Photocatalytic degradation of parabens in aqueous solutions with modified tungsten oxide nanoparticles
- Authors: Ngigi, Eric Mwangi
- Date: 2018
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Environmental chemistry , Nanoparticles
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/295325 , uj:32157
- Description: Abstract: Continuous release of pollutants into water systems has been of great concern to the scientific community because it has adverse effects on living organisms and the ecosystem. Among the most common pollutants that are released into the water systems are pharmaceutical and personal care products (PPCPs). The pollutants are introduced to environmental matrices through hospitals, industrial and domestic wastes. The class associated with personal care products are known as parabens which are endocrine disrupting compounds that have been in use for close to a century. Their release to the wastewater is in minute concentrations but known to interfere with endocrine systems. Scientists have been able to come up with ways of actually degrading these micropollutants using various methods that include among others, ultraviolet, sonochemical and semiconductors. Among the mentioned methods, semiconductors have been commonly used for degradation of these pollutants. Among the most commonly used semiconductor is Titania (TiO2) nanomaterial with the advantage of being available and non-toxic to the environment with its limitation in absorbing UV light as opposed to visible light. This study reported the use of modified tungsten trioxide nanomaterials for the degradation of selected parabens. This was achieved by modifying tungsten trioxide using metal, semiconductor and non-metal doping. The morphological features of the as-synthesized nanomaterials were studied using the following analytical instruments XRD, SEM/EDS, UV-Vis, TGA, HRTEM, FTIR, and Raman. Further, the as-synthesized nanomaterials were employed in use of environmental and biomedical applications on the basis of their physiochemical features. Mostly the application was based on the degradation of selected parabens in synthetic and real wastewater samples and biomedical applications focusing on the toxicity of tungsten trioxide. Thus, the semiconductor for use, in both environmental and biomedical applications. The following are highlights of results obtained in Chapters 4-7... , Ph.D. (Chemistry)
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- Authors: Ngigi, Eric Mwangi
- Date: 2018
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Environmental chemistry , Nanoparticles
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/295325 , uj:32157
- Description: Abstract: Continuous release of pollutants into water systems has been of great concern to the scientific community because it has adverse effects on living organisms and the ecosystem. Among the most common pollutants that are released into the water systems are pharmaceutical and personal care products (PPCPs). The pollutants are introduced to environmental matrices through hospitals, industrial and domestic wastes. The class associated with personal care products are known as parabens which are endocrine disrupting compounds that have been in use for close to a century. Their release to the wastewater is in minute concentrations but known to interfere with endocrine systems. Scientists have been able to come up with ways of actually degrading these micropollutants using various methods that include among others, ultraviolet, sonochemical and semiconductors. Among the mentioned methods, semiconductors have been commonly used for degradation of these pollutants. Among the most commonly used semiconductor is Titania (TiO2) nanomaterial with the advantage of being available and non-toxic to the environment with its limitation in absorbing UV light as opposed to visible light. This study reported the use of modified tungsten trioxide nanomaterials for the degradation of selected parabens. This was achieved by modifying tungsten trioxide using metal, semiconductor and non-metal doping. The morphological features of the as-synthesized nanomaterials were studied using the following analytical instruments XRD, SEM/EDS, UV-Vis, TGA, HRTEM, FTIR, and Raman. Further, the as-synthesized nanomaterials were employed in use of environmental and biomedical applications on the basis of their physiochemical features. Mostly the application was based on the degradation of selected parabens in synthetic and real wastewater samples and biomedical applications focusing on the toxicity of tungsten trioxide. Thus, the semiconductor for use, in both environmental and biomedical applications. The following are highlights of results obtained in Chapters 4-7... , Ph.D. (Chemistry)
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First–principles studies on the development of semiconductor–based photocatalyst materials for applications in photocatalytic water splitting and degradation of pollutants
- Authors: Opoku, Francis
- Date: 2018
- Subjects: Heterostructures , Photocatalysis , Solar energy , Water - Purification - Photocatalysis
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/295334 , uj:32158
- Description: Ph.D. (Chemistry) , Abstract: Please refer to full text to view abstract.
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- Authors: Opoku, Francis
- Date: 2018
- Subjects: Heterostructures , Photocatalysis , Solar energy , Water - Purification - Photocatalysis
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/295334 , uj:32158
- Description: Ph.D. (Chemistry) , Abstract: Please refer to full text to view abstract.
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Photodegradation of dye effluent whilst monitoring the fate and behaviour of TiO2 in a simulated photocatalytic treatment plant
- Authors: Mahlalela, Lwazi Charles
- Date: 2017
- Subjects: Photocatalysis , Water - Purification - Photocatalysis , Titanium dioxide , Nanocomposites (Materials) , Dyes and dyeing - Environmental aspects
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235955 , uj:24140
- Description: M.Sc. (Chemistry) , Abstract: Titania (TiO2) has been seen as one of the best semiconductor photocatalysts capable to photodegrade organic pollutants from water. This presents a method that textile industries can use to remove organic dyes from their effluents before release. The photocatalytic activity of TiO2 nanoparticles was conducted to also examine the influence of electron acceptors on the removal of dyes from water. The interaction between TiO2 nanoparticles and industrial dyes is inevitable because of the possible application of TiO2 in the removal of dyes in textile effluents. Therefore, the possible application of TiO2 in the removal of dyes compels understanding the stability of TiO2 as influenced by industrial dyes and different abiotic factors. This is important for risk assessment purposes. The stability of TiO2 nanoparticles in the presence of disperse dye-stuff was conducted as influenced by pH, ionic strength and type of electrolyte. These parameters also influenced the physicochemical properties of the nanoparticles. Understanding fate and behaviour of engineered nanomaterials (ENMs) in wastewater treatment plants (WWTPs) is important for the environmental risk assessment of ENMs. This is due to the appearance of ENMs in WWTPs that results from the wide spread application in consumer products and industrial applications. TiO2 has been reported as one of them. Thus, before environmental risk assessment can be conducted, studies at the points at which ENMs appear in high concentrations is important and WWTPs is one of them. Due to the in availability of nanoparticle test protocols, the Organisations of Economic Co-operation and Development (OECD) guidelines for testing of chemicals (303A) have been used by several researchers to study fate and behaviour of nanoparticles of interest. Therefore, the fate and behaviour of TiO2 nanoparticles was conducted following the OECD 303A. The findings of this study are summarised as follows:..
