>Magister Scientiae - MSc / The main aim of this study is to investigate theelectrochemical determination of
two beneficial (selenium and zinc) and two toxic (chromium and vanadium)
metals in the potable water within the City of Cape Town's distribution area.
The Water Laboratory of the City's Scientific Services Branch analyses for these
metals in their elemental state, using the Inductively Coupled Plasma Optical
Emission Spectrometer (ICP-OES). This is a standard method used for the
detection of trace metals. The most sensitive voltammetric method for determining these metals is by adsorptive stripping voltammetry, using a thin mercury film electrode with a glassy carbon support. This voltammetric method is used for quantitative determination of specific ionic species. Because of mercury's toxicity it is not really favoured for trace metals anymore. Many other possibilities are under
investigation, e.g. bismuth-film, modified glassy carbon and antimony electrodes.
The boron-doped diamond (BDD) electrode has distinct advantages when used to
determine metal concentrations. Advantages of BDD electrodes include lower
detection limit, speciation and wider potential window. In this study cyclic
voltammetry (CV) was used to determine the copper, cadmium and lead
concentrations in potable water by means of square wave voltammetry (SWV)
and a bare glassy carbon electrode (GCE). Furthermore, a boron-doped diamond
electrode (BDDE) was used to investigate the possibilities of determining
selenium, chromium and vanadium by SWV. Real samples (potable water samples) were analysed electrochemically to qualify and quantify these metals and determine whether they comply with the SANS 241:2006 drinking water guidelines.The copper, cadmium, lead and selenium peaks appear very close to the theoretical values, which indicate that these metals can be detected by SWV method, but further analysis with more samples is advised. Even though responses were observed for vanadium and chromium, it was not reliable and requires further investigation. Further studies into the analyses of zinc are also advised.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/5417 |
| Date | January 2011 |
| Creators | Fillis, Ismarelda Rosaline |
| Contributors | Baker, Priscilla |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Rights | University of the Western Cape |
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