Experimental and Theoretical Investigations of Fundamental Processes Relevant to Chemical Oxidation of Dense Nonaqueous Phase Liquids in Fractured Rock

项目摘要/摘要本研究的目的是对裂隙岩石系统中氧化还原反应的基本过程进行实验、计算和理论研究，包括自然氧化还原过程和与环境修复相关的过程。我们将重点关注裂缝内圈闭不动流体相的氧化，以及氧化剂通过基质扩散进入岩石基质内的溶解物质/固体矿物相的氧化。反应产物对介质改变的影响，以及对流动和输运性质的相关反馈也将被量化。裂缝内自由相NAPL氧化实验将在Lawrence Livermore国家实验室与Russell Detwiler博士合作进行，在一个非侵入式实验系统中，可以进行高分辨率定量测量，同时可视化氧化的复杂后果，包括MnO2的产生和运输。科罗拉多大学将进行岩石基质中溶解NAPLs化学氧化的实验研究和计算/理论建模，以研究氧化锋通过扩散进入岩石基质的运动以及裂缝-基质相互作用在氧化剂运输中的作用。“反应锋面扩散率”的概念和浓度分布的自相似解将用于发展对反应-扩散锋面的理论认识，并将进行三维模拟以评估基质非均质性的后果。裂缝-基质相互作用对氧化剂传输的影响将在受控的实验室实验中进行研究，并将开发计算模型来预测复杂裂隙岩体中氧化-还原过程的行为。更广泛的影响：教育活动将涉及科罗拉多大学（CU）工程卓越基金的内部赠款（25,000美元，P.I. Rajaram）。这项拨款的目的是使多孔介质的教育实验室现代化，其范围将通过增加反应传输组件而大大增强。侦探本系在环境工程方面设有一个REU网站，通过该网站将招募本科生参与本研究。在项目的后期阶段，将开发一个专门研究断裂岩体中氧化还原反应的教育网站，其中包括有关文献的参考书目、说明基本过程的基本教程、实验结果的动画和可免费下载的简单计算机代码。我们还将与专注于将氧化技术应用于裂隙岩石修复或水质评估的咨询公司发展协同效应。

Project Summary/Abstract The objective of this research is to carry out experimental, computational and theoretical investigations of fundamental processes involved in oxidation-reduction reactions in fractured rock systems, encompassing natural redox processes and processes relevant to environmental remediation. We will focus on oxidation of an entrapped immobile fluid phase within fractures, and oxidation of dissolved species/solid mineral phases within the rock matrix that are accessed by the oxidant via matrix diffusion. The influence of the reaction products on medium alteration, and associated feedback on flow and transport properties will also be quantified. Experiments on oxidation of free-phase NAPL within fractures will be carried out at Lawrence Livermore National Laboratory in collaboration with Dr. Russell Detwiler, in a non-intrusive experimental system where high-resolution quantitative measurements can be performed while visualizing the complex consequences of oxidation, including MnO2 generation and transport. Experimental studies and computational/theoretical modeling of chemical oxidation of dissolved NAPLs in the rock matrix will be carried out at the University of Colorado to investigate the movement of an oxidation front into a rock matrix by diffusion and the role of fracture-matrix interactions in the transport of oxidant. The concept of "reaction front diffusivity" and self-similar solutions for the concentration profiles will be pursued to develop theoretical understanding of reaction-diffusion fronts, and three-dimensional simulations will be pursued to evaluate the consequences of matrix heterogeneity. The influence of fracture-matrix interactions on oxidant transport will be investigated in controlled laboratory experiments and computational models will be developed to predict behavior of oxidation-reduction processes in complex fractured rock masses. Broader Impacts: Educational activities will involve synergy with an internal grant ($25,000, P.I. Rajaram) from the Engineering Excellence Fund at the University of Colorado (CU). The objective of this grant is to modernize the educational laboratories for porous media, and its scope will be greatly enhanced by adding a reactive transport component. The P.I.'s Department hosts a REU site in environmental engineering, through which undergraduate students will be recruited to participate in this research. An educational web site devoted to oxidation-reduction reactions in fractured rock masses will be developed in the later stages of the project, including a bibliography of relevant literature, basic tutorials illustrating fundamental processes, animations of experimental results and simple computer codes that may be downloaded freely. We will also develop synergy with consulting companies focused on applying oxidation technologies in fractured rock sites for remediation or water quality assessment.