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- Authors: Mahlalela, Lwazi Charles
- Date: 2017
- Subjects: Photocatalysis , Water - Purification - Photocatalysis , Titanium dioxide , Nanocomposites (Materials) , Dyes and dyeing - Environmental aspects
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235955 , uj:24140
- Description: M.Sc. (Chemistry) , Abstract: Titania (TiO2) has been seen as one of the best semiconductor photocatalysts capable to photodegrade organic pollutants from water. This presents a method that textile industries can use to remove organic dyes from their effluents before release. The photocatalytic activity of TiO2 nanoparticles was conducted to also examine the influence of electron acceptors on the removal of dyes from water. The interaction between TiO2 nanoparticles and industrial dyes is inevitable because of the possible application of TiO2 in the removal of dyes in textile effluents. Therefore, the possible application of TiO2 in the removal of dyes compels understanding the stability of TiO2 as influenced by industrial dyes and different abiotic factors. This is important for risk assessment purposes. The stability of TiO2 nanoparticles in the presence of disperse dye-stuff was conducted as influenced by pH, ionic strength and type of electrolyte. These parameters also influenced the physicochemical properties of the nanoparticles. Understanding fate and behaviour of engineered nanomaterials (ENMs) in wastewater treatment plants (WWTPs) is important for the environmental risk assessment of ENMs. This is due to the appearance of ENMs in WWTPs that results from the wide spread application in consumer products and industrial applications. TiO2 has been reported as one of them. Thus, before environmental risk assessment can be conducted, studies at the points at which ENMs appear in high concentrations is important and WWTPs is one of them. Due to the in availability of nanoparticle test protocols, the Organisations of Economic Co-operation and Development (OECD) guidelines for testing of chemicals (303A) have been used by several researchers to study fate and behaviour of nanoparticles of interest. Therefore, the fate and behaviour of TiO2 nanoparticles was conducted following the OECD 303A. The findings of this study are summarised as follows:..
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Rare earth doped Titania/Carbon nanomaterials composite photocatalysts for water treatment
- Authors: Mamba, Gcina
- Date: 2015-11-12
- Subjects: Water - Purification - Photocatalysis , Nanostructured materials , Photocatalysis , Titanium dioxide
- Type: Thesis
- Identifier: uj:14557 , http://hdl.handle.net/10210/15090
- Description: PhD. (Chemistry) , Pre-synthesised gadolinium oxide decorated multiwalled carbon nanotubes (MWCNT-Gd) were coupled with titania to form nanocomposite photocatalysts (MWCNT-Gd/TiO2) using a sol-gel method. Rare earth metal ions (Eu, Nd and Gd), nitrogen and sulphur tridoped titania were decorated on MWCNT-Gd to yield composite photocatalysts (MWCNT-Gd/Eu/Nd/Gd/N,S-TiO2) by a similar method, using thiourea as nitrogen and sulphur source. Different carbon nanomaterials were incorporated into tridoped titania to form various composite photocatalysts (MWCNT/Gd,N,S-TiO2, MWCNT/Nd,N,S-TiO2, SWCNT (single walled carbon nanotube)/Nd,N,S-TiO2 and rGO (reduced graphene oxide)/Nd,N,S-TiO2) via the sol-gel method. Likewise, gadolinium doped graphitic carbon nitride (g-C3N4-Gd3+) was obtained by heating a mixture of gadolinium nitrate hexahydrate and cyanoguanidine and subsequently hybridised with MWCNT/TiO2 using the sol-gel method to yield composite photocatalysts with varying g-C3N4-Gd3+ loadings. All the prepared photocatalysts were characterised by microscopic tools (FE/FIB-SEM-EDX, TEM), crystallographic technique (XRD), spectroscopic tools (UV-Vis, Raman and FT-IR) and nitrogen sorption technique (BET).
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- Authors: Mamba, Gcina
- Date: 2015-11-12
- Subjects: Water - Purification - Photocatalysis , Nanostructured materials , Photocatalysis , Titanium dioxide
- Type: Thesis
- Identifier: uj:14557 , http://hdl.handle.net/10210/15090
- Description: PhD. (Chemistry) , Pre-synthesised gadolinium oxide decorated multiwalled carbon nanotubes (MWCNT-Gd) were coupled with titania to form nanocomposite photocatalysts (MWCNT-Gd/TiO2) using a sol-gel method. Rare earth metal ions (Eu, Nd and Gd), nitrogen and sulphur tridoped titania were decorated on MWCNT-Gd to yield composite photocatalysts (MWCNT-Gd/Eu/Nd/Gd/N,S-TiO2) by a similar method, using thiourea as nitrogen and sulphur source. Different carbon nanomaterials were incorporated into tridoped titania to form various composite photocatalysts (MWCNT/Gd,N,S-TiO2, MWCNT/Nd,N,S-TiO2, SWCNT (single walled carbon nanotube)/Nd,N,S-TiO2 and rGO (reduced graphene oxide)/Nd,N,S-TiO2) via the sol-gel method. Likewise, gadolinium doped graphitic carbon nitride (g-C3N4-Gd3+) was obtained by heating a mixture of gadolinium nitrate hexahydrate and cyanoguanidine and subsequently hybridised with MWCNT/TiO2 using the sol-gel method to yield composite photocatalysts with varying g-C3N4-Gd3+ loadings. All the prepared photocatalysts were characterised by microscopic tools (FE/FIB-SEM-EDX, TEM), crystallographic technique (XRD), spectroscopic tools (UV-Vis, Raman and FT-IR) and nitrogen sorption technique (BET).
