Pusat Pengajian Sains Kimia - Tesis

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Sintesis Dan Pencirian Polimer-polimer Terbitan Daripada Getah Asli 50%-Terepoksida Dan Natrium 1,3,3,5,5, -Pentakis(Trifluoroetoksi) -1-Oksosiklotrifosfazenat
(1993-04)
Loo Swee Chow
Getah asli SO%-terepoksida (ENR-SO) telah ditindakbalaskan dengan natrium 1,3,3,S,S-pentakis(trifluoroetoksi)-1-oksosiklotrifosfazenat (mononatrium fosfazenat) dalam 1,4- dioksana refluks. Polimer-polimer terbitan yang diperolehi daripada nisbah berat ENR-SO:mononatrium fosfazenat yang berlainan (1.00:0.50, 1.00:1.00, 1.00:2.00, 1.00:3.00, 1.00: 4.50 dan 1.00:5.50) didapati mempunyai nilai-nilai suhu peralihan kaca (Tg) yang lebih tinggi daripada nilai Tg ENR- 50. Walau bagaimanapun, kesemua polimer terbitan didapati larut dalam 1,4-dioksana, tetrahidrofuran dan etanol.
Pengolahan Air Buangan Pencelup Melalui Penambahan Serbuk Karbon Diaktifkan Ke Dalam Enapan Teraktif Dalam Reaktor Kelompok Berturutan
(1998-02)
Er Cheow Chin
Penyelidikan ini bertujuan untuk mengkaji pengolahan air buangan berpencelup Biru Asid dan Kuning Bes dengan sistem PACT berlangkah SBRT. Lima jenis bahan penjerap iaitu serbuk karbon diaktifkan (PAC), tanah gambut, abuk kayu, sekam padi dan biomas telah diselidik dari segi kecekapan penyingkiran terhadap kedua-dua pencelup Biru Asid dan Kuning Bes.
Species Composition And Spatial Variation Of Benthic Diatoms At Intertidal Zone Under The Influence Of Environmental Parameters
(2017-12)
Ahmad Nordin, Noor Alia
Benthic diatoms play a significant role in the primary productivity and sediment dynamics of coastal and estuarine intertidal ecosystems. Thus, this study aims to determine the spatial distribution of benthic diatoms in intertidal flats from different environmental gradients. The spatial changes of benthic diatom composition under the influence of environmental variables in the tidal flats were studied. Canonical Correspondence Analysis (CCA) was conducted to define the relationships between environmental variables and diatom communities. Sediment samples were collected during low tide at six sampling stations four times in November 2013, February 2014, July 2014 and December 2014 in the coastal area of Tanjung Bungah, and in August 2014, January 2015, May 2015 and September 2015 in Tanjung Rhu, Langkawi estuary.
Natural Rubber And Natural Rubber Grafted Chitosan Films For Removal Of Dyes
(2019-08)
Hasanuddin, Nurul Hasliza
In this study, adsorption experiments of methylene blue (MB) onto the surface of natural rubber (NR) were accomplished under optimized conditions of initial dye concentration, pH and temperature. The adsorption process of MB onto NR in the concentrations range from 3.2 mg L’1 — 16.0 mg L"1 were found to follow linearized pseudo 2nd order: Type 1. The adsorption isotherm of NR onto MB obeyed the Langmuir isotherm with an agreement of R2= 0.9750. The calculated values of AH, AS, AG and Ea were found to be -21732.58 J mol’1, +14.24 J K‘* mol and - 26047.30 J mol'1 and +23.71 kJ mol'1 respectively. This adsorption study was shown to be spontaneous and exothermic in nature. However, NR took days to adsorb MB and failed to adsorb methyl orange (MO). Thus NR grafted chitosan (NR-g-Chi) with varied ratios of 80:20, 75:25 and 70:30 were implemented to improve the adsorption performance. The unpurified and purified NR-g-Chi was characterized using FTIR, TGA and DSC. Both NR and NR-g-Chi were studied for their PZC and swelling behavior. The performance adsorption of MB using NR-g-Chi showed better results than NR adsorption itself with shorter time taken.
