An analytical approach to the characterization and removal of natural organic matter from water using ozone and cyclodextrin polyurethanes
- Authors: Nkambule, Thabo Innocent
- Date: 2010-04-08T08:44:47Z
- Subjects: Water purification , Organic water pollutants , Ion exchange resins , Cyclodextrins , Polyurethanes
- Type: Thesis
- Identifier: uj:6765 , http://hdl.handle.net/10210/3171
- Description: M.Sc. , The prevalence of natural organic matter (NOM) in water remains a huge challenge for water treatment companies and municipalities. NOM, however, is not a stand-alone problem as it affects water quality in many ways. NOM is largely responsible for the formation of disinfection by-products (DBPs) via its interaction with disinfectants during water disinfection. It is implicated for the undesirable colour, taste and odour of water and NOM even inhibits precipitation precursors which form the backbone of drinking water treatment. There is therefore no question that NOM, which is either a precursor to or direct cause of the problems highlighted above, should be considered as one of the critical design parameters to be considered for drinking water treatment. In our laboratories, research that involves the use of cyclodextrin (CD) polyurethanes for the removal of organic pollutants from water has been extensively investigated, and the CD polyurethanes have demonstrated the ability to effectively remove the organic species from water at low (ppb) concentrations. CDs, which are cyclic oligomers consisting of glucopyranosyl units linked together through α-1,4 glycosidic linkages, behave like molecular hosts. They are capable of forming inclusion complexes with guest molecules and hence can be utilised for the removal of organic contaminants from water. Their solubility in water, however, limits their application in the removal of organic contaminants from water. This limitation is easily resolved by polymerising the CDs into water-insoluble polymers with bifunctional linkers such as hexamethylene diisocyanate (HMDI). In this study, CD polyurethanes and ion exchange resins were used for the removal of NOM and possibly its DBPs from water. This study first investigated the local NOM source to establish its type and character, hence the study involved the characterization of the bulk water samples and fractionating the NOM using ion exchange resins for further characterization. The water samples were found to consist mainly of humic substances in the form of hydrophobic NOM, with the hydrophilic basic (HpiB) fraction being the most abundant NOM fraction in all samples. Trihalomethanes (THMs) were used as a representative of DBPs in this vii study. THMs formation studies of the individual NOM fractions indicated that all six NOM fractions were found to form THMs but in varying proportions. The HpiB fraction was found to be the most reactive precursor fraction for THMs formation. The ozonation process was also independently evaluated for its ability to remove the NOM fractions from water. Ozonation was found not to be very effective at NOM removal since it only resulted in a 12% overall decrease of the NOM in the water samples. The CD polyurethanes, when used alone, were also not very effective at removing the NOM fractions from water (maximum of 33% NOM removal). On the other hand, the combination method (i.e. the use of CD polyurethanes and ozonation for NOM removal) resulted in a good capability of the CD polyurethanes at decreasing some NOM fractions in water as evidenced by a 73% and 88% decrease of the HpiB and hydrophilic acid (HpiA) fractions, respectively. The 73% reduction of the HpiB fraction demonstrates a great success of the combination approach employed herein, as this study reports this fraction as the most reactive precursor fraction for THM formation.
- Full Text:
- Authors: Nkambule, Thabo Innocent
- Date: 2010-04-08T08:44:47Z
- Subjects: Water purification , Organic water pollutants , Ion exchange resins , Cyclodextrins , Polyurethanes
- Type: Thesis
- Identifier: uj:6765 , http://hdl.handle.net/10210/3171
- Description: M.Sc. , The prevalence of natural organic matter (NOM) in water remains a huge challenge for water treatment companies and municipalities. NOM, however, is not a stand-alone problem as it affects water quality in many ways. NOM is largely responsible for the formation of disinfection by-products (DBPs) via its interaction with disinfectants during water disinfection. It is implicated for the undesirable colour, taste and odour of water and NOM even inhibits precipitation precursors which form the backbone of drinking water treatment. There is therefore no question that NOM, which is either a precursor to or direct cause of the problems highlighted above, should be considered as one of the critical design parameters to be considered for drinking water treatment. In our laboratories, research that involves the use of cyclodextrin (CD) polyurethanes for the removal of organic pollutants from water has been extensively investigated, and the CD polyurethanes have demonstrated the ability to effectively remove the organic species from water at low (ppb) concentrations. CDs, which are cyclic oligomers consisting of glucopyranosyl units linked together through α-1,4 glycosidic linkages, behave like molecular hosts. They are capable of forming inclusion complexes with guest molecules and hence can be utilised for the removal of organic contaminants from water. Their solubility in water, however, limits their application in the removal of organic contaminants from water. This limitation is easily resolved by polymerising the CDs into water-insoluble polymers with bifunctional linkers such as hexamethylene diisocyanate (HMDI). In this study, CD polyurethanes and ion exchange resins were used for the removal of NOM and possibly its DBPs from water. This study first investigated the local NOM source to establish its type and character, hence the study involved the characterization of the bulk water samples and fractionating the NOM using ion exchange resins for further characterization. The water samples were found to consist mainly of humic substances in the form of hydrophobic NOM, with the hydrophilic basic (HpiB) fraction being the most abundant NOM fraction in all samples. Trihalomethanes (THMs) were used as a representative of DBPs in this vii study. THMs formation studies of the individual NOM fractions indicated that all six NOM fractions were found to form THMs but in varying proportions. The HpiB fraction was found to be the most reactive precursor fraction for THMs formation. The ozonation process was also independently evaluated for its ability to remove the NOM fractions from water. Ozonation was found not to be very effective at NOM removal since it only resulted in a 12% overall decrease of the NOM in the water samples. The CD polyurethanes, when used alone, were also not very effective at removing the NOM fractions from water (maximum of 33% NOM removal). On the other hand, the combination method (i.e. the use of CD polyurethanes and ozonation for NOM removal) resulted in a good capability of the CD polyurethanes at decreasing some NOM fractions in water as evidenced by a 73% and 88% decrease of the HpiB and hydrophilic acid (HpiA) fractions, respectively. The 73% reduction of the HpiB fraction demonstrates a great success of the combination approach employed herein, as this study reports this fraction as the most reactive precursor fraction for THM formation.
- Full Text:
Application of cyclodextrin nanoporous polymers in the removal of organic pollutants from water
- Authors: Sithole, Soraya P.
- Date: 2009-04-30T09:21:20Z
- Subjects: Water purification , Cyclodextrins , Polymers , Organic water pollutants
- Type: Thesis
- Identifier: uj:8318 , http://hdl.handle.net/10210/2446
- Description: M.Sc. , The removal of organic pollutants from industrial and municipal water is a great challenge to water providers worldwide. Some of these pollutants are very toxic and pose serious health risks to both humans and animals. Additionally, the presence of organic pollutants in the water often leads to the corrosion of turbines used for power generation at power stations. This obviously makes the power generation process less efficient and thus has cost implications, especially for the end user. Besides the corrosion of turbines, organic water pollutants impact on the cost of generating clean water. To this end, municipalities and industries sourcing water from Rand Water’s treatment plants and Eskom’s power stations (coal-fired power station) may be plagued by high water costs. Geosmin and 2-MIB are detectable by the human nose at concentration levels as low as 10 ng/L. These common water pollutants and are renowned for causing bad taste and odour in drinking water. Although geosmin and 2-MIB do not pose any serious health risks to humans, they impact on the aesthetic and consumer acceptability of drinking water. Currently available technologies such as activated carbon are unable to remove these pollutants to low levels (i.e. ppb levels). In our laboratories, we have found cyclodextrin-based polyurethanes to be effective in the removal of a range of organic pollutants from water to the desired ppb levels. However, these investigations were confined to water samples deliberately spiked with specific pollutants and have not been proven with "real" water samples. We sought to integrate data accumulated in the laboratory by testing and applying these polymers on a larger scale and on real systems. Cyclodextrin (CD) polymers were employed in the removal of 2-MIB, geosmin and other organic pollutants from water. The water was sampled from a coal-fired power station and Zuikerbosch Water Treatment Plant (Rand Water). After using Solid Phase Microextraction (SPME) for the extraction of organic pollutants from the water samples the organic pollutants were identified and quantified using Gas chromatography-mass spectrometry (GC-MS). The new cyclodextrin polymer technology was compared with treatment methods currently applied at both the power station and treatment plant. To determine the environmental friendliness of this technology, polymer degradation studies were also carried out. These entailed performing soil burial tests prior to the characterization of the polymers. Thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Braunner Emmet Tellet (BET) analysis were used for the characterization of the polymers. The techniques were also used to determine if any degradation modifications occurred on the polymeric material. The findings of the study are summarized below: • SPME extraction and GC-MS analyses of geosmin, 2-MIB and other pollutants were successfully accomplished. • The cyclodextrin polymers were effective in the removal of geosmin and 2-MIB (up to 90%) from water sampled at Zuikerbosch water treatment plant. The polymers remained effective (90%) in the absorption of geosmin and 2-MIB even when the water samples were spiked with a competing pollutant (i.e. humic acid). Activated carbon has been noted to have reduced adsorption capacity when humic acid is present in water. • The polymers demonstrated the ability to remove as much as 90% of organic pollutants from raw water compared to the 50% removed by the polyelectrolyte and optimum minimal polyaluminium chloride employed at the coal-fired power station. Analyses of the samples using TOC before and after treatment were accomplished. Reduction in the TOC was noted at the different sampling points after Eskom’s water treatment regime. • Results from the study indicated that the β-CD TDI polymers underwent a greater weight-loss during soil burial when first digested in sulphuric acid (ca. 50% maximum mass loss). On the other hand, β-CD HMDI polymers appeared to be unaffected by predigestion and experienced the same amount mass loss for the digested and undigested polymers (ca. 30% maximum mass loss). SEM studies revealed changes in the surface morphology of the polymers. Moreover, thermogravimetric analysis (TGA) gave an indication of polymer degradation under all soil burial conditions the polymer was subjected to.
