Probing the reactivity of bio-engineered magnetic magnetite nanoparticles with metals and metalloids

点击翻译按钮获取中文摘要

Global challenges associated with heavy metal and metalloid pollution in drinking water are widespread due to uses in electronics, industrial activities or release during waste disposal. These challenges include threats to human health and food supplies, which have the potential to increase in severity in decades to come. To address these issues, alternative strategies need to be developed to either remove pollutants from water supplies after they have entered, or prevent them from getting into the ecosystem. Amongst some of the potential options available, adsorption remains one of the most effective, particularly when using magnetite as an adsorbent. Magnetite is a mixed-valent, magnetic mineral which contains both Fe(II) and Fe(III). Microbial strategies to producing magnetite nanoparticles have the potential to produce highly magnetic particles with narrow size distributions corresponding to high surface to volume ratios in addition to high Fe(II) content. Furthermore, those magnetite particles are associated with reactive organic compounds and offer a cost effective, and environmentally benign solution which could offer a sustainable approach to toxic metal or metalloid remediation. This proposal aims to use naturally occurring, microbial processes to synthesize bio-engineered magnetic nanoparticles, which can efficiently and effectively induce metal redox changes (i.e. reduction) as well as sorb and sequester a range of toxic metals and metalloids. We want to understand the underlying processes which take place when these pollutants are associated with the mineral surface and the stability of the complexes that form. We will also explore the potential impact of natural organic matter compounds to interfere with and potentially block reactive surface sites on the mineral. Finally, we will investigate how transport processes such as continuous flow conditions affect the efficacy of bio-engineered magnetite nanoparticles to treat toxic metals and metalloids in larger scale systems, analogous to an environmental setting such as an aquifer. For this work we will employ a range of techniques including standard chemical analysis, mineralogical, magnetic, electron microscopy and synchrotron-based analytical methods. The main goal of this proposed PhD project will be to enhance our understanding of how toxic metals and metalloids can become associated with naturally occurring and bioengineered minerals in order to promote future remediation strategies using environmentally benign, sustainable and biologically inspired (bio-engineered) approaches.