β-cyclodextrin dendritic-polymers and nanostructured materials for water treatment
- Authors: Malinga, Soraya Phumzile
- Date: 2013-07-24
- Subjects: Nanostructured materials , Cyclodextrins , Water purification - Membrane filtration , Dendrimers
- Type: Thesis
- Identifier: uj:7670 , http://hdl.handle.net/10210/8538
- Description: D.Phil. (Chemistry) , The application of dendritic-based materials has attracted great interest. For the first time this research has investigated the feasibility of poly (propyleneimine) (PPI) dendrimers and hyperbranched polyethyleneimine (HPEI) in combination with beta-cyclodextrin (β-CD) embedded in polysulfone (PSf) membrane for water treatment. The advantage of embedding these conjugates (β-CD-PPI and β-CD-HPEI) in PSf membranes is the presence of numerous nanocavities which can act as water channels allowing easy water passage through the membrane improving water permeability. Secondly, the presence of functional groups such as –OH and –NH greatly improves hydrophilicity of membranes. Commercial polysulfone (PSf) ultrafiltration membranes were crosslinked with β-cyclodextrin-poly (propyleneimine) (β-CD-PPI) and β-cyclodextrin-hyperbranched polyethyleneimine (β-CD-HPEI) using trimesoyl chloride (TMC) by interfacial polymerisation. These membranes were used in the rejection of Aldrich humic acid (molecular weight: 4.1 kDa) from synthetic water samples prepared in the laboratory. Moreover, β-cyclodextrin-poly (propyleneimine) (β-CD-PPI) was used as a host for the preparation of Fe/Ni nanoparticles. The new membranes were synthesised by crosslinking β-CD-PPI with trimesoyl chloride and subsequently loading Fe/Ni nanoparticles and this was supported on a commercial polysulphone (PSf) layer for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP). The membrane surfaces were characterised using Fourier transform infrared/attenuated total reflectance (FT-IR/ATR) spectroscopy , scanning electron microscopy (SEM), atomic force microscopy (AFM), high resolution transmission electron microscopy (HR-TEM), water-contact angle, and water-intake capacity...
- Full Text:
- Authors: Malinga, Soraya Phumzile
- Date: 2013-07-24
- Subjects: Nanostructured materials , Cyclodextrins , Water purification - Membrane filtration , Dendrimers
- Type: Thesis
- Identifier: uj:7670 , http://hdl.handle.net/10210/8538
- Description: D.Phil. (Chemistry) , The application of dendritic-based materials has attracted great interest. For the first time this research has investigated the feasibility of poly (propyleneimine) (PPI) dendrimers and hyperbranched polyethyleneimine (HPEI) in combination with beta-cyclodextrin (β-CD) embedded in polysulfone (PSf) membrane for water treatment. The advantage of embedding these conjugates (β-CD-PPI and β-CD-HPEI) in PSf membranes is the presence of numerous nanocavities which can act as water channels allowing easy water passage through the membrane improving water permeability. Secondly, the presence of functional groups such as –OH and –NH greatly improves hydrophilicity of membranes. Commercial polysulfone (PSf) ultrafiltration membranes were crosslinked with β-cyclodextrin-poly (propyleneimine) (β-CD-PPI) and β-cyclodextrin-hyperbranched polyethyleneimine (β-CD-HPEI) using trimesoyl chloride (TMC) by interfacial polymerisation. These membranes were used in the rejection of Aldrich humic acid (molecular weight: 4.1 kDa) from synthetic water samples prepared in the laboratory. Moreover, β-cyclodextrin-poly (propyleneimine) (β-CD-PPI) was used as a host for the preparation of Fe/Ni nanoparticles. The new membranes were synthesised by crosslinking β-CD-PPI with trimesoyl chloride and subsequently loading Fe/Ni nanoparticles and this was supported on a commercial polysulphone (PSf) layer for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP). The membrane surfaces were characterised using Fourier transform infrared/attenuated total reflectance (FT-IR/ATR) spectroscopy , scanning electron microscopy (SEM), atomic force microscopy (AFM), high resolution transmission electron microscopy (HR-TEM), water-contact angle, and water-intake capacity...
- Full Text:
WO3-SnO2 nanostructures supported on carbon nanomaterials for electrochemical energy storage
- Authors: Kganyago, Peter
- Date: 2020
- Subjects: Energy storage , Nanostructured materials , Storage batteries , Supercapacitors
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/458469 , uj:40723
- Description: Abstract: Electrochemical energy storage devices such as ion batteries or super-capacitors have been developed as energy carriers for new portable technologies. The electrochemical performance of an electrochemical device depends on the physico-chemical properties of the electrode materials. In supercapacitors, the design and composition of the electrode widely influence its performance. Great efforts have been undertaken to fabricate electrode materials of supercapacitors in a quest to improve the electrochemical performance of the electrode. In this project we focus on fabrication of TMOs on carbon nanomaterials. Carbon nanomaterials and transition metal oxides offers an interesting synergistic relationship which can be utilised in electrochemical energy storage devices. The types of metal oxide incorporated into the carbon nanomaterial as well as the nano-architecture of the materials affects the electrochemical properties and thus the performance of supercapacitors. Thus, this project is focused on the development of SnO2 nanostructures supported on carbonaceous 2D materials for electrochemical energy storage devices. The physico-chemical attributes of the nanocomposite were investigated using P-XRD, FTIR, TEM, SEM, TGA and BET. The electrochemical performance of the electrodes was tested using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) in 2M KOH electrolyte in a three-electrode configuration. The hybrid electrodes of NGs/WO3, NGs/SnO2 and NGs/WO3/SnO2 exhibits a maximum specific capacitance of 14 F/g ,30 F/g and 11.2 F/g respectively... , M.Sc. (Nanoscience)
- Full Text:
- Authors: Kganyago, Peter
- Date: 2020
- Subjects: Energy storage , Nanostructured materials , Storage batteries , Supercapacitors
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/458469 , uj:40723
- Description: Abstract: Electrochemical energy storage devices such as ion batteries or super-capacitors have been developed as energy carriers for new portable technologies. The electrochemical performance of an electrochemical device depends on the physico-chemical properties of the electrode materials. In supercapacitors, the design and composition of the electrode widely influence its performance. Great efforts have been undertaken to fabricate electrode materials of supercapacitors in a quest to improve the electrochemical performance of the electrode. In this project we focus on fabrication of TMOs on carbon nanomaterials. Carbon nanomaterials and transition metal oxides offers an interesting synergistic relationship which can be utilised in electrochemical energy storage devices. The types of metal oxide incorporated into the carbon nanomaterial as well as the nano-architecture of the materials affects the electrochemical properties and thus the performance of supercapacitors. Thus, this project is focused on the development of SnO2 nanostructures supported on carbonaceous 2D materials for electrochemical energy storage devices. The physico-chemical attributes of the nanocomposite were investigated using P-XRD, FTIR, TEM, SEM, TGA and BET. The electrochemical performance of the electrodes was tested using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) in 2M KOH electrolyte in a three-electrode configuration. The hybrid electrodes of NGs/WO3, NGs/SnO2 and NGs/WO3/SnO2 exhibits a maximum specific capacitance of 14 F/g ,30 F/g and 11.2 F/g respectively... , M.Sc. (Nanoscience)
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Utilization of coal-based sorbents and their fabrication into carbon nanomaterials for the removal of organics from wastewater
- Authors: Langwenya, Siphiwe P.
- Date: 2011-05-16T06:58:03Z
- Subjects: Sorbents , Nanostructured materials , Carbon , Water purification , Coal absorption and adsorption , Organic compounds removal
- Type: Thesis
- Identifier: uj:7068 , http://hdl.handle.net/10210/3630
- Description: M.Sc. , With increasing industrial activities in South Africa, many of its waters are contaminated with both organic and inorganic pollutants. This is also a worldwide challenge which has resulted in an escalation in research efforts to combat it. Organic pollutants, for example, can be harmful to human health and the environment. Even when present at low concentrations, they tend to bio-accumulate and interact with endocrine systems. Therefore it is necessary that these pollutants are removed from effluents before they are integrated with water systems such as rivers and lakes. In an effort to utilize economic and efficient removal techniques, low cost and locally available materials have been used as potential adsorbents for the removal of these organic pollutants from synthetic wastewater. These coal-based materials were further fabricated into nanoporous sorbents through activation processes to improve their adsorption properties. The project reported in this dissertation was thus undertaken to explore, specifically, the efficacy of coal and coal-based sorbents (acid treated coal, activated carbon and activated fly ash) in their ability to remove phenolic compounds from wastewater.
- Full Text:
- Authors: Langwenya, Siphiwe P.
- Date: 2011-05-16T06:58:03Z
- Subjects: Sorbents , Nanostructured materials , Carbon , Water purification , Coal absorption and adsorption , Organic compounds removal
- Type: Thesis
- Identifier: uj:7068 , http://hdl.handle.net/10210/3630
- Description: M.Sc. , With increasing industrial activities in South Africa, many of its waters are contaminated with both organic and inorganic pollutants. This is also a worldwide challenge which has resulted in an escalation in research efforts to combat it. Organic pollutants, for example, can be harmful to human health and the environment. Even when present at low concentrations, they tend to bio-accumulate and interact with endocrine systems. Therefore it is necessary that these pollutants are removed from effluents before they are integrated with water systems such as rivers and lakes. In an effort to utilize economic and efficient removal techniques, low cost and locally available materials have been used as potential adsorbents for the removal of these organic pollutants from synthetic wastewater. These coal-based materials were further fabricated into nanoporous sorbents through activation processes to improve their adsorption properties. The project reported in this dissertation was thus undertaken to explore, specifically, the efficacy of coal and coal-based sorbents (acid treated coal, activated carbon and activated fly ash) in their ability to remove phenolic compounds from wastewater.