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Efficiency of modified WO3 nanoparticles on the photoreduction of metal ions in water
- Authors: Thwala, Mpendulo Mphumelelo
- Date: 2018
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Doped semiconductors , Nanocomposites (Materials)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279265 , uj:29988
- Description: M.Sc. (Chemistry) , Abstract: With an increased need for clean water in South Africa, there is a need to find more techniques for water purification. The improved standards required by the World Health Organization (WHO) has led to a quest of technological advancements in finding more effective and cost friendly techniques for water purification. The use of nanoparticles (semiconductor metal oxides) has emerged as a promising approach to purify water, removing pollutants from water to low concentrations that meet the WHO standards. Tungsten trioxide (WO3) is considered as one of the best semiconductor photocatalyst capable of photodegradading organic compounds. Pristine WO3 is, however not capable of photoreducing inorganic substances in water. Therefore, this work presents a modified WO3 to improve the photocatalytic activity in the photoreduction of Cr(VI) and Cu(II) in wastewater. The modification was carried out through doping with magnesium and yttrium metals respectively. Although these aforementioned dopant metals come costly, the synthesis routes and efficiency of the doped WO3 in the reduction of Cr(VI) and Cu(II) is worthwhile. The hydrothermal method was used to synthesize WO3, Mg doped WO3 and Y doped WO3 nanoparticles. In order to understand the structure of the synthesized nanoparticles, the nanoparticles were characterized using X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), Filed emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, zeta potential, Brunauer–Emmett– Teller (BET) surface area, UV-visible spectroscopy (UV-vis), X-Ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). The as-synthesized materials were confirmed to be composed of crystalline monoclinic polymorphs as shown by the XRD, FTIR and Raman spectroscopy. The average crystallite size was found to be around 32 nm with an average particle strain of 0.002498. The particle sizes were found to be of 141 nm in average as confirmed by TEM. The difference in d spacing were observed for the doped nanoparticles...
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- Authors: Thwala, Mpendulo Mphumelelo
- Date: 2018
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Doped semiconductors , Nanocomposites (Materials)
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/279265 , uj:29988
- Description: M.Sc. (Chemistry) , Abstract: With an increased need for clean water in South Africa, there is a need to find more techniques for water purification. The improved standards required by the World Health Organization (WHO) has led to a quest of technological advancements in finding more effective and cost friendly techniques for water purification. The use of nanoparticles (semiconductor metal oxides) has emerged as a promising approach to purify water, removing pollutants from water to low concentrations that meet the WHO standards. Tungsten trioxide (WO3) is considered as one of the best semiconductor photocatalyst capable of photodegradading organic compounds. Pristine WO3 is, however not capable of photoreducing inorganic substances in water. Therefore, this work presents a modified WO3 to improve the photocatalytic activity in the photoreduction of Cr(VI) and Cu(II) in wastewater. The modification was carried out through doping with magnesium and yttrium metals respectively. Although these aforementioned dopant metals come costly, the synthesis routes and efficiency of the doped WO3 in the reduction of Cr(VI) and Cu(II) is worthwhile. The hydrothermal method was used to synthesize WO3, Mg doped WO3 and Y doped WO3 nanoparticles. In order to understand the structure of the synthesized nanoparticles, the nanoparticles were characterized using X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), Filed emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, zeta potential, Brunauer–Emmett– Teller (BET) surface area, UV-visible spectroscopy (UV-vis), X-Ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). The as-synthesized materials were confirmed to be composed of crystalline monoclinic polymorphs as shown by the XRD, FTIR and Raman spectroscopy. The average crystallite size was found to be around 32 nm with an average particle strain of 0.002498. The particle sizes were found to be of 141 nm in average as confirmed by TEM. The difference in d spacing were observed for the doped nanoparticles...
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Molybdenum sulfide nanostructures : synthesis and their catalytic applications
- Authors: Madima, Ntakadzeni
- Date: 2017
- Subjects: Water - Purification - Photocatalysis , Nanostructured materials , Polymeric composites , Photocatalysis , Molybdenum compounds
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235780 , uj:24119
- Description: M.Sc. (Nanoscience) , Abstract: Environmental pollution (i.e. water pollution) has been an issue of great concern across the globe. Water scarcity is reported to be a huge challenge throughout the world. The South Africa water capacity will decrease dramatically in the next 10 years due to various pollutants. Dye molecules such as Methyl Blue (MB) and Rhodamine B (RhB) and heavy metals such as Chromium (Cr(VI)) are reported to be the major cause of water pollution, which results in the scarcity of clean water for human use. These pollutants are present as harmful entities in the environment due to their carcinogenic and mutagenic nature. So, the sustainability of clean water is in greater demand for all forms of life relies upon its availability. Thus the aim of this study was to synthesize molybdenum sulfide nanostructures and its nanocomposite and evaluate their photocatalytic properties towards water treatment. Molybdenum sulfide nanostructures were synthesized via hydrothermal methods using different capping agents namely Polyethylene Glycol (PEG-400) and Ethylenediaminetetraacetic acid (EDTA) and the samples were named PEG-MoS2 and EDTA-MoS2 respectively. The nanocomposite was synthesized from EDTA-MoS2 and manganese chloride. As synthesized nanostructures and nanocomposite were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning electron microscope (SEM) equipped with Energy dispersive X-ray spectroscopy (EDS), Transmission Electron Microscope (TEM), and UV-Vis Spectroscopy. Rhodamine B and Methyl Blue were chosen as a model dyes for evaluation of photocatalytic degradation performance. Using PEG-MoS2, the degradation efficiency of 97.30% was achieved for RhB in 75 min and 98.05% for Methyl Blue was achieved in 90 min. EDTA-MoS2 also shows greater potential in the removal of both RhB and MB in aqueous solution; hence 85.46% and 99.78% removals of RhB and MB dyes respectively were achieved in 90 min. PEG-MoS2 nanostructure was also tested for the photocatalytic reduction of Cr(VI) and shows the reduction efficiency of 91.05% in 75 min. The nanocomposite was tested for the photocatalytic degradation of RhB, and results show the degradation efficiency of 98.78% in 75 min. All photocatalytic studies were done under visible light irradiation (Xenon lamp was used throughout).
