The synthesis of functionalized carbon nanomaterial from waste tyre sourced carbon for chemosensing during purification processes
- Authors: Du Plessis, Jacolien
- Date: 2018
- Subjects: Nanostructured materials , Nanotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/29925 , vital:30794
- Description: The short lifetime of tyres causes great environmental harm due to their non-biodegradable nature resulting in land and water pollution. Exploration of novel uses for recycled tyres is therefore imperative. The use of recycled waste tyres as carbon source for the synthesis of fluorescent chemosensing carbon nanomaterial for the detection of harmful chemicals in water is proposed in this work. Three key problems are addressed in this study: i) re-using of waste tyre products, ii) synthesis of low-cost carbon nanomaterial, iii) detection of harmful compounds within environment systems. The fluorescent triazolyl-coumarin compound, 7-(diethylamino)-3-(4-(1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)-2H-chromen-2-one, was synthesized in multiple steps from 4-diethylamino salicylaldehyde. The last step included the use of Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (“click-reaction”) to form a triazole ring. Carbon spheres were synthesized through catalytic chemical vapour deposition (CVD) from waste tyre pyrolysis oil (WTPO), as the carbon source, in the presence of a catalytic amount of ferrocene. The quality and quantity of the carbon spheres had an overall improvement as the synthesis temperatures increased from 800 oC to 950 oC. The diameter of the carbon spheres reduced from 1017 nm to 577 nm as seen in TEM and SEM imaging. TGA and XRD analysis indicated a direct relationship between an increase in synthesis temperatures with an increase in the crystallinity of the carbon spheres. Commercially available naphthenic oil was used as a reference to compare the impact of the starting carbon precursor on the morphology of the carbon nanomaterial under the same reaction conditions. Multi-walled carbon nanotubes were synthesized at the lower temperatures of 800-850 oC. Carbon fibres and carbon spheres were observed at the synthesis temperatures of 900-950 oC. The carbon source played a role in the morphology of the carbon nanomaterial as it could be seen between the complex natured WTPO and the pure naphthenic oil. The purified carbon spheres synthesized at 950 oC from WTPO were functionalized with the triazolyl-coumarin units on the surface through Steglich esterification using DCC/DMAP to yield fluorescent carbon spheres. Complexation studies of the functionalized carbon spheres were done using UV/Vis spectroscopy and fluorescence with a wide range of ions; Ag+, Al3+, Co2+, Cr3+, Cu2+, Fe3+, ii Hg2+, Li+, Ni2+, Pb2+ and Zn2+. The triazolyl-coumarin carbon spheres showed reasonable sensitivity and selectivity towards Fe3+ in water with a quenching effect in fluorescence. Titration studies with Fe3+ indicating an exponential decay of quenching in the fluorescence up to 68% with detection limit at 2.73 x 10-5 M.
- Full Text:
- Date Issued: 2018
- Authors: Du Plessis, Jacolien
- Date: 2018
- Subjects: Nanostructured materials , Nanotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/29925 , vital:30794
- Description: The short lifetime of tyres causes great environmental harm due to their non-biodegradable nature resulting in land and water pollution. Exploration of novel uses for recycled tyres is therefore imperative. The use of recycled waste tyres as carbon source for the synthesis of fluorescent chemosensing carbon nanomaterial for the detection of harmful chemicals in water is proposed in this work. Three key problems are addressed in this study: i) re-using of waste tyre products, ii) synthesis of low-cost carbon nanomaterial, iii) detection of harmful compounds within environment systems. The fluorescent triazolyl-coumarin compound, 7-(diethylamino)-3-(4-(1-hydroxyethyl)-1H-1,2,3-triazol-1-yl)-2H-chromen-2-one, was synthesized in multiple steps from 4-diethylamino salicylaldehyde. The last step included the use of Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (“click-reaction”) to form a triazole ring. Carbon spheres were synthesized through catalytic chemical vapour deposition (CVD) from waste tyre pyrolysis oil (WTPO), as the carbon source, in the presence of a catalytic amount of ferrocene. The quality and quantity of the carbon spheres had an overall improvement as the synthesis temperatures increased from 800 oC to 950 oC. The diameter of the carbon spheres reduced from 1017 nm to 577 nm as seen in TEM and SEM imaging. TGA and XRD analysis indicated a direct relationship between an increase in synthesis temperatures with an increase in the crystallinity of the carbon spheres. Commercially available naphthenic oil was used as a reference to compare the impact of the starting carbon precursor on the morphology of the carbon nanomaterial under the same reaction conditions. Multi-walled carbon nanotubes were synthesized at the lower temperatures of 800-850 oC. Carbon fibres and carbon spheres were observed at the synthesis temperatures of 900-950 oC. The carbon source played a role in the morphology of the carbon nanomaterial as it could be seen between the complex natured WTPO and the pure naphthenic oil. The purified carbon spheres synthesized at 950 oC from WTPO were functionalized with the triazolyl-coumarin units on the surface through Steglich esterification using DCC/DMAP to yield fluorescent carbon spheres. Complexation studies of the functionalized carbon spheres were done using UV/Vis spectroscopy and fluorescence with a wide range of ions; Ag+, Al3+, Co2+, Cr3+, Cu2+, Fe3+, ii Hg2+, Li+, Ni2+, Pb2+ and Zn2+. The triazolyl-coumarin carbon spheres showed reasonable sensitivity and selectivity towards Fe3+ in water with a quenching effect in fluorescence. Titration studies with Fe3+ indicating an exponential decay of quenching in the fluorescence up to 68% with detection limit at 2.73 x 10-5 M.
