Pusat Pengajian Sains Kimia - Tesis
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Browsing Pusat Pengajian Sains Kimia - Tesis by Type "doctoral thesis"
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- PublicationDevelopment of polymeric nanocomposite hydrogel using poly (vinyl alcohol) reinforced with organically modified layered double hydroxides for drug delivery systems(2022-12)Nor Jannah binti Mohd SebriA new advanced polymeric material with a potential for drug delivery systems was developed using the versatile poly (vinyl alcohol), PVA, enhanced with layered double hydroxides (LDH) organically modified with sodium dodecyl sulfate (SDS) and sodium isethionate (Ise) via co-precipitation method.
- PublicationDiversity And Distribution Of Benthic Foraminifera In Mangrove Forests Of Penang Island(2023-02)Malek, Muhamad Naim AbdForaminifera is one of the diverse groups of organisms inhabiting mangrove environment, but local studies regarding benthic foraminifera are limited. Therefore, this study was conducted to examine the diversity and distribution patterns of the foraminifera species in mangrove forests around Penang Island, which were Teluk Tempoyak, Pulau Betong, and Kuala Sungai Pinang. A total of 648 surface sediment samples (N=18 points × 3 mangrove forests × 12 months) of 1 cm thick were randomly collected using scoops during the lowest spring tide. The sampling was conducted monthly from March 2017 to February 2018. The results showed low to moderate species diversity (H’ index: 0-1.4), typical of a mangrove environment. Overall, 29 benthic foraminifera species were identified, predominantly agglutinated with some combination of hyaline and porcelaneous tests. Benthic foraminifera in Pulau Betong mangrove recorded the highest species diversity (29 species), followed by Teluk Tempoyak (25 species) and Kuala Sungai Pinang (19 species). The species idetified are commonly found in mangrove swamps and in the coastal environment. Species distribution demonstrated significant variation among the different locations, zones, and seasonal factors in the three mangrove forests (p < 0.05).
- PublicationEnhanced Photocatalytic Degradation Of Bisphenol A Under Visible Light Irradiation Using Nano Disc Rice Husk Ash Silica Templated Oxygen Doped Mesoporous Carbon Nitride And Carbon Dots Modified Graphitic Carbon Nitride(2022-12)Bukola, Shittu FatimahA series of oxygen doped mesoporous carbon nitride (O-MCN) was synthesized via thermal polymerization method. Another series of carbon dots modified graphitic carbon nitride (CDs/g-C3N4) was also synthesized via microwave assisted thermal polymerization method. Both were used for the photodegradation of bisphenol A (BPA) under visible light irradiation. The O-MCN were labelled as xO-MCN ( x = 0.1, 0.2, 0.3, 0.4 and 0.5 g glucose) whereas the CDs/g-C3N4 were labelled as yCDs/g-C3N4 (y = 0.5, 1.0 and 1.5 ml CDs). The Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption (NAD), UV–vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron (XPS) spectroscopy were used to characterize the nanocomposites.
- 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).
- PublicationFunctional Cellulose Nanocrystal-Alginate Hydrogel Beads Prepared From Oil Palm Fronds For The Adsorption Of 4-Chlorophenol In Aqueous Solution(2023-01)Tuan Sherwyn HamidonThe present study aimed to develop efficient cellulose nanocrystal-based hydrogel beads in treating simulated wastewater contaminated with 4-chlorophenol. Initially, cellulose nanocrystals (CNCs) were extracted from oil palm fronds (OPF) employing the sulphuric acid hydrolysis method along with various pretreatments.
- PublicationGreen Zinc Oxide-based Photocatalysts: Preparation, Characterization And Photocatalytic Study For The Degradation Of Dyes Under Visible Light Irradiation(2023-08)Abdullah, Fatin HazirahThere is a scarcity of literature on the fabrication of zinc oxide (ZnO) photocatalyst using a greener biosynthetic route and bio-based materials, with a primary focus on improving the reusability, collection, and recovery of the photocatalyst. Besides, ZnO suffers from low photodegradation efficiency due to low visible light absorption and high recombination of photogenerated charge carriers. In this study, green ZnO-based photocatalysts were successfully synthesized at room temperature using environmentally friendly, low cost, and facile methods. The work highlights the combination of valorization of banana peel (BP) waste and natural rubber (NR) biopolymer to develop effective, economic, and sustainable photocatalysts with good reusability for high removal of dyes. The photoactivity of these photocatalysts were evaluated by the degradation of Methylene Blue (MB) dye under visible light irradiation. The ZnO nanoparticles were initially synthesized using BP extract as reducing and capping agents. The best conditions for green synthesis of ZnO were pH 12, 1 mL BP extract, 0.02 M zinc acetate dihydrate, 3 h synthesis time, and 60 °C temperature. The biosynthesized ZnO exhibited advanced properties and superior photocatalytic performance than the chemically synthesized ZnO, which was prepared for comparison purposes.