Interfacial enhancement of mixed matrix membrane using ionic liquid for co2 separation
(2020-04-10)
Ahmad, Nor Naimah Rosyadah
The use of mixed matrix membrane (MMM) appears to be a promising approach in CO2 separation application due to the synergistic effects of polymer and inorganic materials. However, poor compatibility between inorganic particles and polymer often results in interfacial defects that reduce the MMM gas separation performance. In this study, asymmetric MMMs comprises of polysulfone (PSf) and SAPO-34 zeolite were fabricated via dry-wet phase inversion. The loading of SAPO-34 zeolite in the MMM formulation was first varied from 5 to 15 wt.% to study the effect of zeolite loading to the characteristics of the MMMs and CO2 gas separation performance. Increasing the zeolite loading has enhanced the CO2 permeance of the MMM but reduced the CO2/N2 selectivity as compared to the neat PSf membrane. The incorporation of SAPO-34 zeolite in the PSf membrane has resulted in the voids formation at the polymer/filler interface contact as shown by scanning electron microscopy images. Ionic liquid (IL) which selective towards CO2 was used in this study to modify the MMM by sealing the interface defects in the membrane. Two different approaches namely premodification and post-modification were applied in the MMM modification. Results showed that the post-modification method with IL has improved both polymer/zeolite interface contact and gas separation performance of the MMM as compared to the premodification approach. The post-modification method was further explored by studying the effects of IL concentration, zeolite loading, solvent and IL properties. It was found that the post-modification of the MMM incorporated with 5 wt. % zeolite loading has enhanced the CO2/N2 selectivity about 820 % over the unmodified MMM by increasing the concentration of the IL/ethanol solution from 0.2 to 0.4 M. The CO2/N2 selectivity can also be increased when more polar solvent such as methanol was used in the post-modification of MMM involving low IL concentration (0.2 M). The CO2 permeance and CO2/N2 selectivity of IL-modified MMM was improved to 4.93-7.19 GPU and 26.63-35.21 respectively by using IL with large molecular weight since the reduction in zeolite porosity could be minimized. Analysis of the gas transport parameters revealed that the incorporation of IL into the MMM has increased the CO2 solubility of the membrane but the improvement in the CO2/N2 selectivity was mainly contributed by the diffusivity selectivity. The gas separation performance for the IL-modified MMM was observed to sustain when being exposed to the humid gas condition. Thus, the post-modification approach of MMM using IL can be as an alternative strategy in membrane development for CO2 separation application.
Nitrogen-Doped Biochar As Peroxymonosulfate Activator For Acid Orange 7 Removal
(2021-11)
Zaeni Julia Raudlatul Jannah
The first study shows the oxygen-functionalized biochar that obtained from biowaste through facile method is the promising catalyst as PMS activator and the second study provides insights into Ndoped biochar preparation with favourable intrinsic and extrinsic properties from biowaste for sustainable pollutant removal via PMS activation.
Comparative Analysis Of The Bioethanol Yield And Components Of Sugar Extracted From Oil Palm Frond Under Different Prehydrolysis Treatments
(2021-11)
Dissanayake Mudiyanselage Rushan Lakshitha Bonuwan Diyanilla
this study was designed to produce a high bioethanol yield from OPF adopting eco-friendly and viable pretreatment methods, which are acid, autohydrolysis, alkaline, alkaline peroxide, and alkaline peroxide pretreatment coupled with acidified sodium chlorite (ASC) pretreatment
Synthesis, Characterization, And Photoluminescence Properties Of Ester Oligomers Containing Fluorene, Fluorescein And Curcumin Respectively For Potential Chemosensor Application
(2021-11)
Ong Hoay Ching
Three new homologous series of new ester oligomers containing fluorene (PF), fluorescein (FL) and curcumin (CM) on the backbone, respectively had been successfully synthesized and characterized. The molecular structures of the synthesized monomers and ester oligomers were elucidated by CHN, ATR-FTIR and FT-NMR (1D and 2D NMR). The synthesized ester oligomers showed high solubility in most of the common organic solvents, such as chloroform, tetrahydrofuran and acetone.
Development Of An Electrochemical Sensor Based On Molecularly Imprinted Go/Zno/Ppy Composites On Pencil Graphite Electrode For Determination Of Andrographolide
(2021-12)
Rabia Tasaduq Hussain
This research highlights the development of an electrochemical sensor based on graphene derivatives with a molecularly imprinted polypyyrole (PPy) layer on a pencil graphite electrode (PGE) to detect andrographolide, which is a bioactive component of an ancient plant known as Andrographis paniculata. Conventionally, andrographolide detection based on tedious and heavy instrumentation.
Synthesis Of Large Pore Zeolites For Catalyzing Furanic-Type Fuel Compounds
(2021-12)
Nur Hidayahni Binti Ahmad
Linde 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
Electrochemical Degradation Of Reactive Red 4 Using Graphite/Chitosan-Poly(Vinyl Chloride) Composite Electrodes
(2021-12)
Nadhra Hidayah Binti Mohd Halim
In this study, graphite/chitosan-poly(vinyl chloride) (C/Chi-PVC) composite electrode was used as anode to investigate the degradation of Reactive Red 4 (RR4) in the presence of graphite rod and sodium chloride (NaCl) respectively as cathode and supporting electrolytes.
