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University of Malaya

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Articles 1 - 13 of 13

Full-Text Articles in Environmental Chemistry

Population Genetics Of Rhizophora Apiculata In Peninsular Malaysia Using Microsatellite Markers, Amelia Azman Oct 2020

Population Genetics Of Rhizophora Apiculata In Peninsular Malaysia Using Microsatellite Markers, Amelia Azman

Student Works (2020-2029)

Rampant illegal logging, overharvesting and deforestation coupled with climate change, pose significant threats to the natural stands of Rhizophora apiculata, or locally known as Bakau Minyak; one of the most economically and ecologically important species of mangroves in Peninsular Malaysia. Despite being a dominant mangrove species, the reduction in the number of R. apiculata in its habitat has resulted in concerns over the long-term survival potential of the species. In Malaysia, genetic information to develop effective guidelines for the conservation and management of mangrove species has been lacking, and hence, further research should be conducted to fill this gap. The …


Hexacyanoferrate-Based Nanocomposites For The Electrochemical Sensing Of Hydrogen Peroxide And Nicotine, Lee Pui Kee Sep 2020

Hexacyanoferrate-Based Nanocomposites For The Electrochemical Sensing Of Hydrogen Peroxide And Nicotine, Lee Pui Kee

Student Works (2020-2029)

Metal hexacyanoferrate (MeHCF) is a unique material that not only acquired immense research interest in electrochemical sensing field but also possesses potential as energy storage material. As such, the present thesis sought to investigate the facile method to synthesis MeHCF-based nanocomposites and explore its possible applications. First, comparative research on the synthesis of Prussian blue-polypyrrole (PB-PPy) nanocomposite by novel self-assembly (SA) method and conventional electrodeposition technique was performed. PB-PPy nanocomposites were prepared by the novel self-assembly method and via the electrodeposition approach. The nanocomposites were compared in term of surface morphology and its electrochemical and electrocatalytic characteristics. The results indicated …


Meteorological Conditions And Transport Of Air Pollutants At Bachok Marine Research Station (Bmrs) In Peninsular Malaysia, Mohyeddin Noraini Sep 2020

Meteorological Conditions And Transport Of Air Pollutants At Bachok Marine Research Station (Bmrs) In Peninsular Malaysia, Mohyeddin Noraini

Student Works (2020-2029)

This study is focused at relatively new regional Global Atmospheric Watch (GAW) station at Peninsular Malaysia – Bachok Marine Research Station (BMRS) using the observational and remote sensing data. The study consists of three main objectives. Firstly, to investigate the meteorological conditions during two major Southeast Asia monsoon – NE and SW monsoon. Secondly, to determine the potential sources of air pollution at BMRS during the monsoon periods. Thirdly, to examine the relations of carbon dioxide (CO2), methane (CH4) and particulate matters (PM10, and PM2.5) with the meteorological conditions during intensive case study periods. The first case study (CS1) was …


Optimisation Of Biomass And Lipid Production Of A Tropical Thraustochytrid Aurantiochytrium Sp. Umacc-T023 In Submerged-Liquid Fermentation For Large-Scale Biodiesel Production, Sohedein Mohamad Nor Azzimi Jul 2020

Optimisation Of Biomass And Lipid Production Of A Tropical Thraustochytrid Aurantiochytrium Sp. Umacc-T023 In Submerged-Liquid Fermentation For Large-Scale Biodiesel Production, Sohedein Mohamad Nor Azzimi

Student Works (2020-2029)

A tropical thraustochytrid, Aurantiochytrium sp. UMACC-T023, was optimised for high biomass and lipid production in submerged-liquid fermentation (SLF). Biomass and lipid production were optimised based on glucose, polypeptone, and yeast extract concentration using response surface methodology (RSM). In RSM, the applied central composite design (CCD) showed that the optimisation model was significant for all variables studied. Yeast extract and polypeptone were associated with significant effects in UMACC-T023 biomass production with p < 0.05. The model was validated by employing the optimised media composition in shake flasks and in 1.4-L stirred-tank bioreactors. The optimised media composition for both biomass and lipid production was 10 g L-1 glucose, 15.08 g L-1 polypeptone, and 13.56 g L-1 yeast extract. Biomass production in the bioreactor increased 2.12-fold compared with the shake flask culture utilising the same optimised media composition. This result demonstrated that the optimized media composition can be utilised for large-scale lipid production of UMACC-T023 for potential biodiesel feedstock as it also fulfilled the international standards for biodiesel.