- PublicationHeterogeneous Fenton Degradation Of Ofloxacin In Aqueous Solution Using Fe3O4-Zeolite, Fe3O4-Montmorillonite And Fe3O4-Montmorillonite Alginate Composites(2023-04)Dhahawi, Alamri RahmahThe primary aim of this study is to develop an economical, stable and effective heterogeneous catalyst for wastewater remediation via the Fenton oxidation process. Fe3O4 can effectively activate H2O2 to produce hydroxyl radicals, but the particles agglomerate easily. To solve this problem, Fe3O4-zeolite (FeZ) and Fe3O4-montmorillonlite (FeM) composites were synthesized via a facile co-precipitation method and characterized using various techniques. The performance of each of the catalysts was evaluated via the Fenton degradation of ofloxacin (OFL), an antibiotic and a recalcitrant pollutant because of its high activity and poor biodegradability. The effect of parameters such as amount of Fe precursor, catalyst dosage, initial solution pH, initial OFL concentration, different oxidants, H2O2 dosage, reaction temperature and inorganic salts on the OFL removal percentage were investigated. Loading of Fe3O4 onto zeolites resulted in the formation composites with higher surface area and pore volume. Experimental results revealed that as much as 88% OFL from the aqueous OFL solution 20 mg/L and 51.2% total organic carbon (TOC) could be removed in 120 min using FeZ-8 catalyst at the optimum condition. Since montmorillonite is capable to adsorb OFL at higher concentration, the OFL initial concentration was adjusted to 50 mg/L for FeM.
- PublicationModification Of Chitosan With Deep Eutectic Solvent For The Adsorption Of Malachite Green(2022-07)Chadi, Sadiq AbubakarThe presence of dye in environmental wastewater is a serious concern as it poses a threat to the ecosystem. This thesis provides background information about different techniques to remove malachite green (MG) from an aqueous medium. Various treatment technologies have been studied to remove dye, adsorption and semi-permeable membrane extraction using polymer inclusion membrane (PIM). These methods are considered efficient methods for the decontamination of dyes from wastewater in this study. Chitosan (CH) is considered a promising, readily available, and inexpensive adsorption material obtained as a by-product from the seafood industry and other sources. Meanwhile, CH was functionalised and used as an adsorbent. CH was functionalised with using deep eutectic solvents (DES) to syntheses beads, magnetic nano-sized particles and was used as extractants and plasticisers at a different ratio. DES such as bis-(2-Ethylhexyl) phosphate (B2EHP), Aliquat 336, and dioctyl phthalate (DOP) were used to prepared PIMs. Various techniques such as pH point of zero charge (pHpzc), solubility, scanning electron microscopy (SEM), energy dispersion X-ray (EDX), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), thermo gravimetric/differential thermal analyses (TGA/DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer-Emett-Teller (BET) were carried out to analyse the physicochemical characteristics of the newly prepared CH materials. The characterisation analysis has shown surface modifications, incorporated B2EHP, DOP, Aliquat 336, iron, and chloride ions onto the CH molecules.
