Collaborative Research: Understanding the Effect of Transient Interfacial Dynamic in the Transport and Deposition of Particles in the Vadose Zone

合作研究：了解瞬态界面动力学对气包带中颗粒运输和沉积的影响小悬浮颗粒，即胶体颗粒，在地质介质中的运输一直是许多研究的主题，部分原因是它在污染物扩散和水净化中很重要。渗透带，即土壤柱的上层，是地下水水库补给的入口点，因此，颗粒的运输和命运是水资源可持续性的关键。含有污染物的微粒，从致病微生物到工业应用中使用的越来越多的纳米颗粒，都可能污染地下水水库。此外，研究表明，胶体颗粒可以促进分子污染物的运输。不幸的是，在气包带中胶体颗粒的运输和命运的预测模型的发展已被证明是特别难以捉摸的。更好地了解非饱和多孔介质中驱动颗粒运输的机制可以为水净化工艺的设计、污染风险的管理、修复策略的开发带来新的范例，并将促进纳米技术材料的回收和再循环。这项工作的影响在于教育和外联、公共卫生以及其技术支持能力。培训将提供给研究生，本科生和高中学生在一个跨学科的环境中，包括材料和界面科学以及运输和建模领域的强烈暴露。研究者的教育理念旨在培养学生对科学的真正热情，让他们有机会积极地生产科学材料，而不是被动地充当消费者。调查人员的外展和教育工作将包括课程开发，以及本科生和高中生对研究活动的持续参与。调查小组还将采用为期一年的课后教室（每周访问教室），学生将在训练有素的协调员的指导下，参与水资源可持续性领域的动手干活动。在实验室里，本科生和高中生被鼓励在小组内外展示他们的发现，包括在同行评审的科学出版物上发表论文。拟议工作的技术部分在于地下水污染物修复的广泛科学，技术和经济重要性，特别是随着饮用水资源变得越来越稀缺，合成颗粒和纳米材料的使用增加，能源成本飙升。所提出的工作的变革性质在于通过整合最先进的实验和模拟工具，提供对非平衡水动力和化学瞬态在空气-水（-固体）界面上颗粒附着/脱离的作用的粒子级理解。这项工作的结果在其他科学领域也很重要，如水过滤、采油、微流控装置中的污垢和堵塞。因此，在瞬态条件下，理解颗粒在空气-水（-固体）界面的吸附和解吸机制具有重要的科学和工程理论依据。设计简单而通用的实验来解决这些问题，将为研究非饱和多孔介质中的颗粒沉积提供一个理想的平台。此外，为这项工作开发的工具将允许在未来研究更复杂的胶体的沉积，如细菌、病毒或各种形状的矿物，以及在流体界面上吸附的倾向。

1436482Frechette1437478DrazerCollaborative Research: Understanding the effect of transient interfacial dynamics in the transport and deposition of particles in the vadose zoneThe transport of small suspended particles, referred to as colloidal particles, in geological media has been the subject of numerous studies, due in part to its importance in contaminant spreading and water purification. The vadose zone, the upper levels of the soil column, is the entry point for the replenishment of groundwater reservoirs and, therefore, the transport and fate of particulates is key to the sustainability of water resources. Particulates containing contaminants, ranging from pathogenic microbes to the increasing number of nanoparticles used in industrial applications, can pollute groundwater reservoirs. In addition, it has been shown that colloidal particles can facilitate the transport of molecular contaminants. Unfortunately, the development of predictive models for the transport and fate of colloidal particles in the vadose zone has proven especially elusive. A better understanding of the mechanisms driving the transport of particulates in unsaturated porous media could lead to new paradigms in the design of water purification processes, the management of contamination risk, the development of remediation strategies, and would facilitate the recovery and recycling of technological nanomaterials. The impact of this work lies in both education and outreach, public health, as well as on its technologically enabling capabilities. Training will be provided to graduate students, undergraduates, and high school students in an interdisciplinary environment that includes a strong exposure to the fields of materials and interfacial science as well as transport and modeling. The investigators educational philosophy is designed to foster a true passion for science in students by giving them opportunities to actively produce scientific material, rather than acting as passive consumers. Outreach and educational efforts by the investigators will include course development, and the ongoing participation of undergraduates and high school students to the research activities. The investigators groups will also adopt an after-school classroom for a year (visiting the classroom weekly) in which students, under the guidance of a trained facilitator, will engage in hands-on STEM activities in the area of sustainability of water resources. In the lab, undergraduates and high school students are encouraged to present their findings within the group and externally, including authorship in peer-reviewed scientific publications.The technical portion of the proposed work lies in the broad scientific, technological, and economical importance of remediation of contaminants from groundwater, especially as the resources for potable water are becoming scarcer, the use of synthetic particulate and nanomaterials increases, and the cost of energy is skyrocketing. The transformative nature of the proposed work lies in providing a particle-level understanding of the role of non-equilibrium hydrodynamic and chemical transients on the attachment/detachment of particles from air-water (-solid) interfaces by the integration of state-of-the-art experimental and simulation tools. The results from the proposed work will also be important in other scientific areas such as water filtration, oil recovery, fouling in microfluidic devices, and clogging. Therefore, there is an important scientific and engineering rationale in understanding the mechanisms for particles adsorption and desorption from an air-water (-solid) interface during transient conditions. The design of simple and versatile experiments to address these issues will lead to an ideal platform to study particle deposition in unsaturated porous media. In addition, tools that will be developed for this work will allow, in the future, to study the deposition of more complex colloids such as bacteria, viruses, or minerals of various shapes and propensity to adsorb at fluid interfaces.