Dao, Hien Van (2007) An investigation into factors affecting the efficacy of oil removal from wildlife using magnetic particle technology. PhD thesis, Victoria University.

Abstract

Utilising iron powder as a dry cleansing agent, factors affecting the efficacy of the magnetic removal of oil contamination from a variety of matrices, including feathers and plumage, have been investigated. Employing electron microscopy and an established gravimetric methodology, detailed investigations into the effect of particle size, particle structure and surface texture have been carried out, demonstrating that the efficacy of removal can be successfully manipulated by varying such properties. Consequently, a grade of particle has been identified whereby, within experimental error, 100% removal of a variety of contaminants from a number of different matrices, including feathers, can be achieved. Having identified these improved particles, their ability to remove tarry and weathered/tarry residues from feathers and plumage has been explored. The effect of the ambient temperature at which cleansing takes place has been shown to be important in regard to the latter. Temperature dependent in vitro studies on duck and penguin feather clusters and penguin carcasses, contaminated by “worst case scenario”, highly viscous, tarry oil, have been carried out using established gravimetric methodologies. A remarkable temperature dependency for contaminant removal has been observed for both feather clusters and plumage whereby, below and at certain temperatures, little removal is achieved but, above these temperatures, the removal rapidly approaches 100%. It is notable that this phenomenon occurs within a narrow temperature range of only a few degrees and the high level of removal is achieved at a temperature that is well below the temperature at which the tarry residue becomes a flowing liquid. These results hold promise that a very high removal of tarry residue from feathers is possible, under temperature conditions that would be benign to a bird. In order to explain the phenomenon, the thermodynamics of the process have been investigated. These studies show the process to be highly endothermic and entropy driven, hence providing insight into the phenomenon. Similar experiments, above the acute temperature, carried out on tarry residue that had been allowed to weather for different periods of time, demonstrated that the same high levels of removal can be achieved, although the initial removals were lower for longer periods of weathering. The role of pre-conditioners used in conjunction with magnetic cleansing has also been investigated. It is found that pre-conditioners enhance the optimum removal and reduce the number of treatments required to achieve this. It has been demonstrated that the application of a pre-conditioner approximately half way through the treatment achieves the maximum advantage. The magnetic cleansing technique lends itself to, and has been successfully applied to, the relative quantitative assessment of a range of candidate pre-conditioners. These indicators are also expected to carry over with fidelity to the use of pre-conditioners for more conventional detergentbased cleansing.

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