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Understanding the C and N modifying effect on borophene as a highly selective and sensitive acetone sensor : a DFT study
- Authors: Molefi, Reitumetse Precious
- Date: 2021
- Subjects: Volatile organic compounds , Gas detectors , Nanostructured materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/484113 , uj:43959
- Description: Abstract: Detection of volatile organic compounds (VOCs) and flammable gases for health and security purposes using two-dimensional (2D) based materials for gas sensing has fascinated and attracted a great attention owing to their remarkable high surface to volume ratio and unique electronic properties. Furthermore, 2D based materials have attracted a great deal of interests due to their high sensitivity, selectivity as well as fast response. It is well known that for a material to be regarded as a gas sensor, it should have a certain combination of properties, such as high sensitivity, exceptional selectivity, high stability and rapid response time, while operating at normal conditions. Most of these properties are dependent on the surface area to volume ratio, high comparative number of defects and the crystal structure of 2D material sensing sheet. Moreover, the high demand for gas sensors worldwide justifies this work, as the market is estimated to increase to $1,336.2 million by 2027 from $823.1 million in 2019. The World Health Organisation (WHO) has reported that about 5.5 million deaths occur in a year due to air pollution... , M.Sc. (Nanoscience)
- Full Text:
- Authors: Molefi, Reitumetse Precious
- Date: 2021
- Subjects: Volatile organic compounds , Gas detectors , Nanostructured materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/484113 , uj:43959
- Description: Abstract: Detection of volatile organic compounds (VOCs) and flammable gases for health and security purposes using two-dimensional (2D) based materials for gas sensing has fascinated and attracted a great attention owing to their remarkable high surface to volume ratio and unique electronic properties. Furthermore, 2D based materials have attracted a great deal of interests due to their high sensitivity, selectivity as well as fast response. It is well known that for a material to be regarded as a gas sensor, it should have a certain combination of properties, such as high sensitivity, exceptional selectivity, high stability and rapid response time, while operating at normal conditions. Most of these properties are dependent on the surface area to volume ratio, high comparative number of defects and the crystal structure of 2D material sensing sheet. Moreover, the high demand for gas sensors worldwide justifies this work, as the market is estimated to increase to $1,336.2 million by 2027 from $823.1 million in 2019. The World Health Organisation (WHO) has reported that about 5.5 million deaths occur in a year due to air pollution... , M.Sc. (Nanoscience)
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Toxicity assessment of multiwalled carbon nanotubes and fullerenes to Pseudokirchneriella subcapitata, Daphnia magna and Poecilia reticulata in simulated fresh water systems
- Authors: Nyembe, Dumsile W.
- Date: 2016
- Subjects: Nanotechnology - Toxicity testing , Nanostructured materials , Nanotubes
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/124853 , uj:20966
- Description: Abstract: A huge variety of benefits are expected from the application of carbon based nanomaterials. Currently, the nanoproducts that can be found on the market can be classified as consumer products whereas future applications are presumed to encompass areas such as medicine, water purification and industrial applications. Nanomaterials are used mainly for their unique physicochemical properties which are known to improve products’ characteristics. Contrary to the physicochemical goodness, it is these very unique properties that have since raised health and the environmental concerns for. For the sustainability of this innovation and protection of the environment as well as human health, pro-active effort to understand and alleviate potential risks is vital. Current knowledge on nanoecotoxicology is clouded by uncertainties pertaining their fate and behaviour in the environment. With the increase in nanotechnology, carbon-based nanomaterials’ (CBN) have been earmarked for water purification. Their (CBN) behaviour in the aquatic environment, their biovailability in aquatic systems, interaction with and internalization by living organisms and their sub-lethal effects to aquatic organisms are key-determinates to their toxicity, yet they have only just began to emerge. The overarching aim of this thesis therefore was to address the existing gap in knowledge and further bring understanding of fate and behaviour of multi-walled carbon nanotubes (MWCNT) and fullerenes (C60) and their acute and sub-lethal toxicity to algae (Pseudokirchneriella subcapitata), daphnia (Daphnia magna) and fish (Poecilia reticulata) in simulated fresh water systems of varied salinity. The MWCNT and C60 were successfully synthesized using nebulized spray pyrolysis and chemical vapour deposition, respectively, as evidenced by characteristic peaks (D and G bands) identified using Raman spectroscopy. Acid oxidation of p-MWCNT and p-C60 yielded o-MWCNT and o-C60 respectively... , Ph.D. (Chemistry)
- Full Text:
- Authors: Nyembe, Dumsile W.
- Date: 2016
- Subjects: Nanotechnology - Toxicity testing , Nanostructured materials , Nanotubes
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/124853 , uj:20966
- Description: Abstract: A huge variety of benefits are expected from the application of carbon based nanomaterials. Currently, the nanoproducts that can be found on the market can be classified as consumer products whereas future applications are presumed to encompass areas such as medicine, water purification and industrial applications. Nanomaterials are used mainly for their unique physicochemical properties which are known to improve products’ characteristics. Contrary to the physicochemical goodness, it is these very unique properties that have since raised health and the environmental concerns for. For the sustainability of this innovation and protection of the environment as well as human health, pro-active effort to understand and alleviate potential risks is vital. Current knowledge on nanoecotoxicology is clouded by uncertainties pertaining their fate and behaviour in the environment. With the increase in nanotechnology, carbon-based nanomaterials’ (CBN) have been earmarked for water purification. Their (CBN) behaviour in the aquatic environment, their biovailability in aquatic systems, interaction with and internalization by living organisms and their sub-lethal effects to aquatic organisms are key-determinates to their toxicity, yet they have only just began to emerge. The overarching aim of this thesis therefore was to address the existing gap in knowledge and further bring understanding of fate and behaviour of multi-walled carbon nanotubes (MWCNT) and fullerenes (C60) and their acute and sub-lethal toxicity to algae (Pseudokirchneriella subcapitata), daphnia (Daphnia magna) and fish (Poecilia reticulata) in simulated fresh water systems of varied salinity. The MWCNT and C60 were successfully synthesized using nebulized spray pyrolysis and chemical vapour deposition, respectively, as evidenced by characteristic peaks (D and G bands) identified using Raman spectroscopy. Acid oxidation of p-MWCNT and p-C60 yielded o-MWCNT and o-C60 respectively... , Ph.D. (Chemistry)
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Towards the synthesis of doped carbon nanotube/polysulfone nanofiltration membranes for the removal of organic pollutants from water
- Authors: Yokwana, Kholiswa
- Date: 2014-06-26
- Subjects: Organic water pollutants , Carbon composites , Nanostructured materials , Nanotubes
- Type: Thesis
- Identifier: uj:11603 , http://hdl.handle.net/10210/11315
- Description: M.Tech. (Chemistry) , Please refer to full text to view abstract
- Full Text:
- Authors: Yokwana, Kholiswa
- Date: 2014-06-26
- Subjects: Organic water pollutants , Carbon composites , Nanostructured materials , Nanotubes
- Type: Thesis
- Identifier: uj:11603 , http://hdl.handle.net/10210/11315
- Description: M.Tech. (Chemistry) , Please refer to full text to view abstract
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Towards HIV sensing : the development of electrochemical DNA/RNA aptamer biosensors on dendrimer-gold platforms
- Authors: Vivian, John Suru
- Date: 2013-07-30
- Subjects: HIV infections - Diagnosis , Biosensors , Electrochemical sensors , Nanomedicine , Nanostructured materials , Dendrimers , Gold
- Type: Thesis
- Identifier: uj:7716 , http://hdl.handle.net/10210/8580
- Description: M.Sc. (Chemistry) , With the increase in the number of new Human Immunodeficiency Virus (HIV) infection and mortality rate worldwide partly due to diagnostic drawbacks which gives false negatives during the window period, it is imperative to find an alternative method of detection. The need for prompt, bed-side and field applicable analytical devices for biomedical purposes cannot be over emphasized in our fast paced world today. As a contribution to meeting these challenges, this dissertation reports (i) the development of novel electrochemical DNA/RNA aptamer biosensor for HIV sensing and (ii) the development of other DNA sequence specific electrochemical biosensors. These biosensors were based on composite platforms of dendrimer and gold nanoparticles...
- Full Text:
- Authors: Vivian, John Suru
- Date: 2013-07-30
- Subjects: HIV infections - Diagnosis , Biosensors , Electrochemical sensors , Nanomedicine , Nanostructured materials , Dendrimers , Gold
- Type: Thesis
- Identifier: uj:7716 , http://hdl.handle.net/10210/8580
- Description: M.Sc. (Chemistry) , With the increase in the number of new Human Immunodeficiency Virus (HIV) infection and mortality rate worldwide partly due to diagnostic drawbacks which gives false negatives during the window period, it is imperative to find an alternative method of detection. The need for prompt, bed-side and field applicable analytical devices for biomedical purposes cannot be over emphasized in our fast paced world today. As a contribution to meeting these challenges, this dissertation reports (i) the development of novel electrochemical DNA/RNA aptamer biosensor for HIV sensing and (ii) the development of other DNA sequence specific electrochemical biosensors. These biosensors were based on composite platforms of dendrimer and gold nanoparticles...
