CAREER: Natural Organic Matter Mediated Processes in the Subsurface: Heavy Metal Adsorption and Nanoparticle Migration

天然有机物质（NOM）是自然生物和化学过程的产物，是自然界中普遍存在的大小和反应性各异的有机分子的非均质混合物。NOM控制着污染物和颗粒的环境命运，这一职业发展计划将阐明具有环境意义的NOM酸如何影响土壤和地下水系统中铅和纳米颗粒氧化铁的命运的具体细节。具体的研究目标是：(a)表征氧化铁/水界面上的NOM酸的配位结构，并确定酸如何影响相同界面上的铅配位；(b)将氧化铁/水界面上的NOM酸的配位模式和结构与纳米氧化铁颗粒通过多孔介质的最终运输联系起来。该研究将结合原子、分子、微观和宏观水平的技术与水动力活性实验，以提供有关铅形态和纳米颗粒运输受NOM影响的前所未有的详细信息。该研究将阐明矿物界面上NOM配位的具体细节信息。目前的反应传递和化学物种形成模型没有适当地解释这些相互作用，并产生错误的预测。确定NOM的不同组分，即已知结构酸和非均相结构酸对重金属行为的决定作用。研究纳米赤铁矿在纳米粒子存在下通过多孔介质的运移，将有助于环境纳米科学和纳米技术的新兴领域，并将为评估纳米粒子在环境中的风险提供所需的信息。新组合的宏观，微观，分子和原子水平的技术对NOM和铅的吸附将提供无与伦比的分辨率信息。除了对污染场地管理和颗粒运输的直接好处外，从这项工作中收集的详细信息还将有助于原位污染物修复和水处理的研究。解决我们社会面临的关键环境问题需要具有广泛不同背景的科学家、工程师和政策制定者的共同努力。为这些人准备这样一项任务需要一个教育系统，强调为所有学生提供适用于环境的自然科学和物理科学的坚实基础。这一教育计划的目标是建立一个框架，将良好的环境科学和工程概念传授给STEM管道的多个组成部分，从中学到研究生院，以及不同种族、社会和性别群体的学生。为了实现这一教育目标，PI将通过专业发展和电子视频会议计划向K-12教师和学生提供服务，将本科生和研究生整合到多学科团队中，并通过结合现实世界的例子、团队作业和专业实践主题来提高研究生和本科生课程的学习成果。综合研究和教育工作将涉及广泛的受众，并通过外联和征聘活动，将增加不同群体对科学和工程的参与。外展活动将涉及当地社区和全国各地的K-12学生和教师。科学成果的传播将是广泛的，并将有助于环境工程、环境化学、表面化学和水地球化学领域。新的课程内容将包括团队合作、领导和解决问题等关键技能，从而更好地为学生毕业后的职业成功做好准备。改善异质系统中重金属形态的机制和结构信息将通过改善场地修复和管理实践造福社会。纳米级赤铁矿运输的细节还将为开发管理人为纳米材料排放的监管系统提供所需的具体信息。最后，预期密切协调研究、教育和外联活动将使所有参与者更加认识到研究和工程在社会中的重要性和应用。

0954991Lenhart Natural organic matter (NOM), the product of natural biological and chemical processes, is a heterogeneous mixture of organic molecules of varying size and reactivity that is ubiquitous in nature. NOM controls the environmental fate of contaminants and particles and this career development plan will elucidate specific details of how NOM acids of environmental significance influence the fate of lead and nanoparticulate iron oxides in soil and ground water systems. The specific research objectives are to: (a) characterize the coordination structures of NOM acids at iron oxide/water interfaces and determine how the acids influence lead coordination at the same interfaces, and (b) relate the coordination modes and structures of NOM acids at iron oxide/water interfaces to the resultant transport of nano-sized iron oxide particles through porous media. The research will combine atomic-, molecular-, microscopic-, and macroscopic-level techniques with hydrodynamically-active experiments in order to provide direct information of unprecedented detail on lead speciation and nanoparticle transport as influenced by NOM. The research will elucidate specific detailed information of NOM coordination at mineral interfaces. Current reactive transport and chemical speciation models do not appropriately account for these interactions and produce erroneous predictions. The role that different components of NOM, namely acids of known structure and those of heterogeneous structure, have on determining heavy metal behavior will be determined. Research on the transport of nano-sized hematite through porous media in the presence of NOM will contribute to the emerging fields of environmental nanoscience and nanotechnology and will provide information needed to assess the risk of nanoparticles in the environment. The novel combination of macroscopic-, microscopic-, molecular-, and atomic-level techniques for NOM and lead adsorption will provide information of unsurpassed resolution. In addition to the direct benefits to contaminated site management and particle transport, the detailed information collected from this work will also benefit research on in situ contaminant remediation and water treatment. Solving the critical environmental problems our society faces will require a concerted effort by scientists, engineers, and policy makers with widely varying backgrounds. Preparing these individuals for such a task requires an educational system that places emphasis on providing all students with a sound foundation in the natural and physical sciences as they apply to the environment. The goal of this educational plan is to establish a framework to impart sound environmental science and engineering concepts to multiple components of the STEM pipeline, from middle school through graduate school and to students across a spectrum of ethnic, social, and gender groups. To meet this educational goal the PI will perform outreach to K-12 teachers and students through professional development and electronic videoconferencing initiatives, integrate undergraduate and graduate students into multi-disciplinary teams, and enhance learning outcomes in graduate and undergraduate courses by incorporating real-world examples, team-based assignments, and professional practice topics. The integrated research and education efforts will reach a wide audience, and through outreach and recruitment activities, will increase the participation of diverse groups in science and engineering. Outreach initiatives will reach out to K-12 students and teachers in the local community and across the country. Dissemination of the scientific results will be wide and will contribute to the fields of environmental engineering, environmental chemistry, surface chemistry, and aqueous geochemistry. New course components will incorporate critical skills such as team-work, leadership and problem-solving thereby better preparing students for professional success upon graduation. The improved mechanistic and structural information of heavy metal speciation in heterogeneous systems will benefit society by improving site remediation and management practices. The details on the transport of the nano-sized hematite will also provide specific information needed to develop a regulatory system to manage the discharge of anthropogenic nanomaterials. Finally, it is expected that closely coordinating the research, educational and outreach activities will foster a greater awareness among all participants of the importance and application of research and engineering in society.