- PublicationOptimization Of Heterogeneous Fenton And Photo Fenton Reactions For The Treatment Of Palm Oil Mill Effluent Using Response Surface Methodology(2022-08)Sani, SadiqDisposal of untreated palm oil mill effluent (POME) has adverse effects on aquatic biota and the environment due to its high chemical oxygen demand (COD) and total organic carbon (TOC) content. This work investigated the effectiveness of magnetite nanoparticles (Fe3O4 NPs) and carbon-encapsulated magnetite nanocomposites (Fe3O4@C NCs) as heterogeneous Fenton and photo-Fenton catalysts for POME treatment. Solvothermal and hydrothermal methods were employed to synthesise the two catalysts. The catalysts were characterised using various techniques and the optimisation of the experimental parameters were investigated via a one-step screening using a Box-Behnken design via response surface methodology involving seven variables which are catalyst dosage, H2O2 concentration, contact/irradiation time, dilution ratio, pH of POME, agitation speed, and absorption time. Four response variables: TOC reduction (TOCr), TOC reduction efficiency (ETOC), COD reduction (CODr) and COD reduction efficiency (ECOD) were evaluated and a total of 62 runs were considered. The models developed were refined, tested by analysis of variance (ANOVA) and validated using experimental data. The catalyst recyclability, kinetics and thermodynamics of POME removal were investigated.
- PublicationPreparation And Characterization Of 4ꞌ-(4,4ꞌ-Isopropylidenediphynyl-1,1ꞌdiyldioxy) Dianiline/ 4,4ꞌ- (4,4ꞌ-Isopropylidenediphenoxy) Bis- (Phthalic Anhydride) Polyimide Nickel Nanocomposites (Bpada-Bapp Pi-Nincs)(2023-06)Nuru-Deen JajiThis work focusing specifically on the preparation and characterization of the 4ꞌ-(4,4ꞌ-isopropylidenediphynyl-1,1ꞌ-diyldioxy)dianiline/4,4ꞌ-(4,4ꞌ-isopropylidene-diphenoxy) bis- (phthalic anhydride) polyimide nickel nanocomposites (BPADA-BAPP PINiNCs).
- PublicationRemoval Of Pharmaceutically Active Compounds In Environmental Waters Using Polymer Inclusion Membranes(2022-11)Olasupo, AyoThe presence of residues of pharmaceutically active compounds in aquatic environments is a daunting issue of great concern. The occurrence, fate and potential toxicity of these contaminants in different environmental media have triggered the interest of the science community. They have been found in varying concentrations from ng/L to mg/L in different environmental matrices. As a result of their high solubility and low volatility, they are often found in the aquatic environment and the wastewater treatment plants (WWTPs) are their major reservoir. However, conventional WWTPs are incapable of removing these contaminants completely during treatments; hence, there is a need to explore other advanced wastewater treatments to compensate for the lapses of conventional WWTPs. In this study, an investigation on the removal of recalcitrant contaminants such as ciprofloxacin (CIP), sulfamethoxazole (SMZ), and diclofenac (DCF) from wastewater using polymer inclusion membranes (PIMs) fabricated from different base polymers (polyvinyl chloride (PVC) and cellulose triacetate (CTA), different carriers (bis-2-(ethylhexyl) phosphate (B2EHP) and tricapryl-methylammonium chloride (Aliquat 336)), and different plasticizers (dioctyl phthalate (DOP) and 2-nitro phenyl ether (NPOE)).
- PublicationRemoval, Pre-concentration And Determination Of Selected Pharmaceuticals From Environmental Water Samples(2022-06)Mohammad, Rania Edrees AdamPharmaceuticals are emerging contaminants that have been widely used in various applications, including human and veterinary medicine, as well as agricultural activities. The pharmaceutical analysis relies on accurate quantification of target pharmaceuticals from a complex matrix, yet this remains a difficult task due to their low concentrations. Therefore, this research demonstrated the use of different sample preparation methods for the determination of selected pharmaceuticals in water samples. A microextraction technique based on vortex-assisted liquid-liquid microextraction with back extraction (VALLME-BE) was developed for the determination of nonsteroidal anti-inflammatory drugs (NSAIDs) namely, ketoprofen, naproxen, diclofenac, and ibuprofen. The procedure was carried out by adding 225 μL of butyl acetate into 10 mL spiked working standard for VALLME procedure, followed by the back-extraction