From X-ray fluorescence (XRF) analysis, the silica content increased from 8-11 % to more than 90 % for both acid and alkali treatment Moreover, the intensity of X-ray diffraction (XRD) peaks increased along the increased in temperature between 500 ºC to 700 ºC. The Field emission scanning electron microscopy (FESEM) images was analysed and showed rod-like structure of the CHA that was irregular in sizes and become slightly smaller after acid and alkali treatment. Besides that, broad bands were found by Fourier Transform Infrared spectroscopy (FTIR) at wavenumber 1066 cm⁻¹, 788 cm⁻¹ and 432 cm⁻¹ which related to Si-O-Si thus confirmed the presence of silica in CHA. The optical band gap of CHA untreated, acid treated, and alkali treated were 4.05 eV, 4.34 eV and 4.21 eV respectively. Next, ZnO-SiO2 composite were prepared by mixing zinc oxide (ZnO) powder with silica from CHA with 1:1 ratio by solid state method sintered at 600 ºC-1000 ºC to investigate the effect of sintering temperature on the properties of ZnO-SiO2 composite. First, XRD spectrum showed the zinc silicate was formed at sintering temperature 600oC and the peaks intensity increased along the sintering temperature. The composite shows well-distinct boundaries of rhombohedral-like particle when sintered at 1000 ºC that indicates the high crystallinity of the zinc silicate when sintered. Furthermore, the FTIR results shows the formation of Si-O-Si, ZnO4 and SiO4 vibration in the composite spectrum becoming narrow and stronger as the sintering temperature increased. The absorbance intensity of the ZnO-SiO2 composite was observed to decrease with the sintering temperature and the optical band gap of the composite at room temperature is 3.22 eV. The value increased to 3.26 eV at 600 ºC and decreasing until 900 ºC before rapidly increased to 4.05 eV at 1000 ºC. In the nutshell, the CHA has great potential to be used as silica substitute in preparation of ZnO-SiO2 composite. 2020-06 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/90574/1/FS%202020%2022%20-%20IR.pdf Anuar, Muhammad Fahmi (2020) Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk. Masters thesis, Universiti Putra Malaysia. Nanotechnology - Environmental aspects Waste products Coconut |
| spellingShingle | Nanotechnology - Environmental aspects Waste products Coconut Anuar, Muhammad Fahmi Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title | Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title_full | Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title_fullStr | Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title_full_unstemmed | Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title_short | Synthesis, structural and optical properties of ZnO-SiO₂ composite derived from waste coconut husk |
| title_sort | synthesis, structural and optical properties of zno-sio₂ composite derived from waste coconut husk |
| topic | Nanotechnology - Environmental aspects Waste products Coconut |
| url | http://psasir.upm.edu.my/id/eprint/90574/ http://psasir.upm.edu.my/id/eprint/90574/1/FS%202020%2022%20-%20IR.pdf |