Understanding the effects of metal surface additives on the reactivity of iron-based bimetallic reductants used for the remediation of chlorinated organic compounds.

摘要

The widespread use of chlorinated organic compounds prior to the late 1980s has resulted in the contamination of many groundwater sources. While many remediation technologies have been developed to deal with this problem, one of the most promising is harnessing the ability of iron to reduce these compounds to less harmful products. While iron metal reacts efficiently with many chlorinated organic compounds, others appear inert. One method for improving the reactivity of the iron is to deposit a metal additive onto the surface of the iron, thereby generating what are referred to as bimetallic reductants.; This body of work will discuss experiments conducted to probe the mechanisms responsible for the reactivity enhancements afforded by these metal additives. Surface analytical tools were employed to link particle reactivity towards organohalides with surface properties (i.e. additive loading, oxidation state and two-dimensional surface coverage). From the studies contained in this work we were able to determine the site of organohalide reduction, the fate of the additive as the particles react via column studies, and possible mechanisms by which the additive increases the rate of organohalide reduction.; This body of work is instrumental in the optimal design and development of bimetallic materials for field applications. Namely, the additive loading needed to achieve particle reactivity and the effect of temperature on the reactivity of bimetallic reductants. Results from Chapter 4 provide evidence that bimetallic reductants are an environmentally safe remediation technology.