Please refer to full text to view abstract

Thesis (DTech. degree in Environmental, Water & Earth Sciences)--Tshwane University of Technology, 2009. / The potential of tassel from R52 maize cultivar for the removal of heavy metals from simulated and environmental aqueous samples as well as the physicochemical characteristics of tassel were investigated. Milled tassel powder was employed in metal removal from simulated aqueous sample and thereafter, the developed method was applied to environmental samples. This research has demonstrated the potential of maize tassel to adsorb metal ions from both simulated and environmental samples. Furthermore, metals adsorbed on tassel were easily desorbed suggesting that tassel can be employed in metal recycling.

No description available.

No description available.

Graduation date: 1993

Wu Xiujuan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 88-93). / Abstracts in English and Chinese. / ABSTRACT (Chinese) / ABSTRACT / ACKNOWLEDGEMENT / TABLE OF CONTENTS / LIST OF TABLES / LIST OF FIGURES / Chapter CHAPTER ONE: --- INTRODUCTION / Chapter 1.1 --- General B ackground --- p.1 / Chapter 1.2 --- Chromium in Environment and its Analysis --- p.2 / Chapter 1.2.1 --- Source of Chromium and its Harmful Effects on Human --- p.2 / Chapter 1.2.2 --- Methods for Separation and Determination of Chromium Species --- p.4 / Chapter 1.3 --- Arsenic in the Environment and its Toxicity --- p.4 / Chapter 1.4 --- Properties of TiO2 and Its Applications --- p.6 / Chapter 1.4.1 --- Photocatalytic Property of TiO2 --- p.6 / Chapter 1.4.2 --- Surface Acid-Basic Property of TiO2 --- p.8 / Chapter 1.5 --- Adsorption --- p.11 / Chapter 1.6 --- Fundamental of ICP-AES and ICP-MS --- p.12 / Chapter 1.6.l --- Principle of ICP-AES --- p.12 / Chapter 1.6.2 --- Principle of ICP-MS --- p.14 / Chapter 1.7 --- Scope of Work --- p.18 / Chapter CHAPTER TWO: --- SEPERATION OF CHROMIUM SPECIES ON TIO2 / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Experimental --- p.23 / Chapter 2.2.1 --- Materials --- p.23 / Chapter 2.2.2 --- Instruments --- p.24 / Chapter 2.2.2.1 --- Coupling of TiO2 column and ICP-AES --- p.24 / Chapter 2.2.2.2 --- Coupling of TiO2 column and ICP-MS --- p.26 / Chapter 2.2.3. --- Procedure --- p.29 / Chapter 2.3 --- Results and Discussion --- p.33 / Chapter 2.3.1 --- Preliminary study on the adsorption of Cr(III) and Cr(VI) on TiO2 --- p.33 / Chapter 2.3.2 --- Development and Verification of the proposed method for speciation of Cr(III) and Cr(VI) in aqueous solution --- p.42 / Chapter 2.3.3 --- Practical application of the proposed method for separation and determination of Cr(III) and Cr(VI) --- p.46 / Chapter CHAPTER THREE: --- ADSORPTION OF ARSENIC SPECIES ON TiO2 / Chapter 3.1 --- Introduction --- p.61 / Chapter 3.2 --- Experimental --- p.66 / Chapter 3.2.1 --- Materials --- p.66 / Chapter 3.2.2 --- Instruments --- p.69 / Chapter 3.2.3 --- Procedure --- p.70 / Chapter 3.3 --- Results and Discussion --- p.71 / Chapter 3.3.1 --- Adsorption Kinetics --- p.71 / Chapter 3.3.2 --- Effect of pH on Adsorption of Arsenic Species --- p.71 / Chapter 3.3.3 --- Adsorption Isotherm --- p.74 / Chapter 3.3.4 --- Adsorption Model --- p.76 / Chapter 3.3.5 --- Factors Affecting the Adsorption of Arsenic Species on p25 and Rutile TiO2 --- p.83 / Chapter CHAPTER FOUR: --- CONCLUSION --- p.86 / REFERENCES --- p.88

M.Tech. (Extraction Metallurgy) / For many decades, carbon nanotubes (CNTs) have been used as adsorbents for the removal of pollutants from wastewaters because of their unique properties such as inert surface, resistance to acid and base environment, rigidity and strength. Herein is a report of application of functionalised CNTs on the adsorption of metal ions from aqueous solutions and mine leachates. The CNTs were first synthesised in-house, purified, functionalised and characterised with various characterisation techniques: FTIR (Fourier Transform Infrared), SEM (Scanning Electron Microscopy, TEM (Transmission Electron Microscopy), EDS (Energy Dispersive Spectroscopy), Raman Spectroscopy, TGA (Thermal Gravimetric Analysis) and BET (Brunauer-Emmet-Teller). Together, these techniques gave substantiation for structure, surface and chemical modification of the synthesised moieties. After characterisation, the functional groups were attached to the walls of the tubes and this implies successful functionalisation...