Synthesis And Characterizations Of Biomass-Based Graphene Metal Oxide Anodes In Microbial Fuel Cells (MFCs) Applications
(2021-12)
Asim Ali Yaqoob
Microbial 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.
Preparation, Characterization, And Computational Study Of Bimetallic Iron Oxide Based Catalyst For Catalytic Oxidative Desulfurization Of Model Diesel
(2021-12)
Nor Atiq Syakila Binti Mohd Nazmi
Catalytic oxidative desulfurization (Cat-ODS) has been introduced as a new technique in achieving ultra-low sulfur diesel. In this study, Fe catalyst supported on alumina were prepared by wetness impregnation method and characterized using N2- adsorption/desorption (NA), field emission scanning electron microscopic (FESEM), X-ray diffraction (XRD) and High-Resolution Transmission Electron (HRTEM).
Preparation Of A Stabilized Nano-Lignin Emulsifier From Oil Palm Empty Fruit Bunch
(2022-01)
Siti Hajar Binti Sekeri
A study was carried out to determine the effectiveness of lignin, extracted from oil palm (Elaeis guineensis) biomass as a water-in-oil (W/O) emulsifier. To achieve this goal, soda lignin (SL) was extracted via soda pulping process and a series of nanosized soda lignin (NSL) was prepared using a homogenizer at three different speeds i.e., 10400 rpm (NSL 10), 11400 rpm (NSL 11), and 12400 rpm (NSL 12) for one hour.
Characterization, Kinetics And Equilibrium Studies Of Paracetamol Adsorption On The Oil Palm Fronds (Opf) Cellulose Nanocrystals
(2022-02)
Idris, Nor Najhan
Pollution of water via pharmaceutical drugs such as paracetamol have been a highly concerning issue; and effective measures must be taken to treat these aquatic contaminants. Hence, the present study explored use of cellulose nanocrystals (CNC) isolated from oil palm fronds (OPF) through pre-treatments and acid hydrolysis as an environmental friendly adsorbent. The complementary analyses showed that the OPF CNC possesses a crystallinity index of 43.60 %, surface area (10.51 m2 g-1), and an aspect ratio of 19.98. Besides, the OPF CNC and OPF CNC-AC hydrogel beads have been successfully produced, optimised, and applied for paracetamol removal. The modification of OPF CNC-AC hydrogel beads with the commercial activated carbon (AC) has improved the BET surface area up to 85.19 m2 g-1. The adsorption studies of paracetamol onto OPF CNC and OPF CNC-AC hydrogel beads can be achieved at 60 g and 0.6 g of adsorbent dosage, respectively, at a pH 3 with a contact time of 170 min under room temperature. It was observed that the produced data fitted best with the pseudo-second order kinetic model and Freundlich isotherm model for characterising the adsorption of paracetamol onto OPF CNC hydrogel beads with a maximum adsorption capacity, qmax of 0.03 mg g-1. Meanwhile, for OPF CNC-AC hydrogel beads, the pseudo-second order kinetic model and Langmuir isotherm model showed the best correlation for the adsorption of paracetamol with a qmax value of 21.31 mg g-1. Therefore, the output from this study may suggest that OPF CNC and OPF CNC- xxiv AC hydrogel beads can be used as natural adsorbents for the removal of paracetamol waste.
Synthesis, Structural Characterization And Anticancer Studies Of Asymmetrical And Symmetrical Dinuclear Silver(I) Di-nheterocyclic Carbene Complexes
(2022-03)
Nazri, Muhammad Zulhelmi
This thesis presents the synthesis, structural characterization, and anticancer studies of asymmetrical and symmetrical dinuclear silver(I) di-N-heterocyclic carbene (NHC) complexes which are mainly derived from bis- and tetrakis-benzimidazolium salts. The asymmetrical bis-benzimidazolium salts were prepared in two different substituents series comprising N-(2-bromoethyl)-N’-benzylbenzimidazolium bromide with R-alkyl group (R = CH3, C2H5, C3H7, C4H9, C5H11 and C6H13) (1‧Br – 6‧Br) as the first series and R-aryl group (R = 2-CN, 3-CN and 4-CN) (7‧Br – 15‧PF6) as the second series consisting of ethylene, propylene and butylene bridges, respectively. As for the symmetrical tetrakis-imidazolium salt was comprised reaction of 1,2,4,5- tetrakis(bromomethyl)benzene with imidazole moiety of 16‧Br. All the asymmetry bis-benzimidazolium and symmetry tetrakis-imidazolium salts were converted into their respective complexes by in-situ deprotonation reaction with Ag2O by varying the salt and metal molar ratio, thus resulting the formation of dinuclear silver(I) di-NHC complexes (Ag1 – Ag16). The structures of the bis-benzimidazolium (1‧Br – 15‧PF6), tetrakis-imidazolium (16‧Br) salts as well as Ag(I) di-NHC complexes (Ag1 – Ag16) were characterized by combination of spectroscopic data (FTIR, 1H- and 13C-NMR), CHN elemental analysis and single crystal X-ray diffraction technique. The single crystal X-ray diffraction studies of complex Ag4 suggest the complex crystallized in orthorhombic space group while the macrocyclic complex of Ag16 has cylinder-type structure.
