Date of Award

12-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Environmental Engineering and Earth Science

Advisor

Finneran, Kevin Thomas

Committee Member

Freedman , David L

Committee Member

Powell , Brain A

Abstract

Electron mediator's usage in remediation technologies might be an excellent alternative to increase the rate of transformation of various contaminants such as nitroamine, polyhalogenated compounds and many others. Employing electron shuttles open up different pathways for the contaminant transformation and the reaction goes to completion at a much faster rate. Anthraquinone-2,6-disulfonate (AQDS) has been known to be a model electron shuttle with good shuttling capacity followed by humic acids. But the necessity for identifying electron shuttles suitable for field applications is important. As remediation technologies will command application of the shuttles on a large scale, tracing shuttles which are cheap, easily available and non-toxic is vital. This study mainly aimed at studying the efficiency of military smoke dyes as electron shuttles. Dispersed red 11 and quinoline yellow were the two military smoke dyes tested.
This study demonstrates that the smoke dyes act as electron shuttles for transforming poorly crystalline Fe(III) oxide to reactive Fe(II). Higher extent of transformation could be observed in amendments with the electron shuttles and disperse red 11 was found to be as effective as AQDS in increasing the transformation. Increase in concentration proportionately increased the shuttling ability as well. The shuttling ability of quinoline yellow was found to be lower than the other shuttles. Electron mediated transformation was also investigated in amendments with royal demolition explosive (RDX) as the electron acceptor. The military smoke dyes did not transfer electrons directly to RDX. The experiments were also carried at two different pH conditions to study the variation in shuttling ability with the change in pH conditions. A higher pH condition did not bring a significant increase in Fe(III) transformation in amendments though a minor increase could be observed in the Fe(II) concentration. The pH variation had no impact on the RDX amendments. Though the electron shuttles exhibited limited capacity to transform RDX directly, their potential to transform Fe(III) to Fe(II) suggests that they can be exploited to reduce RDX by a Fe(II) mediated pathway.

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