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Tin oxide nanomaterials : synthesis and their potential in photocatalysis
- Malindisa, Ramokone Christina
- Authors: Malindisa, Ramokone Christina
- Date: 2018
- Subjects: Photocatalysis , Nanostructured materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279594 , uj:30028
- Description: M.Sc. (Nanoscience) , Abstract: The lack of easy access to clean water is an issue of great concern worldwide due to the fact that clean water is essential for life. Most water bodies are now contaminated with toxic organic pollutants, particularly textile dyes, as a result of the continuous discharge of industrial and agricultural wastewater into them. The presence of these contaminants in the water bodies pose serious threat to human health and aquatic life. The need for the appropriate technology for the removal of these pollutants from water has therefore become a subject of great interest in the scientific community. Semiconductors have been widely used as the photocatalytic degradation of organic dyes in wastewater. However, this process encounters certain challenges. These challenges include the fast recombination rate of the photogenerated electron-hole pairs and the inability of the photocatalysts to function under visible light due to their wide band energy gaps. Steps to synthesize semiconductors that are able to utilize visible light and reduce the recombination rate of the electrons and holes are under consideration. In this study, we strive to synthesize semiconductors for the photocatalytic degradation of dyes and further improve their photocatalytic performance by doping them with metals and non-metals to form nanomaterials with different morphologies by use of surfactants. Hydrothermal method of synthesis was adopted in the fabrication of the nanomaterials in this research work. All the synthesized catalysts were characterized by using X–ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, and energy dispersive spectroscopy (EDS). These techniques helped to obtain information on the nanomaterial’s structure, formation, morphology, size and elemental analysis. Firstly, a comparison study on the effect of surfactant on the photocatalytic degradation performance of SnO nanoparticle was performed on the methyl orange dye under visible light illumination with interesting results. These samples were also observed to be present in the tetragonal romarchite phase of SnO. The band gaps of the surfactant modified SnO samples were wider and their visible light activities poorer compared to the pure SnO...
- Full Text:
- Authors: Malindisa, Ramokone Christina
- Date: 2018
- Subjects: Photocatalysis , Nanostructured materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279594 , uj:30028
- Description: M.Sc. (Nanoscience) , Abstract: The lack of easy access to clean water is an issue of great concern worldwide due to the fact that clean water is essential for life. Most water bodies are now contaminated with toxic organic pollutants, particularly textile dyes, as a result of the continuous discharge of industrial and agricultural wastewater into them. The presence of these contaminants in the water bodies pose serious threat to human health and aquatic life. The need for the appropriate technology for the removal of these pollutants from water has therefore become a subject of great interest in the scientific community. Semiconductors have been widely used as the photocatalytic degradation of organic dyes in wastewater. However, this process encounters certain challenges. These challenges include the fast recombination rate of the photogenerated electron-hole pairs and the inability of the photocatalysts to function under visible light due to their wide band energy gaps. Steps to synthesize semiconductors that are able to utilize visible light and reduce the recombination rate of the electrons and holes are under consideration. In this study, we strive to synthesize semiconductors for the photocatalytic degradation of dyes and further improve their photocatalytic performance by doping them with metals and non-metals to form nanomaterials with different morphologies by use of surfactants. Hydrothermal method of synthesis was adopted in the fabrication of the nanomaterials in this research work. All the synthesized catalysts were characterized by using X–ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, and energy dispersive spectroscopy (EDS). These techniques helped to obtain information on the nanomaterial’s structure, formation, morphology, size and elemental analysis. Firstly, a comparison study on the effect of surfactant on the photocatalytic degradation performance of SnO nanoparticle was performed on the methyl orange dye under visible light illumination with interesting results. These samples were also observed to be present in the tetragonal romarchite phase of SnO. The band gaps of the surfactant modified SnO samples were wider and their visible light activities poorer compared to the pure SnO...
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Thin spray rock liners with different concentrations of nanoclays
- Van Tonder, P., Booysen, C.J, Van Tonder, P
- Authors: Van Tonder, P. , Booysen, C.J , Van Tonder, P
- Date: 2014
- Subjects: Nanostructured materials , Polymer-impregnated concrete , Reinforced concrete construction
- Type: Article
- Identifier: uj:5080 , ISBN 9781614994657 , ISBN 9781614994664 , http://hdl.handle.net/10210/13651
- Description: This study investigates the possibility of effectively replacing polymers in thin sprayed liners (TSL’s) with nanoclay particles. In the industry Nano particles are used in many different products to enhance their properties. The strength properties was analysed to see if the addition of nanoclays improve the strengths of the TSL product. Different concentrations of nanoclay were added to a standard TSL mixture in the place of polymer particles. The different composites were tested for Tensile Strength, Compression Strength, Shear Strength and Shear Bond Strength. Though there are other parameters to be tested, the study will only focus on those mentioned above, as they were considered to be the most important. The materials used for testing these characteristics were supplied by Oxyfibre. The mixtures have consisted of four different composites that included the standard mixture, 2% nanoclays, 4% nanoclays and 6% nanoclays.
- Full Text:
- Authors: Van Tonder, P. , Booysen, C.J , Van Tonder, P
- Date: 2014
- Subjects: Nanostructured materials , Polymer-impregnated concrete , Reinforced concrete construction
- Type: Article
- Identifier: uj:5080 , ISBN 9781614994657 , ISBN 9781614994664 , http://hdl.handle.net/10210/13651
- Description: This study investigates the possibility of effectively replacing polymers in thin sprayed liners (TSL’s) with nanoclay particles. In the industry Nano particles are used in many different products to enhance their properties. The strength properties was analysed to see if the addition of nanoclays improve the strengths of the TSL product. Different concentrations of nanoclay were added to a standard TSL mixture in the place of polymer particles. The different composites were tested for Tensile Strength, Compression Strength, Shear Strength and Shear Bond Strength. Though there are other parameters to be tested, the study will only focus on those mentioned above, as they were considered to be the most important. The materials used for testing these characteristics were supplied by Oxyfibre. The mixtures have consisted of four different composites that included the standard mixture, 2% nanoclays, 4% nanoclays and 6% nanoclays.
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The use of carbon nanotubes co-polymerized with calixarenes for the removal of cadmium and organic contaminants from water
- Authors: Makayonke, Nozuko Thelma
- Date: 2012-05-02
- Subjects: Water pollution , Nanotubes , Calixarenes , Organic water pollutants , Cadmium toxicology , Carbon , Nanostructured materials , Water purification , Organic compounds removal , Cadmium removal
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/${Handle} , uj:2231 , http://hdl.handle.net/10210/4671
- Description: M.Sc. , The contamination of water by toxic compounds is one of the most serious environmental problems today. These toxic compounds mostly originate from industrial effluents, agriculture runoff, natural sources (e.g. heavy metals in water from rocks and soil erosion) and human waste. The contamination, which is both “organic” and “inorganic” has an impact on the environment and human health. The demand for water and the pressure to re-use this valuable resource has increased the need for improved techniques and materials to remove pollutants from water. The Nanomaterials Science research group at the University of Johannesburg has focused on developing synthetic polymers that can be employed in water treatment and pollutant monitoring. Recently, cyclodextrins (CD) and carbon nanotubes (CNTs) have been included in polymers for this application. For example, CD-co-hexamethylene-/toluene-diisocyanate polyurethanes and CNT-modified equivalents have been developed and have been successfully applied in removing organic contaminants from water to very low levels.1 Calixarenes are synthetic analogues of cyclodextrins that can be exploited via chemical modification to express a range of properties. In the present study, calixarenes, thiacalixarenes and carbon nanotube-based polymeric materials incorporating these molecules have been synthesised, characterised and tested for removing both organic pollutants (such as p-nitrophenol) and inorganic pollutants (Cd2+, Pb2+) from water. Lead(II) and Cadmium(II) are a threat in South Africa because of their toxicity, and while p-nitrophenol is much less of a problem it represents a useful model organic pollutant. The absorption capacity of the polymers towards heavy metals and organic contaminants was tested by mixing the polymer with synthetic water containing known concentration of the contaminants at about 10 mg/L. Atomic absorption spectrometry (AAS) and ultraviolet-visible spectrometry (UV-vis) were used to determine the levels of heavy metals and organic contaminants, respectively. The target pollutants (Cd2+, 1 see KL Salipira MTech dissertation, University of Johannesburg 2008 Pb2+ and p-nitrophenol) were all successfully removed from water by the various polymers, however the degree of removal and loading capacities of the polymers differed. This information gives some insight into what functional components are needed for making successful adsorbents. It was observed, for example, that ptert- butylcalix[8]arene/hexamethylene diisocyanate (C8A/HMDI) had a higher adsorption capacity towards p-nitrophenol and Pb2+ than towards Cd2+, and also a higher capacity than the corresponding calix[4]arene polymers with smaller calixarene cavities.
