This thesis presents work that focused on the customised detection and measurement of aluminium (Al) in labile and simple organic speciation in natural waters with particular reference to water treatment. The techniques developed were applied to several alum-based coagulation studies of water from the Myponga reservoir. Experiments examined total Al levels as well as the proportion of Al that was bound to natural organic matter (NOM). / The detection of Al was based upon the electrochemical determination of its complex with the ligand 1, 2-dihydroxyanthraquinone-3-sulphonic acid (DASA). The voltammetry of this complex allows the measurement of low levels of Al (LOD of 10 µg/L). This can be achieved by indirect analysis through oxidation by amperometry of DASA (+0.6V vs Ag/AgCl/KCl at a glassy carbon electrode) or by the reduction of the Al-DASA complex through adsorptive cathodic stripping voltammetry (-1.15V vs Ag/AgCl at a mercury film electrode). / An automated flow injection analysis (FIA-Al) manifold was developed based upon the above detection methods. The manifold utilised a number of switching valves, pumps and reactors under computer control. Reductive Al-DASA chemistry at the mercury film electrode to FIA-Al encountered a number of difficulties which prevented its application to real samples. Oxidative amperometry was successfully applied to probe Al levels during water treatment with coagulation. An instream low-level UV lamp, placed between switching valves, allowed Al speciation to be probed by preferentially irradiating different samples. Two Al fractions were thus determined, labile Al- the DASA reactive fraction without UV treatment, and total Al, the DASA reactive fraction processed semi-automatically with a high degree control of the key reaction conditions leading to good reproducibility. / The Al protocol developed was applied to different coagulation experiments with alum. In these experiments, standard and enhanced coagulation conditions were explored with both jar test apparatus and a coagulation/ flocculation pilot plant. This application of the FIA-Al process to the pilot plant allowed the Al levels in treated water to be determined on-line for a wide range of residual Al. / The application of organic matter characterisation techniques enabled further correlation between the Al speciation as derived by the FIA-Al procedure and the character of NOM that binds most readily with Al. Al speciation observed in this study follows the generalised trends observed in other more complex Al studies. During the treatment process, a proportion of Al exists as complex Al polynuclear species and as Al bound to NOM. After the precipitation/ sedimentation process has removed the majority of NOM and colloidal species, the majority of Al exists as the labile form that is free or bound to simple inorganic ions such as hydroxide, fluoride and sulphate. / Thesis ([PhDBiomedicalScience])--University of South Australia, 2004.
| Identifer | oai:union.ndltd.org:ADTP/267569 |
| Creators | Thomas, Shaun David. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | copyright under review |
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