- Full Text:
- Authors: Sithole, Soraya P.
- Date: 2009-04-30T09:21:20Z
- Subjects: Water purification , Cyclodextrins , Polymers , Organic water pollutants
- Type: Thesis
- Identifier: uj:8318 , http://hdl.handle.net/10210/2446
- Description: M.Sc. , The removal of organic pollutants from industrial and municipal water is a great challenge to water providers worldwide. Some of these pollutants are very toxic and pose serious health risks to both humans and animals. Additionally, the presence of organic pollutants in the water often leads to the corrosion of turbines used for power generation at power stations. This obviously makes the power generation process less efficient and thus has cost implications, especially for the end user. Besides the corrosion of turbines, organic water pollutants impact on the cost of generating clean water. To this end, municipalities and industries sourcing water from Rand Water’s treatment plants and Eskom’s power stations (coal-fired power station) may be plagued by high water costs. Geosmin and 2-MIB are detectable by the human nose at concentration levels as low as 10 ng/L. These common water pollutants and are renowned for causing bad taste and odour in drinking water. Although geosmin and 2-MIB do not pose any serious health risks to humans, they impact on the aesthetic and consumer acceptability of drinking water. Currently available technologies such as activated carbon are unable to remove these pollutants to low levels (i.e. ppb levels). In our laboratories, we have found cyclodextrin-based polyurethanes to be effective in the removal of a range of organic pollutants from water to the desired ppb levels. However, these investigations were confined to water samples deliberately spiked with specific pollutants and have not been proven with "real" water samples. We sought to integrate data accumulated in the laboratory by testing and applying these polymers on a larger scale and on real systems. Cyclodextrin (CD) polymers were employed in the removal of 2-MIB, geosmin and other organic pollutants from water. The water was sampled from a coal-fired power station and Zuikerbosch Water Treatment Plant (Rand Water). After using Solid Phase Microextraction (SPME) for the extraction of organic pollutants from the water samples the organic pollutants were identified and quantified using Gas chromatography-mass spectrometry (GC-MS). The new cyclodextrin polymer technology was compared with treatment methods currently applied at both the power station and treatment plant. To determine the environmental friendliness of this technology, polymer degradation studies were also carried out. These entailed performing soil burial tests prior to the characterization of the polymers. Thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Braunner Emmet Tellet (BET) analysis were used for the characterization of the polymers. The techniques were also used to determine if any degradation modifications occurred on the polymeric material. The findings of the study are summarized below: • SPME extraction and GC-MS analyses of geosmin, 2-MIB and other pollutants were successfully accomplished. • The cyclodextrin polymers were effective in the removal of geosmin and 2-MIB (up to 90%) from water sampled at Zuikerbosch water treatment plant. The polymers remained effective (90%) in the absorption of geosmin and 2-MIB even when the water samples were spiked with a competing pollutant (i.e. humic acid). Activated carbon has been noted to have reduced adsorption capacity when humic acid is present in water. • The polymers demonstrated the ability to remove as much as 90% of organic pollutants from raw water compared to the 50% removed by the polyelectrolyte and optimum minimal polyaluminium chloride employed at the coal-fired power station. Analyses of the samples using TOC before and after treatment were accomplished. Reduction in the TOC was noted at the different sampling points after Eskom’s water treatment regime. • Results from the study indicated that the β-CD TDI polymers underwent a greater weight-loss during soil burial when first digested in sulphuric acid (ca. 50% maximum mass loss). On the other hand, β-CD HMDI polymers appeared to be unaffected by predigestion and experienced the same amount mass loss for the digested and undigested polymers (ca. 30% maximum mass loss). SEM studies revealed changes in the surface morphology of the polymers. Moreover, thermogravimetric analysis (TGA) gave an indication of polymer degradation under all soil burial conditions the polymer was subjected to.
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Comparative study for the removal of natural organic matter from different raw waters by ion exchange
- Lobanga, K.P., Haarhoff, J., Mamba, B.B., Van Staden, S.J.
- Authors: Lobanga, K.P. , Haarhoff, J. , Mamba, B.B. , Van Staden, S.J.
- Date: 2011
- Subjects: Water - Purification - Adsorption , Organic water pollutants , Carbon, Activated , Water - Purification - Organic compounds removal
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16647 , uj:15793 , Lobanga, K.P. et al.(2011) Comparitive study for the removal of natural organic matter from different raw waters by ion exchange. In: Proceedings of the 4th IWA Specialty Conference on NOM: From Source to Tap and Beyond, held in Costa Mesa, USA. 27-29 July 2011, 9 p.
- Description: Abstract South African water treatment plants mainly utilise surface water sources whose quality is continuously compromised due to indirect reuse and high return flows. In general the methods used by these water treatment plants are based on the removal of turbidity, various chemical contaminants and microorganisms. Recently introduced NOM regulations added the removal of natural organic matter (NOM) as a priority. Basic anion exchange resins are one way of NOM removal, reported on this paper. Due to the variability in the composition of NOM in natural raw water, eight natural raw waters were collected throughout South Africa as representative of the different water types of the country. They were collected three times during a period of eight months. The strong and weak – base anion resins used in the study were chosen for their availability and competitive price at the local market. The removal of the NOM fractions was assessed by measuring ultraviolet absorption at a wavelength of 254 nm (UV254). Freundlich equilibrium isotherms were fitted. It was observed that the Freundlich parameters K and n are related reducing the Freundlich isotherm to a single-parameter model. The two parameters cluster for some waters regardless of season. Two performance indicators, namely 65% initial UV254 removal and absolute level of 6 /m, were adopted. It was found that if the initial UV254 is less than about 15 /m the absolute level of 6 /m is reached first while when the initial UV254 is greater than 20 /m the removal of 65% of UV254 is reached first. It was also observed that the resin usage rate is not only dependent on the initial UV254 value but also on the nature and concentration of the NOM, indicating a need for a better NOM characterization.
- Full Text: false
- Authors: Lobanga, K.P. , Haarhoff, J. , Mamba, B.B. , Van Staden, S.J.
- Date: 2011
- Subjects: Water - Purification - Adsorption , Organic water pollutants , Carbon, Activated , Water - Purification - Organic compounds removal
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16647 , uj:15793 , Lobanga, K.P. et al.(2011) Comparitive study for the removal of natural organic matter from different raw waters by ion exchange. In: Proceedings of the 4th IWA Specialty Conference on NOM: From Source to Tap and Beyond, held in Costa Mesa, USA. 27-29 July 2011, 9 p.
- Description: Abstract South African water treatment plants mainly utilise surface water sources whose quality is continuously compromised due to indirect reuse and high return flows. In general the methods used by these water treatment plants are based on the removal of turbidity, various chemical contaminants and microorganisms. Recently introduced NOM regulations added the removal of natural organic matter (NOM) as a priority. Basic anion exchange resins are one way of NOM removal, reported on this paper. Due to the variability in the composition of NOM in natural raw water, eight natural raw waters were collected throughout South Africa as representative of the different water types of the country. They were collected three times during a period of eight months. The strong and weak – base anion resins used in the study were chosen for their availability and competitive price at the local market. The removal of the NOM fractions was assessed by measuring ultraviolet absorption at a wavelength of 254 nm (UV254). Freundlich equilibrium isotherms were fitted. It was observed that the Freundlich parameters K and n are related reducing the Freundlich isotherm to a single-parameter model. The two parameters cluster for some waters regardless of season. Two performance indicators, namely 65% initial UV254 removal and absolute level of 6 /m, were adopted. It was found that if the initial UV254 is less than about 15 /m the absolute level of 6 /m is reached first while when the initial UV254 is greater than 20 /m the removal of 65% of UV254 is reached first. It was also observed that the resin usage rate is not only dependent on the initial UV254 value but also on the nature and concentration of the NOM, indicating a need for a better NOM characterization.
- Full Text: false
Development and validation of analytical methodologies for simultaneous determination of selected emerging organic pollutants in wastewater
- Authors: Mpupa, Anele
- Date: 2017
- Subjects: Organic water pollutants , Organic water pollutants - Environmental aspects , Water - Purification - Organic compounds removal , Pathogenic microorganisms - Detection , Cosmetics - Materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271175 , uj:28836
- Description: M.Sc. (Chemistry) , Abstract: Personal care products (PCPs) refer to chemicals used as active ingredients in cosmetics, fragrances, shampoos, toothpastes and soaps which are believed to have endocrine disrupting potential. Personal care products are currently categorised as emerging pollutants, since there are no regulations put in place on their allowed levels in the environment. They have been a focus of research since the 1990s as a result of their constant introduction to the environment. Personal care products are either excreted or washed off after use. These pollutants enter the environment via different paths including run off from water bodies, leaking septic tanks and the release of waste water effluents, hence the release of these chemicals into the environment is constant. For this reason, there is a need to monitoring the presence and levels of these chemicals. In addition, emerging pollutants are present in the environment in trace or ultratrace levels or incorporated in complex matrices which makes it difficult to detect them directly using analytical detection techniques. Therefore, the aim of this work was to develop different sample preparation methods to address some of the shortcomings of conventional analytical detection techniques (such as Ultraviolet-Visible spectrophotometry and high pressure liquid chromatography) encountered during the analysis of personal care products. To achieve the aim of the study, three different sample techniques were explored: solid phase extraction, vortex assisted supramolecular solvent based microextraction and ultrasound assisted solid phase nanoextraction. In the first experimental section, a solid phase extraction (SPE) procedure using commercially available ion exchange resin as an adsorbent was evaluated for preconcentration of benzophenone and sulisobenzone in wastewater samples prior to UV-Vis spectrophotometric determination. The solid phase material used displayed attractive factures such as selectivity, wide chemical stability, wide operation pH ranges and predictable solid surface/ analyte interactions. Under optimised conditions, the SPE significantly improved the limits of detection (0.15-0.28 μg L-1) and limits of quantifications (0.50-0.93 μg L-1) of the UV-Vis spectrophotometry towards the detection of the selected analytes. In addition, the developed method had relatively wide dynamic linear range, high precisions (intra-day and inter-day) and satisfactory recoveries (>95%). The second experimental work reports the development of a vortex assisted supramolecular solvent based microextraction combined with UV-Vis spectrophotometry...