The Influence Of Carbon Nanotubes And Mn Dopant Onto Zinc Oxide For Degradation Of Organic Pollutant Model Under Visible Light Irradiation, Ab Wahab Norfarhanah Jul 2020

The Influence Of Carbon Nanotubes And Mn Dopant Onto Zinc Oxide For Degradation Of Organic Pollutant Model Under Visible Light Irradiation, Ab Wahab Norfarhanah

Student Works (2020-2029)

Globally untreated industrial wastewaters are contaminating soil, surface water, groundwater, and consequently, the environment. Therefore, there is a huge interest in developing efficient and effective removal methods, such as photocatalytic advanced oxidation processes (AOP) under visible light (~47% of solar irradiation). In this work, the effectiveness of Mn-doped ZnO composite decorated onto multiwall carbon nanotubes (MWCNTs) on photodegrading organic pollutants was studied. This composite was simultaneously synthesized by sol gel method. XRD was used to confirm the formation of ZnO/Mn nanocomposite and the crystalline phase changes as ZnO content decreases when other elements were added to form the nanocomposite. The …


Green Synthesis Of Reduced Graphene Oxide For Efficient Adsorption-Photocatalysis Studies In Methylene Blue Dye Degradation, Ling Er Valerie Siong May 2020

Green Synthesis Of Reduced Graphene Oxide For Efficient Adsorption-Photocatalysis Studies In Methylene Blue Dye Degradation, Ling Er Valerie Siong

Student Works (2020-2029)

Dyes are one of the major components of industrial effluents. Owing to the complex structures of these toxic organic compounds, the removal of dyes from effluents possesses a great challenge in wastewater treatment. In order to tackle this issue, one of the effective methods is to remove dyes via the combination of adsorption and photocatalysis processes. In the present work, reduced graphene oxide (rGO) was fabricated from graphene oxide (GO) by using an environmentally friendly solvothermal approach, whereby ethanol was employed as a non-toxic reductant. In order to investigate the formation of rGO, the reduction of GO was carried out …


Synthesis And Fabrication Of Trimetallic (Ru-Mn Co) Catalyst Supported On Tio2 And Ni(Oh)2 Thin Films For Photoelectrochemical Applications, Che Mat Ahmad Nazeer Mar 2020

Synthesis And Fabrication Of Trimetallic (Ru-Mn Co) Catalyst Supported On Tio2 And Ni(Oh)2 Thin Films For Photoelectrochemical Applications, Che Mat Ahmad Nazeer

Student Works (2020-2029)

Anatase supported heterogeneous photocatalyst consisting of RuO2, MnO2 and Co3O4 (1:13:13 ratio) was synthesized by precipitation method. The film of the prepared catalyst was fabricated by electrophoretic deposition technique in an aqueous solution of 0.1 mM ammonia and tested for photoelectrocatalytic (PEC) oxidation of methanol in 0.1M KOH under visible light irradiation. The as-prepared photocatalyst was characterized by FTIR, UV–Vis, XRD, Raman spectroscopy, FESEM/EDX, TEM, BET, XPS and TPR. The PEC study by cyclic voltammetry indicates that the oxidation of methanol to CO2 and H2O upon exposure to visible light occurs between 400 and 800 nm. The smaller value of …


Ionic Liquid Functionalized Β-Cyclodextrin Modified Electrode As Electrochemical Sensor For 2,4-Dichlorophenol, Fairuz Liyana Mohd Rasdi Jan 2020

Ionic Liquid Functionalized Β-Cyclodextrin Modified Electrode As Electrochemical Sensor For 2,4-Dichlorophenol, Fairuz Liyana Mohd Rasdi

Student Works (2020-2029)

This thesis described the synthesis and characterization of ionic liquid monofunctionalized β-cyclodextrin (β-CD-1-BIMOTs) and ionic liquid difunctionalized β-cyclodextrin (β-CD-2-BIMOTs) for sensor applications. The physical characterizations of these compounds have been conducted using nuclear magnetic resonance (NMR), Fourier transform infra-red (FTIR), energy dispersive x-ray (EDX), x-ray diffraction (XRD) and Brunauer-Emmet-Teller (BET) analyses. These compounds were used as modifiers for carbon paste electrode (CPE). Cyclic voltammetry and chrono-amperometry methods were employed to examine the electrochemical responses of all prepared CPEs. All prepared electrodes show responses towards the target analyte of 2,4-dichlorophenol (2,4-DCP). Both β-CD-1-BIMOTs/CPE and β-CD-2-BIMOTs/CPE give higher current (i) responses compared …