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- Authors: Madima, Ntakadzeni
- Date: 2017
- Subjects: Water - Purification - Photocatalysis , Nanostructured materials , Polymeric composites , Photocatalysis , Molybdenum compounds
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/235780 , uj:24119
- Description: M.Sc. (Nanoscience) , Abstract: Environmental pollution (i.e. water pollution) has been an issue of great concern across the globe. Water scarcity is reported to be a huge challenge throughout the world. The South Africa water capacity will decrease dramatically in the next 10 years due to various pollutants. Dye molecules such as Methyl Blue (MB) and Rhodamine B (RhB) and heavy metals such as Chromium (Cr(VI)) are reported to be the major cause of water pollution, which results in the scarcity of clean water for human use. These pollutants are present as harmful entities in the environment due to their carcinogenic and mutagenic nature. So, the sustainability of clean water is in greater demand for all forms of life relies upon its availability. Thus the aim of this study was to synthesize molybdenum sulfide nanostructures and its nanocomposite and evaluate their photocatalytic properties towards water treatment. Molybdenum sulfide nanostructures were synthesized via hydrothermal methods using different capping agents namely Polyethylene Glycol (PEG-400) and Ethylenediaminetetraacetic acid (EDTA) and the samples were named PEG-MoS2 and EDTA-MoS2 respectively. The nanocomposite was synthesized from EDTA-MoS2 and manganese chloride. As synthesized nanostructures and nanocomposite were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning electron microscope (SEM) equipped with Energy dispersive X-ray spectroscopy (EDS), Transmission Electron Microscope (TEM), and UV-Vis Spectroscopy. Rhodamine B and Methyl Blue were chosen as a model dyes for evaluation of photocatalytic degradation performance. Using PEG-MoS2, the degradation efficiency of 97.30% was achieved for RhB in 75 min and 98.05% for Methyl Blue was achieved in 90 min. EDTA-MoS2 also shows greater potential in the removal of both RhB and MB in aqueous solution; hence 85.46% and 99.78% removals of RhB and MB dyes respectively were achieved in 90 min. PEG-MoS2 nanostructure was also tested for the photocatalytic reduction of Cr(VI) and shows the reduction efficiency of 91.05% in 75 min. The nanocomposite was tested for the photocatalytic degradation of RhB, and results show the degradation efficiency of 98.78% in 75 min. All photocatalytic studies were done under visible light irradiation (Xenon lamp was used throughout).
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Biopolymer based nanocomposites for water treatment
- Authors: Anku, William Wilson
- Date: 2017
- Subjects: Photocatalysis , Biopolymers - Analysis , Water - Purification - Photocatalysis , Dyes and dyeing - Environmental aspects
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/261579 , uj:27583
- Description: Ph.D. (Chemistry) , Abstract: The devastating effects of toxic organic pollutants on human health and the environment have necessitated the need to devise holistic techniques for their effective removal from polluted water. Among these pollutants are toxic organic dyes, which are resistant to biodegradation and therefore persist in the environment for a long period of time. These dyes are also resistant to chemical, physical and other conventional methods of water treatment. Although semiconductor photocatalysis is deemed as a holistic method for the judicious eradication of dye pollutants from water, the technology is hindered by some inherent problems including the fact that most of the photocatalysts are active under ultraviolet light (UV) instead of visible light due to their wide band gap. In addition, these photocatalysts have a fast recombination rate of the photogenerated holes and electrons, which are responsible for the photocatalytic degradation process. This research work was therefore designed to modify some selected metal oxide photocatalysts including TiO2, ZrO2, ZnO, Cu2O and ZnS with transition metals, non–metals and multiwalled carbon nanotubes (MWCNTs). It was envisaged that the modified catalysts would possess superior properties over their bare counterparts, overcome their limitation, and possess excellent photocatalytic properties for the effective removal of organic pollutants from water. Three different methods of synthesis were employed in this work. These include homogeneous co–precipitation, sol–gel, and in situ copolymerisation. All the catalysts synthesised in this work were characterised using X–ray powder diffraction (XRD),..
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- Authors: Anku, William Wilson
- Date: 2017
- Subjects: Photocatalysis , Biopolymers - Analysis , Water - Purification - Photocatalysis , Dyes and dyeing - Environmental aspects
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/261579 , uj:27583
- Description: Ph.D. (Chemistry) , Abstract: The devastating effects of toxic organic pollutants on human health and the environment have necessitated the need to devise holistic techniques for their effective removal from polluted water. Among these pollutants are toxic organic dyes, which are resistant to biodegradation and therefore persist in the environment for a long period of time. These dyes are also resistant to chemical, physical and other conventional methods of water treatment. Although semiconductor photocatalysis is deemed as a holistic method for the judicious eradication of dye pollutants from water, the technology is hindered by some inherent problems including the fact that most of the photocatalysts are active under ultraviolet light (UV) instead of visible light due to their wide band gap. In addition, these photocatalysts have a fast recombination rate of the photogenerated holes and electrons, which are responsible for the photocatalytic degradation process. This research work was therefore designed to modify some selected metal oxide photocatalysts including TiO2, ZrO2, ZnO, Cu2O and ZnS with transition metals, non–metals and multiwalled carbon nanotubes (MWCNTs). It was envisaged that the modified catalysts would possess superior properties over their bare counterparts, overcome their limitation, and possess excellent photocatalytic properties for the effective removal of organic pollutants from water. Three different methods of synthesis were employed in this work. These include homogeneous co–precipitation, sol–gel, and in situ copolymerisation. All the catalysts synthesised in this work were characterised using X–ray powder diffraction (XRD),..
