Collaborative Research: Retention of Anisotropic Colloids in Porous Media: A Modeling and Experimental Investigation at Multiple Scales

合作研究：多孔介质中各向异性胶体的保留：多尺度的建模和实验研究

• 批准号: 1521428
• 负责人: Yusong Li
• 金额: $ 20.01万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1521428&HistoricalAwards=false
• 关键词: Collaborative; Research; Retention; Anisotropic; Colloids

Collaborative Research: Retention of Anisotropic Colloids in Porous Media: A Modeling and Experimental Investigation at Multiple ScalesAbstractGroundwater is one of the most important components of the hydrologic cycle, serving as the source of about 33 percent of public water supply and providing drinking water to more than 90 percent of the rural population in the United States. Biological (bacteria) and non-biological (soil particles) natural colloids are ubiquitous in groundwater. The transport of pathogens (biological colloids) is relevant to producing safe drinking water, and the transport of heavy metals as facilitated by colloids (non-biological colloids) in groundwater has been widely recognized as a serious public concern. Almost all natural colloids are anisotropic in nature, being non-spherical in shape and possessing varied degrees of heterogeneity in surface charge. This project addresses the limitations of our current understanding of transport and fate of colloidal particles in porous media that stem from approximations of spherical shape and uniform surface charge used in previous studies. An improved understanding of colloid transport and retention in the environment will provide critical knowledge needed for producing safe drinking water and protecting sustainable water resources, essential steps for human health and development. Results from this work will be incorporated into undergraduate and graduate curriculums. Interactive demonstrations on environmental aspects of colloids and nanomaterials will engage middle- and high-school students during a two-week summer camp that encourages interest in STEM disciplines among women and under-represented minorities.This project is a combined experimental and modeling study that integrates considerations of shape anisotropy and surface-charge heterogeneity. The research uses a multi-scale approach to investigate the retention of anisotropic colloids onto flat surfaces, at grain-to-grain contacts, and in complex porous media. Systematic experiments using laboratory-prepared rod-shaped colloidal particles with various aspect ratios and surface-charge heterogeneity will be analyzed in novel ways. Applications of cutting-edge methodologies in microelectronics, high-resolution mass sensing, optical microscopy, and laser-scanning cytometry will enable observations of colloid attachment rates on the surfaces and pore throats of the mineral grains comprising porous media and reveal phenomena appropriate to scaling up observations to aquifers. In parallel, a numerical simulation model that is capable of tracking both the movement and orientation of anisotropic colloids within porous media will be developed. The results of this project provide predictive quantification on how non-spherical shape and surface-charge heterogeneity impact transport and retention of anisotropic colloids.

合作研究：各向异性胶体在多孔介质中的滞留：多尺度下的模拟与实验研究摘要地下水是水文循环中最重要的组成部分之一，约占美国公共供水的33%，并为90%以上的农村人口提供饮用水。生物（细菌）和非生物（土壤颗粒）天然胶体在地下水中无处不在。病原体（生物胶体）的迁移与安全饮用水的生产有关，地下水中胶体（非生物胶体）促进的重金属迁移已被广泛认为是一个严重的公共问题。几乎所有的天然胶体在性质上都是各向异性的，在形状上是非球形的，并且在表面电荷上具有不同程度的不均匀性。该项目解决了我们目前对多孔介质中胶体颗粒的运输和命运的理解的局限性，这些局限性源于以前研究中使用的近似球形和均匀表面电荷。更好地了解胶体在环境中的迁移和保留，将提供生产安全饮用水和保护可持续水资源所需的关键知识，这是人类健康和发展的重要步骤。这项工作的结果将纳入本科和研究生课程。在为期两周的夏令营期间，将举办胶体和纳米材料环境方面的互动演示，鼓励女性和少数民族对STEM学科的兴趣。该项目是一项综合考虑形状各向异性和表面电荷异质性的实验和建模研究。 该研究使用多尺度方法来研究各向异性胶体在平坦表面上、颗粒与颗粒接触处以及复杂多孔介质中的保留。系统的实验使用实验室制备的棒状胶体颗粒与各种纵横比和表面电荷的异质性将在新的方式进行分析。 微电子学、高分辨率质量传感、光学显微镜和激光扫描细胞术中的尖端方法的应用将使对包括多孔介质的矿物颗粒的表面和孔喉上的胶体附着率的观察成为可能，并揭示适合于扩大对含水层的观察的现象。与此同时，将开发一个能够跟踪多孔介质中各向异性胶体的运动和取向的数值模拟模型。该项目的结果提供了非球形形状和表面电荷异质性如何影响各向异性胶体的传输和保留的预测量化。