Shewan, Angela (2023) The Development of a Magnetic Paste to Remove Recalcitrant Oil from Feathers. Research Master thesis, Victoria University.

Abstract

This project explores the utility of so-called “magnetic pastes” (MPs) that combine the use of “magnetic cleansing” (MPT) with pre-treatment agents (PTA) and other additives that could potentially facilitate the removal of recalcitrant contamination from feathers. This concept has been systematically explored via the formulation of 21 such pastes, some with different proportions of iron powder and across various categories of PTAs and additives. Using an established gravimetric methodology, these pastes have been systematically tested for their relative quantitative efficacies for the removal of Bua Ban (BB-medium) and Bunker 380 (B380 - heavy) crude oils from clusters of domestic duck feathers. All experiments have been conducted in five-fold replicate. As the physical properties of oil are influenced by temperature, selected MPs were heated to 35°C to test the effect of paste temperature on contaminant removal. Oil contamination of wildlife, particularly birds, presents a threat to their survival and it is important to develop appropriate methods for efficient removal of a wide variety of contaminants. MPT has shown potential to work as an effective cleaning method of oiled wildlife. This project has shown that MPT can be developed into MPs that have the potential for the removal of medium to heavy contaminants, that might be otherwise recalcitrant. Thus, it has been shown that some MPs are more efficient at removing a heavy contaminant (B380) from duck feathers than iron powder alone. Valuable insights into the potential usefulness of such magnetic cleansing agents have been gleaned from these experiments. Notable is the effectiveness of the 4% v/v acetic acid (i.e., vinegar) paste for the removal of both medium and heavy contaminants from duck feather clusters. It has also been demonstrated that MPs are contaminant specific, suggesting that such pastes can be tailored to specific contaminants. In this regard, the experiments conducted with two different vegetable oils as additives, for which the relative fatty acid compositions are known, demonstrate that it is feasible to rationally design pastes that are more specific for heavier contaminants. It is evident that some MPs are more efficient overall than iron powder alone. For example, pastes made from conventional PTAs such as methyl soyate, mineral oil, esterol and olive oil are more efficient for the removal of B380 than iron powder alone. Counterintuitively, removal experiments conducted with the pastes heated to a higher temperature (35 C°) show that the effectiveness of some pastes have an inverse relationship to temperature. This suggests a potential application for lower temperature regimes. Heated MPs have also highlighted the important interaction between the physical chemistry of a paste additive and iron powder on removal efficacy. Finally, these studies help to delineate the effects of various physical properties such as the relative proportion of iron power in a formulation, the effect of additive and contaminant viscosity and iron powder adhesion on oil removal efficacy. More work is warranted to formulate and test a wider range of pastes to further delineate and improve their removal efficacy and capacity. Since removal is contaminant dependent, a wider range of contaminants should also be explored. Of particular importance is the further investigation of the temperature dependency of paste removal.

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