Fate, reactivity and environmental impact of using iron nanoparticles for site clean-up

在NERC的水主题下，拟议的项目旨在确定部署纳米级铁颗粒（INP）的命运、反应性和环境风险，以清理英国周围受污染的地点和地下水。该项目由URS/Scott Wilson提供CASE支持，DEFRA （Helinor Johnston博士）和CL:AIRE （John Henstock博士）提供咨询意见。问题：工程纳米材料的不断发展和使用，通过在不同行业开发的众多产品中加以利用，有可能为社会带来巨大的利益。纳米材料的一些应用具有提供环境效益的潜力，特别令人感兴趣的是使用纳米级零价铁颗粒对受污染的土地和地下水进行就地清理。理论和实践证据表明，与传统方法相比，这些INPs可用于快速修复受污染场地，成本大大降低。最重要的是，它们也适用于各种危险化学品，包括多氯联苯；重金属，甚至放射性核素。迄今为止，英国政府已经采取了一种预防措施，防止纳米材料故意释放到环境中，因此，英国环境署目前不允许使用INP修复技术。2010年7月，DEFRA委托进行了一项研究（CB0440），以评估故意向环境中排放无机污染物所带来的假设或已知的有害影响是否超过使用无机污染物进行场地清理可能带来的好处。虽然这项研究尚未完成，但布里斯托尔小组最近提供的一份详细审查报告强调，对于注入地下的INP的真实地球化学命运，它们清理污染物的真正效率以及它们可能对环境产生的影响程度，仍有许多未知之处。解决方案：通过学术界与工业界的合作，目前的项目建议弥合我们目前认识的差距，并提供有关环境中INPs生命周期的有价值的现场数据。该项目将建立在布里斯托尔界面分析中心（IAC）和URS/Scott Wilson（一家国际知名的岩土工程和地质环境工程咨询公司）之间的现有联系之上。IAC是英国在INPs研究方面最强大的团体。在项目期间，学生将使用不同尺寸和类型的INP（湿成型、干成型、退火、表面活性剂涂层）进行实验室和实地调查，以评估它们在复杂地球化学自然水体中污染物修复的相对性能。该项目还将寻求更好地了解注入孔隙水系统的INP的具体基本生命周期方面，特别是控制运输、转化、污染物-INP反应性和微生物影响的因素。对该项目有特殊价值的是，URS/Scott Wilson将提供进入英国和/或海外受污染地点的途径，学生将在CASE主管的监督下，参与使用INP进行修复项目的规划、部署和监测。在英国，学生还可以使用位于诺丁汉URS/Scott Wilson实验室的专业50立方米水文地球化学测试单元，在那里使用INP的地下水修复系统将被原型化和优化。目前的学生将得到DEFRA和CL:AIRE的建议，将产生数据和实践知识，这将有助于塑造未来英国在现场清理中使用INP的立法和行业最佳实践。

Targeted under NERC's Water theme, the proposed project is aimed at determining the fate, reactivity and environmental risk of deploying nanoscale iron particles (INP) for the cleanup of polluted sites and groundwaters around the UK. The project is CASE supported by URS/Scott Wilson with advisory input from DEFRA (Dr Helinor Johnston) and CL:AIRE (Dr John Henstock). The Problem: The increased development and use of engineered nanomaterials has the potential to offer great benefits to society through their exploitation within numerous products developed by diverse industries. Some applications of nanomaterials have the potential to afford environmental benefits and of particular interest is the use of nanoscale particles of zerovalent iron (INPs) for the in situ cleanup of contaminated land and groundwater. Theoretical and practical evidence suggests that these INPs can be used to rapidly remediate contaminated sites at a significantly reduced cost relative to conventional methods. Most significantly they are also applicable for a wide range of hazardous chemicals, including polychlorinated biphenyls (PCBs); heavy metals and even radionuclides. To date the UK government has adopted a precautionary approach to the deliberate release of nanomaterials into the environment and consequently the use of INP remediation technology is not currently permitted by the UK Environment Agency. In July 2010 DEFRA commissioned a study (CB0440) to evaluate whether the hypothesised or known detrimental effects associated with the intentional release of INPs into the environment, outweigh the benefits that may be realised by using INP for site cleanup. Whilst this study has not yet been completed, a recent detailed review provided by the Bristol group has highlighted that much is still unknown about the true geochemical fate of INP injected into the subsurface, their true efficiency for cleanup of pollutants and the level of impact they may have on the environment. The Solution: By partnering academia with industry, the current project proposes to bridge the gaps in our current understanding and provide valuable site-derived data relating to the lifecycle of INPs in the environment. The project will build upon existing links between the Bristol Interface Analysis Centre (IAC), a group with the strongest UK track record for INPs research, and URS/Scott Wilson, an internationally renowned geotechnical and geoenvironmental engineering consultancy. Over the period of the project, the student will perform both laboratory and field-based investigations using INP of different sizes and types (wet-formed, dry-formed, annealed, surfactant coated) to evaluate their relative performance for contaminant remediation in natural waters of complex geochemistry. The project will also seek to better understand specific fundamental lifecycle aspects of INP injected into pore-water systems, specifically the factors that control transport, transformation, contaminant-INP reactivity and microbial impact. Of specific value to the project, URS/Scott Wilson will provide access to contaminated sites within the UK and/or overseas where the student, under supervision of the CASE supervisor, will participate in the planning, deployment and monitoring of a remediation project using INP. In the UK the student will also have access to a specialist 50m3 hydrogeochemical test cell located at URS/Scott Wilson's laboratories in Nottingham, where groundwater remediation systems using INP's will be prototyped and optimised. It is considered that the current studentship, which will be advised by both DEFRA and CL:AIRE, will produce data and practical knowledge that will help to shape future UK legislation and industry best practice for the use of INP in site clean-up.