M.Sc. / Inorganic pollutants like heavy metals are some of the major water pollutants worldwide. They are toxic and in some cases carcinogenic even at low concentrations. Their removal from industrial aqueous solutions, wastewater and hydrometallurgical process solutions prior to their release to the environment is necessary for a healthy biosphere which includes human beings, aquatic life and plants. There are several technologies used to remove metals such as Cu, Co, Zn, Hg from water. These include among others, ion exchange, membrane filtration, activated carbon, electrochemical treatment, chemical precipitation, reverse osmosis, coagulation and flocculation. Although they have been used in the removal of metal pollutants from water, these technologies produce high quantities of sludge. They are also expensive to operate and need well trained personnel to operate large chemical plants. Since current metal removal techniques have limitations, a need exists for the development of environmentally friendly and cost effective techniques for the removal of metal ions from aqueous media. The focus of this research project is on the use of micro-organisms as biosorbents for copper and cobalt pollutants in aqueous solutions. The experimental work was carried out on a laboratory scale and a summary of our findings is presented as follows: Synthetic sulphate solutions of copper and cobalt were prepared using CuSO4. 7H2O and CoSO4. 5H2O powders. Concentrations of 0.002 M, 0.07 M and 0.2 M copper and cobalt ions in solution were used as test synthetic solutions for our experiments. Mixed strains of bioleaching bacteria were sourced from Mintek (Randburg, South Africa) to test the viability of this research project. This consortium contained Acidithiobacillus caldus, Leptospirillum spp, Ferroplasma spp and Sulphobacillus spp. These bacteria were able to remove up to 55% copper and 25% cobalt from low concentrated copper and cobalt sulphate solutions with 69% and 58% removal demonstrated in the case of mine effluents emanating from metallurgical operations. Different strains of micro-organisms (bacteria) were isolated from mine dumps and mine operation effluents and soil from the Palabora Mining Company in Limpopo, a northern province in South Africa and Nigel Town in the Gauteng Province. The isolated bacterial strains were then identified using PCR analysis and strains from the Bacillus genre were found to be predominant. Shewanella spp was also present. Pseudomonas spp was isolated using Pseudomonas agar base. These bacteria were then cultured at different species-specific culture conditions and their capabilities to remove copper and cobalt ions first from synthetic solutions and subsequently from mine effluents emanating from metallurgical operations were tested. In the first stage of biosorption experiments, factors that affect biosorption mechanisms which include, solution concentration, biomass concentration, pH, contact time and the presence of other metal co-ions were investigated. A decrease in the amount of metal sorbed as solution concentrations increased was observed with all the bacterial strains. An increase in metal sorption was also observed when biomass concentration was increased. The pH was found to be a species dependant parameter.

Ph.D. (Chemistry) / This study presents work on the preparation, characterisation and application of agricultural waste residue, maize tassel in the production of activated carbon (AC) using both physical and chemical methods of activation in their production. The activated carbon produced from maize tassel (MTAC) or steam-produced activated carbon (STAC) were later added as a filler – together with beta-cyclodextrin (β-CD), and raw tassel (RT) – in the production of polyurethane composite adsorbent (PUCAD) material for the removal of selected inorganic (such as Cd2+, Cr3+, Pb2+) and organic pollutants (phenolic compound - bisphenol A (BPA), ortho-nitrophenol (O-NTP), para-chlorophenol (PCP), polychlorinated biphenyl (PCB), and methylene blue (MB) as adsorbate/analytes from aqueous medium. Both batch and solid-phase extraction adsorption methods (SPE), were used for separation and preconcentration. The investigations included reactivity using Fourier transform infrared (FT-IR) spectroscopy, surface morphology analysis using scanning electron microscopy (SEM), thermal stability using thermogravimetric analysis (TGA), heat flow using differential scanning calorimetry (DSC), and crystallinity using X-ray diffraction (XRD) coupled with energy dispersive X-ray spectrometry (EDX). The FT-IR analysis revealed that there was interaction between the polymeric material and all the fillers. The hydrogen bonding and N-H group interaction between all the materials and the polyurethane polymer composite (PCAD) showed compatibility between the polymeric materials and the fillers.

M.Tech. (Chemical Engineering) / Please refer to full text to view abstract