- Full Text:
- Authors: Makayonke, Nozuko Thelma
- Date: 2012-05-02
- Subjects: Water pollution , Nanotubes , Calixarenes , Organic water pollutants , Cadmium toxicology , Carbon , Nanostructured materials , Water purification , Organic compounds removal , Cadmium removal
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/${Handle} , uj:2231 , http://hdl.handle.net/10210/4671
- Description: M.Sc. , The contamination of water by toxic compounds is one of the most serious environmental problems today. These toxic compounds mostly originate from industrial effluents, agriculture runoff, natural sources (e.g. heavy metals in water from rocks and soil erosion) and human waste. The contamination, which is both “organic” and “inorganic” has an impact on the environment and human health. The demand for water and the pressure to re-use this valuable resource has increased the need for improved techniques and materials to remove pollutants from water. The Nanomaterials Science research group at the University of Johannesburg has focused on developing synthetic polymers that can be employed in water treatment and pollutant monitoring. Recently, cyclodextrins (CD) and carbon nanotubes (CNTs) have been included in polymers for this application. For example, CD-co-hexamethylene-/toluene-diisocyanate polyurethanes and CNT-modified equivalents have been developed and have been successfully applied in removing organic contaminants from water to very low levels.1 Calixarenes are synthetic analogues of cyclodextrins that can be exploited via chemical modification to express a range of properties. In the present study, calixarenes, thiacalixarenes and carbon nanotube-based polymeric materials incorporating these molecules have been synthesised, characterised and tested for removing both organic pollutants (such as p-nitrophenol) and inorganic pollutants (Cd2+, Pb2+) from water. Lead(II) and Cadmium(II) are a threat in South Africa because of their toxicity, and while p-nitrophenol is much less of a problem it represents a useful model organic pollutant. The absorption capacity of the polymers towards heavy metals and organic contaminants was tested by mixing the polymer with synthetic water containing known concentration of the contaminants at about 10 mg/L. Atomic absorption spectrometry (AAS) and ultraviolet-visible spectrometry (UV-vis) were used to determine the levels of heavy metals and organic contaminants, respectively. The target pollutants (Cd2+, 1 see KL Salipira MTech dissertation, University of Johannesburg 2008 Pb2+ and p-nitrophenol) were all successfully removed from water by the various polymers, however the degree of removal and loading capacities of the polymers differed. This information gives some insight into what functional components are needed for making successful adsorbents. It was observed, for example, that ptert- butylcalix[8]arene/hexamethylene diisocyanate (C8A/HMDI) had a higher adsorption capacity towards p-nitrophenol and Pb2+ than towards Cd2+, and also a higher capacity than the corresponding calix[4]arene polymers with smaller calixarene cavities.
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The synthesis of phosphorylated multiwalled carbon nanotubes and their use in the removal of Mercury(ll) and Chromium(Vl) ions from aqueous solution
- Authors: Velempini, Tarisai Phillipa
- Date: 2014-06-30
- Subjects: Carbon , Nanotubes , Nanostructured materials , Mercury , Water - Purification - Chromium removal
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/391557 , uj:11617 , http://hdl.handle.net/10210/11330
- Description: M.Sc. (Chemistry) , Please refer to full text to view abstract
- Full Text:
- Authors: Velempini, Tarisai Phillipa
- Date: 2014-06-30
- Subjects: Carbon , Nanotubes , Nanostructured materials , Mercury , Water - Purification - Chromium removal
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/391557 , uj:11617 , http://hdl.handle.net/10210/11330
- Description: M.Sc. (Chemistry) , Please refer to full text to view abstract
- Full Text:
The evaluation of dendrimer encapsulated ruthenium nanoparticles, immobilised on silica, as catalysts in various catalytic reactions and the effect of ionic liquids on the catalytic activity
- Authors: Antonels, Nathan Charles
- Date: 2015-04-22
- Subjects: Dendrimers , Catalysis , Nanostructured materials , Nanoparticles
- Type: Thesis
- Identifier: uj:13555 , http://hdl.handle.net/10210/13696
- Description: Ph.D. (Chemistry) , This study discusses the preparation of various sized dendrimer encapsulated ruthenium nanoparticles (RuDEN) with the use of the generation 4 (G4), generation 5 (G5) and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents. The size of the nanoparticles ranges from 1.1-2.2 nm. The RuDENs were used as nanoparticle solutions in catalytic reactions or immobilised on amorphous silica 60 and silica 100 and subsequently referred to as RuSil catalysts. These catalysts were evaluated in the reduction of 4-nitrophenol, toluene hydrogenation, citral hydrogenation, cinnamaldehyde hydrogenation and styrene oxidation...
- Full Text:
- Authors: Antonels, Nathan Charles
- Date: 2015-04-22
- Subjects: Dendrimers , Catalysis , Nanostructured materials , Nanoparticles
- Type: Thesis
- Identifier: uj:13555 , http://hdl.handle.net/10210/13696
- Description: Ph.D. (Chemistry) , This study discusses the preparation of various sized dendrimer encapsulated ruthenium nanoparticles (RuDEN) with the use of the generation 4 (G4), generation 5 (G5) and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents. The size of the nanoparticles ranges from 1.1-2.2 nm. The RuDENs were used as nanoparticle solutions in catalytic reactions or immobilised on amorphous silica 60 and silica 100 and subsequently referred to as RuSil catalysts. These catalysts were evaluated in the reduction of 4-nitrophenol, toluene hydrogenation, citral hydrogenation, cinnamaldehyde hydrogenation and styrene oxidation...
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The enhancement of the activity of commercial antifungal agents using Aspalathus linearis synthesized gold nanoparticles
- Authors: Thipe, Velaphi Clement
- Date: 2015-06-30
- Subjects: Chemical tests and reagents , Antifungal agents , Nanoparticles - Synthesis , Nanostructured materials - Health aspects , Green chemistry , Nanostructured materials
- Type: Thesis
- Identifier: uj:13660 , http://hdl.handle.net/10210/13844
- Description: M.Sc.(Nanoscience) , The synthesis and application of gold nanoparticles (AuNPs) has been intensively studied worldwide. However, the toxicity of these nanoparticles is still a concern. We considered that various physiochemical methods used to synthesize AuNPs are energy driven, costly and require the use of harmful chemicals. Thus, this makes them not environmentally-friendly. The aim of this study was therefore to synthesize AuNPs via a greener route using Aspalathus linearis tea leaves. The AuNPs were used to coat eight commercial antifungal discs (i.e. amphotericin B, fluconazole, clotrimazole, econazole, flucytosine, ketoconazole, miconazole and nystatin) against four Aspergillus spp. for enhanced antifungal activity. The aqueous extract of A. linearis was characterized by high performance liquid chromatography and liquid chromatography–mass spectroscopy. The AuNPs were characterized using ultravioletvisible (UV-vis) spectroscopy, dynamic light scattering, nanoparticle tracking analysis, Fourier transforms infrared spectroscopy (FTIR), high-resolution transmission electron microscopy and X-ray diffraction. The toxicity of the synthesized AuNPs was studied by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and xCELLigence test on HepG-2 cell lines and results revealed very little to no toxicity of the AuNPs. The pristine antifungal and AuNPs coated antifungal discs were characterized by FTIR, scanning electron microscopy (SEM) and antifungal activity performed using the disc diffusion method. A strong resonance peak was observed at 529 nm of the AuNPs measured using UV-vis spectroscopy. Average size of AuNPs was ~44±1 nm and demonstrated excellent in-vitro stability under various solutions (5% NaCl, phosphate buffered saline) at varying pH levels. The SEM images revealed that the AuNPs were attached onto the coated antifungal discs when compared with the pristine antifungal discs. Antifungal results indicated that AuNPs significantly (p<0.001) enhanced the antifungal activity of the coated antifungal discs against the tested fungi when compared to the pristine antifungal discs. The AuNPs coated econazole disc exhibited the greatest (broad spectrum) activity than other antifungal agents tested. In conclusion, A. linearis can be used as a reducing agent in the synthesis of stable AuNPs. Furthermore, the AuNPs coated antifungal discs demonstrated considerable antifungal activity over the pristine antifungal discs...
- Full Text:
- Authors: Thipe, Velaphi Clement
- Date: 2015-06-30
- Subjects: Chemical tests and reagents , Antifungal agents , Nanoparticles - Synthesis , Nanostructured materials - Health aspects , Green chemistry , Nanostructured materials
- Type: Thesis
- Identifier: uj:13660 , http://hdl.handle.net/10210/13844
- Description: M.Sc.(Nanoscience) , The synthesis and application of gold nanoparticles (AuNPs) has been intensively studied worldwide. However, the toxicity of these nanoparticles is still a concern. We considered that various physiochemical methods used to synthesize AuNPs are energy driven, costly and require the use of harmful chemicals. Thus, this makes them not environmentally-friendly. The aim of this study was therefore to synthesize AuNPs via a greener route using Aspalathus linearis tea leaves. The AuNPs were used to coat eight commercial antifungal discs (i.e. amphotericin B, fluconazole, clotrimazole, econazole, flucytosine, ketoconazole, miconazole and nystatin) against four Aspergillus spp. for enhanced antifungal activity. The aqueous extract of A. linearis was characterized by high performance liquid chromatography and liquid chromatography–mass spectroscopy. The AuNPs were characterized using ultravioletvisible (UV-vis) spectroscopy, dynamic light scattering, nanoparticle tracking analysis, Fourier transforms infrared spectroscopy (FTIR), high-resolution transmission electron microscopy and X-ray diffraction. The toxicity of the synthesized AuNPs was studied by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and xCELLigence test on HepG-2 cell lines and results revealed very little to no toxicity of the AuNPs. The pristine antifungal and AuNPs coated antifungal discs were characterized by FTIR, scanning electron microscopy (SEM) and antifungal activity performed using the disc diffusion method. A strong resonance peak was observed at 529 nm of the AuNPs measured using UV-vis spectroscopy. Average size of AuNPs was ~44±1 nm and demonstrated excellent in-vitro stability under various solutions (5% NaCl, phosphate buffered saline) at varying pH levels. The SEM images revealed that the AuNPs were attached onto the coated antifungal discs when compared with the pristine antifungal discs. Antifungal results indicated that AuNPs significantly (p<0.001) enhanced the antifungal activity of the coated antifungal discs against the tested fungi when compared to the pristine antifungal discs. The AuNPs coated econazole disc exhibited the greatest (broad spectrum) activity than other antifungal agents tested. In conclusion, A. linearis can be used as a reducing agent in the synthesis of stable AuNPs. Furthermore, the AuNPs coated antifungal discs demonstrated considerable antifungal activity over the pristine antifungal discs...
