Redefining Surface Area: Understanding Reactive Interfaces in Heterogeneous Porous Media

重新定义表面积：了解非均质多孔介质中的反应界面天然地下的生物地球化学反应速率通常由不同性质和条件的流体和固体相遇的“热”反应界面的反应速率控制。这些界面通常被限制在相对小的、尖锐的区域，其速率比其他区域高几个数量级。该项目的研究成果将对能源、水和环境关系的广泛应用具有重要意义。特别是，他们将促进对页岩气开发、酸性矿井排水、核废料处理、地质二氧化碳封存、地热能和污染物运输等重要的物理、化学和生物过程的理解和预测。对地球系统的基本理解，包括人类居住的关键地带，对于土壤肥力和生产力、水的可持续性和能源安全也至关重要，所有这些都受到气候变化和人类世激烈的人类活动的影响。在这项研究中，研究者假设反应界面的出现和性质是由空间非均质性、多孔介质性质和条件的空间变化所决定的。这些反应性接口最终控制大规模流程和系统功能。虽然在过去的几十年里，水文学家已经记录了物理非均质性对流体流动和溶质运输的重大影响，但目前对物理和地球化学非均质性在决定（生物）地球化学过程中的作用的理解还没有跟上。研究者建议理解控制反应性接口的发生和功能的基本原则。最终目标是发展地球化学过程的概念和预测框架在自然，非均质地下。提出的工作将整合二维流动通过实验和多尺度反应输运建模。二维流动池将使用方解石、绿泥石和石英进行填充，这些矿物的反应性差异很大，在自然系统中无处不在。理解反应性接口将使跨尺度统一观察迈出重要的一步。教育和推广计划的目标是，以超越时间、空间和个别学科限制的方式，为科学界和公众提供工具和教育。研究者建议(1)开发一个以“异质性”为重点的在线模块，作为宾夕法尼亚州立大学世界校区急需的在线反应传输建模（RTM）课程的一部分；(2)建立资源库网站，组织在线教材，向公众免费开放；(3)通过为代表性不足的高中生提供“水流过岩石”的暑期研究机会，促进多样性和环境意识。该计划将为社区提供环境管理、水资源管理以及自然资源保护和可持续利用方面的知识和预测工具。

Redefining Surface Area: Understanding Reactive Interfaces in Heterogeneous Porous MediaBiogeochemical reaction rates in the natural subsurface are typically controlled by those at the "hot" reactive interfaces where fluids and solids of different properties and conditions meet. These interfaces are often restricted to relatively small, sharp zones with rates orders of magnitude higher than those at the rest of the domain. The research outcomes from this project will be important for a broad spectrum of applications at the nexus of energy, water, and environment. In particular, they will advance understanding and predicting of physical, chemical, and biological processes important for shale gas development, acid mine drainage, nuclear waste disposal, geological CO2 sequestration, geothermal energy, and contaminant transport. Fundamental understanding of the earth systems, including the Critical Zone where humans live, is also essential for soil fertility and productivity, water sustainability, and energy security, all of which are subject to climate change and intense human activities in the Anthropocene.In this study the investigator hypothesizes that the emergence and nature of reactive interfaces are dictated by spatial heterogeneities, the spatial variations in porous medium properties and conditions. These reactive interfaces ultimately govern large scale processes and system functioning. Whereas hydrologists have documented significant impacts of physical heterogeneities on fluid flow and solute transport in the past decades, present understanding on the role of physical and geochemical heterogeneities in determining (bio)geochemical processes has not kept pace. The investigator proposes to understand fundamental principles that govern the occurrence and functioning of reactive interfaces. The ultimate goal is to develop conceptual and predictive framework for geochemical processes in natural, heterogeneous subsurface. The proposed work will integrate two-dimensional flow-through experiments and multi-scale reactive transport modeling. The 2D flow cells will be packed using calcite, chlorite, and quartz-minerals that differ drastically in reactivity and are ubiquitous in natural systems. Understanding reactive interfaces will enable a significant step toward unifying observations across scales. The goal of the education and outreach plan is to empower the science community and general public with tools and education in ways that transcend limits of time, space, and individual disciplines. The investigator proposes to (1) develop an online module with a "heterogeneity" focus as part of a much-needed online reactive transport modeling (RTM) course for delivery through Penn State's World Campus; (2) develop a repository website that organizes the online teaching materials for free access to the public; (3) promote diversity and environmental awareness by offering underrepresented high school students a summer research opportunity on "Water flow through rocks". The plan will equip the community with knowledge and predictive tools for environmental stewardship, water management, as well as protection and sustainable use of natural resources.