Multiphysics of bubbles and nanoparticles in porous media: Novel approaches to the remediation of subsurface environments contaminated by chlorinated organic substances

加拿大废弃工业设施（棕地）的土壤和地下水在停止使用氯化挥发性有机化合物（VOCs）很久之后仍然受到污染。氯化有机物比水密度大，在地下水位深处造成地下污染。它们的中间副产品被认为是强致癌物，因此对地下水资源构成重大威胁。许多补救策略的成功受到限制，因为很难在地下水位以下的VOC源区域内均匀地引入气相，这对于将VOC转移到流动的气相或提供供污染物降解细菌使用的活性气体（例如氧气，氢气，甲烷）是必要的。拟议研究的总体目标是开发全新的替代方案，以修复受挥发性有机化合物危害的广泛地下环境（例如，地下深处和破裂岩石中的污染）。该研究计划的新颖之处在于使用气过饱和注水（SWI）作为在原位引入流动气相的手段。在这个过程中，气体不是注入的，而是从注入的含有过量溶解气体的水中溶解出来的（类似于打开一罐汽水）。通过在微观（孔隙水平）和宏观（连续体）尺度上的实验和建模的协同作用，我们解决了以下问题。首先，什么机制控制着流动的气泡与土壤和岩石中捕获的VOC团块的相互作用，以及我们如何在实际相关的尺度上通过挥发和/或动员来预测VOC去除的程度？其次，我们如何利用流动气泡和疏水纳米颗粒之间的相互作用来原位产生泡沫，以及如何使用这种泡沫来修复被污染的地下环境？总之，这项研究计划将开发创新技术，可以增加活跃在现场重建领域的加拿大公司的竞争优势。(2)提高SWI过程中的波及效率；(3)控制纳米级零价铁纳米颗粒的就位。我们将通过在1D和2D砂包和岩心中进行实验来补充这些研究，目的是验证具有非平衡相间传质的三相流的连续尺度模型，该模型可以作为设计现场规模测试的工具。拟议的研究计划将整合从单个气液界面尺度（纳米颗粒不可逆吸附过程中的动态表面张力）到孔网络尺度（油节-气泡动力学）到宏观一维和二维域的尺度的实验和建模。它将为2名博士，2名硕士和2名本科生提供hqp培训，为技术领域的发现提供独特的机会，不仅限于土壤修复，还包括提高石油采收率和二氧化碳的地质封存。

Soil and groundwater at abandoned industrial facilities (brown-field sites) in Canada remain contaminated by chlorinated volatile organic compounds (VOCs), long after the use of these chemicals has ceased. Chlorinated organics are denser than water, causing subsurface contamination deep below the water table. Their intermediate by-products are believed to be potent carcinogens and are thus a major threat to groundwater resources. The success of many remediation strategies is limited by the difficulty of introducing a gas phase uniformly within VOC source zones below the water table, as would be necessary for transferring a VOC into the flowing gas phase or for supplying reactive gases (e.g., oxygen, hydrogen, methane) for use by contaminant-degrading bacteria. The overall aim of the proposed research is to develop radically new alternatives to present-day strategies for the remediation of a wide spectrum of subsurface environments (e.g., contamination deep below the water table and in fractured rock) compromised by VOCs. The proposed research program derives its novelty from the use of gas-supersaturated water injection (SWI) as the means for introducing a mobile gas-phase in situ. In this process, gas is not injected but exsolved in situ from injected water that contains an excess of dissolved gas (analogous to opening a can of soda pop). Using a synergy of experimentation and modeling at both the microscopic (pore-level) and macroscopic (continuum) scales, we address the following questions. Firstly, what mechanisms govern the interaction of flowing gas bubbles with VOC blobs trapped within soil and rock and how do we predict the extent of VOC removal by volatilization and/or mobilization at practically relevant scales? Secondly, how do we harness the interactions between flowing bubbles and hydrophobic nanoparticles to generate foam in situ and how can such a foam be used to remediate contaminated subsurface environments? In summary, this research program will develop innovative technologies that could increase the competitive advantage of Canadian companies active in the area of site redevelopment.displace a residual oil phase, (ii) improve sweep efficiency during SWI and (iii) control the emplacement of nano-scale zero-valent iron nanoparticles. We will complement these studies by experiments in 1D and 2D sand packs and rock cores with an aim to validate a continuum-scale model ofthree-phase flow with non-equilibrium inter-phase mass transfer that could serve as a tool for the design offield-scale tests.The proposed research program will integrate experiments and modeling at scales ranging from the scale of asingle gas-liquid interface (dynamic surface tension during irreversible adsorption of nanoparticles) to the porenetwork scale (oil gangion-gas bubble dynamics) to macroscopic 1D and 2D domains. It will provide HQPtraining for 2 PhD, 2MASc and 2 undergraduate co-op students, offering unique opportunities for discoveriesin technological fields not limited to soil remediation, but including enhanced oil recovery and geologicalsequestration of carbon dioxide.