- Full Text:
- Authors: Mpupa, Anele
- Date: 2017
- Subjects: Organic water pollutants , Organic water pollutants - Environmental aspects , Water - Purification - Organic compounds removal , Pathogenic microorganisms - Detection , Cosmetics - Materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271175 , uj:28836
- Description: M.Sc. (Chemistry) , Abstract: Personal care products (PCPs) refer to chemicals used as active ingredients in cosmetics, fragrances, shampoos, toothpastes and soaps which are believed to have endocrine disrupting potential. Personal care products are currently categorised as emerging pollutants, since there are no regulations put in place on their allowed levels in the environment. They have been a focus of research since the 1990s as a result of their constant introduction to the environment. Personal care products are either excreted or washed off after use. These pollutants enter the environment via different paths including run off from water bodies, leaking septic tanks and the release of waste water effluents, hence the release of these chemicals into the environment is constant. For this reason, there is a need to monitoring the presence and levels of these chemicals. In addition, emerging pollutants are present in the environment in trace or ultratrace levels or incorporated in complex matrices which makes it difficult to detect them directly using analytical detection techniques. Therefore, the aim of this work was to develop different sample preparation methods to address some of the shortcomings of conventional analytical detection techniques (such as Ultraviolet-Visible spectrophotometry and high pressure liquid chromatography) encountered during the analysis of personal care products. To achieve the aim of the study, three different sample techniques were explored: solid phase extraction, vortex assisted supramolecular solvent based microextraction and ultrasound assisted solid phase nanoextraction. In the first experimental section, a solid phase extraction (SPE) procedure using commercially available ion exchange resin as an adsorbent was evaluated for preconcentration of benzophenone and sulisobenzone in wastewater samples prior to UV-Vis spectrophotometric determination. The solid phase material used displayed attractive factures such as selectivity, wide chemical stability, wide operation pH ranges and predictable solid surface/ analyte interactions. Under optimised conditions, the SPE significantly improved the limits of detection (0.15-0.28 μg L-1) and limits of quantifications (0.50-0.93 μg L-1) of the UV-Vis spectrophotometry towards the detection of the selected analytes. In addition, the developed method had relatively wide dynamic linear range, high precisions (intra-day and inter-day) and satisfactory recoveries (>95%). The second experimental work reports the development of a vortex assisted supramolecular solvent based microextraction combined with UV-Vis spectrophotometry...
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Development of advanced carbon based composite electrodes for the detection and the degradation of organic pollutants in water via electrochemical/photoelectrochemical processes
- Authors: Ntsendwana, Bulelwa
- Date: 2014-07-15
- Subjects: Carbon composites , Electrodes, Carbon , Organic water pollutants , Electrochemical analysis , Photoelectrochemistry
- Type: Thesis
- Identifier: uj:11656 , http://hdl.handle.net/10210/11379
- Description: Ph.D. (Chemistry) , In this study, carbon based electrode materials such as glassy carbon, graphene, diamond and exfoliated graphite were explored as suitable electrode materials for electrochemical detection, electrochemical and photoelectrochemical degradation of organic water pollutants. Graphene modified glassy carbon electrode sensor was developed for bisphenol A. Cyclic voltammetry was used to study the electrochemical properties of the prepared graphene- modified glassy carbon electrode using potassium ferricyanide as a redox probe. The prepared graphene- modified glassy carbon electrode exhibited more facile electron kinetics and enhanced current of about 75% when compared to the unmodified glassy carbon electrode...
- Full Text:
- Authors: Ntsendwana, Bulelwa
- Date: 2014-07-15
- Subjects: Carbon composites , Electrodes, Carbon , Organic water pollutants , Electrochemical analysis , Photoelectrochemistry
- Type: Thesis
- Identifier: uj:11656 , http://hdl.handle.net/10210/11379
- Description: Ph.D. (Chemistry) , In this study, carbon based electrode materials such as glassy carbon, graphene, diamond and exfoliated graphite were explored as suitable electrode materials for electrochemical detection, electrochemical and photoelectrochemical degradation of organic water pollutants. Graphene modified glassy carbon electrode sensor was developed for bisphenol A. Cyclic voltammetry was used to study the electrochemical properties of the prepared graphene- modified glassy carbon electrode using potassium ferricyanide as a redox probe. The prepared graphene- modified glassy carbon electrode exhibited more facile electron kinetics and enhanced current of about 75% when compared to the unmodified glassy carbon electrode...
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Development of sample preparation and chromatographic mass spectrometric techniques for determination of selected organic pollutants in wastewater
- Authors: Muckoya, Vallerie Akinyi
- Date: 2019
- Subjects: Organic water pollutants , Water quality management , Mass spectrometry , Sample preparation (Chemistry)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/401444 , uj:33549
- Description: Abstract : In the recent past, there has been a great concern on the ever-increasing emergence of organic contaminants in the various environmental compartments, that pose great health concerns to humans and aquatic life. These organic pollutants have been ubiquitous in the environment for decades, however, they were not identifiable until the emergence of new and advanced analytical technologies. Therefore, the main objective of this study was to develop robust and efficient analytical and modelling techniques, for the extraction and analysis of selected multiclass organic contaminants from wastewater samples. This is because their analytical determination is very challenging due to their occurrence in trace levels (ng L-1 to μg L-1) in the environment. The analytical techniques comprise of optimization of both the sample preparation procedures and instrumental analysis for detection and quantification. Solid phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and ultrasonic-assisted magnetic solid phase dispersive extraction (UA-MSPDE) were the selected sample preparation techniques used for the extraction and preconcentration of methylparaben, ethylparaben, propylparaben, ethoprofos, parathion methyl, azinphos methyl and chlorpyrifos in water samples. This was followed by instrumental analysis for their detection and quantification using liquid chromatography tandem mass spectrometry (LC-MS/MS). The developed analytical techniques were applied in real environmental samples obtained from different water treatment stages of a local wastewater treatment plant in Gauteng province, South Africa. Experimental factors that had an influence on the analytical response in terms on highest percentage recoveries were optimized using both univariate (one factor a time) and multivariate approach for all the experiments in this study. Multivariate optimization was accomplished using Statistica and Minitab software. The performance characteristics of the LC-MS/MS facilitated the determination of these organic contaminants at trace levels. Multiple reaction monitoring mode (MRM) was used for specific and sensitive targeted analysis, where the quadrupole analyzers were set at multiple ion frequencies for the specific analytes under investigation together with their product fragment ions. MRM is ideally suitable for trace level analysis of complex mixtures. Oasis HLB cartridges were found to be suitable for extraction of parabens giving satisfactory results. Vortex assisted dispersive liquid-liquid microextraction (VA-DLLME) was used for the extraction and enrichment of organophosphorus pesticides in wastewater samples. Selection of the appropriate organic solvent (extractant and disperser solvents) used for this method was of utmost importance and was performed using univariate optimization. v The results revealed chloroform to be the most suitable extractant solvent while acetone was the optimum disperser solvent. This was followed by the chemometric optimization of the independent variables that significantly affect the outcome of the analytical response. The organophosphorus compounds that were extracted in wastewater samples using this technique with satisfactory results were ethoprofos, parathion methyl and azinphos methyl. Also, a novel method was developed for the extraction and preconcentration of multiclass organic compounds (parabens and organophosphorus pesticides) using synthesized pristine carbon nanodots (CNDs) applied as SPE adsorbent. A comparison between the synthesized CNDs and commercial based SPE sorbent was analyzed. Two-level factorial design and response surface methodology based on central composite design were used for multivariate optimization of the experimental variables. Furthermore, the CNDs were also functionalized with magnetite. The magnetic CNDs were applied for the development of magnetic solid phase dispersive extraction method with ultrasonic dispersion for the simultaneous extraction of chlorpyrifos and triclosan in environmental water samples. This method offered a very rapid and simple extraction and preconcentration of these organic contaminants with satisfactory results. , Ph.D. (Chemistry)
- Full Text:
- Authors: Muckoya, Vallerie Akinyi
- Date: 2019
- Subjects: Organic water pollutants , Water quality management , Mass spectrometry , Sample preparation (Chemistry)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/401444 , uj:33549