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The effects of succussion on nanoparticles in ferrum metallicum 30C
- Authors: Hobson, Deborah Dawn
- Date: 2019
- Subjects: Homeopathic pharmacy , Nanoparticles , Nanostructured materials , Nanomedicine , Homeopathy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/399657 , uj:33319
- Description: Abstract : Nanoparticles are microscopic materials which range in length from 1-100 nanometres (nm). Nanoparticles have unique properties due to their size and shape, which include an increase in surface area, surface reactivity, thermal energy and diffusion rate. Nanomedicine refers to the application of nanoparticles in medicine, particularly in diagnostic techniques and as drug delivery systems. Nanoparticles are ideal for this as they provide greater bioavailability, are more easily absorbed by the body and produce a therapeutic effect with fewer side effects. Laboratory techniques to create nanoparticles include the top-down and bottom-up methods. Within these two methods are various synthesis techniques for creating nanoparticles, including solid phase synthesis, liquid phase synthesis, gas phase synthesis and green synthesis. Homoeopathy uses the top-down method by physically breaking down the starting substance via the process of potentization. Homoeopathy is a branch of complementary medicine (CM) founded by Dr Samuel Hahnemann in the late 1700’s. It is based on the principle similia similibus curantur, which translates to ‘like cures like’. Homoeopathic remedies are highly diluted substances which retain minute particles of the starting substance in the form of nanoparticles. The method used to make homoeopathic remedies is referred to as ‘potentization’ and includes trituration (grinding and serial dilution) of solid substances and succussion (violent shaking) of liquid substances. However, while homoeopathy has set guidelines for the trituration part of potentization, it lacks standardisation regarding the number of succussions which should be used. Iron (Fe) is a highly reactive silvery-white metal that easily forms compounds and alloys with other metals and has unique ferromagnetic properties which are stronger at lower temperatures. Ferrum metallicum, the homoeopathic remedy made from iron, can be used for a wide range of conditions when prepared in homoeopathic form. The aim of this study was to investigate the effect of succussion on the presence, size and distribution of nanoparticles in Ferrum metallicum 30C, when prepared with 0, 10 or 100 succussions, using transmission electron microscopy (TEM). iv This was a quantitative, experimental study performed at the Department of Chemistry, at the University of Johannesburg. Three batches of Ferrum metallicum 30C, with 0, 10 and 100 succussions respectively, and three controls of 43% ethanol with 0, 10 and 100 succussions respectively, were manufactured by the researcher. This was done at the laboratory of a registered manufacturer of homoeopathic medicines in Johannesburg. The researcher underwent training on the use of each of the laboratory analysis techniques. The sample preparation, experimental design and analysis of the samples was conducted by the researcher, under supervision and help of the laboratory technicians. Transmission Electron Microscopy (TEM) was conducted on two batches of samples. The first batch of samples showed contamination of the ethanol used to manufacture the test and control samples. The test samples were therefore manufactured a second time and TEM analysis conducted again. Additional analysis techniques were used to determine whether the first batch of test and control samples were contaminated and how the contamination had occurred. These analysis techniques included Energy Dispersive Spectroscopy (EDS), Inductively Couples Plasma Emission Spectroscopy (ICP-OES), Dynamic Light Scattering (DLS). An analysis for zeta potential of the samples and controls was conducted to explain the agglomeration of particles. TEM photographs were analysed by the researcher, under guidance of the co-supervisor, using the computer programme ImageJ. The results for EDS, ICP-OES, DLS and Zeta Potential were generated by the built-in software of the analysis machines, either as graphs or as numerical values. These were then analysed by the researcher under the guidance of the laboratory technicians. A total of five experimental procedures were conducted. The results of the experiments showed that the first batch of test and control samples was contaminated as the ethanol used to manufacture the samples contained traces of iron and unidentified particles. The additional analysis techniques helped confirm the contamination, and it was discovered that purified water, which was used to manufacture the ethanol used in the study, is not completely free of particles. The second batch of test and control samples, manufactured with distilled water, which is almost completely particle-free, showed positive results. The presence of spherically-shaped iron nanoparticles was confirmed for the test samples. Batch 1, Samples 1 and 2 (Ferrum v metallicum 30C with 0 and 10 succussions respectively), contained nanoparticles which were evenly distributed and unagglomerated. Batch 1, Sample 3 (Ferrum metallicum 30C with 100 succussions) had nanoparticles which were smaller in size, greater in number and agglomerated. Batch 2, Samples 1-2 (Ferrum metallicum 30C with 0 and 10 succussions respectively) contained nanoparticles which were more defined in shape, with similar numbers and sizes, and existed mainly as well-distributed, unagglomerated nanoparticles. Batch 2, Sample 3 (Ferrum metallicum 30C with 100 succussions) had nanoparticles which were slightly less in number and smaller, according to the automatic analysis by ImageJ, and which appeared to be distributed unevenly in smaller clusters. The first batch of control samples contained a large number of unidentified particles. The second batch of control samples also contained particles, although significantly less than the first batch of controls. Overall, the experiments showed that the number of succussions given does affect the number, size and distribution of nanoparticles in a homoeopathic remedy. The results of this experiment help to support the current research on nanoparticles in homoeopathic remedies and help to explain the effect of succussion on the nanoparticles within the remedies. , M.Tech. (Homoeopathy)
- Full Text:
- Authors: Hobson, Deborah Dawn
- Date: 2019
- Subjects: Homeopathic pharmacy , Nanoparticles , Nanostructured materials , Nanomedicine , Homeopathy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/399657 , uj:33319
- Description: Abstract : Nanoparticles are microscopic materials which range in length from 1-100 nanometres (nm). Nanoparticles have unique properties due to their size and shape, which include an increase in surface area, surface reactivity, thermal energy and diffusion rate. Nanomedicine refers to the application of nanoparticles in medicine, particularly in diagnostic techniques and as drug delivery systems. Nanoparticles are ideal for this as they provide greater bioavailability, are more easily absorbed by the body and produce a therapeutic effect with fewer side effects. Laboratory techniques to create nanoparticles include the top-down and bottom-up methods. Within these two methods are various synthesis techniques for creating nanoparticles, including solid phase synthesis, liquid phase synthesis, gas phase synthesis and green synthesis. Homoeopathy uses the top-down method by physically breaking down the starting substance via the process of potentization. Homoeopathy is a branch of complementary medicine (CM) founded by Dr Samuel Hahnemann in the late 1700’s. It is based on the principle similia similibus curantur, which translates to ‘like cures like’. Homoeopathic remedies are highly diluted substances which retain minute particles of the starting substance in the form of nanoparticles. The method used to make homoeopathic remedies is referred to as ‘potentization’ and includes trituration (grinding and serial dilution) of solid substances and succussion (violent shaking) of liquid substances. However, while homoeopathy has set guidelines for the trituration part of potentization, it lacks standardisation regarding the number of succussions which should be used. Iron (Fe) is a highly reactive silvery-white metal that easily forms compounds and alloys with other metals and has unique ferromagnetic properties which are stronger at lower temperatures. Ferrum metallicum, the homoeopathic remedy made from iron, can be used for a wide range of conditions when prepared in homoeopathic form. The aim of this study was to investigate the effect of succussion on the presence, size and distribution of nanoparticles in Ferrum metallicum 30C, when prepared with 0, 10 or 100 succussions, using transmission electron microscopy (TEM). iv This was a quantitative, experimental study performed at the Department of Chemistry, at the University of Johannesburg. Three batches of Ferrum metallicum 30C, with 0, 10 and 100 succussions respectively, and three controls of 43% ethanol with 0, 10 and 100 succussions respectively, were manufactured by the researcher. This was done at the laboratory of a registered manufacturer of homoeopathic medicines in Johannesburg. The researcher underwent training on the use of each of the laboratory analysis techniques. The sample preparation, experimental design and analysis of the samples was conducted by the researcher, under supervision and help of the laboratory technicians. Transmission Electron Microscopy (TEM) was conducted on two batches of samples. The first batch of samples showed contamination of the ethanol used to manufacture the test and control samples. The test samples were therefore manufactured a second time and TEM analysis conducted again. Additional analysis techniques were used to determine whether the first batch of test and control samples were contaminated and how the contamination had occurred. These analysis techniques included Energy Dispersive Spectroscopy (EDS), Inductively