RUI: SusChEM: Mechanisms of Nanoparticle Aggregation and Corresponding Effects on Metal Sorption, Desorption, and Incorporation Processes

在这个由美国国家科学基金会化学部环境化学科学项目资助的项目中，查普曼大学的克里斯托弗·金教授正在进行一项涉及氢氧化铁纳米颗粒聚集体详细表征的研究。这些表征研究包括批量和实时金属离子吸附/解吸实验，以及基于同步加速器的x射线光谱方法，以改进纳米级铁氢氧化物的金属吸收/保留的预测建模。无机矿物相纳米颗粒在水基环境系统中广泛存在。天然纳米粒子和合成纳米粒子在污染水体的修复策略中非常有效，例如金属矿石开采活动造成的污染。本研究开发了预测金属在自然水道中的命运和运输的模型。这些研究最大限度地保留了金属，减少了污染系统中的金属流动性。这项工作的更广泛影响包括为本科生、社区学院和高中生（以女性、代表性不足的少数民族和低收入人群为目标）创造独立研究机会，为学生提供使用国家同步加速器用户设施的经验，并将纳米粒子研究的新发现纳入环境和无机化学的本科课程。高中化学和环境科学教师通过校园访问和课程开发参与研究方法和成果。吸附在聚集的纳米颗粒上的金属离子的命运和形态在很大程度上是未知的。纳米聚集体对金属的吸附是一种重要的自然衰减手段，为金属污染的表面水系统的有效修复提供了巨大的潜力。具体来说，随着聚集状态、盐度和时间的增加，由于反应表面积的损失，金属的吸收量下降，但由于吸附的离子被捕获到更复杂的受限聚集结构上，金属的保留率可能会增加。该项目促进了我们对控制金属离子在纳米级氧化铁颗粒及其聚集体上的保留和隔离的基本过程的理解。该研究影响了环境纳米科学的新兴领域，特别是纳米颗粒在金属污染场地修复中的作用。

In this project, funded by the Environmental Chemical Sciences Program in the Division of Chemistry at the National Science Foundation, Professor Christopher Kim of Chapman University is performing research that involves detailed characterization of iron oxyhydroxide nanoparticle aggregates. These characterization studies include batch and real-time metal ion adsorption/desorption experiments and synchrotron-based X-ray spectroscopic methods to improve predictive modeling of metal uptake/retention to nanoscale iron oxyhydroxides. Nanoparticles of inorganic mineral phases are widespread in water-based environmental systems. Natural and synthetic nanoparticles are highly effective in remediation strategies for contaminated waters, such as those that result from metal ore mining activities. This research develops models to predict metal fate and transport in natural waterways. These studies maximize metal retention and reduce metal mobility in contaminated systems. Broader impacts of this work include the creation of independent research opportunities for undergraduate, community college, and high school students (targeting females, under-represented minorities, and low-income populations), providing students with experiences using national synchrotron user facilities, and incorporating new findings in nanoparticle research to the undergraduate curricula in environmental and inorganic chemistry. High school chemistry and environmental science teachers are engaged in the research methods and outcomes through on-campus visits and lesson development.The fate and speciation of metal ion species sorbed to aggregated nanoparticles are largely unknown. Metal sorption to nanoaggregates serves as an important means of natural attenuation and provides considerable potential for the effective remediation of metal-contaminated surface aqueous systems. Specifically, with increasing aggregation state, salinity, and time, metal uptake declines due to loss of reactive surface area but metal retention may increase due to trapping of sorbed ions onto/into the more complex confined aggregate structures. This project advances our understanding of the fundamental processes that control the retention and sequestration of metal ions onto nanoscale iron oxyhydroxide particles and their aggregates. The research impacts the emerging field of environmental nanoscience, particularly the role that nanoscale particles play in the remediation of metal-contaminated sites.