- Description: Abstract : In the recent past, there has been a great concern on the ever-increasing emergence of organic contaminants in the various environmental compartments, that pose great health concerns to humans and aquatic life. These organic pollutants have been ubiquitous in the environment for decades, however, they were not identifiable until the emergence of new and advanced analytical technologies. Therefore, the main objective of this study was to develop robust and efficient analytical and modelling techniques, for the extraction and analysis of selected multiclass organic contaminants from wastewater samples. This is because their analytical determination is very challenging due to their occurrence in trace levels (ng L-1 to μg L-1) in the environment. The analytical techniques comprise of optimization of both the sample preparation procedures and instrumental analysis for detection and quantification. Solid phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and ultrasonic-assisted magnetic solid phase dispersive extraction (UA-MSPDE) were the selected sample preparation techniques used for the extraction and preconcentration of methylparaben, ethylparaben, propylparaben, ethoprofos, parathion methyl, azinphos methyl and chlorpyrifos in water samples. This was followed by instrumental analysis for their detection and quantification using liquid chromatography tandem mass spectrometry (LC-MS/MS). The developed analytical techniques were applied in real environmental samples obtained from different water treatment stages of a local wastewater treatment plant in Gauteng province, South Africa. Experimental factors that had an influence on the analytical response in terms on highest percentage recoveries were optimized using both univariate (one factor a time) and multivariate approach for all the experiments in this study. Multivariate optimization was accomplished using Statistica and Minitab software. The performance characteristics of the LC-MS/MS facilitated the determination of these organic contaminants at trace levels. Multiple reaction monitoring mode (MRM) was used for specific and sensitive targeted analysis, where the quadrupole analyzers were set at multiple ion frequencies for the specific analytes under investigation together with their product fragment ions. MRM is ideally suitable for trace level analysis of complex mixtures. Oasis HLB cartridges were found to be suitable for extraction of parabens giving satisfactory results. Vortex assisted dispersive liquid-liquid microextraction (VA-DLLME) was used for the extraction and enrichment of organophosphorus pesticides in wastewater samples. Selection of the appropriate organic solvent (extractant and disperser solvents) used for this method was of utmost importance and was performed using univariate optimization. v The results revealed chloroform to be the most suitable extractant solvent while acetone was the optimum disperser solvent. This was followed by the chemometric optimization of the independent variables that significantly affect the outcome of the analytical response. The organophosphorus compounds that were extracted in wastewater samples using this technique with satisfactory results were ethoprofos, parathion methyl and azinphos methyl. Also, a novel method was developed for the extraction and preconcentration of multiclass organic compounds (parabens and organophosphorus pesticides) using synthesized pristine carbon nanodots (CNDs) applied as SPE adsorbent. A comparison between the synthesized CNDs and commercial based SPE sorbent was analyzed. Two-level factorial design and response surface methodology based on central composite design were used for multivariate optimization of the experimental variables. Furthermore, the CNDs were also functionalized with magnetite. The magnetic CNDs were applied for the development of magnetic solid phase dispersive extraction method with ultrasonic dispersion for the simultaneous extraction of chlorpyrifos and triclosan in environmental water samples. This method offered a very rapid and simple extraction and preconcentration of these organic contaminants with satisfactory results. , Ph.D. (Chemistry)
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Die effek van myn-, nywerheids- en rioolafloopwaters op die waterkwaliteit van die Elsburgspruit, Germiston met spesiale verwysing na die voorkoms en akkumulering van geselekteerde swaarmetale in die ekosisteem
- Van der Merwe, Christiaan Gideon
- Authors: Van der Merwe, Christiaan Gideon
- Date: 2014-02-18
- Subjects: Water - Pollution , Heavy metals - Environmental aspects , Acid pollution of rivers, lakes, etc. , Organic water pollutants
- Type: Thesis
- Identifier: uj:4149 , http://hdl.handle.net/10210/9496
- Description: Ph.D. , An investigation was made into the physical, chemical and biological conditions of the Elsburgspruit to establish the extent and quality of pollution over a period of two and a half years from January 1987 June 1989. The results obtained during the investigation can be summarised as follows. Serious faecal pollution as reflected by faecal coliforms, faecal streptococci and coliphage organisms occurs over a large stretch of the river, posing a health risk to the people using the recreational area at' Vosloosrust, downstream from the Elsburgspruit near Kathlehong. The occurrence and large numbers of coliphage organisms occurring at certain sampling localities suggest the possible presence of the pathogenic viruses Salmonella, Pseudomonas and Candida. Effluent and seepage waters from mining areas, discharged into the Elsburgspruit were found to be low in pH and high in concentrations of certain metals such as zinc, manganese and iron. Due to the large volume of this particular effluent, the effects thereof on the water quality and fauna of the streams are felt over a distance of more than seven kilometres. As a result, the recovery of the stream from pollution is severely retarded. A number of species of the numerically dominant aquatic and semi-aquatic macrophytes which occurred within the flood-plain of the Elsburgspruit, were found to be able to absorb and to accumulate substantial concentrations of the various heavy metals, directly from the water, or from adjacent moist soils. It was also found that the Spanish reed, Arundo donax, which covers a large area of the wetland region of the Elsburgspruit in its lower section, absorbed and accumulated substantial quantities of the different heavy metals from the water of the stream. A comparison was made of the extent to which metals are deposited into the sediment under both acidic and alkaline conditions...
- Full Text:
- Authors: Van der Merwe, Christiaan Gideon
- Date: 2014-02-18
- Subjects: Water - Pollution , Heavy metals - Environmental aspects , Acid pollution of rivers, lakes, etc. , Organic water pollutants
- Type: Thesis
- Identifier: uj:4149 , http://hdl.handle.net/10210/9496
- Description: Ph.D. , An investigation was made into the physical, chemical and biological conditions of the Elsburgspruit to establish the extent and quality of pollution over a period of two and a half years from January 1987 June 1989. The results obtained during the investigation can be summarised as follows. Serious faecal pollution as reflected by faecal coliforms, faecal streptococci and coliphage organisms occurs over a large stretch of the river, posing a health risk to the people using the recreational area at' Vosloosrust, downstream from the Elsburgspruit near Kathlehong. The occurrence and large numbers of coliphage organisms occurring at certain sampling localities suggest the possible presence of the pathogenic viruses Salmonella, Pseudomonas and Candida. Effluent and seepage waters from mining areas, discharged into the Elsburgspruit were found to be low in pH and high in concentrations of certain metals such as zinc, manganese and iron. Due to the large volume of this particular effluent, the effects thereof on the water quality and fauna of the streams are felt over a distance of more than seven kilometres. As a result, the recovery of the stream from pollution is severely retarded. A number of species of the numerically dominant aquatic and semi-aquatic macrophytes which occurred within the flood-plain of the Elsburgspruit, were found to be able to absorb and to accumulate substantial concentrations of the various heavy metals, directly from the water, or from adjacent moist soils. It was also found that the Spanish reed, Arundo donax, which covers a large area of the wetland region of the Elsburgspruit in its lower section, absorbed and accumulated substantial quantities of the different heavy metals from the water of the stream. A comparison was made of the extent to which metals are deposited into the sediment under both acidic and alkaline conditions...
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Electrochemical detection of arsenic and selenium on modified carbon based nanocomposite electrodes
- Authors: Idris, Azeez Olayiwola
- Date: 2016
- Subjects: Nanostructured materials , Electrodes, Carbon , Electrochemical analysis , Organic water pollutants , Carbon composites
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/124946 , uj:20978
- Description: Abstract: This study explores the applications of nanomaterial modified on glassy carbon electrode (GCE) in the electroanalysis of arsenic and selenium ions in water. GCE was modified with gold nanoparticles and reduced graphene oxide. Gold nanoparticle (AuNPs) modified GCE (GCE-AuNPs) was prepared by electrochemical deposition of gold from 5 mM of HAuCl4 solutions by cycling the potential from -400 mV to 1100 mV for 10 cycles at a scan rate of 50 mVs-1. GCEAuNPs was electrochemically investigated using redox probes which are [Fe (CN) 6]3-/4- and Ru (NH3)62+/3+. The current and the reversibility of the redox probes were enhanced in the presence of modifiers. The electrochemical determination of selenium by square wave anodic stripping voltammetry (SWASV) using GCE-AuNPs was carried out under the optimised conditions: pH 1, deposition potential of -100 mV, deposition time of 60 s and 0.1 M H2SO4 as supporting electrolyte. A detection limit of 0.64 μg L-1 was obtained. Cu and Cd were the only significant interferences observed for the electrochemical detection of selenium. Attempt was also made to sense selenium in tap water, concentration of 8.86 (± 0.34) ppb Se, was calculated for the tap water. The electrochemical method was validated with ICP-OES. Furthermore, arsenic was detected on GCE-AuNPs by SWASV. The sensing of arsenic was also optimised at different analytical conditions and a detection limit of 0.75 μgL-1 was obtained. Cu, Cd and Hg were the major interferences in arsenic sensing. Ammonia, EDTA and G3 PPI were used as ligands to mask the interference effect of copper on arsenic sensing in the bid to remove interference. Graphene oxide was synthesised by using Hummer`s methods and was further reduced to reduced graphene oxide using ascorbic acid. The reduced graphene oxide was used to modify GCE, the modification of GCE with rGO-GCE resulted in an increase in the electroactive surface area of the electrode which led to enhance the redox peak of [Fe(CN)6]3-/4- in comparison to the bare GCE. SWASV was used to detect Se (IV) in water at the following optimum conditions: 0.1 M HNO3 as supporting electrolyte, deposition potential of -100 mV and pre-concentration time of 240 s. The rGO-GCE sensor was able to detect Se (IV) to the limit of 2.2 ppb and was not susceptible to many interfering cations except Cu (II) and Cd (II). , M.Sc. (Chemistry)