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Preparation of doped nanotitanium dioxide (TIO2) immobilized on polyethersulphone (PES) nanofiberes for photocatalytic degradation of water pollutants
- Authors: Chabalala, Mandla Brian
- Date: 2016
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Nanofiltration , Titanium dioxide
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/84406 , uj:19216
- Description: Abstract: As the world’s population continue to grow annually, the demand of drinking water also increases. Countries that are facing water scarcity are currently facing high demand rates of clean water. One of the major contributors to water scarcity is water pollution; this is often caused by the release of wastewater by various sectors which include factories, industries and laboratories, among others. Such wastewater contains toxic materials which end up in drinking water sources and these materials are suspected of being endocrine-disruptive-chemicals (EDCs). The increase in concentrations of contaminants (particularly dyes) in water show that conventional wastewater treatments methods are not efficient enough, hence advanced technologies such as Advanced Oxidation Processes (AOPs) should be implemented to treat persistent contaminants in water. AOPs are characterized by the production of highly reactive hydroxyl (HO•) and superoxide (O2-•) anion radicals, which are suitable for a rapid, continuous and indiscriminative reaction with organic compounds inducing almost complete degradation. Such AOPs include the Fenton’s process which uses peroxide-iron (II) (H2O2/Fe2+) as the Fenton reagent and Photocatalysis which makes use of semiconductors such as titanium dioxide (TiO2). AOPs are classified as clean technology for the treatment of wastewater and can degrade micro pollutants with reaction rate of up to 109 Lmol-1s-1 yielding CO2, H2O and inorganic ions as the final products Pristine and doped TiO2 photocatalysts were prepared using a modified sol-gel method in both acidic and basic medium. The loading of N was varied from 1 to 5 %. Polyethersulphone (PES) nanofibers were electrospun from a PES polymer solution that was prepared by dissolving PES in N,N-Dimethylfomamide (DMF) at room temperature overnight. The polymer solutions of concentration 18 to 29 % PES/DMF (m/m %) were obtained. The resulting solutions were electrospun at the following conditions: 20 - 25 cm tip to collector distance, 12 kV working voltage and 0.5 ml flow rate. The electrospinning of PES/Photocatalyst (PES/PC) nanofiber was performed under the optimized conditions of PES nanofibers. The photocatalysts loading was varied between 1.5, 2 and 2.5 % while PES was , M.Sc. (Chemistry)
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- Authors: Chabalala, Mandla Brian
- Date: 2016
- Subjects: Water - Purification - Photocatalysis , Photocatalysis , Nanofiltration , Titanium dioxide
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/84406 , uj:19216
- Description: Abstract: As the world’s population continue to grow annually, the demand of drinking water also increases. Countries that are facing water scarcity are currently facing high demand rates of clean water. One of the major contributors to water scarcity is water pollution; this is often caused by the release of wastewater by various sectors which include factories, industries and laboratories, among others. Such wastewater contains toxic materials which end up in drinking water sources and these materials are suspected of being endocrine-disruptive-chemicals (EDCs). The increase in concentrations of contaminants (particularly dyes) in water show that conventional wastewater treatments methods are not efficient enough, hence advanced technologies such as Advanced Oxidation Processes (AOPs) should be implemented to treat persistent contaminants in water. AOPs are characterized by the production of highly reactive hydroxyl (HO•) and superoxide (O2-•) anion radicals, which are suitable for a rapid, continuous and indiscriminative reaction with organic compounds inducing almost complete degradation. Such AOPs include the Fenton’s process which uses peroxide-iron (II) (H2O2/Fe2+) as the Fenton reagent and Photocatalysis which makes use of semiconductors such as titanium dioxide (TiO2). AOPs are classified as clean technology for the treatment of wastewater and can degrade micro pollutants with reaction rate of up to 109 Lmol-1s-1 yielding CO2, H2O and inorganic ions as the final products Pristine and doped TiO2 photocatalysts were prepared using a modified sol-gel method in both acidic and basic medium. The loading of N was varied from 1 to 5 %. Polyethersulphone (PES) nanofibers were electrospun from a PES polymer solution that was prepared by dissolving PES in N,N-Dimethylfomamide (DMF) at room temperature overnight. The polymer solutions of concentration 18 to 29 % PES/DMF (m/m %) were obtained. The resulting solutions were electrospun at the following conditions: 20 - 25 cm tip to collector distance, 12 kV working voltage and 0.5 ml flow rate. The electrospinning of PES/Photocatalyst (PES/PC) nanofiber was performed under the optimized conditions of PES nanofibers. The photocatalysts loading was varied between 1.5, 2 and 2.5 % while PES was , M.Sc. (Chemistry)
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Metal and nonmetal doped semiconductor photocatalysts for water treatment
- Authors: Agorku, Eric Selorm
- Date: 2015-07-01
- Subjects: Water - Purification - Photocatalysis , Doped semiconductors , Dyes and dyeing - Environmental aspects
- Type: Thesis
- Identifier: uj:13669 , http://hdl.handle.net/10210/13853
- Description: PhD. (Chemistry) , Please refer to full text to view abstract
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- Authors: Agorku, Eric Selorm
- Date: 2015-07-01
- Subjects: Water - Purification - Photocatalysis , Doped semiconductors , Dyes and dyeing - Environmental aspects
- Type: Thesis
- Identifier: uj:13669 , http://hdl.handle.net/10210/13853
- Description: PhD. (Chemistry) , Please refer to full text to view abstract
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Photodegradation of pesticides in water using metal doped multi-component heterojunction photocatalyst
- Authors: Molopo, Kgoetlana Charlie
- Date: 2019
- Subjects: Photocatalysis , Water - Purification - Photocatalysis , Pesticides
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/401075 , uj:33502
