Ethyl Cellulose Nanoparticles and Porous Media: Fundamentals and Applications

在运输或工业活动过程中排放的非水相液体对地表和地下水生环境的健康都是一个令人严重关切的问题。特别地，它们从地下的去除是一个令人烦恼的问题，这是由于在源区域的表征和靶向、修复性能的监测以及具有对污染物的选择性的修复剂的原位递送方面存在很大困难。 工程纳米材料在提高现有和新型修复技术的功效方面具有巨大潜力;然而，材料可持续性的挑战以及纳米颗粒在多孔介质中运输和分布的障碍阻碍了广泛部署的进展。该研究计划的长期愿景是解决这些挑战，在未来五年内，战略性地将我们的直接努力集中在一种新兴的可持续纳米材料乙基纤维素（EC）上，该材料来源于丰富的纤维素。利用我们对表面力在EC纳米颗粒（NP）在气-液和液-液界面处的附着和组装中所起的作用的定量理解，我们将使用EC- NP悬浮液作为模型系统来研究NP与多孔介质中的移动的和非移动的流体-流体界面（即，在孔隙网络和连续体尺度上）。在不同尺度上操作的物理过程的系统表征是拟议的研究计划的一个显着特点。 从EC-NPs研究中获得的基础知识将使不仅基于EC-NPs，而且基于来自纤维素或木质素的更复杂的可持续纳米材料的应用的合理开发成为可能。拟议的研究计划将在两个主要方向展开。首先将调查，使用实验和模拟，基本方面的EC-NP运输主机多孔介质（土壤和岩石），在单相，两相和三相流的条件下。这是重要的，因为NP在流体界面处的附着影响不混溶驱替的动力学并且受其影响，不混溶驱替的动力学是地下修复中的应用（例如，NP--稳定泡沫驱，NP的污染物传感，疏水污染物的固定，原位污染物屏障），石油回收和纪念碑保护。第二个方向将在实验上解决使用由EC-NP稳定的油-水（O/W）乳液作为用于创建用于O/W分离的疏水/亲油多孔材料的模板和作为用于润湿性控制的涂层。最终，这项研究将导致可持续技术的发展和高素质的人员在胶体科学和多孔介质中的运输接口的培训，领域看到显着的增长，并需要训练有素的人员作为先进的材料开始部署在地质环境。

The discharge of non-aqueous phase liquids in the course of transportation or industrial activity is a cause of grave concern for the health of both surface and subsurface aquatic environments. Their removal from the subsurface in particular, is a vexing problem, due to great difficulty with the characterization and targeting of source zones, the monitoring of remediation performance, and the in situ delivery of remediation agents with selectivity toward contaminants. Engineered nanomaterials have great potential to improve the efficacy of existing and novel remediation technologies; however, challenges with material sustainability and barriers to nanoparticle transport and distribution in porous media, have hampered progress towards widespread deployment. The long term vision of this research program is to address these challenges, strategically focusing our immediate efforts over the next five years on an emerging sustainable nanomaterial, ethyl cellulose (EC), derived from abundantly available cellulose. Capitalizing on our quantitative understanding of the role surface forces play in the attachment and assembly of EC nanoparticles (NPs) at gas--liquid and liquid--liquid interfaces, we will use EC- NP suspensions as a model system to investigate NP interactions with mobile and immobile fluid--fluid interfaces  in porous media (i.e., at the pore- network and continuum scales). The systematic characterization of physical processes operative at different scales is a distinguishing feature of the proposed research program. Fundamental knowledge gained from the study of EC-NPs will enable the rational development of applications based not only on EC-NPs, but on more complex sustainable nanomaterials derived from cellulose or lignin. The proposed research program will unfold in two main directions. The first will investigate, using experiments and simulations, fundamental aspects of EC-NP transport in host porous media (soil and rock), under conditions of single-, two- and three--phase flow. This is important because NP attachment at fluid interfaces affects and is affected by the dynamics of immiscible displacement - dynamics which underpin applications in subsurface remediation (e.g., NP--stabilized foam flooding, contaminant sensing by NPs, immobilization of hydrophobic contaminants, in situ contaminant barriers), oil recovery and monument preservation. The second direction will address experimentally the use of oil--water (O/W) emulsions stabilized by EC- NPs as templates for the creation of hydrophobic/oleophilic porous materials used for O/W separation and as coatings for wettability control. Ultimately, this research will lead to the development of sustainable technologies and the training of highly-qualified personnel at the interface of colloid science and transport in porous media, fields seeing significant growth and requiring highly trained personnel as advanced materials are beginning to be deployed in geologic settings.