Couples Plasma Emission Spectroscopy (ICP-OES), Dynamic Light Scattering (DLS). An analysis for zeta potential of the samples and controls was conducted to explain the agglomeration of particles. TEM photographs were analysed by the researcher, under guidance of the co-supervisor, using the computer programme ImageJ. The results for EDS, ICP-OES, DLS and Zeta Potential were generated by the built-in software of the analysis machines, either as graphs or as numerical values. These were then analysed by the researcher under the guidance of the laboratory technicians. A total of five experimental procedures were conducted. The results of the experiments showed that the first batch of test and control samples was contaminated as the ethanol used to manufacture the samples contained traces of iron and unidentified particles. The additional analysis techniques helped confirm the contamination, and it was discovered that purified water, which was used to manufacture the ethanol used in the study, is not completely free of particles. The second batch of test and control samples, manufactured with distilled water, which is almost completely particle-free, showed positive results. The presence of spherically-shaped iron nanoparticles was confirmed for the test samples. Batch 1, Samples 1 and 2 (Ferrum v metallicum 30C with 0 and 10 succussions respectively), contained nanoparticles which were evenly distributed and unagglomerated. Batch 1, Sample 3 (Ferrum metallicum 30C with 100 succussions) had nanoparticles which were smaller in size, greater in number and agglomerated. Batch 2, Samples 1-2 (Ferrum metallicum 30C with 0 and 10 succussions respectively) contained nanoparticles which were more defined in shape, with similar numbers and sizes, and existed mainly as well-distributed, unagglomerated nanoparticles. Batch 2, Sample 3 (Ferrum metallicum 30C with 100 succussions) had nanoparticles which were slightly less in number and smaller, according to the automatic analysis by ImageJ, and which appeared to be distributed unevenly in smaller clusters. The first batch of control samples contained a large number of unidentified particles. The second batch of control samples also contained particles, although significantly less than the first batch of controls. Overall, the experiments showed that the number of succussions given does affect the number, size and distribution of nanoparticles in a homoeopathic remedy. The results of this experiment help to support the current research on nanoparticles in homoeopathic remedies and help to explain the effect of succussion on the nanoparticles within the remedies. , M.Tech. (Homoeopathy)
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The advances in biomedical applications of carbon nanotubes based on drug delivery system by using MD and DFT modeling
- Authors: Karimzadeh, Sina
- Date: 2020
- Subjects: Carbon nanotubes , Nanostructured materials , Drug delivery systems , Density functionals , Molecular dynamics - Simulation methods , Doxorubicin , Cancer - Chemotherapy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/480174 , uj:43458
- Description: Abstract: In this work, interaction and bond properties of anticancer drug doxorubicin (DOX), (6,6) armchair single-walled carbon nanotube (SWCNT), and hydroxyl- and carboxyl-functionalized SWCNT (ƒ-SWCNT) have been investigated based on DFT theory to design, improve and expand carbon nanotube (CNT) drug carriers for any biomedical system. Geometrical, structural, electrical, bonding and thermodynamic properties as well as equilibrium distances, adsorption energies, quantum molecular descriptors and frontier molecular orbitals or different drug arrangements on CNT at the highest equilibrium at WB97XD/6-31+G (d, p) level of theory at aqueous and gas phases were explored. Our calculations showed that hydrogen bonds between active sites of the spontaneous adsorption of doxorubicin (DOX) molecule and hydroxyl- and carboxyl-functionalized CNTs played a more important role than those with pristine CNTs in the adsorption and fixation of the studied complexes. Using quantum theory of atoms in molecules (QTAIMs) method, intermolecular interactions and corresponding descriptors at critical bonding points in aqueous and gas phases were also investigated. Evaluation of the results obtained from the natural bond orbital (NBO) analysis showed that the direction of electron movement was generally from drug molecule to CNT... , M.Ing. (Mechanical Engineering)
- Full Text:
- Authors: Karimzadeh, Sina
- Date: 2020
- Subjects: Carbon nanotubes , Nanostructured materials , Drug delivery systems , Density functionals , Molecular dynamics - Simulation methods , Doxorubicin , Cancer - Chemotherapy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/480174 , uj:43458
- Description: Abstract: In this work, interaction and bond properties of anticancer drug doxorubicin (DOX), (6,6) armchair single-walled carbon nanotube (SWCNT), and hydroxyl- and carboxyl-functionalized SWCNT (ƒ-SWCNT) have been investigated based on DFT theory to design, improve and expand carbon nanotube (CNT) drug carriers for any biomedical system. Geometrical, structural, electrical, bonding and thermodynamic properties as well as equilibrium distances, adsorption energies, quantum molecular descriptors and frontier molecular orbitals or different drug arrangements on CNT at the highest equilibrium at WB97XD/6-31+G (d, p) level of theory at aqueous and gas phases were explored. Our calculations showed that hydrogen bonds between active sites of the spontaneous adsorption of doxorubicin (DOX) molecule and hydroxyl- and carboxyl-functionalized CNTs played a more important role than those with pristine CNTs in the adsorption and fixation of the studied complexes. Using quantum theory of atoms in molecules (QTAIMs) method, intermolecular interactions and corresponding descriptors at critical bonding points in aqueous and gas phases were also investigated. Evaluation of the results obtained from the natural bond orbital (NBO) analysis showed that the direction of electron movement was generally from drug molecule to CNT... , M.Ing. (Mechanical Engineering)
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Template synthesis of palladium and platinum nanoparticles by dendrimer and reverse microemulsions for the catalytic evaluation on various reactions
- Authors: Noh, Ji-Hyang
- Date: 2015-11-09
- Subjects: Palladium catalysts , Chemical reactors , Chemistry, Inorganic , Nanostructured materials , Platinum , Catalysis
- Type: Thesis
- Identifier: uj:14524 , http://hdl.handle.net/10210/15047
- Description: PhD. (Chemistry) , Well-defined palladium and platinum nanoparticles were synthesized by two template methods, namely dendrimer template and reverse microemulsions. For dendrimer template, three dendrimers, generation 4, 5, and 6 hydroxyl terminated poly(amidoamine) dendrimers (PAMAM), G4-OH, G5-OH, and G6-OH, were used as stabilizing agent, with PdCl4 2- or PtCl4 2- metal ions to dendrimer ratio of 40, 80, and 160, respectively. For reverse microemulsions, we employed water/AOT surfactant/isooctane system with water to surfactant ratios (ω0) of 5, 10, and 13, capped with thiol, to produce Pd and Pt nanoparticles. A total of twelve catalysts were characterized by techniques such as UV-Vis spectroscopy, TEM, EDX, and p-XRD. In the dendrimer template method, the synthesis of Pd and Pt nanoparticles in lower concentrations produced smaller sizes with narrower size distributions (2.02 ± 0.45 ~ 2.35 ± 0.58 nm Pd nanoparticles, 1.90 ± 0.44 nm ~ 2.48 ± 0.60 nm Pt nanoparticles) compared to those in higher concentrations (2.74 ± 0.44 ~ 3.32 ± 0.86 nm Pd nanoparticles, 2.81 ± 0.70 nm ~ 3.03 ± 0.47 nm Pt nanoparticles). In the case of thiol-capped Pd and Pt nanoparticles by reverse microemulsions, the range of average particle sizes were 3.47 - 7.51 nm and 3.51 - 4.23 nm for Pd and Pt nanoparticles, respectively. This indicated that a wider size regime was obtained by the reverse microemulsion method as compared to the dendrimer template method. Overall, smaller sizes with narrower size distributions were achieved by using the dendrimer-templated synthetic method rather than reverse microemulsions for both Pd and Pt nanoparticles.
- Full Text:
- Authors: Noh, Ji-Hyang
- Date: 2015-11-09
- Subjects: Palladium catalysts , Chemical reactors , Chemistry, Inorganic , Nanostructured materials , Platinum , Catalysis
- Type: Thesis
- Identifier: uj:14524 , http://hdl.handle.net/10210/15047
- Description: PhD. (Chemistry) , Well-defined palladium and platinum nanoparticles were synthesized by two template methods, namely dendrimer template and reverse microemulsions. For dendrimer template, three dendrimers, generation 4, 5, and 6 hydroxyl terminated poly(amidoamine) dendrimers (PAMAM), G4-OH, G5-OH, and G6-OH, were used as stabilizing agent, with PdCl4 2- or PtCl4 2- metal ions to dendrimer ratio of 40, 80, and 160, respectively. For reverse microemulsions, we employed water/AOT surfactant/isooctane system with water to surfactant ratios (ω0) of 5, 10, and 13, capped with thiol, to produce Pd and Pt nanoparticles. A total of twelve catalysts were characterized by techniques such as UV-Vis spectroscopy, TEM, EDX, and p-XRD. In the dendrimer template method, the synthesis of Pd and Pt nanoparticles in lower concentrations produced smaller sizes with narrower size distributions (2.02 ± 0.45 ~ 2.35 ± 0.58 nm Pd nanoparticles, 1.90 ± 0.44 nm ~ 2.48 ± 0.60 nm Pt nanoparticles) compared to those in higher concentrations (2.74 ± 0.44 ~ 3.32 ± 0.86 nm Pd nanoparticles, 2.81 ± 0.70 nm ~ 3.03 ± 0.47 nm Pt nanoparticles). In the case of thiol-capped Pd and Pt nanoparticles by reverse microemulsions, the range of average particle sizes were 3.47 - 7.51 nm and 3.51 - 4.23 nm for Pd and Pt nanoparticles, respectively. This indicated that a wider size regime was obtained by the reverse microemulsion method as compared to the dendrimer template method. Overall, smaller sizes with narrower size distributions were achieved by using the dendrimer-templated synthetic method rather than reverse microemulsions for both Pd and Pt nanoparticles.