- Description: Abstract : For many years now, South Africa has been facing water crisis. Availability of clean water is lacking, and human population increases every year. Available water is contaminated with variety of pollutants such as microbials, organic and inorganic pollutants. This is because of increased industrial and agricultural practices to satisfy the growing population demand. Organic pollutants are prominent due to high agricultural production whereby pesticides and fertilizers are applied to optimize product output. Pesticides are of huge concern due to their persistence and toxic behaviour in the environment. They are found in rivers and ground water streams after application in the field via run-off or seep into ground. Chlorpyrifos is an organophosphate pesticide widely used to control pest. Chlorpyrifos has been detected at high levels in water in Western Cape of South Africa. Department of Agriculture in South Africa banned its use as an ingredient in domestic products and pesticides in 2010 but it is still detected in the environment. Chlorpyrifos is an endocrine disrupting chemical, nerve agent and causes dizziness. This pollutant can enter human body by ingestion, dermal adsorption or inhalation. The WHO limit of chlorpyrifos in water is 30 μg/L. Several methods have been used to remove chlorpyrifos and other pollutants in water such as biological treatment and advanced oxidation processes. Advanced oxidation processes are regarded as safe and efficient pollutant removal, removing a variety of pollutants in water. This is due to utilization of highly reactive species such as hydroxyl and superoxide radicals, known for their rapid and indiscriminative behaviour towards organic compounds resulting in a complete mineralization. Photocatalysis which is a semiconductor-based method emerged as a promising organic pollutant removal method. Tungsten trioxide (WO3) has been extensively studied for degradation of heavy metals and organic pollutants. But suffer from photogenerated charge vi recombination. To curb that, doping has been used with metal/non-metal dopant and by formation of heterojunction with another semiconductor catalyst to name a few. In this study, WO3 was successfully synthesized using a hydrothermal treatment method. It was further modified with Mn2+ ion and SnS2 to improve its photocatalytic activity towards chlorpyrifos degradation by formation of Mn-WO3/SnS2. Mn- WO3/SnS2 was formed with rectangular shapes confirmed through HRTEM and FESEM. A mixture of monoclinic and hexagonal phases was identified using XRD, Raman and SAED indexing. The optical and electrochemical properties of Mn-WO3/SnS2 were studied using EIS, PL and UV-Vis-DRS. Low emission intensity corresponding to less charge recombination, smaller semi-circle diameter corresponding to less charge transfer impedance and high visible light absorbance wavelength (582 nm) were observed in comparison to those of WO3 (466 nm), Mn-WO3 (472 nm), SnS2 (512 nm) and WO3/SnS2 (572 nm). Mn-WO3/SnS2 displayed good stability and increased surface area (77 m2/g) compared to WO3 (6 m2/g). The materials were mesoporous as determined by BET analysis with pore volumes in the range of 0.02 to 0.07. Except SnS2 which displayed porous adsorbent properties. The Mn-doped composite (Mn-WO3/SnS2) nanoparticles displayed high efficiency for the degradation of chlorpyrifos in synthetic water samples within 60 minutes. UHPLC-MS-MS was used to evaluate the concentration of chlorpyrifos and deduce the degradation pathway. Mn-WO3/SnS2 degraded up to 95% chlorpyrifos removal compared to 50, 65, 75, and 85% using WO3, Mn-WO3, SnS2 and WO3/SnS2 respectively. After optimization of conditions such as pH, initial chlorpyrifos concentration and initial photocatalyst loading, 100% chlorpyrifos removal was achieved at pH 7, 1 g of nanoparticles and 1000 ppb of chlorpyrifos concentration. The complete degradation of chlorpyrifos and its major degradation by-product TCP was achieved. vii TCP was completely degraded to innocuous materials. Kinetic studies were deduced to a second order reaction at 209x10-3 M-1s-1. , M.Sc. (Chemistry)
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- Authors: Molopo, Kgoetlana Charlie
- Date: 2019
- Subjects: Photocatalysis , Water - Purification - Photocatalysis , Pesticides
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/401075 , uj:33502
- Description: Abstract : For many years now, South Africa has been facing water crisis. Availability of clean water is lacking, and human population increases every year. Available water is contaminated with variety of pollutants such as microbials, organic and inorganic pollutants. This is because of increased industrial and agricultural practices to satisfy the growing population demand. Organic pollutants are prominent due to high agricultural production whereby pesticides and fertilizers are applied to optimize product output. Pesticides are of huge concern due to their persistence and toxic behaviour in the environment. They are found in rivers and ground water streams after application in the field via run-off or seep into ground. Chlorpyrifos is an organophosphate pesticide widely used to control pest. Chlorpyrifos has been detected at high levels in water in Western Cape of South Africa. Department of Agriculture in South Africa banned its use as an ingredient in domestic products and pesticides in 2010 but it is still detected in the environment. Chlorpyrifos is an endocrine disrupting chemical, nerve agent and causes dizziness. This pollutant can enter human body by ingestion, dermal adsorption or inhalation. The WHO limit of chlorpyrifos in water is 30 μg/L. Several methods have been used to remove chlorpyrifos and other pollutants in water such as biological treatment and advanced oxidation processes. Advanced oxidation processes are regarded as safe and efficient pollutant removal, removing a variety of pollutants in water. This is due to utilization of highly reactive species such as hydroxyl and superoxide radicals, known for their rapid and indiscriminative behaviour towards organic compounds resulting in a complete mineralization. Photocatalysis which is a semiconductor-based method emerged as a promising organic pollutant removal method. Tungsten trioxide (WO3) has been extensively studied for degradation of heavy metals and organic pollutants. But suffer from photogenerated charge vi recombination. To curb that, doping has been used with metal/non-metal dopant and by formation of heterojunction with another semiconductor catalyst to name a few. In this study, WO3 was successfully synthesized using a hydrothermal treatment method. It was further modified with Mn2+ ion and SnS2 to improve its photocatalytic activity towards chlorpyrifos degradation by formation of Mn-WO3/SnS2. Mn- WO3/SnS2 was formed with rectangular shapes confirmed through HRTEM and FESEM. A mixture of monoclinic and hexagonal phases was identified using XRD, Raman and SAED indexing. The optical and electrochemical properties of Mn-WO3/SnS2 were studied using EIS, PL and UV-Vis-DRS. Low emission intensity corresponding to less charge recombination, smaller semi-circle diameter corresponding to less charge transfer impedance and high visible light absorbance wavelength (582 nm) were observed in comparison to those of WO3 (466 nm), Mn-WO3 (472 nm), SnS2 (512 nm) and WO3/SnS2 (572 nm). Mn-WO3/SnS2 displayed good stability and increased surface area (77 m2/g) compared to WO3 (6 m2/g). The materials were mesoporous as determined by BET analysis with pore volumes in the range of 0.02 to 0.07. Except SnS2 which displayed porous adsorbent properties. The Mn-doped composite (Mn-WO3/SnS2) nanoparticles displayed high efficiency for the degradation of chlorpyrifos in synthetic water samples within 60 minutes. UHPLC-MS-MS was used to evaluate the concentration of chlorpyrifos and deduce the degradation pathway. Mn-WO3/SnS2 degraded up to 95% chlorpyrifos removal compared to 50, 65, 75, and 85% using WO3, Mn-WO3, SnS2 and WO3/SnS2 respectively. After optimization of conditions such as pH, initial chlorpyrifos concentration and initial photocatalyst loading, 100% chlorpyrifos removal was achieved at pH 7, 1 g of nanoparticles and 1000 ppb of chlorpyrifos concentration. The complete degradation of chlorpyrifos and its major degradation by-product TCP was achieved. vii TCP was completely degraded to innocuous materials. Kinetic studies were deduced to a second order reaction at 209x10-3 M-1s-1. , M.Sc. (Chemistry)
