Modification of surfactant chemical structure for optimising graphene oxide systhesis as an efficient removal of methylene blue
<p>This research aimed to optimising the properties of surfactant-exfoliated graphene</p><p>oxide (sEGO) as adsorbent and photocatalyst for methylene blue (MB) removal in</p><p>aqueous solution. Modification of surfactants were ma...
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| Format: | thesis |
| Language: | eng |
| Published: |
2023
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| Subjects: | |
| Online Access: | https://ir.upsi.edu.my/detailsg.php?det=9802 |
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| Summary: | <p>This research aimed to optimising the properties of surfactant-exfoliated graphene</p><p>oxide (sEGO) as adsorbent and photocatalyst for methylene blue (MB) removal in</p><p>aqueous solution. Modification of surfactants were made by increasing chain</p><p>branching and exchanged in counter-ion with aromatic groups namely 1-butyl-3-</p><p>methyl-imidazolium (BMIM) and anilinium. The role of these modified surfactants</p><p>were compared to commercial surfactants. The mechanism in the stabilisation of</p><p>sEGO, sEGO incorporated with nanofibrillated kenaf cellulose (NFC) and sEGO</p><p>fabricated with titanium dioxide (TiO2) were systematically compared. Modified</p><p>surfactants have been studied via proton nuclear magnetic resonance (1H NMR)</p><p>spectroscopy, air water (a/w) surface tension measurement, zeta potential</p><p>measurement and dynamic light scattering. The morphology of the synthesised</p><p>adsorbents and photocatalytic materials were observed by field emission scanning</p><p>electron microscopy (FESEM), Raman spectroscopy and high-resolution transmission</p><p>electron microscopy (HRTEM). The performance of adsorbents (sEGO and</p><p>sEGO/NFC) and photocatalysts (sEGO/TiO2) were also monitored through</p><p>ultraviolet-visible (UV-vis) spectroscopy. The aggregation behaviour of modified</p><p>surfactants in aqueous phase and in sEGO presence were analysed using small-angle</p><p>neutron scattering (SANS) analysis. Results showed that increasing surfactant chain</p><p>branching and exchange with counter-ions (BMIM and anilinium) enhance the</p><p>graphite surface affinity and sheet exfoliation. Thus, contribute increment of</p><p>adsorption sites of sEGO for MB removal (up to 99%) in aqueous solution. SANS</p><p>analysis revealed that addition of chain branching and exchanged in counter-ion</p><p>influenced micelle structure formation of modified surfactant similar with lamellar</p><p>layered of graphene. In conclusion, the chain branching and counter-ions exchange</p><p>modification in surfactant chemical structure optimise sEGO properties as efficient</p><p>MB removal in aqueous solution. As implications, modification of surfactant in</p><p>sEGO as adsorbents and photocatalysts opens up new alternative approach for</p><p>wastewater treatment.</p> |
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