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

由于在电子产品、工业活动或废物处理过程中的排放，与饮用水中的重金属和类金属污染相关的全球挑战普遍存在。这些挑战包括对人类健康和粮食供应的威胁，这些威胁有可能在未来几十年加剧。为了解决这些问题，需要制定替代战略，要么在污染物进入水供应后将其移除，要么防止它们进入生态系统。在现有的一些可能的选择中，吸附仍然是最有效的选择之一，特别是当使用磁铁矿作为吸附剂时。磁铁矿是一种混价磁性矿物，既含有Fe(II)又含有Fe(III)。微生物生产磁铁矿纳米颗粒的策略有可能生产出高度磁性的颗粒，其粒度分布窄，对应于高表面积与体积比以及高Fe(II)含量。此外，这些磁铁矿颗粒与活性有机化合物有关，提供了一种成本效益高、环境友好的解决方案，可以为有毒金属或类金属修复提供一种可持续的方法。这项提议旨在利用自然发生的微生物过程来合成生物工程磁性纳米颗粒，这种纳米颗粒可以高效和有效地诱导金属氧化还原变化(即还原)以及吸附和隔离一系列有毒金属和类金属。我们想要了解当这些污染物与矿物表面和形成的络合物的稳定性相关时发生的潜在过程。我们还将探索天然有机物化合物对矿物表面活性部位的潜在影响。最后，我们将研究连续流动条件等运输过程如何影响生物工程磁铁纳米颗粒在更大规模的系统中处理有毒金属和类金属的效率，类似于环境环境，如含水层。在这项工作中，我们将使用一系列技术，包括标准化学分析、矿物学、磁学、电子显微镜和基于同步加速器的分析方法。这个拟议的博士项目的主要目标将是加强我们对有毒金属和类金属如何与自然产生的和生物工程矿物相关联的理解，以便利用环境友好、可持续和生物启发(生物工程)方法促进未来的补救战略。

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.