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- Authors: Idris, Azeez Olayiwola
- Date: 2016
- Subjects: Nanostructured materials , Electrodes, Carbon , Electrochemical analysis , Organic water pollutants , Carbon composites
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/124946 , uj:20978
- Description: Abstract: This study explores the applications of nanomaterial modified on glassy carbon electrode (GCE) in the electroanalysis of arsenic and selenium ions in water. GCE was modified with gold nanoparticles and reduced graphene oxide. Gold nanoparticle (AuNPs) modified GCE (GCE-AuNPs) was prepared by electrochemical deposition of gold from 5 mM of HAuCl4 solutions by cycling the potential from -400 mV to 1100 mV for 10 cycles at a scan rate of 50 mVs-1. GCEAuNPs was electrochemically investigated using redox probes which are [Fe (CN) 6]3-/4- and Ru (NH3)62+/3+. The current and the reversibility of the redox probes were enhanced in the presence of modifiers. The electrochemical determination of selenium by square wave anodic stripping voltammetry (SWASV) using GCE-AuNPs was carried out under the optimised conditions: pH 1, deposition potential of -100 mV, deposition time of 60 s and 0.1 M H2SO4 as supporting electrolyte. A detection limit of 0.64 μg L-1 was obtained. Cu and Cd were the only significant interferences observed for the electrochemical detection of selenium. Attempt was also made to sense selenium in tap water, concentration of 8.86 (± 0.34) ppb Se, was calculated for the tap water. The electrochemical method was validated with ICP-OES. Furthermore, arsenic was detected on GCE-AuNPs by SWASV. The sensing of arsenic was also optimised at different analytical conditions and a detection limit of 0.75 μgL-1 was obtained. Cu, Cd and Hg were the major interferences in arsenic sensing. Ammonia, EDTA and G3 PPI were used as ligands to mask the interference effect of copper on arsenic sensing in the bid to remove interference. Graphene oxide was synthesised by using Hummer`s methods and was further reduced to reduced graphene oxide using ascorbic acid. The reduced graphene oxide was used to modify GCE, the modification of GCE with rGO-GCE resulted in an increase in the electroactive surface area of the electrode which led to enhance the redox peak of [Fe(CN)6]3-/4- in comparison to the bare GCE. SWASV was used to detect Se (IV) in water at the following optimum conditions: 0.1 M HNO3 as supporting electrolyte, deposition potential of -100 mV and pre-concentration time of 240 s. The rGO-GCE sensor was able to detect Se (IV) to the limit of 2.2 ppb and was not susceptible to many interfering cations except Cu (II) and Cd (II). , M.Sc. (Chemistry)
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Electrochemical detection of organic and inorganic water pollutants using recompressed exfoliated graphite electrodes
- Authors: Ndlovu, Thabile
- Date: 2012-11-05
- Subjects: Exfoliated graphite electrodes , Organic water pollutants , Inorganic compounds - Environmental aspects , Water analysis , Electrodes
- Type: Thesis
- Identifier: uj:7343 , http://hdl.handle.net/10210/8091
- Description: Ph.D. , This study explored the possible application of a relatively new electrode called exfoliated graphite electrode (EG electrode) in the electroanalysis of organic and inorganic water pollutants. This study also explored the applicability of this electrode in the removal of heavy metal pollutants in water. The EG material was successfully prepared by intercalating bisulphate ions into graphite flakes (>300 μm) followed by thermal shock at 800°C to obtain an exfoliated graphite. After compressing the EG at high pressure, the obtained circular sheets were used to fabricate electrodes. The electrochemical profiles of EG electrode and glassy carbon electrodes (GCE) were recorded and compared using cyclic voltammetryand square wave voltammetry in the presence of various supporting electrolytes and [Fe(CN)6]3-/4-, [Ru(NH3)6]2+/3+, ferrocene redox probes. In the supporting electrolytes (KCl, H2SO4, NaOH, tetrabutylammoniumtetraflouroborate, phosphate buffers), the potential windows of EG were found, in some cases, to be about 300 mV larger than that of GCE. The diffusion coefficients (cm2s-1) of the redox probes were calculated to be 3.638 x 10-6, 1.213 x 10-6 and 4.411 x 10-6 for [Fe(CN)6]3-/4-, [Ru(NH3)6]2+/3+ and ferrocene, respectively. These values are comparable to those obtained from GCE. Furthermore, EG was modified with various nanomaterials such as poly (propylene imine) dendrimer (PPI), gold nanoparticles, silver nanoparticles, dendrimer–gold nanoparticles composite, cobalt oxide and bismuth. The morphologies of the modified electrodes were studied using scanning electron microscopy and their electrochemical reactivities in the three redox probes were investigated. The current and the reversibility of redox probes were enhanced in the presence of modifiers in different degrees with dendrimer and gold nanoparticles having a favourable edge. The electrochemical determination of o-nitrophenol by square wave voltammetry using a nanocomposite of generation 2 poly(propyleneimine) dendrimer and gold nanoparticles modified GCEand EG electrode were compared. A characteristic reduction peak between -600 mV and -700 mV for o-nitrophenol was observed with enhanced current on both GCE and EG modified electrodes.
- Full Text:
- Authors: Ndlovu, Thabile
- Date: 2012-11-05
- Subjects: Exfoliated graphite electrodes , Organic water pollutants , Inorganic compounds - Environmental aspects , Water analysis , Electrodes
- Type: Thesis
- Identifier: uj:7343 , http://hdl.handle.net/10210/8091
- Description: Ph.D. , This study explored the possible application of a relatively new electrode called exfoliated graphite electrode (EG electrode) in the electroanalysis of organic and inorganic water pollutants. This study also explored the applicability of this electrode in the removal of heavy metal pollutants in water. The EG material was successfully prepared by intercalating bisulphate ions into graphite flakes (>300 μm) followed by thermal shock at 800°C to obtain an exfoliated graphite. After compressing the EG at high pressure, the obtained circular sheets were used to fabricate electrodes. The electrochemical profiles of EG electrode and glassy carbon electrodes (GCE) were recorded and compared using cyclic voltammetryand square wave voltammetry in the presence of various supporting electrolytes and [Fe(CN)6]3-/4-, [Ru(NH3)6]2+/3+, ferrocene redox probes. In the supporting electrolytes (KCl, H2SO4, NaOH, tetrabutylammoniumtetraflouroborate, phosphate buffers), the potential windows of EG were found, in some cases, to be about 300 mV larger than that of GCE. The diffusion coefficients (cm2s-1) of the redox probes were calculated to be 3.638 x 10-6, 1.213 x 10-6 and 4.411 x 10-6 for [Fe(CN)6]3-/4-, [Ru(NH3)6]2+/3+ and ferrocene, respectively. These values are comparable to those obtained from GCE. Furthermore, EG was modified with various nanomaterials such as poly (propylene imine) dendrimer (PPI), gold nanoparticles, silver nanoparticles, dendrimer–gold nanoparticles composite, cobalt oxide and bismuth. The morphologies of the modified electrodes were studied using scanning electron microscopy and their electrochemical reactivities in the three redox probes were investigated. The current and the reversibility of redox probes were enhanced in the presence of modifiers in different degrees with dendrimer and gold nanoparticles having a favourable edge. The electrochemical determination of o-nitrophenol by square wave voltammetry using a nanocomposite of generation 2 poly(propyleneimine) dendrimer and gold nanoparticles modified GCEand EG electrode were compared. A characteristic reduction peak between -600 mV and -700 mV for o-nitrophenol was observed with enhanced current on both GCE and EG modified electrodes.
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Electrochemical/photoelectrochemical studies of nickel(II) dimethylglyoxime and gold nanoparticles and their applications in the detection of phenolic water pollutants
- Authors: Olorundare, Foluke O. Grace
- Date: 2017
- Subjects: Organic water pollutants , Nanostructured materials , Phenols , Mass spectrometry , Phenols - Identification
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235745 , uj:24114
- Description: M.Sc. (Chemistry) , Abstract: The electrochemical behaviour and detection of phenols such as o-nitrophenol (o-NP) and p-nitrophenol (p-NP) and also 2-chlorophenol (2-CP) and 3-chlorophenol (3-CP), has been studied on a gold nanoparticle - nickel dimethylglyoxime complex (N(II)DMG) modified glassy carbon electrode (GCE). The electrode was prepared by drop coating nickel dimethylglyoxime complex on a GCE followed by the electrodeposition of gold nanoparticle. Each step in the electrode modification was characterised by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and high resolution scanning electron microscopy (HRSEM). There two redox probes hexacyanoferrate (III) - hexacyanoferrate(II) ion ([Fe(CN)6]3−/4− ) and hexaammineruthenium (III) chloride – hexaammineruthenium (II) chloride [Ru(NH3)6 ]2+/3+ were applied to verify the suitability of the modified electrode (i.e. GCE/NiDMG-AuNP) with satisfactory results. The results showed that nickel dimethylglyoxime complex/gold nanoparticles electrode had improved conductivity, reversibility and electron transfer rate in selected redox probe than the unmodified GCE. The GCE/NiDMG-AuNP electrode was used in the determination of o-NP and p-NP in water. Under the optimal conditions, detection limits of 0.58 μM and 0.103 μM were calculated for o-NP and p-NP respectively. The GCE/NiDMG-AuNP electrode was applied to real water sample and the effects of interferences were studied. Photoelectrochemical analysis was done with p-NP with substantial results. The GCE/NiDMG-AuNP electrode was also used to investigate the electrochemical behaviour of 2-CP and 3-CP by Cyclic Voltammetry (CV) and differential pulse voltammetry (DPV). The results demonstrated that the GCE/NiDMG-AuNP exhibited remarkable enhancement effects towards 2-CP and 3-CP. Under the optimized conditions, the oxidation peak currents displayed a good linear relationship to concentration in the ranges from 0.5 to 30 μM for 2-CP and 0.5 to 35 μM for 3-CP, with detection limits of 0.097 and 0.093 μM, respectively. This sensor was successfully used in the detection 2-CP and 3-CP of real water samples with good results.
