Collaborative Research: A Multiscale Framework to Investigate the Influence of Attached Phase Soil Organic Matter on the Fate, Transport, and Removal of Carbon-based Nanomaterials

协作LeBoeuf和Li 1133280和1133528这个由纳米技术计划的环境健康和安全NSF奖支持范德比尔特大学的尤金·J·LeBoeuf教授和内布拉斯加大学林肯的李玉松教授和卢永丰教授的工作，以调查附着相有机物质对命运的影响，碳基纳米材料在多孔介质中的迁移和去除：工程纳米材料的生产不断升级，随后在消费品中的掺入增加了向环境释放的可能性。通常，随着时间的推移释放的疏水性颗粒化合物会在有机系统中积累，包括附着相土壤和沉积物有机物（AP-SOM）。特别是在沉积物中，污染物有可能持续很长一段时间;因此，ENM可能会在未来很长一段时间内影响环境。虽然一些努力已经致力于调查环境中的ENM的行为，非常有限的研究都集中在AP-SOM和ENM的相互作用。本建议的目标是建立系统的，机械的理解ENM和AP-SOM之间的相互作用和它们对ENM运输的影响。我们专注于碳基ENM通过选择多壁碳纳米管（MWCNT），富勒烯（C60），和碳纳米洋葱（HOCS）来代表圆柱形，球形和洋葱形系统。同时，选择腐殖酸和干酪根来代表软/年轻和刚性/老AP-SOM。中心假设是ENM聚集体和AP-SOM之间的相互作用受到基本纳米结构（例如，不同的形状）和物理化学特性（例如，大分子橡胶态/玻璃态）。本论文围绕四个目标构建了一个实验与模拟相结合的研究框架：（1）表征SOM和ENM，将AP-SOM的物理化学和大分子特性以及ENM的基本纳米结构与它们的宏观相互作用联系起来：（2）通过石英晶体微天平（QCM）的附着/分离实验量化纳米材料与AP-SOM的相互作用;（3）通过进行柱实验量化AP-SOM对多孔介质中纳米材料传输的影响;（4）开发并实验验证能够模拟AP-SOM存在下多孔介质中纳米材料传输的数学模型。拟议的研究可以是变革性的，因为它的目的是链接基本的纳米结构和属性的行为ENM聚集体运输，特别关注的存在AP-SOM。随着纳米材料的研究和生产的步伐不断增加，这些材料的环境影响的全面研究是迫切需要的。了解纳米材料在多孔介质中的归宿和迁移将提供关于工程纳米材料对生态系统和人类健康影响的关键信息。根据该提案开发的数值模拟器可用于预测工程纳米材料在一系列环境条件下的迁移距离，这可以帮助监管机构制定改进的基于风险的指南，以解决这些新出现的污染物。我们在多孔介质中纳米颗粒保留的基础知识方面的进步也可以用于模拟含有纳米颗粒的饮用水或废水处理的过滤技术的性能。该项目将通过让代表性不足的群体参与项目并将研究成果转移到课堂上，在激励STEM领域的本科生和毕业生方面取得重大进展。从这项工作中产生的基础知识，实验技术和建模工具将以期刊出版物和区域，国家和国际专业会议上的演讲的形式迅速传播到科学界。

Collaborative LeBoeuf and Li1133280 and 1133528This NSF award by the Environmental Health and Safety of Nanotechnology program supports work by Professor Eugene J. LeBoeuf at Vanderbilt University, and Professors Yusong Li and Yongfeng Lu at the University of Nebraska , Lincoln to investigate the influence of attached phase organic matter on the fate, transport and removal of carbon-based nanomaterials in porous media.Escalating production and subsequent incorporation of engineered nanomaterials (ENMs) in consumer products increases the likelihood of release to the environment. Typically, hydrophobic particulate compounds released over time will accumulate in organic systems, including attached phase soil and sediment organic matter (AP-SOM). Especially in sediments, there is the potential for contaminants to persist for significant periods of time; therefore ENMs may impact environments long into the future. Although some effort has been devoted to investigate the behavior of ENMs in the environment, a very limited number of studies have focused on the interactions of AP-SOM and ENM.The goal of this proposal is to build systematic, mechanistic understanding of the interactions between ENM and AP-SOM and their influence on ENM transport. We focus on carbon-based ENMs by selecting multi-walled carbon nanotubes (MWCNT), fullerene (C60), and carbon nano-onions (CNOs) to represent cylindrical, spherical, and onion-shaped systems. Meanwhile, humic acid and kerogen are selected to represent soft/young and rigid/old AP-SOM. The central hypothesis is that the interactions between ENM aggregates and AP-SOM are affected by the fundamental nanostructure (e.g., different shapes) of ENMs and physicochemical characteristics (e.g., macromolecular rubbery/glassy states) of AP- SOM. An integrated experimental and modeling research framework is structured around four objectives: (1) Characterize SOM and ENMs to link physicochemical and macromolecular characteristics of AP-SOM and the fundamental nanostructure of ENM with their macroscopic interactions; (2) Quantify the interactions of nanomaterials and AP-SOM by conducting Quartz Crystal Microbalance (QCM) attachment/detachment experiments; (3) Quantify the influence of AP-SOM on the transport of nanomaterials in porous media by conducting column experiments; and (4) Develop and experimentally validate a mathematical model that is capable of simulating nanomaterial transport in porous media in the presence of AP-SOM. The proposed research can be transformative because it aims to link fundamental nanostructure and properties to the behaviors of ENM aggregate transport, with a particular focus on the presence of AP-SOM.As the pace of research and production of nanomaterials continues to increase, comprehensive studies on the environmental impact of these materials are urgently needed. Understanding the fate and transport of nanomaterials in porous media will provide critical information on the influence of engineered nanomaterials on ecosystems and human health. The numerical simulator developed from this proposal can be used to predict the mobility distance of engineered nanomaterials under a range of environmental conditions, which can assist regulatory agencies in developing improved, risk-based guidelines that address these emerging contaminants. The advancement in our fundamental knowledge of nanoparticle retention in porous media can also be used to model the performance of filtration technologies for treatment of drinking water or wastewater containing nanoparticles. The project will initiate significant advancements in motivating undergraduates and graduates in the STEM areas by involving underrepresented groups in the project and transferring research results into the classroom. The fundamental knowledge, experimental techniques, and modeling tools produced from this work will be rapidly disseminated to the scientific community in the form of journal publications and presentations at regional, national, and international professional meetings.