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”反应界面处的反应速率控制。这些接口往往被限制在相对较小的，尖锐的区域与率的数量级高于其余的域。该项目的研究成果对于能源，水和环境的广泛应用至关重要。特别是，他们将推进对页岩气开发，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。对地球系统的基本了解，包括人类生活的关键地带，对于土壤肥力和生产力，水的可持续性和能源安全也是至关重要的，所有这些都受到气候变化和人类世强烈活动的影响。在这项研究中，研究人员假设反应界面的出现和性质是由空间异质性决定的，多孔介质性质和条件的空间变化。这些反应界面最终控制大规模过程和系统功能。虽然水文学家在过去的几十年中记录了流体流动和溶质运移的物理非均质性的显着影响，目前的理解的物理和地球化学的非均质性在确定（生物）地球化学过程的作用没有跟上。研究人员建议了解控制反应界面的发生和功能的基本原则。最终目标是为自然非均质地下的地球化学过程建立概念性和预测性框架。拟议的工作将整合二维流通实验和多尺度反应传输建模。2D流动池将使用方解石、方解石和石英矿物进行包装，这些矿物的反应性差异很大，在自然系统中无处不在。理解反应界面将使跨尺度统一观测迈出重要一步。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，向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，作为急需的在线反应性运输建模（RTM）课程的一部分，通过宾夕法尼亚州立大学的世界校园提供;（2）开发一个存储库网站，组织在线教学材料，供公众免费访问;（3）为代表性不足的高中生提供一个暑期研究机会，以促进多元化和环保意识。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.