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- Authors: Olorundare, Foluke O. Grace
- Date: 2017
- Subjects: Organic water pollutants , Nanostructured materials , Phenols , Mass spectrometry , Phenols - Identification
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235745 , uj:24114
- Description: M.Sc. (Chemistry) , Abstract: The electrochemical behaviour and detection of phenols such as o-nitrophenol (o-NP) and p-nitrophenol (p-NP) and also 2-chlorophenol (2-CP) and 3-chlorophenol (3-CP), has been studied on a gold nanoparticle - nickel dimethylglyoxime complex (N(II)DMG) modified glassy carbon electrode (GCE). The electrode was prepared by drop coating nickel dimethylglyoxime complex on a GCE followed by the electrodeposition of gold nanoparticle. Each step in the electrode modification was characterised by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and high resolution scanning electron microscopy (HRSEM). There two redox probes hexacyanoferrate (III) - hexacyanoferrate(II) ion ([Fe(CN)6]3−/4− ) and hexaammineruthenium (III) chloride – hexaammineruthenium (II) chloride [Ru(NH3)6 ]2+/3+ were applied to verify the suitability of the modified electrode (i.e. GCE/NiDMG-AuNP) with satisfactory results. The results showed that nickel dimethylglyoxime complex/gold nanoparticles electrode had improved conductivity, reversibility and electron transfer rate in selected redox probe than the unmodified GCE. The GCE/NiDMG-AuNP electrode was used in the determination of o-NP and p-NP in water. Under the optimal conditions, detection limits of 0.58 μM and 0.103 μM were calculated for o-NP and p-NP respectively. The GCE/NiDMG-AuNP electrode was applied to real water sample and the effects of interferences were studied. Photoelectrochemical analysis was done with p-NP with substantial results. The GCE/NiDMG-AuNP electrode was also used to investigate the electrochemical behaviour of 2-CP and 3-CP by Cyclic Voltammetry (CV) and differential pulse voltammetry (DPV). The results demonstrated that the GCE/NiDMG-AuNP exhibited remarkable enhancement effects towards 2-CP and 3-CP. Under the optimized conditions, the oxidation peak currents displayed a good linear relationship to concentration in the ranges from 0.5 to 30 μM for 2-CP and 0.5 to 35 μM for 3-CP, with detection limits of 0.097 and 0.093 μM, respectively. This sensor was successfully used in the detection 2-CP and 3-CP of real water samples with good results.
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Evaluation of water treatment processes in the removal of natural organic matter from water and its disinfection by-products using cyclodextrin polyurethanes
- Authors: Matsebula, Banelisiwe
- Date: 2012-10-18
- Subjects: Water -- Purification -- Organic compounds removal , Water -- Purification -- Disinfection -- By-products. , Organic water pollutants , Cyclodextrins , Polyurethanes
- Type: Thesis
- Identifier: uj:10409 , http://hdl.handle.net/10210/7876
- Description: M.Sc. , Natural Organic Matter (NOM) is a complex of organic material present in a natural surface water. Odour, taste and acidity are some of the problems associated with NOM in water systems. Futhermore, it causes the yellow or brown colour of water, whic is aesthetically unpleasant to consumers. NOM is also the energy source of bacterial re-growth and aids in the transportation of metal ions in the distribution system.Moreover, NOM in water can react with disinfectants, e.g. chlorine, to form disinfection by products (DBPs) such as trihalomethanes (THMs) and habacetic acids (HAAs). DBPs have recently been found to have adverse effects in humans. This study was undertaken in order to assess the effectiveness of some of the water treatment techniques employed by selected water supplying companies in dealing with NOM. To achive this, the water treatment processes used by these companies to reduce NOM and metal ions were coagulation, sand filtration, the use of granular activated carbon, ozonation and chlorination. In addition, β-cyclodextrin (β-CD) polyurethanes synthesized in our laboratories were used to remove the DBPs present in the water samples.
- Full Text:
- Authors: Matsebula, Banelisiwe
- Date: 2012-10-18
- Subjects: Water -- Purification -- Organic compounds removal , Water -- Purification -- Disinfection -- By-products. , Organic water pollutants , Cyclodextrins , Polyurethanes
- Type: Thesis
- Identifier: uj:10409 , http://hdl.handle.net/10210/7876
- Description: M.Sc. , Natural Organic Matter (NOM) is a complex of organic material present in a natural surface water. Odour, taste and acidity are some of the problems associated with NOM in water systems. Futhermore, it causes the yellow or brown colour of water, whic is aesthetically unpleasant to consumers. NOM is also the energy source of bacterial re-growth and aids in the transportation of metal ions in the distribution system.Moreover, NOM in water can react with disinfectants, e.g. chlorine, to form disinfection by products (DBPs) such as trihalomethanes (THMs) and habacetic acids (HAAs). DBPs have recently been found to have adverse effects in humans. This study was undertaken in order to assess the effectiveness of some of the water treatment techniques employed by selected water supplying companies in dealing with NOM. To achive this, the water treatment processes used by these companies to reduce NOM and metal ions were coagulation, sand filtration, the use of granular activated carbon, ozonation and chlorination. In addition, β-cyclodextrin (β-CD) polyurethanes synthesized in our laboratories were used to remove the DBPs present in the water samples.
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Functionalized synthetic-and bio-sorbents for removal of inorganic and organic contaminants in water
- Authors: Mwangi, Isaac Waweru
- Date: 2013-07-25
- Subjects: Water - Purification - Organic compounds removal , Organic water pollutants , Water purification - Inorganic compounds removal , Sorbents , Adsorption
- Type: Thesis
- Identifier: uj:7702 , http://hdl.handle.net/10210/8568
- Description: D.Phil. (Chemistry) , This thesis describes the improvement of sorption capacity and efficiency of synthetic and biological adsorbents towards selected pollutants by introducing functional groups on the sorbents. Functionalization was achieved by chemically modifying the binding sites of the studied adsorbents. The sorbent materials considered were chemical resins (Amberlite XAD 1180) and biomass (maize tassels and seaweed). The adsorbents were modified with ethylenediamine in order to improve their capacity for extraction of heavy metals, namely lead, copper and cadmium from water. For the removal of phenols from water, maize tassels was modified with polydiallyldimethylammonium chloride (polyDADMAC). The main focus of the proposed study was to formulate cheap and sustainable ways of purifying contaminated water by exploiting the pollutants’ affinity towards the adsorbents. Parameters such as contact time, sorbent quantities, analyte concentrations, desorption solution (for stripping adsorbed metals for sorbent reuse) and pH were optimized. Different isotherms were applied on the experimental data to establish sorption mechanisms and energies involved during the sorption process. The Langmuir isotherm was used to test for monolayer sorption while the Freundlich model tested multilayer adsorption on heterogeneous surfaces...
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Functionalized synthetic-and bio-sorbents for removal of inorganic and organic contaminants in water
- Authors: Mwangi, Isaac Waweru
- Date: 2013-07-25
- Subjects: Water - Purification - Organic compounds removal , Organic water pollutants , Water purification - Inorganic compounds removal , Sorbents , Adsorption
- Type: Thesis
- Identifier: uj:7702 , http://hdl.handle.net/10210/8568
- Description: D.Phil. (Chemistry) , This thesis describes the improvement of sorption capacity and efficiency of synthetic and biological adsorbents towards selected pollutants by introducing functional groups on the sorbents. Functionalization was achieved by chemically modifying the binding sites of the studied adsorbents. The sorbent materials considered were chemical resins (Amberlite XAD 1180) and biomass (maize tassels and seaweed). The adsorbents were modified with ethylenediamine in order to improve their capacity for extraction of heavy metals, namely lead, copper and cadmium from water. For the removal of phenols from water, maize tassels was modified with polydiallyldimethylammonium chloride (polyDADMAC). The main focus of the proposed study was to formulate cheap and sustainable ways of purifying contaminated water by exploiting the pollutants’ affinity towards the adsorbents. Parameters such as contact time, sorbent quantities, analyte concentrations, desorption solution (for stripping adsorbed metals for sorbent reuse) and pH were optimized. Different isotherms were applied on the experimental data to establish sorption mechanisms and energies involved during the sorption process. The Langmuir isotherm was used to test for monolayer sorption while the Freundlich model tested multilayer adsorption on heterogeneous surfaces...
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Modelling studies of interactions between natural organic matter and metals : effects on cooling water precipitation potentials in power generation plants
- Authors: Parshotam, Heena
- Date: 2014
- Subjects: Water chemistry , Organic compounds , Electric power-plants , Organic water pollutants
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/62578 , uj:16950
- Description: Abstract: Please refer to full text to view abstract , D.Phil. (Chemistry)
- Full Text:
- Authors: Parshotam, Heena
- Date: 2014
- Subjects: Water chemistry , Organic compounds , Electric power-plants , Organic water pollutants
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/62578 , uj:16950
- Description: Abstract: Please refer to full text to view abstract , D.Phil. (Chemistry)
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Natural organic matter (NOM) in South African waters : characterization, treatability and method development for effective NOM removal from water
- Nkambule, T. I., Krause, R. W. M., Mamba, B. B., Haarhoff, J., Van Staden, S. J.
- Authors: Nkambule, T. I. , Krause, R. W. M. , Mamba, B. B. , Haarhoff, J. , Van Staden, S. J.
- Date: 2010
- Subjects: Water - Purification - Organic compound removal , Organic water pollutants , Cyclodextrins , Polyurethanes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16488 , uj:15780 , Nkambule, T.I. et al. 2010. Natural organic matter (NOM) in South African waters : characterization, treatability and method development for effective NOM removal from water. In: Proceedings of the 12th Biennial Conference of the Water Institute of Southern Africa, 18-21 April, Durban, 11 p.