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Synthesis, characterization and cytotoxic activity of gold nanoparticles using natural occurring flavonoids
- Authors: Nemandava, Livhuwani
- Date: 2017
- Subjects: Flavonoids , Nanostructured materials , Nanomedicine , Gold , Flavonoids - Therapeutic use
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/243968 , uj:25224
- Description: M.Sc. (Nanoscience) , Abstract: Plant phytochemicals have been under extensive research because of their preferable properties. Phytochemicals are phenolic compounds which may vary structurally which distinguish their intended applications. They possess anti-oxidant activities which have been a good requirement for treatment against certain ailments which include cancer. The anti-oxidant properties of phytochemicals are capable of relieving stress from cells by scavenging on reactive oxygen species or free radicals. The use of antioxidants has been in use for decades since it is in the human diet, hence extraction of these compounds for medical applications may be ideal since no significant side effects have been reported upon normal consumption. The effectiveness of anti-oxidants possessed by plant phytochemicals depends on the type of phytochemicals, their structural composition and the concentration. Research has uncovered the use of anti-oxidants as reducing agents for the synthesis of metallic nanoparticles for various applications. The synthesis has been found to be cost effective and amenable to optimization for preferred applications. This study describes the synthesis of gold nanoparticles by flavonoids; Sigmoidin A, Sigmoidin B isolated from Erythrina species and Durmillone isolated from Griffoniana species. The natural compounds have been fully characterized by UV-Vis, NMR and FT-IR. The compounds and their relative synthesized AUNPs were tested for anti-cancer activities against Normal Kidney Fibroblasts (BHK 21) and colorectal carcinoma (HCT 116) cell line. A modified tuckervich method was used to synthesize AuNPs which were further characterized by UV-Vis, DLS, TEM, EDX and FT-IR. The synthesis was successful as was observed by a colour change of chloroauric solution from golden yellow to pink-wine red colours. The assumed presence of AuNPs in solution was determined by UV-Vis which measured 595.9nm for Sigmoidin A, 554.5nm for Sigmoidin B and 531nm for Durmillone. These maximum wavelengths of absorption by the AuNPs synthesized by all three flavonoids are characteristic of AuNPs as reported by literature. Average particle size, dispersity and zeta potential values of the synthesized AuNPs were determined by DLS. Properties of Sigmoidin A-AuNPs as per DLS results were 0.143 PDI, 64.8 d.nm and 0.170 mV which mean that the AuNPs were not aggregated but not stable as per the zeta potential value. Sigmoidin B-AuNPs properties by DLS were 0.443 Pdi, 34.4 d.nm and -0.0772 mV which meant that the nanoparticles were monodispersed but not stable as per the zeta-potential. Durmillone-AuNPs properties were 0.153 PDI, 32.7 d.nm and 0.0549 mV which...
- Full Text:
- Authors: Nemandava, Livhuwani
- Date: 2017
- Subjects: Flavonoids , Nanostructured materials , Nanomedicine , Gold , Flavonoids - Therapeutic use
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/243968 , uj:25224
- Description: M.Sc. (Nanoscience) , Abstract: Plant phytochemicals have been under extensive research because of their preferable properties. Phytochemicals are phenolic compounds which may vary structurally which distinguish their intended applications. They possess anti-oxidant activities which have been a good requirement for treatment against certain ailments which include cancer. The anti-oxidant properties of phytochemicals are capable of relieving stress from cells by scavenging on reactive oxygen species or free radicals. The use of antioxidants has been in use for decades since it is in the human diet, hence extraction of these compounds for medical applications may be ideal since no significant side effects have been reported upon normal consumption. The effectiveness of anti-oxidants possessed by plant phytochemicals depends on the type of phytochemicals, their structural composition and the concentration. Research has uncovered the use of anti-oxidants as reducing agents for the synthesis of metallic nanoparticles for various applications. The synthesis has been found to be cost effective and amenable to optimization for preferred applications. This study describes the synthesis of gold nanoparticles by flavonoids; Sigmoidin A, Sigmoidin B isolated from Erythrina species and Durmillone isolated from Griffoniana species. The natural compounds have been fully characterized by UV-Vis, NMR and FT-IR. The compounds and their relative synthesized AUNPs were tested for anti-cancer activities against Normal Kidney Fibroblasts (BHK 21) and colorectal carcinoma (HCT 116) cell line. A modified tuckervich method was used to synthesize AuNPs which were further characterized by UV-Vis, DLS, TEM, EDX and FT-IR. The synthesis was successful as was observed by a colour change of chloroauric solution from golden yellow to pink-wine red colours. The assumed presence of AuNPs in solution was determined by UV-Vis which measured 595.9nm for Sigmoidin A, 554.5nm for Sigmoidin B and 531nm for Durmillone. These maximum wavelengths of absorption by the AuNPs synthesized by all three flavonoids are characteristic of AuNPs as reported by literature. Average particle size, dispersity and zeta potential values of the synthesized AuNPs were determined by DLS. Properties of Sigmoidin A-AuNPs as per DLS results were 0.143 PDI, 64.8 d.nm and 0.170 mV which mean that the AuNPs were not aggregated but not stable as per the zeta potential value. Sigmoidin B-AuNPs properties by DLS were 0.443 Pdi, 34.4 d.nm and -0.0772 mV which meant that the nanoparticles were monodispersed but not stable as per the zeta-potential. Durmillone-AuNPs properties were 0.153 PDI, 32.7 d.nm and 0.0549 mV which...
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Synthesis, characterization and assessment of new nanohybrid materials for topical applications
- Authors: Mosangi, Damodar
- Date: 2017
- Subjects: Nanostructured materials , Nanocomposites (Materials)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/493458 , uj:45104
- Description: Abstract: The chemical stability, degradation and penetration ability of pharmaceutically active drugs in topical applications are the greatest challenges in cosmetics because of problems with the protection of actives for long times and with delivery. Therefore, the development of unique and efficient material is required for protection and for controlled drug release systems. Layered double hydroxides (LDHs), also known as hydrotalcite-like compounds, are 3D crystals formed by 2D laminates which are orderly arranged in longitudinal directions. The host LDHS layers possess positive charges due to isomorphic substitutions, which are counterbalanced by hydrated exchangeable anions located in the interlayer region. Some of the active drug molecules can be intercalated into the inner region of the LDHs host through ionic bonding, hydrogen bonding, or Van Der Waals’ interaction to form nanohybrids, which are more potent for protection and controlled-release systems. For example, aspirin, also known as acetylsalicylic acid (ASA), is a class of NSAID and is a traditional analgesic available on the market. ASA is an organic compound having easily polarizable carboxylic groups, it is therefore easily intercalated into the LDH host, to yield an LDH-ASA nanohybrid. Generally, ASA is used as a pain relief ingredient in topical skin care products. ASA is usually an unstable molecule, and easy to degrade into small fragments (salicylic acid and acetic acid) which give unwanted side effects; thus, to improve the chemical stability of ASA, the degradation behaviour of ASA is of great importance in cosmetic formulations. In this concern, LDHs nanoparticles have attracted specific attention because of their many desirable properties- particularly the protecting capacity after intercalation of drugs into LDH interlayers... , Ph.D. (Chemistry)
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- Authors: Mosangi, Damodar
- Date: 2017
- Subjects: Nanostructured materials , Nanocomposites (Materials)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/493458 , uj:45104
- Description: Abstract: The chemical stability, degradation and penetration ability of pharmaceutically active drugs in topical applications are the greatest challenges in cosmetics because of problems with the protection of actives for long times and with delivery. Therefore, the development of unique and efficient material is required for protection and for controlled drug release systems. Layered double hydroxides (LDHs), also known as hydrotalcite-like compounds, are 3D crystals formed by 2D laminates which are orderly arranged in longitudinal directions. The host LDHS layers possess positive charges due to isomorphic substitutions, which are counterbalanced by hydrated exchangeable anions located in the interlayer region. Some of the active drug molecules can be intercalated into the inner region of the LDHs host through ionic bonding, hydrogen bonding, or Van Der Waals’ interaction to form nanohybrids, which are more potent for protection and controlled-release systems. For example, aspirin, also known as acetylsalicylic acid (ASA), is a class of NSAID and is a traditional analgesic available on the market. ASA is an organic compound having easily polarizable carboxylic groups, it is therefore easily intercalated into the LDH host, to yield an LDH-ASA nanohybrid. Generally, ASA is used as a pain relief ingredient in topical skin care products. ASA is usually an unstable molecule, and easy to degrade into small fragments (salicylic acid and acetic acid) which give unwanted side effects; thus, to improve the chemical stability of ASA, the degradation behaviour of ASA is of great importance in cosmetic formulations. In this concern, LDHs nanoparticles have attracted specific attention because of their many desirable properties- particularly the protecting capacity after intercalation of drugs into LDH interlayers... , Ph.D. (Chemistry)
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Synthesis, characterization and application of carbon nanotube and graphene based nanocomposite platforms in the electrochemical sensing of arsenic and mercury in water
- Authors: Jimana, Amandla
- Date: 2017
- Subjects: Electrochemical analysis , Nanostructured materials , Carbon nanotubes , Heavy metals - Analysis , Water - Analysis
- Language: English
- Type: Masters (Thesis)
- Identifier: http://ujcontent.uj.ac.za8080/10210/376448 , http://hdl.handle.net/10210/244112 , uj:25242
- Description: M.Tech. (Chemistry) , Abstract: This study developed carbon nanocomposite modified on exfoliated graphite electrodes that are sensitive and selective for the electrochemical detection of mercury and arsenic. This research explores the new material called exfoliated graphite for the detection of heavy metals in water. The material is relatively cheap and is a promising material for the detection of heavy metals. The exfoliated graphite was prepared by intercalation of natural graphite flakes with a particle size of 300 μm by soaking them in a mixture of concentrated acids, sulphuric acid and nitric acid in the ratio 3:1 respectively. After the intercalation the resulting material was exfoliated. The exfoliation was achieved by subjecting the intercalated graphite to high temperatures of 800 ºC in a furnace for about 30 seconds. The puffed up material was named exfoliated graphite (EG). The EG was compressed into pellets of 5mm using high pressure hydraulic press. The mercury nanocomposite sensor was designed by incorporation of carbon nanotube/polyaniline (CNT/PANI) composite followed by electrodeposition of gold nanoparticles onto the EG electrode. This electrode was named CNT/PANI/AuNPs-EG. The dispersion of carbon nanotubes onto the polymer was obtained via the in situ polymerization method. This electrode was name CNT/PANI/EG. The electrodeposition of gold nanoparticles was achieved by preparing 5 mM of HAuCl4 solution and cycling the potential from -200 mV to 1100 mV for 10 cycles at a scan rate of 50 mV/s. this electrode was used for the detection of mercury in water. The detection limit was calculated to be 0.046 ppb (0.229 nM) and the limit of quantification was 0.152 ppb with a correlation coefficient of 0.9984. Another electrode was prepared for the detection of arsenic. Reduced graphene oxide/cobalt nanoparticles modified on EG electrode. A good detection limit and limit of quantification were found to be 0.31 ppb and 1.01 ppb respectively. The linear regression equation was 𝑦=6.64608×10−4 𝑥+1.96169×10−5 with a high correlation coefficient of 0.9984.
