Pusat Pengajian Sains Kimia - Tesis
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- PublicationThe Effects Of Alkaline Earth Metals In Nimo-x (X = Mg, Ca, Sr, Ba) Catalysts On The Characteristics Of Carbon Nanotubes Derived From Plastics Pyrolysis(2024-08)Lim, Xiu XianThe increased usage of face masks has spurred environmental concerns, necessitating effective waste management strategies. One effective approach is to upcycle face mask plastic waste into carbon nanotubes (CNTs) through catalytic pyrolysis. Typically, the plastic-derived hydrocarbons, at high temperatures, contact the metal catalysts, allowing the supersaturation state of metal carbide and the formation of CNTs. To date, most research only reports the alkali earth metal elements as thermal supporting material without clarifying their impacts on metal activity in CNTs synthesis, limiting the manipulation of CNTs characteristic for applications. As such, this study aims to investigate the impacts of alkali earth metals towards the CNTs synthesis from the perspective of surface Ni activity, surface characteristic, and metal phases loading. This study utilized the NiMo-Ca-n (n = 0, 7, 15, and 32) and NiMo-X (X = Mg, Ca, Sr, Ba) catalysts prepared via solution combustion synthesis for one-pot synthesis of CNTs from face masks. In the first part of the study, it was discovered that at optimum Ca loading (n = 15), the presence of CaMoO4 (14.1 wt.%) and CaCO3 (13.4 wt.%) phases yielded longer CNTs with a carbon yield of 6.4 wt.% instead of carbon nanospheres and carbon fragments. Further increase in Ca loading with a high CaCO3 fraction (29.7 wt.%) would lower its carbon yield to 5.4 wt.% with short CNTs appearance. In the second part of the study, it was found that weaker Ni-X interaction moving down the Group 2 elements within NiMo-X jeopardizes the formation of CNTs, resulting in carbon flakes instead, especially from NiMo-Ba with a carbon yield at 3.1 wt.%.
- PublicationSynthesis, Characterisation And Molecular Docking Of Quinoxaline-isoxazole Hybrids As Potential Anti-hyperglycemic Agent(2024-09)Phongphane, LacksanyDiabetes mellitus is a chronic metabolic disorder that affects millions of people worldwide, leading to severe complications such as cardiovascular disease, obesity, and retinopathy. Despite advances in treatment, effective management of diabetes remains a significant challenge due to the limitations of current therapeutic options, including side effects and limited efficacy in controlling blood glucose levels. Hence, in our effort to develop anti-hyperglycemic agents that potentially inhibiting α-amylase and α-glucosidase enzymes, a series of new quinoxaline-isoxazole hybrids were successfully synthesised via five-step cyclisation. The new quinoxaline-isoxazole derivatives (84a-84v) were successful synthesised and obtained twenty-two compounds in a good yield within the range of 54% to 95%. Subsequently, these synthesised compounds were characterised and elucidated by several spectroscopies methods consisting of Fourier transform-infrared (FT-IR), and nuclear magnetic resonance (1D and 2D-NMR) including high-resolution mass spectrometry (HRMS). The synthesised compounds were further evaluated for the in vitro -amylase and -glucosidase inhibitory activities using acarbose as a positive control. Among 22 synthesised compounds, the results revealed that compound 84j showed dual inhibitory towards -amylase and -glucosidase with promising IC50 values of 17.0 and 40.1 μM, respectively. Moreover, compound 84c was also displayed the good dual activity for the inhibition of -amylase (IC50 = 24.0 μM) and -glucosidase (IC50 = 41.7 μM).
- 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.