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Photodegradation of a selected antiretroviral drug from South Africa's effluent with a heterostructure of few layer black phosphorus-niobium oxide nanoparticles (FL-BP/Nb2O5)
- Authors: Bhembe, Yoliswa Anittah
- Date: 2020
- Subjects: Photocatalysis , Water - Purification - Photocatalysis
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/458412 , uj:40716
- Description: Abstract: Over the years, viral infections such as influenza, herpes, and hepatitis have widely spread, with the human immunodeficiency virus (HIV) becoming even rifer. Antiretroviral (ARVs) drugs have been formulated to suppress virus activity in the body and prevent the transmission of these viruses effectively. However, the invention has come at a price as the drugs and their excreted metabolism/breakdown products generates have since generated pharmaceutical waste. With their continuous production and consumption, the pharmaceutical waste has found its passage to the central water systems, contributing to the depletion of the quality of water. The principal culprits that perpetuate the occurrence of these pollutants in various water bodies are the wastewater treatment plants (WWTPs). South Africa, facing non-ending droughts, has its hydrologic cycle unrefreshed, compelling the nation to resort to the use of recycled water. However, the removal and breaking down of these contaminants of emerging concern has thus far been a challenge and blocking access to clean and safer drinking water. A few to none effective technologies have been developed to degrade ARVs in water specifically. There is a need, therefore, to develop effective techniques to remove these pollutants, and thus purify water. Heterogeneous photocatalysis, with the use of nanomaterials, has emerged as one of the promising technologies that can be incorporated in the WWTPs to increase their efficiency. Thus, this work presents the use of a novel nanocomposite of niobium (V) oxide nanoflowers intercalated into the walls of few-layer black phosphorus (FL-BP@Nb2O5) for the photodegradation of nevirapine. Nevirapine is an ARV drug that is frequently detected from the central water bodies... , M.Sc. (Chemistry)
- Full Text:
- Authors: Bhembe, Yoliswa Anittah
- Date: 2020
- Subjects: Photocatalysis , Water - Purification - Photocatalysis
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/458412 , uj:40716
- Description: Abstract: Over the years, viral infections such as influenza, herpes, and hepatitis have widely spread, with the human immunodeficiency virus (HIV) becoming even rifer. Antiretroviral (ARVs) drugs have been formulated to suppress virus activity in the body and prevent the transmission of these viruses effectively. However, the invention has come at a price as the drugs and their excreted metabolism/breakdown products generates have since generated pharmaceutical waste. With their continuous production and consumption, the pharmaceutical waste has found its passage to the central water systems, contributing to the depletion of the quality of water. The principal culprits that perpetuate the occurrence of these pollutants in various water bodies are the wastewater treatment plants (WWTPs). South Africa, facing non-ending droughts, has its hydrologic cycle unrefreshed, compelling the nation to resort to the use of recycled water. However, the removal and breaking down of these contaminants of emerging concern has thus far been a challenge and blocking access to clean and safer drinking water. A few to none effective technologies have been developed to degrade ARVs in water specifically. There is a need, therefore, to develop effective techniques to remove these pollutants, and thus purify water. Heterogeneous photocatalysis, with the use of nanomaterials, has emerged as one of the promising technologies that can be incorporated in the WWTPs to increase their efficiency. Thus, this work presents the use of a novel nanocomposite of niobium (V) oxide nanoflowers intercalated into the walls of few-layer black phosphorus (FL-BP@Nb2O5) for the photodegradation of nevirapine. Nevirapine is an ARV drug that is frequently detected from the central water bodies... , M.Sc. (Chemistry)
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Photodegradation of agricultural pollutants in water using a semi conductor like metal-organic-framework fused with Black Phosphorus (BP) : heterojunction
- Authors: Hlophe, Philani Vusumuzi
- Date: 2020
- Subjects: Agricultural chemicals - Environmental aspects , Water - Purification - Photocatalysis , Phosphorus
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/473956 , uj:42704
- Description: Abstract: Water pollution is one of the pressing issues facing South Africa as a country. There is insufficient availability of clean water, yet there is increase in human population every year and this comes with an increase in demand for clean water. Furthermore, the available water is contaminated with a variety of organic and inorganic pollutants, which emanates from industrial and agricultural activities... , M.Sc. (Chemistry)
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- Authors: Hlophe, Philani Vusumuzi
- Date: 2020
- Subjects: Agricultural chemicals - Environmental aspects , Water - Purification - Photocatalysis , Phosphorus
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/473956 , uj:42704
- Description: Abstract: Water pollution is one of the pressing issues facing South Africa as a country. There is insufficient availability of clean water, yet there is increase in human population every year and this comes with an increase in demand for clean water. Furthermore, the available water is contaminated with a variety of organic and inorganic pollutants, which emanates from industrial and agricultural activities... , M.Sc. (Chemistry)
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Unique crystal facet design of heterojunction bismuth vanadate nanoparticles for the photodegradation of herbicides in a photocatalytic wastewater treatment plant
- Authors: Mahlalela, Lwazi Charles
- Date: 2020
- Subjects: Water - Purification - Photocatalysis , Nanocomposites (Materials)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/474047 , uj:42715