Removal, Pre-concentration And Determination Of Selected Pharmaceuticals From Environmental Water Samples
(2022-06)
Mohammad, Rania Edrees Adam
Pharmaceuticals 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
Winged Beans Extract-Doped-Hybrid Composite Sol-Gel Coating For Corrosion Resistance Of Carbon Steel In 0.5 M Hydrochloric Acid
(2022-07)
Farah Athena, Zakaria
The present work focuses on the extraction of winged bean (WB) with different polarity of solvent for the application of corrosion inhibitor to reduce the corrosivity of carbon steel in 0.5 M HCl medium. It was revealed that winged bean water extract (WBW) had the highest percentage yield, followed by winged bean ethanol (WBE), methanol (WBM), and hexane (WBH) extract. Further characterization using complementary analyses disclosed the values of TPC, TFC and FRAP in trend such WBW (TPC: 117.40; TFC: 54.65) > WBE (TPC: 98.52; TFC: 52.67) > WBM (TPC: 82.64; TFC: 37.29) > WBH (TPC: 23.80; TFC: 17.59). A series of phytochemical screening and HPLC analysis qualitatively show the presence of phenolic compounds like gallic acid and ferulic acid which then quantified. FTIR spectra of WB extract discovered the presence of functional groups that characterize good corrosion inhibitors. The inhibition action of WB extracts studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PD), and electrochemical noise measurement (ENM) techniques revealed that WBW and WBE inhibition efficiencies (IE) from the three different techniques at 1000 ppm were beyond 80%. Overall data obtained suggested the Langmuir adsorption isotherm and physisorption mechanism with ΔGads ≤ -20 kJ mol-1, best described the inhibitory process of both WB extracts. Further application of WB extracts as additive in sol-gel coating results in the formation of Fe-Si-O from the characterization through FTIR-ATR and SEM-EDX with good hydrophobicity with wetting angle of > 100°.
Modification Of Chitosan With Deep Eutectic Solvent For The Adsorption Of Malachite Green
(2022-07)
Chadi, Sadiq Abubakar
The 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.
Synthesis, Characterization And Catalytic Study Of Microporous Silicoaluminophosphates In The Esterification Of Levulinic Acid With Ethanol
(2022-07)
Ma, Yik Ken
Silicoaluminophosphate (SAPO-n) number 34 (SAPO-34) and number 35 (SAPO-35) are eight-membered small pore zeolites commonly used as catalysts in the petrochemical industry. However, the time-dependent formation study of these zeolites is rarely studied and their syntheses generally require long crystallization time (at least 24 h) due to the use of organic aminic structural directing agents (SDAs). This project focuses on the hydrothermal synthesis and time-dependent evolution of SAPO-34 and SAPO-35 using a novel 1-propylpyridinium hydroxide ([PPy]OH) SDA. The microscopic and spectroscopic investigations reveal that induction and nucleation precede the formation of fully crystalline SAPO-34 at 200 oC for 19 h which partially transformed into SAPO-36 at 30 h, while pure SAPO-35 (200 oC, 21 h) was obtained from the intrazeolite transformation from SAPO-34. Notably, the [PPy]OH-templated SAPO-34 and SAPO-35 show higher porosity, silicon content and acidity compared to other templating systems. The crystallized SAPO-34 and SAPO-35 were also used to catalyze the esterification of levulinic acid and ethanol under non-microwave instant heating method. The SAPO-34 and SAPO-35 show 93.4% and 96.3% LA conversion, respectively, with 100% selectivity to ethyl levulinate at 190 oC and 20 min. The catalysts also show excellent reusability for at least five cycles and are potential alternatives to the traditional homogenous acid catalysts in the esterification reaction.

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