Nguang, Sing Yew (2017) Adsorption and photocatalytic removal of Methylene blue using graphene oxide-supported engelhard titanosilicate-10. Masters thesis, Universiti Malaysia Sabah.
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Abstract
In this study, ETS-10 precursors were mixed with graphene oxide (GO) suspension to obtain GO incorporated ETS-10 (GO/ETS-10) with improved adsorption ability and photocatalytic activity in comparison to that of ETS-10. The GO/ETS-10 composite prepared with different GO to ETS-10 ratios, i.e. 1:15, 1:10 and 1:5 were confirmed by XRD, FTIR, EDX and XPS analyses. The results showed that GO and ETS-10 were chemically bound through Ti–O–C and Si–O–C bonding. SEM images showed that the truncated bipyramidal ETS-10 crystals were grown firmly on the GO surface and have crystal sizes range between 0.5 to 1.0 μm. Thermogravimetric analysis revealed that the synthesized GO/ETS-10 composite was thermally stable up to 150 ˚C and decomposed fully above 400 ˚C due to the disintegration of GO from ETS-10. The band gap energy for GO/ETS-10(1:5) was determined to be 3.12 eV which was lower than ETS-10 (3.48 eV). The adsorption study revealed that the adsorption behavior of MB onto GO/ETS-10 was mainly monolayer due to the chemisorption interaction between MB and GO/ETS-10 surface. The maximum equilibrium adsorption capacity of GO/ETS-10 was calculated to be 294 mg/g, which is much higher than ETS-10 with only 139 mg/g. Besides that, GO/ETS-10 can be photoexcited by both UV-A and visible radiations which gave similar removal of MB in water. This implies that the presence of GO can help to widen the light responsive range of ETS-10 by lowering the band gap energy and suppress the electron-hole recombination. 0.075 g/L of GO/ETS-10(1:5) in 20-ppm MB solution with UV-A irradiation (as GO/ETS-10(1:5)/UV-A), for instance, can achieve about 65 % of MB removal after 6 hours and still increasing with a consistent rate of removal in comparison to 60 % of MB removal achieved by GO/ETS-10(1:5)/Dark system, which has reached plateau after 6 hours of reaction. The results showed that the photocatalytic activity of GO/ETS-10 was low under UV-A irradiation but it is important to ensure continuous adsorption-photocatalytic removal throughout the process. Besides, it was found that addition of 5 x 10-3 mol/L H2O2 in the photocatalytic system (as GO/ETS-10(1:5)/H2O2/UV-A system) was capable to enhance about 20 % of MB removal, which giving a total of 93 % after 8 hours. This study implies that GO/ETS-10 composite can be a potential material specifically for the elimination of organic pollutant via adsorption and eventually through photocatalytic decomposition under sunlight.
| Item Type: | Thesis (Masters) |
|---|---|
| Keyword: | ETS-10 precursors, Graphene oxide, Photocatalytic |
| Subjects: | Q Science > QD Chemistry > QD1-999 Chemistry > QD450-801 Physical and theoretical chemistry > QD701-731 Photochemistry |
| Department: | FACULTY > Faculty of Science and Natural Resources |
| Depositing User: | DG MASNIAH AHMAD - |
| Date Deposited: | 27 Jun 2024 15:42 |
| Last Modified: | 27 Jun 2024 15:42 |
| URI: | https://eprints.ums.edu.my/id/eprint/38962 |
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