- Description: Abstract: Water is an essential resource for the livelihood of humans and animals. Due to population growth that impacts directly on the expansion of industries. Industrial growth also requires water which in the process produces highly polluted effluents that require treatment to prevent the pollution of the environment. Pollutants maybe materials from personal care products, pharmaceuticals, organic dyes, and pesticides. Part of the effluents find their way into conventional wastewater treatment plants (WWTPs) which should further treat them before the effluent can be either purified for drinking purposes or passed out into a nearby river. For the purposes of this work, pesticides (atrazine and tebuthiuron) were of interest. Wastewater treatment plants have been reported in literature to be unable to completely degrade pesticides which have been reported as contaminants of emerging concern (CECs)... , Ph.D. (Chemistry)
- Full Text:
- Authors: Mahlalela, Lwazi Charles
- Date: 2020
- Subjects: Water - Purification - Photocatalysis , Nanocomposites (Materials)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/474047 , uj:42715
- Description: Abstract: Water is an essential resource for the livelihood of humans and animals. Due to population growth that impacts directly on the expansion of industries. Industrial growth also requires water which in the process produces highly polluted effluents that require treatment to prevent the pollution of the environment. Pollutants maybe materials from personal care products, pharmaceuticals, organic dyes, and pesticides. Part of the effluents find their way into conventional wastewater treatment plants (WWTPs) which should further treat them before the effluent can be either purified for drinking purposes or passed out into a nearby river. For the purposes of this work, pesticides (atrazine and tebuthiuron) were of interest. Wastewater treatment plants have been reported in literature to be unable to completely degrade pesticides which have been reported as contaminants of emerging concern (CECs)... , Ph.D. (Chemistry)
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Visible light photocatalytic degradation of pollutants in surface water, Limpopo, South Africa
- Authors: Ntobeng, Mahubedu Khutso
- Date: 2021
- Subjects: Water - Purification - Photocatalysis , Titanium dioxide
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/481968 , uj:43688
- Description: Abstract: A novel silver and vanadium co-doped titanium dioxide (Ag, V-TiO2) photocatalyst was achieved by a simple sol-gel hydrothermal method. The co-doped Ag, V-TiO2 photocatalyst exhibited high photocatalytic activity as compared to synthesised titanium dioxide (TiO2), silver doped titanium dioxide (Ag-TiO2) and Vanadium dope titanium dioxide (V-TiO2). The co-doped Ag, V-TiO2 illustrated a shift in the absorption edge, enhancing the visible light absorption capacity. The optical absorption of co-doped Ag, V-TiO2 achieved a reduced band gap energy (Eg) of 2.2eV as compared to Ag-TiO2 (2.8eV) and V-TiO2 (2.3eV), while TiO2 obtained a band gap energy of 2.9eV. The codoped photocatalyst inherited morphological and structural compositions that depicted the lattice fringes for both anatase and rutile in its crystalline phase. This analysis was in good agreement with results obtained by X-ray diffraction (XRD) characterisation techniques. Co-doped Ag, V-TiO2 showed excellent photocatalytic abilities under visible light irradiation. The degradation of Methylene blue (MB) was achieved within the first 15min. The kinetic study for the degradation of (MB) followed the pseudo-first order reaction. More interestingly, it was found that the photocatalytic degradation performance had a direct relation with the intensity plane ratio corresponding to [101] / [110]. The effects of co-doping showed a shift in spectrum to the visible light region. This was evident in the study of binding energies presented by X-ray photoelectron spectroscopy (XPS). Thus, the effects of co-doping TiO2 showed achieving well desirable reduction in the band gap energy and enhancements in the photocatalytic activity, reporting excellent removal rates of 99.33%. The evaluation of photocatalytic degradation of pollutants in water from River water in Limpopo (Mathibeng) and Mpumalanga Witbank (Ezinabeni) gave a clear indication that the synthesized Ag, V co-doped TiO2 photocatalyst was effective in removing nitrate, nitrites, humic substance, aromatics, Trihalomethanes (THM) and organic concentration. Furthermore, the GC-MS analysis of the water samples proved the organic pollutants removal with a removal efficiency of 77.84%. These finding open up a solution for the treatment of surface and river water where the concentration of pollutants are low. , M.Ing. (Mechanical Engineering)
- Full Text:
- Authors: Ntobeng, Mahubedu Khutso
- Date: 2021
- Subjects: Water - Purification - Photocatalysis , Titanium dioxide
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/481968 , uj:43688
- Description: Abstract: A novel silver and vanadium co-doped titanium dioxide (Ag, V-TiO2) photocatalyst was achieved by a simple sol-gel hydrothermal method. The co-doped Ag, V-TiO2 photocatalyst exhibited high photocatalytic activity as compared to synthesised titanium dioxide (TiO2), silver doped titanium dioxide (Ag-TiO2) and Vanadium dope titanium dioxide (V-TiO2). The co-doped Ag, V-TiO2 illustrated a shift in the absorption edge, enhancing the visible light absorption capacity. The optical absorption of co-doped Ag, V-TiO2 achieved a reduced band gap energy (Eg) of 2.2eV as compared to Ag-TiO2 (2.8eV) and V-TiO2 (2.3eV), while TiO2 obtained a band gap energy of 2.9eV. The codoped photocatalyst inherited morphological and structural compositions that depicted the lattice fringes for both anatase and rutile in its crystalline phase. This analysis was in good agreement with results obtained by X-ray diffraction (XRD) characterisation techniques. Co-doped Ag, V-TiO2 showed excellent photocatalytic abilities under visible light irradiation. The degradation of Methylene blue (MB) was achieved within the first 15min. The kinetic study for the degradation of (MB) followed the pseudo-first order reaction. More interestingly, it was found that the photocatalytic degradation performance had a direct relation with the intensity plane ratio corresponding to [101] / [110]. The effects of co-doping showed a shift in spectrum to the visible light region. This was evident in the study of binding energies presented by X-ray photoelectron spectroscopy (XPS). Thus, the effects of co-doping TiO2 showed achieving well desirable reduction in the band gap energy and enhancements in the photocatalytic activity, reporting excellent removal rates of 99.33%. The evaluation of photocatalytic degradation of pollutants in water from River water in Limpopo (Mathibeng) and Mpumalanga Witbank (Ezinabeni) gave a clear indication that the synthesized Ag, V co-doped TiO2 photocatalyst was effective in removing nitrate, nitrites, humic substance, aromatics, Trihalomethanes (THM) and organic concentration. Furthermore, the GC-MS analysis of the water samples proved the organic pollutants removal with a removal efficiency of 77.84%. These finding open up a solution for the treatment of surface and river water where the concentration of pollutants are low. , M.Ing. (Mechanical Engineering)
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