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No full textExam paper (Supplementary) for second semester 202
The development of electrochemical (APTA) sensors based on carbon nanofiber composite and silver nanocomposite platforms and their applications on the detection of endocrine disrupting Bisphenol A
Get PDFAbstract: The primary focus of this research was on the development of three electrochemical sensing systems for the detection of Bisphenol A (BPA) - an endocrine disrupting compound. Studies of health effects on humans associated with BPA exposures reported increased risks of heart diseases, coronary diseases, diabetes and cancer. In recent years, the concern over the effects of BPA on humans has been highlighted by the fact that infants and children are estimated to have the highest daily intake of BPA. Electrochemical methods of detection for BPA have proven to be the most effective and practical ones, when compared conventional techniques such as chromatography. However, the electro-oxidation of BPA is an irreversible process with products that cause surface fouling of electrodes, which always limits the electro-detection of BPA. This surface fouling of electrode surfaces is considered a major challenge on electro-analytical based techniques for determining not only BPA molecule but also other phenolic molecules. To mitigate this major issue, this dissertation reports the use of a regenerable exfoliated graphite (EG) electrode. Regeneration was achieved by mechanical polishing of the robust electrode on emery paper...M.Sc. (Chemistry
Evaluation of heavy metal pollution and its ecological risk in water from the Sasolburg region
Get PDFAbstract: Pollution of heavy metals is a worldwide problem, and the evaluation of heavy metals and their exposure to the environment has attracted international attention due to the health risk towards plants, humans, and animals. The accumulation of these metals within the environment has increased due to anthropogenic activities such as fertilizers and pesticides, mining, and industrial development, among others. Thus, it is crucial that research should be conducted on the metals to understand their mobility, bioavailability, and toxicity in sediments and water. Therefore, the purpose of the study was to determine the concentration levels of trace/heavy metals in sediments and surface waters (for domestic and farming use) from Sasolburg (Free State, South Africa). Inductively coupled plasma – optical emission spectrometry (ICP – OES) was used to quantify the concentrations of Al, As, Cd, Co, Cr, Fe, Mn, Mo, Ni, Pb, Sb, Se, Sr, Tl, and V. For the bioavailability and determination of trace/heavy metals in sediments single extraction technique and pseudo-total digestion was used. To help evaluate the potential health risk of trace and heavy metals in sediments and water, environmental assessments were utilized such as enrichment factor (Ef), contamination factor (Cf), geo-accumulation index (Igeo), and pollution load index (PLI) to name a few...M.Sc. (Chemistry
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