into sodium hydroxide prior to high performance liquid chromatography-UV-Vis (HPLC-UV-Vis) analysis. Under optimum conditions, the proposed technique provided good linearity (R2 ≥ 0.9809), repeatability (%RSD; 3.4 – 16.1), and excellent the limits of detection (LOD) and limit of quantification (LOQ) values (ketoprofen (0.134 and 0.407 μg L-1), naproxen (0.015 and 0.047 μg L-1), diclofenac (0.03 and 0.091 μg L-1) and ibuprofen (0.05 and 0.152 μg L-1) were obtained. On the other hand, graphene oxide (GO), graphene oxide magnetite (GO@Fe3O4), and graphene oxide magnetite-deep eutectic solvent ferrofluid (GO@Fe3O4-DES FF) adsorbents were successfully synthesized and characterized
- PublicationSynthesis And Characterizations Of Biomass-Based Graphene Metal Oxide Anodes In Microbial Fuel Cells (MFCs) Applications(2021-12)Asim Ali YaqoobMicrobial fuel cells (MFCs) ranked among the most promising bioelectrochemical approaches for generating electrical energy while removing pollutants from wastewater, however, their relatively poor performance, has limited their commercial viability. The fabrication of advanced electrode material for MFCs is the most potential topic at present to address the issue of low electron transfer rates in the MFCs operation. In the present work, green synthesized metal oxides (ZnO and TiO2) nanoparticles (NPs) were introduced to biomass-derived graphene oxide (GO) as nanocomposite anodes. The GO/metal oxide nanocomposite anodes provide efficient energy transfer and metal ions remediation. Several toxic metals such as lead, cadmium, chromium, nickel, cobalt, and mercury were targeted in the current study.
- PublicationSynthesis Of Chitosan-Activated Carbon Composites Using Hydrophilic Imidazolium-Based Ionic Liquids For Adsorption Of Acid Blue 25 Dye, Cd(ii) And Pb(ii) From Aqueous Solutions(2022-08)Olalekan, Saheed IsmailaChitosan is a promising adsorbent for the removal of contaminants but its instability in acidic medium limits its potentials, and therefore its modification is necessary. Green synthesis approach featuring one pot mixture of chitosan (Ch) and activated charcoal (AC) in some selected hydrophilic imidazolium based ionic liquids (ILs) medium was utilised to modify chitosan into chitosan/activated carbon composite powders, beads and sponges. The prepared composites was utilised for the adsorption of acid blue 25 dye (AB25), Cd(II) and Pb(II) ions from aqueous solutions. Some selected hydrophilic imidazolium ILs including 1-allyl-3-methylimidazolium bromide (AmimBr), 1-allyl-3-methylimidazolium chloride (AmimCl), 1-ethyl-3-methylimidazolium acetate (EmimAc) and 1-butyl-3-methylimidazolium acetate (BmimAc) medium were utilised for the modification. The possible morphological and structural variation with respect to adsorptive characters and stability of the prepared composites were examined using scanning electron microscope (SEM), energy dispersive x-ray spectrometer (EDX), Brunauer–Emmett–Teller (BET) analysis, Fourier transform infrared (FTIR) spectrometer, x-ray diffraction (XRD) analysis and thermogravimetric analysis (TGA).
- PublicationSynthesis Of Large Pore Zeolites For Catalyzing Furanic-Type Fuel Compounds(2021-12)Nur Hidayahni Binti AhmadLinde type L (LTL topology) and offretite (OFF topology) zeolites are large pore zeolites (diameter 7.1 × 7.1 Å2 and 6.7 × 6.8 Å2, respectively). The aim of this project is to synthesize and apply LTL and OFF acidic zeolites in catalyzing various furanic-type reactions
- PublicationSynthesis, Characterization, Cytotoxicity, And Antimicrobial Activity Of Azobenzene-Imidazolium Ionic Liquid Crystals(2023-04)Babamale Halimah FunmilayoFour new series of azobenzene-imidazolium salts were synthesized by azo coupling, followed by alkylation and subsequent quaternization of N-alkylated imidazoles of various chain length with azobenzenes to afford the non-fluorinated (9a-9e), difluorinated (10a-10e) and tetrafluorinated (11a-11e, 12a-12j) salts. The purity of the compounds was confirmed by CHN elemental analysis and their structures were elucidated using the FTIR, 1D and 2D NMR spectroscopies. The liquid crystalline (LC) properties of the salts were studied using the DSC and POM. In vitro cytotoxicity was explored using the MTT assay and their antimicrobial activities were investigated using the disc diffusion method. Smectic A (SmA) phase was observed in almost all compounds.