Collaborative Research: Nano- and micro-particle transport prediction in subsurface media: The role of heterogeneity and structure

合作研究：地下介质中纳米和微米颗粒的输运预测：异质性和结构的作用

• 批准号: 1547533
• 负责人: William Johnson
• 金额: $ 27.06万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1547533&HistoricalAwards=false
• 关键词: Collaborative; Research; Nano; micro; particle

Many water quality contexts exist in which particle transport and retention in saturated sands and gravels is a critical process; e.g., streambed removal of particle-bound contaminants, low energy drinking water treatment using riverbank filtration, engineered subsurface delivery of novel nanoparticles or bacteria for contaminant cleanup, and protection of drinking water supplies from disease-causing pathogen sources. There is yet insufficient capability to predict the observed complex transport behaviors of these particles under environmental conditions. Consequently, the theory to support optimized design of the above environmental systems is lacking. Mathematical models currently can describe but not predict these behaviors because, as yet, the models do not represent the underlying mechanisms and processes for particle attachment to surfaces under environmental conditions. The proposed research aims to determine whether observed complex colloid transport behaviors will emerge from pore-scale representation of the surface heterogeneity responsible for particle attachment. The proposed investigations involve parallel experiments and simulations at pore (micromodel) and network (packed sand column) scales. The research will provide for a transformative platform for researchers and practitioners to perform mechanistic prediction of particle transport for design of solutions to environmental problems. Additional broader impacts include engagement of middle and high school biology, chemistry, and earth science teachers in six-week long summer internships where they undertake field and laboratory experiences examining the role of particles in trace element transport and transformation.The capability to predict the observed complex transport behaviors of colloids under environmental conditions (e.g., non log-linear profiles of retained colloids, extended tailing of low concentrations, blocking, and ripening) is currently lacking. Empirically based continuum-scale rate constants and scaling factors are employed in the advection-dispersion equation to describe, and to a limited extent predict, the observed complex transport behaviors. Whereas these descriptions are extremely useful indicators of mechanisms, true predictive capability will be possible only if the underlying physicochemical mechanisms/processes are identified and parameterized at a more fundamental level. Pore scale (nanoscale) colloid-surface interactions are well-demonstrated to exert profound influences on colloid transport behaviors at the continuum scale (column and field). This research aims to determine whether the continuum-scale rate constants and scaling factors can be predicted, and the whether the observed complex continuum-scale behavior will emerge, from pore-scale representation of surface heterogeneity and network-scale representation of packing structure. This investigation involves parallel experiments and simulations at pore (micromodel) and continuum (column) scales. Coupled pore scale force/torque balance simulations will be conducted to pore/grain network simulations in order to develop mechanistic prediction of continuum scale rate constants and scaling factors. New approaches will be used to represent surface heterogeneity responsible for colloid attachment to bulk repulsive surfaces at the pore scale. The proposed research will also capitalize on, and extend, recent understanding of influences of topology at the continuum (network) scale where the transition between molecular (diffusion-driven) and particle (trajectory-driven) transport behaviors will be explored.

存在许多水质环境，其中颗粒在饱和的沙子和砾石中的颗粒传输和保留是关键过程。例如，溪流污染物的溪流去除，使用河岸过滤的低能饮用水处理，新型纳米颗粒或细菌的工程地下递送以污染污染物清洁，以及从导致病原体来源的饮用水供应的保护。 在环境条件下，这些颗粒的复杂运输行为还不足。 因此，缺乏支持上述环境系统的优化设计的理论。 数学模型当前可以描述但不能预测这些行为，因为到目前为止，这些模型尚未代表在环境条件下粒子附着在表面的基本机制和过程。 拟议的研究旨在确定观察到的复杂胶体转运行为是否会从负责颗粒附着的表面异质性的孔尺度表示中出现。 提出的研究涉及孔（微型模型）和网络（包装砂柱）尺度的平行实验和模拟。 这项研究将为研究人员和从业人员提供一个变革性的平台，以对粒子传输的机械预测，以设计解决环境问题的解决方案。 Additional broader impacts include engagement of middle and high school biology, chemistry, and earth science teachers in six-week long summer internships where they undertake field and laboratory experiences examining the role of particles in trace element transport and transformation.The capability to predict the observed complex transport behaviors of colloids under environmental conditions (e.g., non log-linear profiles of retained colloids, extended tailing of low concentrations, blocking, and ripening) is currently缺乏。 基于经验的连续尺度速率常数和缩放因子在对流范围方程中使用，并在有限的程度上预测观察到的复杂运输行为。 尽管这些描述是机制极为有用的指标，但只有在更基本的层面鉴定并参数化的基本理化机制/过程时，才能实现真正的预测能力。 孔隙尺度（纳米级）胶体表面相互作用很好地表明了对胶体传输行为的深刻影响（柱和场）。 这项研究旨在确定是否可以预测连续尺度的速率常数和缩放因子，以及观察到的复杂的连续尺度行为是否会从表面异质性的孔隙尺度表示和包装结构的网络尺度表示中出现。 这项研究涉及孔隙（微型模型）和连续体（柱）尺度的平行实验和模拟。 将对孔/谷物网络模拟进行耦合孔尺度/扭矩平衡模拟，以开发连续尺度速率常数和缩放因子的机械预测。 新方法将用于表示负责在孔尺度上胶体附着胶体附着的表面异质性。 拟议的研究还将在连续体（网络）尺度上利用并扩展对拓扑影响的最新理解，其中将探索分子（扩散驱动）与粒子（轨迹驱动）传输行为之间的过渡。