- Description: Abstract: NOM is a heterogeneous mixture of organic compounds that can be of human origin or derived primarily from plant and microbial residues. The inadequate removal of NOM has a bearing on the capacity of the other treatment processes to remove organic micro-pollutants or inorganic species that may be present in the water. Owing to the complexity and structure of NOM, the techniques employed for the characterization of NOM have a limitation in terms of an all inclusive characterization protocol of NOM to molecular level. This study is thus aimed at developing a rapid method of NOM characterization. Water samples will be collected from the five geographic water regions of South Africa to effectively study the nature of the South African water source for its NOM composition. The polarity rapid assessment method (PRAM) will be employed as a rapid NOM characterization tool. The characterization under PRAM is based on preferential adsorption of dissolved organic matter (DOM) fractions onto solid phase extraction (SPE) sorbents. By extension, the study would then develop a rapid NOM removal strategy that would remove NOM from source during pre-treatment and along the treatment train. A rapid NOM removal technique will then be employed, where different sorbents (e.g. cyclodextrin polyurethanes impregnated with nano-particles) will be employed as sorbents for NOM removal.
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- Authors: Nkambule, T. I. , Krause, R. W. M. , Mamba, B. B. , Haarhoff, J. , Van Staden, S. J.
- Date: 2010
- Subjects: Water - Purification - Organic compound removal , Organic water pollutants , Cyclodextrins , Polyurethanes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16488 , uj:15780 , Nkambule, T.I. et al. 2010. Natural organic matter (NOM) in South African waters : characterization, treatability and method development for effective NOM removal from water. In: Proceedings of the 12th Biennial Conference of the Water Institute of Southern Africa, 18-21 April, Durban, 11 p.
- Description: Abstract: NOM is a heterogeneous mixture of organic compounds that can be of human origin or derived primarily from plant and microbial residues. The inadequate removal of NOM has a bearing on the capacity of the other treatment processes to remove organic micro-pollutants or inorganic species that may be present in the water. Owing to the complexity and structure of NOM, the techniques employed for the characterization of NOM have a limitation in terms of an all inclusive characterization protocol of NOM to molecular level. This study is thus aimed at developing a rapid method of NOM characterization. Water samples will be collected from the five geographic water regions of South Africa to effectively study the nature of the South African water source for its NOM composition. The polarity rapid assessment method (PRAM) will be employed as a rapid NOM characterization tool. The characterization under PRAM is based on preferential adsorption of dissolved organic matter (DOM) fractions onto solid phase extraction (SPE) sorbents. By extension, the study would then develop a rapid NOM removal strategy that would remove NOM from source during pre-treatment and along the treatment train. A rapid NOM removal technique will then be employed, where different sorbents (e.g. cyclodextrin polyurethanes impregnated with nano-particles) will be employed as sorbents for NOM removal.
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Natural organic matter in drinking water sources: its characterisation and treatability
- Haarhoff, J., Mamba, B., Krause, R. W. M., Van Staden, S., Nkambule, T., Dlamini, S., Lobanga, K. P.
- Authors: Haarhoff, J. , Mamba, B. , Krause, R. W. M. , Van Staden, S. , Nkambule, T. , Dlamini, S. , Lobanga, K. P.
- Date: 2013
- Subjects: Organic water pollutants , Environmental chemistry , Water - Purification - Organic compound removal
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/24530 , uj:16225 , ISBN: 978 1 4312 0354 3 , Citation: Haarhoff, J. et al. 2013. Natural organic matter in drinking water sources : its characterisation and treatability. Report 1883/1/12 to the Water Research Commission.
- Description: Please refer to full text to view abstract
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- Authors: Haarhoff, J. , Mamba, B. , Krause, R. W. M. , Van Staden, S. , Nkambule, T. , Dlamini, S. , Lobanga, K. P.
- Date: 2013
- Subjects: Organic water pollutants , Environmental chemistry , Water - Purification - Organic compound removal
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/24530 , uj:16225 , ISBN: 978 1 4312 0354 3 , Citation: Haarhoff, J. et al. 2013. Natural organic matter in drinking water sources : its characterisation and treatability. Report 1883/1/12 to the Water Research Commission.
- Description: Please refer to full text to view abstract
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Natural organic matter removal from surface waters by enhanced coagulation, granular activated carbon adsorption and Ion exchange
- Authors: Lobanga, Kaluka Paul
- Date: 2014-09-17
- Subjects: Water - Purification - Adsorption , Water - Purification - Organic compounds removal , Carbon, Activated , Organic water pollutants
- Type: Thesis
- Identifier: uj:12322 , http://hdl.handle.net/10210/12109
- Description: M.Ing. (Civil Engineering) , Natural organic matter (NOM) is a complex mixture of organic compounds resulting from the decay of plants and animals. When not properly removed, NOM reacts with disinfectants to form disinfection by-products, of which some are known to be carcinogenic. Regulations have become more and more stringent about the maximum level of NOM in drinking water. Different water treatment processes can be applied to remove NOM. However, because each process targets specific fractions of NOM, this results in the existence of recalcitrant NOM fractions that are not removed, for each treatment process. The main objective of the study was thus to investigate NOM removal by using three advanced water treatment processes alone and in combination. The processes used were enhanced coagulation, granular activated carbon adsorption and ion exchange resin processes. Strong and weak base ion exchange resins were used. Although NOM removal methods have been investigated intensively, little attention is given to a so-called “multi-barrier” approach of NOM removal through enhanced coagulation, granular activated carbon adsorption and ion exchange resin that could be applied in practice. In order to take the seasonal and geographical variability of NOM into account, water samples were collected at eight geographical areas over five to seven seasons from 2010 to 2013. Results showed that different treatment processes remove different NOM fractions with different efficiency. Results also confirmed that EC performs better than the adsorptive treatment processes. But the literature shows that NOM removal by EC is difficult for water with high alkalinity and low SUVA values, which is common with SA waters. The adsorptive processes used for NOM removal revealed that they are not viable options, because even low percentage of NOM removal would require high adsorbent dosages, which removes this approach as a practical option.
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- Authors: Lobanga, Kaluka Paul
- Date: 2014-09-17
- Subjects: Water - Purification - Adsorption , Water - Purification - Organic compounds removal , Carbon, Activated , Organic water pollutants
- Type: Thesis
- Identifier: uj:12322 , http://hdl.handle.net/10210/12109
- Description: M.Ing. (Civil Engineering) , Natural organic matter (NOM) is a complex mixture of organic compounds resulting from the decay of plants and animals. When not properly removed, NOM reacts with disinfectants to form disinfection by-products, of which some are known to be carcinogenic. Regulations have become more and more stringent about the maximum level of NOM in drinking water. Different water treatment processes can be applied to remove NOM. However, because each process targets specific fractions of NOM, this results in the existence of recalcitrant NOM fractions that are not removed, for each treatment process. The main objective of the study was thus to investigate NOM removal by using three advanced water treatment processes alone and in combination. The processes used were enhanced coagulation, granular activated carbon adsorption and ion exchange resin processes. Strong and weak base ion exchange resins were used. Although NOM removal methods have been investigated intensively, little attention is given to a so-called “multi-barrier” approach of NOM removal through enhanced coagulation, granular activated carbon adsorption and ion exchange resin that could be applied in practice. In order to take the seasonal and geographical variability of NOM into account, water samples were collected at eight geographical areas over five to seven seasons from 2010 to 2013. Results showed that different treatment processes remove different NOM fractions with different efficiency. Results also confirmed that EC performs better than the adsorptive treatment processes. But the literature shows that NOM removal by EC is difficult for water with high alkalinity and low SUVA values, which is common with SA waters. The adsorptive processes used for NOM removal revealed that they are not viable options, because even low percentage of NOM removal would require high adsorbent dosages, which removes this approach as a practical option.
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Photocatalytic performance of nitrogen-platinum group metal co-doped Tio2 supported on carbon nanotubes for visible-light degradation of organic pollutants in water
- Authors: Kuvarega, Alex Tawanda
- Date: 2013-07-24
- Subjects: Water purification , Water purification - Organic compounds removal , Organic water pollutants , Titanium dioxide , Photocatalysis , Nanotubes , Carbon
- Type: Thesis
- Identifier: uj:7665 , http://hdl.handle.net/10210/8533
- Description: D.Phil. (Chemistry) , Elimination of toxic organic compounds from wastewater is currently one of the most important subjects in water-pollution control. Among the many organic pollutants are dyes and emerging pollutants such as natural organic matter (NOM). Dyes such as Eosin Yellow (EY), an anionic xanthene fluorescent dye, can originate from many sources such as textile industrial processes, paper pulp industries and agricultural processes. Most dyes are problematic because they are resistant to conventional chemical or biological water-treatment methods and therefore persist in the environment. NOM consists of a highly variable mixture of products found in water and soils. NOM is formed as a result of the decomposition of plant and animal material and is a precursor to the formation of disinfection by-products (DBP) during water disinfection. These organic compounds cause undesirable colour, taste and odour in water. NOM affects the capacity of other treatment processes to effectively remove organic micro-pollutants or inorganic species that may be present in the water. Its removal also uses up chemicals and energy and so it is expensive to treat. Titanium dioxide (TiO2) has emerged as one of the most fascinating materials in the modern era due to its semiconducting and catalytic properties. TiO2 is a large band-gap semiconductor that exists mainly in the anatase (band gap 3.2 eV) and rutile (band gap 3.0 eV) phases. Its response to UV light has led to increased interest in its application in the photocatalysis research field. It has been investigated extensively for its super hydrophilicity and use in environmental remediation and solar fuel production. In spite of extensive efforts to apply TiO2 for environmental remediation, photocatalytic activity in the visible region has remained quite low hence the ultimate goal of this research was to fabricate highly photoactive catalysts composed of non-metal, platinum-group metal (PGM) co-doped TiO2 and carbon nanotubes (CNTs) and to apply them for water purification using solar radiation...
