Collaborative Research: Natural Organic Matter, Capping Agents, and Nanoparticle Transport in Granular Media Filtration

合作研究：天然有机物、封端剂和颗粒介质过滤中的纳米粒子传输

• 批准号: 1336167
• 负责人: Boris Lau
• 金额: $ 17.5万
• 依托单位: Baylor University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1336167&HistoricalAwards=false
• 关键词: Collaborative; Research; Natural; Organic; Matter

CBET - 1336139 and 1336167As the field of nanotechnology continues to expand, increased entry of engineered nanoparticles (NPs) into the environment has resulted in growing environmental and health concerns. The behavior of engineered NPs, many of which serve as an avenue for rapid and long-range transport/transformation of contaminants in the environment, is an important topic for the safety and treatment of drinking water. As natural organic matter (NOM) is ubiquitous in natural waters and known to complex with NP surfaces, a mechanistic understanding of NP-NOM interactions will provide insight to the stability and mobility of NPs in granular media filtration. Our team of investigators takes a three-pronged approach to study the mechanisms by which NOM affects the aqueous transport of "pristine" and "transformed" silver NPs (AgNPs) in granular media filtration. We employ filtration studies to identify and quantify the deviation of NP removal efficiency from its prediction by colloid filtration theory. Where chemical interactions cause deviation from theory, we use a combination of experimental tools to elucidate both the kinetics and the mechanisms of NP-NOM interactions. This research will ultimately improve our ability to removal engineered NPs by granular media filtration.Intellectual Merit :During the formation or release into the aquatic environment, most NPs acquire a surface coating by interacting with organic macromolecules. We expect that the properties of coatings on NP surfaces will play important roles in NP removal in granular media filtration. We hypothesize that: 1) "Pristine" AgNPs (capped with citrate and polyvinyl pyrrolidone (PVP)) and "transformed" AgNPs (partly sulfidized AgNPs) will exhibit reactivity with various NOM components, thereby producing AgNP-NOM complexes with different surface charge and degree of steric hindrance, 2) the kinetics of adsorption of NP-NOM complexes onto silica surfaces is a function of the surface charge produced by the different functional groups of NOM and steric hindrance resulting from the physical arrangement of NOM, and 3) NOM coating on AgNPs as well as collector grain surfaces causes significant deviation in particle removal efficiency. Using a novel combination of molecular spectroscopy, quartz crystal microgravimetry (QCM), and column filtration experiments, we will determine the mechanisms and kinetics of NOM interaction with the surfaces of NP and silica.Broader Impacts :As a means of integrating cutting-edge science into education, we present a 5-Phased Outreach Plan to enhance this exchange: (1) professional education, all three PIs will propose a full-session workshop or special session at "Texas Water", the third largest annual water conference in the U.S. in the third year of the three-year grant. (2) Graduate education, multiple lectures will be developed in four courses. The work outlined here will be used to actively recruit and train undergraduate and graduate students from underrepresented groups. We will employ diversity in choosing the Ph.D. students, and additionally try to support 1-2 undergrads for senior thesis research. (3) College level: we will continue interacting with two major mentoring programs designed to involve under-represented minorities in engineering research programs. (4) Baylor University has an established outreach program focusing on nanotechnology (ThePhysics Circus) which is actively working in the Waco and LaVega middle and high schools. (5) High school level: we will work with students from San Juan Diego High School, a college-preparatory school located near the University of Texas campus that serves economically-disadvantaged, mostly Hispanic, students to increase their college preparedness in science and mathematics. The increasing applications of both natural and engineered NPs represent both a technological panacea and potential health threat. At present, there is insufficient information regarding the environmental transport and fate of NPs. Our work is transformative in providing crucial information for predicting behavior and interactions of NPs with NOM and silica sand surface. Current practice of granular media filtration targets micron-sized particles; however, the potential influences of NOM and other water treatment parameters on the fate of NPs in granular media filtration are largely unknown. The results of this study will provide greater knowledge of the behavior of NPs that could ultimately influence water treatment design and practice, and thereby improve the protection of the public health.

CBET-1336139和1336167随着纳米技术领域的不断扩大，工程纳米颗粒(NPs)越来越多地进入环境，导致越来越多的环境和健康问题。工程NPs的行为是饮用水安全和处理的一个重要课题，其中许多NPs是环境中污染物快速和远距离传输/转化的途径。由于天然有机物(NOM)普遍存在于天然水体中，并且与NP表面复杂，因此从机理上理解NP与NOM的相互作用将有助于深入了解NPs在颗粒介质过滤中的稳定性和流动性。我们的研究团队采取三管齐下的方法来研究NOM影响颗粒介质过滤中“原始”和“转化”的银纳米颗粒(AgNPs)的水溶液传输的机制。我们利用过滤研究来确定和量化NP去除效率与胶体过滤理论预测的偏差。当化学相互作用导致偏离理论时，我们使用一系列实验工具来阐明NP-NOM相互作用的动力学和机制。这项研究将最终提高我们通过颗粒介质过滤去除工程NPs的能力。智力优点：在形成或释放到水环境中时，大多数NPs通过与有机大分子相互作用获得表面涂层。我们预计，在颗粒过滤中，NP表面涂层的性质将对NP的去除起到重要作用。我们假设：1)“原始的”AgNPs(用柠檬酸和聚乙烯吡咯烷酮(PVP)包覆)和“转化的”AgNPs(部分硫化的AgNPs)会与不同的NOM组分发生反应，从而生成具有不同表面电荷和空间位阻程度的AgNP-NOM络合物；2)NP-NOM络合物在二氧化硅表面的吸附动力学是NOM的不同官能团产生的表面电荷的函数，以及NOM的物理排列导致的空间位阻；3)NOM包覆在AgNPs和捕收剂颗粒表面会导致颗粒去除效率的显著偏差。利用分子光谱、石英晶体微重分析(QCM)和柱过滤实验的新组合，我们将确定NOM与NP和硅表面相互作用的机制和动力学。广泛影响：作为将尖端科学整合到教育中的一种手段，我们提出了一个分5个阶段的外展计划来加强这种交流：(1)专业教育，所有三个PI将在为期三年的拨款的第三年在美国第三大年度水会议“Texas Water”上提议举办一次全会研讨会或特别会议。(2)研究生教育，将在四个课程中开展多个讲座。这里概述的工作将用于从代表性不足的群体中积极招聘和培养本科生和研究生。我们将采用多样化的方式选择博士生，并努力支持1-2名本科生进行高级论文研究。(3)大学水平：我们将继续与两个主要的指导计划互动，这些计划旨在让代表不足的少数族裔参与工程研究计划。(4)贝勒大学有一个以纳米技术(物理马戏团)为重点的既定推广方案，该方案正在韦科和拉维加初中和高中积极开展工作。(5)高中水平：我们将与圣胡安·迭戈高中的学生合作，这是一所位于德克萨斯大学校园附近的大学预科学校，服务于经济困难的学生，主要是西班牙裔学生，以提高他们在大学科学和数学方面的准备。越来越多的天然和工程NPs的应用既是一种技术灵丹妙药，也是一种潜在的健康威胁。目前，关于核燃料的环境运输和命运的信息不足。我们的工作在为预测NPs与NOM和石英砂表面的行为和相互作用提供关键信息方面具有变革性。目前颗粒介质过滤的目标是微米级的颗粒；然而，NOM和其他水处理参数对颗粒介质过滤中NPs命运的潜在影响在很大程度上是未知的。这项研究的结果将提供对NPs行为的更多了解，这些行为最终可能影响水处理的设计和实践，从而改善对公众健康的保护。