Molecular Dynamics Simulations Of Phase Behaviour And Structural Studies Of Guanidinium Triflate Ionic Liquid And Its Mixture With Water And N-Methyldiethanolamine For Carbon Dioxide Removal, Naimah Haron Jan 2020

Molecular Dynamics Simulations Of Phase Behaviour And Structural Studies Of Guanidinium Triflate Ionic Liquid And Its Mixture With Water And N-Methyldiethanolamine For Carbon Dioxide Removal, Naimah Haron

Student Works (2020-2029)

Molecular dynamics (MDs) simulations with an all-atom force field have been carried out to understand the phase equilibrium behaviour of aqueous guanidinium triflate [gua][OTf] ionic liquid (IL) (binary system) at 440.15 K, as well as the phase equilibrium behaviour of N-methyl diethanolamine (MDEA) with aqueous [gua][OTf] IL (ternary system) at 298.15 K. This work further elaborated the understanding of absorption mechanism of carbon dioxide (CO2) into ternary system at 298.15 K. For binary system, the simulations measured changes in different physical properties such as density, structural, bonding properties (radial distribution function (RDF)), water clustering and hydrogen bonding) and dynamic property …


Determination Of Lead, Cadmium, Zinc And Nickel Inedible Oil Products By Stripping Voltammetry., Ng Khan Loon Jan 2010

Determination Of Lead, Cadmium, Zinc And Nickel Inedible Oil Products By Stripping Voltammetry., Ng Khan Loon

Student Works (2010-2019)

Edible oil products had become an everyday food that been consumed by most of the people either for dressing or for cooking purpose. Metal has become a common contamination to the food product, which it found the way into the edible oil through environment and processing contamination such as crushing, distillation, and hydrogenation. In this Study, the main focuses of metal analysis are only confined to 4 common metals which are the Cadmium, Lead, Zinc and Nickel. These elements are selected in this study due to reason that Cadmium and Lead are commonly known for their contamination from environment and …


Application Of Solid-Phase Microextraction For The Analysis Of Polycyclic Aromatic Hydrocarbons In Hyophila Involuta As A Natural Biosensor., Elizabeth Fong Yew Mei Jan 2010

Application Of Solid-Phase Microextraction For The Analysis Of Polycyclic Aromatic Hydrocarbons In Hyophila Involuta As A Natural Biosensor., Elizabeth Fong Yew Mei

Student Works (2010-2019)

This work describes a simple and rapid extraction method by using solid-phase microextraction (SPME) technique for the determination of polycyclic aromatic hydrocarbons (PAHs) from mosses of Hyophila involuta which is found commonly and abundantly throughout Peninsular Malaysia. Mosses have been chosen in our study since they are effective bioindicators as they take up nutrients and pollutants directly from the atmosphere and they have no root system. These properties make them ideal for evaluating pollutant levels in the air over a monitored period of time. This study has been developed and optimized based on the extraction of the analytes of interest …


Quality Of Tap Water In 20 Selected Areas In Selangor, Christine Boon Hwee Ong Jan 2002

Quality Of Tap Water In 20 Selected Areas In Selangor, Christine Boon Hwee Ong

Student Works (2000-2009)

The quality of tap water is becoming of great concern to the public all over the wor1d. However, this study only covers the issue of tap water in Selangor and public's reactions towards it. Many of us question whether our tap water is clear, clean and safe enough for consumption. To many of us, the water problem that we face is acid water, contains iron and minerals, bacteria and it is hard water. Acid water Is a real problem nowadays as the environment gets more and more polluted due to gas emitted from industries, for example S02 and CO2. Acid …


Direct Titrimetric Determination And Of Sulphate, Chee Kin Tan Jan 2000

Direct Titrimetric Determination And Of Sulphate, Chee Kin Tan

Student Works (2000-2009)

Interference by foreign ions in direct titrimetric determination of sulphate with barium perchlorate using dimethylsulphonazo III (DMSA Ill) as indicator were studied in this research project. The use of certain water miscible solvents as titration medium has enhanced the determination of end-point. Among the methanol, ethanol, n-propanol and acetone used in the investigation, it was found that medium containing 40 to 50% n-propanol or acetone delivered distinct end-points. The effects of nine cations and eight anions were studied in the above sulphate titration. It was found that the interference caused by Li",Na",K",Mg2"·Mn2", Cd2", NH4", CI and Br are not significant. …