- Full Text:
- Date Issued: 2018
Investigating the possibility of using wild silk fancy yarns to produce upholstery fabrics for home furniture
- Authors: Somi, Bongiwe Promrose
- Date: 2013
- Subjects: Textile design , Textile fabrics
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/7616 , vital:22103
- Description: About a decade ago an attempt to build a viable wild silk industry, prompted by the discovery of the naturally available wild silk cocoons in the North West Province of South Africa, was made and a degumming plant was established in the Ganyesa village. The challenges faced in that establishment soon brought the developments to a standstill and cited among the problems was the lack of designer input in the production stages, which resulted in poor quality products. Focusing on the design problem the intention of this research is to explore a more effective design and production method for the wild silk fabrics. Through assessing the previously produced fabrics in order to identify their limitations, and by experimenting with innovative fabric production processes, a suitable aesthetic quality can be added to the final products. Starting with the investigation of current trends and choosing a design theme as a guide for the production process, fabric samples intended for use in upholstery of home furniture are developed. With the objective of successfully achieving a balance between aesthetic appeal and suitability for the intended end use, the fabrics are subjected to performance assessments based on internationally recognised standards. From the findings of this research it is therefore envisaged that, from the design aspect, proper redevelopment of the South African wild silk industry could encourage further involvement from textile designers. This would bring more improvement to the fabrics produced and encourage their use in different applications.
- Full Text:
- Date Issued: 2013
- Authors: Somi, Bongiwe Promrose
- Date: 2013
- Subjects: Textile design , Textile fabrics
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/7616 , vital:22103
- Description: About a decade ago an attempt to build a viable wild silk industry, prompted by the discovery of the naturally available wild silk cocoons in the North West Province of South Africa, was made and a degumming plant was established in the Ganyesa village. The challenges faced in that establishment soon brought the developments to a standstill and cited among the problems was the lack of designer input in the production stages, which resulted in poor quality products. Focusing on the design problem the intention of this research is to explore a more effective design and production method for the wild silk fabrics. Through assessing the previously produced fabrics in order to identify their limitations, and by experimenting with innovative fabric production processes, a suitable aesthetic quality can be added to the final products. Starting with the investigation of current trends and choosing a design theme as a guide for the production process, fabric samples intended for use in upholstery of home furniture are developed. With the objective of successfully achieving a balance between aesthetic appeal and suitability for the intended end use, the fabrics are subjected to performance assessments based on internationally recognised standards. From the findings of this research it is therefore envisaged that, from the design aspect, proper redevelopment of the South African wild silk industry could encourage further involvement from textile designers. This would bring more improvement to the fabrics produced and encourage their use in different applications.
- Full Text:
- Date Issued: 2013
Mohair and wool fibre surface structure and lustre determination
- Ndlovu, Ntombizikhona Beaulah
- Authors: Ndlovu, Ntombizikhona Beaulah
- Date: 2011
- Subjects: Mohair and wool fibre -- Lustre
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:18484 , http://hdl.handle.net/11260/d1006641
- Description: Textiles have always been one of the essential materials for people and have a great variety of uses such as in clothing, agriculture, medical, automotive and aerospace applications. The sort of properties needed for any type of fabric basically depend on the structure of the fibre surface. Of many geometric attributes that can be used to describe the surface appearance of a fibre, yarn, or fabric sample, one of the more common is lustre. Mohair and wool fibre surface structure have been studied using optical microscopy and Atomic Force Microscopy (AFM). Optical microscopy was also used to take fibre diameter measurements. Another technique, goniophotometry, was used to make quantitative lustre measurements of mohair and wool fibres. The surface structure of mohair has got a faint pattern of scales where the scales are generally unpronounced or flat and relatively long. Wool has got a scaly surface structure where the scales overlap leading to interlocking of fibres. The scale configuration on the surface of mohair and wool fibres also differs. A qualitative connection between fibre lustre and the fibre surface structure was found. Because of its smooth surface relative to that of wool, mohair reflects a greater amount of incident light specularly whereas wool reflects most of the incident light diffusely. In general, mohair fibres have a higher lustre than wool due to its less prominent cuticle structure found on its surface. Furthermore, mohair fibres with the smallest diameters give an even higher lustre.
