CAREER: Quantifying evolution of accessible mineral surface areas and pore connectivity for improved simulation of mineral reaction rates

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Chemical reactions are an important part of natural subsurface environments, and this includes natural rock weathering, contaminant movement and breakdown, and industrial processes such as carbon dioxide storage, hydraulic fracturing, and radioactive waste disposal. Many of these processes occur in aquifers and the way that porosity, permeability, and rock surface chemistry change over time is crucial to predicting how contaminants move or the quality of water changes. Computer simulations are often used to help understand how soils and aquifers change over years and centuries but simulation is difficult because measurements of reaction rate in the laboratory are so different from measurements in nature and the reason is not clear. The proposed project will seek to reconcile these differences by using advanced imaging methods, laboratory rock weathering experiments, and computer simulations. This will help us simulate and better understand such processes as contaminant fate, carbon dioxide sequestration, the dissolution and precipitation of minerals, and changes in water quality. The project supports a diverse group of undergraduate and graduate students who will be engaged to help increase interest in STEM fields in K- 12 students through involvement in outreach activities and the Auburn University OutCELL educational programs. The long-term research goal is to enhance understanding and simulation of the rate, extent, and impact of mineral dissolution and precipitation reactions in subsurface systems to better predict flow and transport in these systems, enabling improved risk and impact assessment. As a step towards this goal, the research objective of this CAREER proposal is to test the hypothesis that mineral reaction rates and permeability evolution are a function of mineral accessible surface areas, porosity and pore connectivity. The approach will be to carry out core scale laboratory dissolution experiments, use imaging methods to measure the reactive evolution of accessible mineral surface area, porosity, and pore connectivity, and integrate imaging observations into reactive transport simulations of dissolution experiments. My long-term educational goal is to equip students with the knowledge and skills to assess fate and transport in environmental systems and develop and implement solutions to environmental problems. In pursuit of this goal, the educational objective of this proposal is to increase understanding and awareness of K-12, undergraduate and graduate students of water-rock interactions in environmental systems. The educational approach is to expand K-12 awareness through demonstrations at the Auburn student-led OutCELL facility, develop new undergraduate/graduate course materials, and establish a permanent interdisciplinary student seminar series. The outreach objective of this proposal is to broaden interest and participation in STEM fields by initiating interest at the K-12 level through OutCELL and summer camps and support continued interest at the undergraduate and graduate levels through participation in outreach, mentoring, and research activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.