Pusat Pengajian Sains Kimia - Tesis
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- PublicationOil Palm Kernel Shell-derived Graphene Derivative Anode Electrodes: Characterizations And Application In Microbial Fuel Cell(2024-09)Omenesa, Idris MustaphaMicrobial fuel cell (MFC) has attracted much interest in the bioelectrochemical field as a technique that produces electricity and at the same time removes pollutants from wastewater. However, their abilities to transport electrons is a major barrier in developing the technique to an industrial scale level. The anode material has been highlighted as a critical component of the MFC that needs to be enhanced to address the low electron transportation rate issue. In this study, palm kernel shell (PKS) waste was successfully employed to fabricate the anode electrodes for MFC applications. PKS waste was utilised to synthesise graphene oxide (GO), and reduced graphene oxide (rGO) was prepared from the synthesised GO, which are referred to as PKS-GO and PKS-rGO, respectively. Later, the PKS-rGO was combined with ZnO and TiO2 to generate the composite materials of PKS-rGO/ZnO and PKS-rGO/TiO2, respectively. Several characterization techniques have been used to confirm the successful synthesis of materials for anode production. These fabricated anodes were then evaluated in an MFC to determine power generation performance along with formaldehyde (FA) and naphthalene biodegradation potential. A commercial graphite anode (CGr) has been used in the MFC that serves as a reference to compare the performance of the fabricated anodes. The PKS-rGO/ZnO composite anode showed the highest performance potential in this study.
- PublicationSynthesis And Characterization Of 1,3- Disubstituted Benzimidazolium Salts And Silver(I)-7v-Heterocyclic Carbene Complexes As Potential Ionic Liquid Crystals And Antibacterial Agents(2019-08)Yeap, Choon WanThis work involved the synthesis and characterization of 1,3-disubstituted benzimidazolium salts and their silver(I)-NHC complexes via A-alkylation method and silver base route. The results from Fourier-transform Infrared spectroscopy (FTIR), ‘H-NMR, 13C-NMR spectroscopy and CHN elemental analysis have revealed that the 1,3-disubstituted benzimidazolium salts and their silver(I)-NHC complexes were successfully prepared.
- PublicationSynthesis, Characterisation Of Stilbene–Arylcinnamide Hybrids And Cytotoxic Studies Against Lung Cancer Cell A549(2024-07)Mohd Zaki, Nurain SyazwaniNumerous anticancer drugs have been designed from natural products. Several compounds derived from nature such as alkaloid, flavonoid, cinnamic acid and stilbene, were reported to possess various biological properties primarily as an anticancer agent. In this study, a total of 24 compounds of a new hybrid series has been designed and synthesised, resulting from the coupling of stilbene and arylcinnamide scaffolds. All synthesised stilbene-arylcinnamide hybrids were obtained in 42-80% yield. Elucidation and characterisation of these hybrids have been validated using Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy and High-Resolution Mass Spectrometry (HRMS). The cytotoxicity against human lung cancer A549 cell line was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay, using cisplatin as the positive control. Particularly, compounds 66b and 74b have displayed potent activities on A549 cancer cells with IC50 value of 20.0 μM and 19.9 μM, respectively. This result is comparable to cisplatin with IC50 value of 19.9 μM after 72 hrs post-treatment. The structural activity relationship (SAR) analysis revealed that the presence of an isopropyl group attached to para-position of stilbene phenyl ring (ring A) of compounds 66b and 74b was crucial for a good cytotoxic effect on A549 cells. Additionally, 4-methyl group as the substituents on cinnamide phenyl ring (ring C) contributed to an innumerable cancer cell death.
- PublicationGenetic Diversity Of The Beetle, Paederus Fuscipes Curtis (Coleoptera: Staphylinidae) And Its Symbiotic Diversity With Pederin Polymorphism Based On 16S Rrna Metagenomics Profiling(2023-02)Teoh, Miao ChingPaederus rove beetles are known to carry the pederin toxin that causes linear dermatitis when crushed on skin. The toxin is produced by an unculturable Pseudomonas sp. harboured by the female Paederus beetles. Pederin polymorphism has been observed several Paederus and Paederidus beetle species wherein the (+) female beetles carried the toxin pederin and (−) females lacking this toxic amide. It has been stated that the (−) female Paederus beetles are infected with more bacterial species than (+) females, but the microbial profiles between the two female groups were not revealed. Besides, the association of pederin polymorphism with the host beetle’s genetic is yet to be investigated. Herein, the objectives of this dissertation are to investigate the microbial profile of the two groups of P. fuscipes beetles, and to study the host beetle’s mtDNA COI in association with pederin polymorphism. Pederin polymorphism studies on P. fuscipes beetles were carried out by PCR detection of pederin (ped) biosynthesis genes. The female beetles were then subjected to 16S rRNA amplicon sequencing and mtDNA COI analysis. This study also attempts to culture and isolate the pederin-producing bacteria.
- PublicationEvaluation Of The Insecticidal Activity Of Cashew (Anacardium Occidentale L.) Nut Shell Liquid Against Adult Bactrocera Dorsalis (Hendel) (Diptera: Tephritidae)(2023-10)Keita, SaineyThe Oriental fruit fly, Bactrocera dorsalis (Hendel), is one of the most notorious pests of agricultural fruits. It has been found to attack over 250 host plants, including commercial fruits and a wide variety of crops. The insecticidal activity of Cashew (Anacardium occidentale L.) nut shell liquid (CNSL) against adult B. dorsalis (Hendel) was investigated under laboratory and field conditions. Two extracting solvents, dichloromethane and hexane were used to extract the CNSL from the cashew nut shell. Contact toxicity, topical application and repellency tests were carried out in the laboratory. For both the contact and topical experiments, concentrations of 0.625, 1.25, 2.5, 5.0, 10.0 and 20.0 x 104 ppm were prepared, whereas 0.07, 0.14, 0.21, 0.28 and 0.35 μL/cm2 concentrations were prepared for the repellency tests. The LC50 values recorded after 24 hours of exposure for the contact toxicity tests of the dichloromethane extract was 4.66 x 104 ppm, whereas 6.58 x 104 ppm was recorded for the hexane extract, which showed the dichloromethane extract to be significantly higher with 1.32 times more lethal than the hexane extract against B. dorsalis (t-test, P<0.05).