- Full Text:
- Date Issued: 2011
- Authors: Ndlovu, Ntombizikhona Beaulah
- Date: 2011
- Subjects: Mohair and wool fibre -- Lustre
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:18484 , http://hdl.handle.net/11260/d1006641
- Description: Textiles have always been one of the essential materials for people and have a great variety of uses such as in clothing, agriculture, medical, automotive and aerospace applications. The sort of properties needed for any type of fabric basically depend on the structure of the fibre surface. Of many geometric attributes that can be used to describe the surface appearance of a fibre, yarn, or fabric sample, one of the more common is lustre. Mohair and wool fibre surface structure have been studied using optical microscopy and Atomic Force Microscopy (AFM). Optical microscopy was also used to take fibre diameter measurements. Another technique, goniophotometry, was used to make quantitative lustre measurements of mohair and wool fibres. The surface structure of mohair has got a faint pattern of scales where the scales are generally unpronounced or flat and relatively long. Wool has got a scaly surface structure where the scales overlap leading to interlocking of fibres. The scale configuration on the surface of mohair and wool fibres also differs. A qualitative connection between fibre lustre and the fibre surface structure was found. Because of its smooth surface relative to that of wool, mohair reflects a greater amount of incident light specularly whereas wool reflects most of the incident light diffusely. In general, mohair fibres have a higher lustre than wool due to its less prominent cuticle structure found on its surface. Furthermore, mohair fibres with the smallest diameters give an even higher lustre.
- Full Text:
- Date Issued: 2011
The development of a model to estimate the cost for the provision of free basic water before the implementation of a water project
- Authors: Gillmer, Ir Ronald
- Date: 2003
- Subjects: Water-supply, rural -- South Africa -- Costs , Water-supply, rural -- South Africa -- Government policy
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10874 , http://hdl.handle.net/10948/222 , Water-supply, rural -- South Africa -- Costs , Water-supply, rural -- South Africa -- Government policy
- Description: This research study addresses the problem of whether local government can afford free basic water in rural areas. To achieve this objective a comprehensive literature study was performed, which included: · Lessons in water sector approaches from international experience and how these experiences compare with the South African situation. 1.The current basic water supply legislation in South Africa and how this legislation affects the subsidy arrangements and the financing of free basic water. 2.The operation and maintenance cost and the benefits of effective operation and maintenance of water supply schemes. A model was developed that could estimate the cost of rural water supply per household per month from the operation and maintenance data that was collected over a period of twenty-two months from a water supply scheme. As part of the provision of free basic water, a nine-step flow chart was developed to determine rural water operation and maintenance subsidy and a free basic water policy to help local government make informed decisions. The model was tested on different water supply schemes to verify the accuracy of the models estimation of the cost of rural water supply per household per month. The information obtained from the literature and from the test of the model resulted in various recommendations and conclusions.
- Full Text:
- Date Issued: 2003
- Authors: Gillmer, Ir Ronald
- Date: 2003
- Subjects: Water-supply, rural -- South Africa -- Costs , Water-supply, rural -- South Africa -- Government policy
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10874 , http://hdl.handle.net/10948/222 , Water-supply, rural -- South Africa -- Costs , Water-supply, rural -- South Africa -- Government policy
- Description: This research study addresses the problem of whether local government can afford free basic water in rural areas. To achieve this objective a comprehensive literature study was performed, which included: · Lessons in water sector approaches from international experience and how these experiences compare with the South African situation. 1.The current basic water supply legislation in South Africa and how this legislation affects the subsidy arrangements and the financing of free basic water. 2.The operation and maintenance cost and the benefits of effective operation and maintenance of water supply schemes. A model was developed that could estimate the cost of rural water supply per household per month from the operation and maintenance data that was collected over a period of twenty-two months from a water supply scheme. As part of the provision of free basic water, a nine-step flow chart was developed to determine rural water operation and maintenance subsidy and a free basic water policy to help local government make informed decisions. The model was tested on different water supply schemes to verify the accuracy of the models estimation of the cost of rural water supply per household per month. The information obtained from the literature and from the test of the model resulted in various recommendations and conclusions.
- Full Text:
- Date Issued: 2003
- «
- ‹
- 1
- ›
- »