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- Authors: Kuvarega, Alex Tawanda
- Date: 2013-07-24
- Subjects: Water purification , Water purification - Organic compounds removal , Organic water pollutants , Titanium dioxide , Photocatalysis , Nanotubes , Carbon
- Type: Thesis
- Identifier: uj:7665 , http://hdl.handle.net/10210/8533
- Description: D.Phil. (Chemistry) , Elimination of toxic organic compounds from wastewater is currently one of the most important subjects in water-pollution control. Among the many organic pollutants are dyes and emerging pollutants such as natural organic matter (NOM). Dyes such as Eosin Yellow (EY), an anionic xanthene fluorescent dye, can originate from many sources such as textile industrial processes, paper pulp industries and agricultural processes. Most dyes are problematic because they are resistant to conventional chemical or biological water-treatment methods and therefore persist in the environment. NOM consists of a highly variable mixture of products found in water and soils. NOM is formed as a result of the decomposition of plant and animal material and is a precursor to the formation of disinfection by-products (DBP) during water disinfection. These organic compounds cause undesirable colour, taste and odour in water. NOM affects the capacity of other treatment processes to effectively remove organic micro-pollutants or inorganic species that may be present in the water. Its removal also uses up chemicals and energy and so it is expensive to treat. Titanium dioxide (TiO2) has emerged as one of the most fascinating materials in the modern era due to its semiconducting and catalytic properties. TiO2 is a large band-gap semiconductor that exists mainly in the anatase (band gap 3.2 eV) and rutile (band gap 3.0 eV) phases. Its response to UV light has led to increased interest in its application in the photocatalysis research field. It has been investigated extensively for its super hydrophilicity and use in environmental remediation and solar fuel production. In spite of extensive efforts to apply TiO2 for environmental remediation, photocatalytic activity in the visible region has remained quite low hence the ultimate goal of this research was to fabricate highly photoactive catalysts composed of non-metal, platinum-group metal (PGM) co-doped TiO2 and carbon nanotubes (CNTs) and to apply them for water purification using solar radiation...
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Polymerisation of cyclodextrins and multiwalled carbon nanotubes for use in water purification
- Authors: Salipira, Ketulo Lackson
- Date: 2008-06-24T13:18:46Z
- Subjects: Water purification , Organic water pollutants , Nanotubes
- Type: Thesis
- Identifier: uj:9836 , http://hdl.handle.net/10210/723
- Description: B.B. Mamba
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- Authors: Salipira, Ketulo Lackson
- Date: 2008-06-24T13:18:46Z
- Subjects: Water purification , Organic water pollutants , Nanotubes
- Type: Thesis
- Identifier: uj:9836 , http://hdl.handle.net/10210/723
- Description: B.B. Mamba
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Pro-inflammatory cytokine expression as an indicator of bacterial pathogenicity in water
- Authors: Ghoor, Samira
- Date: 2010-03-31T07:10:37Z
- Subjects: Bacterial pollution of water , Pathogenic microorganisms detection , Organic water pollutants
- Type: Thesis
- Identifier: uj:6732 , http://hdl.handle.net/10210/3134
- Description: M. Tech. , Background: Waterborne disease contributes significantly to the total global disease burden. Populations in rural areas of South Africa depend on untreated waters for consumption and sanitation. Contamination of public water supplies by harmful bacteria such as pathogenic E. coli poses a major risk for public health. Ingestion of these pathogenic microorganisms present in the contaminated and untreated waters could cause infection, leading to systemic inflammatory responses manifested by the production of various proinflammatory cytokines. To date, there is no human system test available to detect whether water, following ingestion, would cause disease (i.e. whether the water is infectious). The current water testing methods only test for the presence of indicator organisms, such as faecal coliforms, total coliforms, and Escherichia coli. A reliable in-vitro bioassay that could assess whether the water would cause an inflammatory response was investigated in this study. Objectives: Pro-inflammatory cytokines and whole-blood have been used in similar studies to detect the inflammatory responses following exposure to specific stimulants such as dust, lipopolysaccharide (LPS), E. coli and various others. It has been reported that larger numbers of these contaminants induced higher levels of pro-inflammatory cytokine expression. This implies that the pro-inflammatory cytokine expression could be used as a marker of infection since, inflammation occurs in response to infection. Successful infection is thus necessary for inflammation to occur, and high levels of pro-inflammatory cytokine expression confirm that infection has occurred. Thus if pro-inflammatory cytokines could serve as indicators for infection, these cytokines could be used as indicators for bacterial pathogenicity of water.
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- Authors: Ghoor, Samira
- Date: 2010-03-31T07:10:37Z
- Subjects: Bacterial pollution of water , Pathogenic microorganisms detection , Organic water pollutants
- Type: Thesis
- Identifier: uj:6732 , http://hdl.handle.net/10210/3134
- Description: M. Tech. , Background: Waterborne disease contributes significantly to the total global disease burden. Populations in rural areas of South Africa depend on untreated waters for consumption and sanitation. Contamination of public water supplies by harmful bacteria such as pathogenic E. coli poses a major risk for public health. Ingestion of these pathogenic microorganisms present in the contaminated and untreated waters could cause infection, leading to systemic inflammatory responses manifested by the production of various proinflammatory cytokines. To date, there is no human system test available to detect whether water, following ingestion, would cause disease (i.e. whether the water is infectious). The current water testing methods only test for the presence of indicator organisms, such as faecal coliforms, total coliforms, and Escherichia coli. A reliable in-vitro bioassay that could assess whether the water would cause an inflammatory response was investigated in this study. Objectives: Pro-inflammatory cytokines and whole-blood have been used in similar studies to detect the inflammatory responses following exposure to specific stimulants such as dust, lipopolysaccharide (LPS), E. coli and various others. It has been reported that larger numbers of these contaminants induced higher levels of pro-inflammatory cytokine expression. This implies that the pro-inflammatory cytokine expression could be used as a marker of infection since, inflammation occurs in response to infection. Successful infection is thus necessary for inflammation to occur, and high levels of pro-inflammatory cytokine expression confirm that infection has occurred. Thus if pro-inflammatory cytokines could serve as indicators for infection, these cytokines could be used as indicators for bacterial pathogenicity of water.
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Removal of natural organic matter from different raw waters by ion exchange resins
- Lobanga, K.P., Haarhoff, J., Van Staden, S.
- Authors: Lobanga, K.P. , Haarhoff, J. , Van Staden, S.
- Date: 2011
- Subjects: Water - Purification - Adsorption , Water - Purification - Organic compounds removal , Carbon, Activated , Organic water pollutants
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/374006 , http://hdl.handle.net/10210/17189 , uj:15856 , Lobanga, K.P., Haarhoff, J., and Van Staden, S.J. (2011) Removal of natural organic matter from different raw waters by ion exchange resins. 2nd Young Water Professionals of Southern Africa Conference, Pretoria, South Africa, 4-5 July 2011.
- Description: Abstract Most South African water treatment plants utilise surface water sources whose quality is continuously compromised due to high return flows and indirect reuse. The water treatment methods used by these plants are based on the removal of turbidity, various chemical contaminants and microorganisms. Recently introduced NOM regulations added the removal of natural organic matter (NOM) as a priority. Basic anion exchange resins can be used to remove NOM. This paper reports this method of NOM removal. Due to the variability in the composition of NOM in natural raw water, eight surface waters were collected throughout South Africa as representative of the different water types of the country. Two resins were used for this study, a strong and a weak – base anion resins. They were chosen for their availability and competitive price at the local market. NOM removal in raw water was quantified by measuring ultraviolet absorbance at a wavelength of 254 nm (UV 254), dissolved organic carbon (DOC) and by calculating the specific ultraviolet absorbance (SUVA) at 254 nm. The Freundlich equilibrium isotherms were also fitted and the Freundlich parameters determined.
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- Authors: Lobanga, K.P. , Haarhoff, J. , Van Staden, S.
- Date: 2011
- Subjects: Water - Purification - Adsorption , Water - Purification - Organic compounds removal , Carbon, Activated , Organic water pollutants
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/374006 , http://hdl.handle.net/10210/17189 , uj:15856 , Lobanga, K.P., Haarhoff, J., and Van Staden, S.J. (2011) Removal of natural organic matter from different raw waters by ion exchange resins. 2nd Young Water Professionals of Southern Africa Conference, Pretoria, South Africa, 4-5 July 2011.
- Description: Abstract Most South African water treatment plants utilise surface water sources whose quality is continuously compromised due to high return flows and indirect reuse. The water treatment methods used by these plants are based on the removal of turbidity, various chemical contaminants and microorganisms. Recently introduced NOM regulations added the removal of natural organic matter (NOM) as a priority. Basic anion exchange resins can be used to remove NOM. This paper reports this method of NOM removal. Due to the variability in the composition of NOM in natural raw water, eight surface waters were collected throughout South Africa as representative of the different water types of the country. Two resins were used for this study, a strong and a weak – base anion resins. They were chosen for their availability and competitive price at the local market. NOM removal in raw water was quantified by measuring ultraviolet absorbance at a wavelength of 254 nm (UV 254), dissolved organic carbon (DOC) and by calculating the specific ultraviolet absorbance (SUVA) at 254 nm. The Freundlich equilibrium isotherms were also fitted and the Freundlich parameters determined.
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