Alginate beads supporting nanocomposites incorporating cyclodextrin polymers and fe/ni decorated carbon nanotubes for the removal of 2,4,6-trichlorophenol in water
- Authors: Kera, Nazia Hassan
- Date: 2013-12-09
- Subjects: Water - Purification - Organic compounds removal , Nanocomposites (Materials) , Nanotubes , Cyclodextrins , Polymers
- Type: Thesis
- Identifier: uj:7841 , http://hdl.handle.net/10210/8736
- Description: M.Sc. (Chemistry) , The quality of fresh water is deteriorating due to pollution by a wide range of substances as a result of industrial, agricultural, domestic, mining and other anthropogenic activities. Even at trace levels in water, some pollutants are toxic to organisms through acute or chronic effects or through bioaccumulation. Conventional water treatment is often ineffective at removing pollutants to the ultra-low levels required by water quality standards and other technologies employed to remove toxic compounds from water have high capital and operating costs and other disadvantages. There is therefore an ongoing need to develop low-cost technologies that are effective for the removal of toxic pollutants from water. In our laboratories, iron and nickel (Fe/Ni) decorated carbon nanotube (CNT)/cyclodextrin polymers (β-CDs) showed promising results in previous studies carried out for the degradation and removal of toxic organic pollutants in water. However, the powder form of the polymer makes its direct application in water treatment difficult. The leaching of metal nanoparticles and carbon nanotubes from the polymer into the water being treated is also of concern due to their potential toxicity. In this study, alginate beads were investigated as supports for two kinds of nanocomposites, Fe/Ni decorated carbon nanotubes and Fe/Ni decorated carbon nanotube/cyclodextrin polymers. Alginate beads were selected as supports to render the nanocomposites more conducive towards water treatment applications since they are easy to handle and recover from water and are also stable supports that can prevent the leaching of nanomaterials into treated water.
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- Authors: Kera, Nazia Hassan
- Date: 2013-12-09
- Subjects: Water - Purification - Organic compounds removal , Nanocomposites (Materials) , Nanotubes , Cyclodextrins , Polymers
- Type: Thesis
- Identifier: uj:7841 , http://hdl.handle.net/10210/8736
- Description: M.Sc. (Chemistry) , The quality of fresh water is deteriorating due to pollution by a wide range of substances as a result of industrial, agricultural, domestic, mining and other anthropogenic activities. Even at trace levels in water, some pollutants are toxic to organisms through acute or chronic effects or through bioaccumulation. Conventional water treatment is often ineffective at removing pollutants to the ultra-low levels required by water quality standards and other technologies employed to remove toxic compounds from water have high capital and operating costs and other disadvantages. There is therefore an ongoing need to develop low-cost technologies that are effective for the removal of toxic pollutants from water. In our laboratories, iron and nickel (Fe/Ni) decorated carbon nanotube (CNT)/cyclodextrin polymers (β-CDs) showed promising results in previous studies carried out for the degradation and removal of toxic organic pollutants in water. However, the powder form of the polymer makes its direct application in water treatment difficult. The leaching of metal nanoparticles and carbon nanotubes from the polymer into the water being treated is also of concern due to their potential toxicity. In this study, alginate beads were investigated as supports for two kinds of nanocomposites, Fe/Ni decorated carbon nanotubes and Fe/Ni decorated carbon nanotube/cyclodextrin polymers. Alginate beads were selected as supports to render the nanocomposites more conducive towards water treatment applications since they are easy to handle and recover from water and are also stable supports that can prevent the leaching of nanomaterials into treated water.