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- Authors: Jimana, Amandla
- Date: 2017
- Subjects: Electrochemical analysis , Nanostructured materials , Carbon nanotubes , Heavy metals - Analysis , Water - Analysis
- Language: English
- Type: Masters (Thesis)
- Identifier: http://ujcontent.uj.ac.za8080/10210/376448 , http://hdl.handle.net/10210/244112 , uj:25242
- Description: M.Tech. (Chemistry) , Abstract: This study developed carbon nanocomposite modified on exfoliated graphite electrodes that are sensitive and selective for the electrochemical detection of mercury and arsenic. This research explores the new material called exfoliated graphite for the detection of heavy metals in water. The material is relatively cheap and is a promising material for the detection of heavy metals. The exfoliated graphite was prepared by intercalation of natural graphite flakes with a particle size of 300 μm by soaking them in a mixture of concentrated acids, sulphuric acid and nitric acid in the ratio 3:1 respectively. After the intercalation the resulting material was exfoliated. The exfoliation was achieved by subjecting the intercalated graphite to high temperatures of 800 ºC in a furnace for about 30 seconds. The puffed up material was named exfoliated graphite (EG). The EG was compressed into pellets of 5mm using high pressure hydraulic press. The mercury nanocomposite sensor was designed by incorporation of carbon nanotube/polyaniline (CNT/PANI) composite followed by electrodeposition of gold nanoparticles onto the EG electrode. This electrode was named CNT/PANI/AuNPs-EG. The dispersion of carbon nanotubes onto the polymer was obtained via the in situ polymerization method. This electrode was name CNT/PANI/EG. The electrodeposition of gold nanoparticles was achieved by preparing 5 mM of HAuCl4 solution and cycling the potential from -200 mV to 1100 mV for 10 cycles at a scan rate of 50 mV/s. this electrode was used for the detection of mercury in water. The detection limit was calculated to be 0.046 ppb (0.229 nM) and the limit of quantification was 0.152 ppb with a correlation coefficient of 0.9984. Another electrode was prepared for the detection of arsenic. Reduced graphene oxide/cobalt nanoparticles modified on EG electrode. A good detection limit and limit of quantification were found to be 0.31 ppb and 1.01 ppb respectively. The linear regression equation was 𝑦=6.64608×10−4 𝑥+1.96169×10−5 with a high correlation coefficient of 0.9984.
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Synthesis, characterisation and application of ethylene diamine functionalised carbon nanoparticles for the removal of cadmium (II) and lead (II) from water
- Authors: Tshwenya, Luthando
- Date: 2017
- Subjects: Water - Purification , Cadmium , Nanostructured materials , Nanotubes , Carbon
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235777 , uj:24118
- Description: M.Tech. (Chemistry) , Abstract: This work explores the synthesis, characterisation and application of carbon nanoparticles derived from glucose (GCNPs) and functionalised with ethylene diamine (EDA), towards the removal of Cd(II) and Pb(II) in water samples. Glucose is a simple sugar that is readily available in nature, since it is organic, it can be easily converted to carbon through dehydration. GCNPs were successfully modified to form EDA-GCNPs and characterised by electron microscopy (TEM and SEM), CHNS elemental analysis, Brunauer–Emmett–Teller (BET), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Modification of GCNPs with EDA was confirmed from an increase in C-H stretch. Disappearance of carboxyl in the GCNPs and appearance of an amide linkage in the infrared spectra. Based on the particle size results obtained from TEM studies, it was also confirmed that indeed carbon nanoparticles were formed (as the particle sizes were in the nanorange). The adsorption behavior of the two materials for Cd(II) and Pb(II) was investigated by batch adsorption and the effect of several conditions such as contact time, pH, initial metal concentration and competing ions on cadmium and lead uptake were investigated. The adsorption results show that both adsorbents could effectively remove Cd2+ and Pb2+, with lead adsorption being more favoured as compared to that of cadmium. Equilibrium results best fitted the Langmuir model, and the maximum adsorption capacities for Pb(II) were found to be 15.15 and 28.99 mg g-1 for GCNPs and EDA-GCNPs, respectively, whilst Cd(II) adsorption resulted in lower sorption capacities (GCNPs = 10.31 mg g-1 and EDA-GCNPs=18.71 mg g-1). The adsorption processes were found to favour chemisorption, given that the pseudo-second-order kinetic model and Langmuir isotherms best fitted the adsorption results, implying that the functional groups present on the adsorbent surfaces are behind the uptake of these metal ions. The adsorbents showed applicability in real water samples and multi-elemental systems, with competing ions not affecting adsorption processes, moreover, regeneration studies show that both adsorbents are fully recyclable, indicating possible industrial applicability.
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- Authors: Tshwenya, Luthando
- Date: 2017
- Subjects: Water - Purification , Cadmium , Nanostructured materials , Nanotubes , Carbon
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235777 , uj:24118
- Description: M.Tech. (Chemistry) , Abstract: This work explores the synthesis, characterisation and application of carbon nanoparticles derived from glucose (GCNPs) and functionalised with ethylene diamine (EDA), towards the removal of Cd(II) and Pb(II) in water samples. Glucose is a simple sugar that is readily available in nature, since it is organic, it can be easily converted to carbon through dehydration. GCNPs were successfully modified to form EDA-GCNPs and characterised by electron microscopy (TEM and SEM), CHNS elemental analysis, Brunauer–Emmett–Teller (BET), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Modification of GCNPs with EDA was confirmed from an increase in C-H stretch. Disappearance of carboxyl in the GCNPs and appearance of an amide linkage in the infrared spectra. Based on the particle size results obtained from TEM studies, it was also confirmed that indeed carbon nanoparticles were formed (as the particle sizes were in the nanorange). The adsorption behavior of the two materials for Cd(II) and Pb(II) was investigated by batch adsorption and the effect of several conditions such as contact time, pH, initial metal concentration and competing ions on cadmium and lead uptake were investigated. The adsorption results show that both adsorbents could effectively remove Cd2+ and Pb2+, with lead adsorption being more favoured as compared to that of cadmium. Equilibrium results best fitted the Langmuir model, and the maximum adsorption capacities for Pb(II) were found to be 15.15 and 28.99 mg g-1 for GCNPs and EDA-GCNPs, respectively, whilst Cd(II) adsorption resulted in lower sorption capacities (GCNPs = 10.31 mg g-1 and EDA-GCNPs=18.71 mg g-1). The adsorption processes were found to favour chemisorption, given that the pseudo-second-order kinetic model and Langmuir isotherms best fitted the adsorption results, implying that the functional groups present on the adsorbent surfaces are behind the uptake of these metal ions. The adsorbents showed applicability in real water samples and multi-elemental systems, with competing ions not affecting adsorption processes, moreover, regeneration studies show that both adsorbents are fully recyclable, indicating possible industrial applicability.
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