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Conducting nanocomposites for the removal of heavy metals from wastewater
- Authors: Kera, Nazia Hassan
- Date: 2018
- Subjects: Heavy metals - Absorption and adsorption , Sewage - Purification - Heavy metals removal , Water - Purification , Nanocomposites (Materials) , Water chemistry
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://ujcontent.uj.ac.za8080/10210/366683 , http://hdl.handle.net/10210/278783 , uj:29923
- Description: Ph.D. (Chemistry) , Abstract: Hexavalent chromium, Cr(VI), is a toxic heavy metal pollutant that occurs in wastewater produced from mining and industrial activities such as leather tanning, chrome plating, wood preservation and alloy manufacture. Cr(VI) released into the environment is of concern due to its high mobility in water and soil and harmful effects on human health. The treatment of wastewater is necessary to prevent Cr(VI) contamination of water bodies in the environment. Conducting polymers, such as polypyrrole (PPy) and polyaniline (PANI), have the potential to be used as adsorbents for Cr(VI) in wastewater due to their abundant nitrogen-containing functional groups, anion-exchange sites and capacity to reduce Cr(VI) to the significantly less toxic, trivalent chromium, Cr(III). However, conducting polymers have shown low adsorption capacities for Cr(VI) due to agglomeration of particles and are also difficult to separate from treated water. The focus of this study was on the development of conducting polymer composites for the treatment of wastewater containing Cr(VI). In particular, the aim of the research carried out was the modification of conducting polymers to obtain adsorbents with high adsorption capacities for Cr(VI) that are well-suited towards water treatment applications. Three novel conducting polymer composites were prepared in this study, namely, polypyrrole/2,5-diaminobenzenesulfonic acid (PPy/DABSA) composite, polypyrrole-polyaniline/iron oxide (PPy-PANI/Fe3O4) magnetic nanocomposite and polypyrrole-m-phenylenediamine (PPy-mPD) polymer for the desired application of removing Cr(VI) from industrial wastewater. The composites were synthesized easily and effectively by in situ chemical oxidative polymerization and their physicochemical properties characterized using various techniques including attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. Batch studies were carried out to investigate the effect of parameters such as initial solution pH, adsorbent dose, initial Cr(VI) concentration, temperature and co-existing ions in solution on Cr(VI) removal by the different composites...
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- Authors: Kera, Nazia Hassan
- Date: 2018
- Subjects: Heavy metals - Absorption and adsorption , Sewage - Purification - Heavy metals removal , Water - Purification , Nanocomposites (Materials) , Water chemistry
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://ujcontent.uj.ac.za8080/10210/366683 , http://hdl.handle.net/10210/278783 , uj:29923
- Description: Ph.D. (Chemistry) , Abstract: Hexavalent chromium, Cr(VI), is a toxic heavy metal pollutant that occurs in wastewater produced from mining and industrial activities such as leather tanning, chrome plating, wood preservation and alloy manufacture. Cr(VI) released into the environment is of concern due to its high mobility in water and soil and harmful effects on human health. The treatment of wastewater is necessary to prevent Cr(VI) contamination of water bodies in the environment. Conducting polymers, such as polypyrrole (PPy) and polyaniline (PANI), have the potential to be used as adsorbents for Cr(VI) in wastewater due to their abundant nitrogen-containing functional groups, anion-exchange sites and capacity to reduce Cr(VI) to the significantly less toxic, trivalent chromium, Cr(III). However, conducting polymers have shown low adsorption capacities for Cr(VI) due to agglomeration of particles and are also difficult to separate from treated water. The focus of this study was on the development of conducting polymer composites for the treatment of wastewater containing Cr(VI). In particular, the aim of the research carried out was the modification of conducting polymers to obtain adsorbents with high adsorption capacities for Cr(VI) that are well-suited towards water treatment applications. Three novel conducting polymer composites were prepared in this study, namely, polypyrrole/2,5-diaminobenzenesulfonic acid (PPy/DABSA) composite, polypyrrole-polyaniline/iron oxide (PPy-PANI/Fe3O4) magnetic nanocomposite and polypyrrole-m-phenylenediamine (PPy-mPD) polymer for the desired application of removing Cr(VI) from industrial wastewater. The composites were synthesized easily and effectively by in situ chemical oxidative polymerization and their physicochemical properties characterized using various techniques including attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. Batch studies were carried out to investigate the effect of parameters such as initial solution pH, adsorbent dose, initial Cr(VI) concentration, temperature and co-existing ions in solution on Cr(VI) removal by the different composites...
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