In-situ Atomic Force Microscopy study of etch-pits mediated olivine dissolution
Olivine [Mg, Fe]2SiO4 is a promising material for Carbon Capture and Storage (CCS) technologies, as it naturally undergoes chemical weathering. Olivine dissolution produces cations [1] that subsequently react. In this multiscale process, the dissolution rate is determined by dynamic phenomena at the microscopic scale of the crystal facets, where much remains to be understood. In-situ Atomic Force Microscopy is a well-suited technique for monitoring the mineral interface while the dissolution reaction is happening [2]. Etch pits form during dissolution, connected to the crystallographic plane and the reactive fluid composition. Understanding the connection between the pit parameters and the reaction process can reveal pathways towards enhanced olivine dissolution.
Research objectives
In this project, you will dissolve polished olivine pebbles in acidic solutions while looking at them with AFM. Post-processing of the image data will provide quantitative information about the time-dependent geometry on the dissolving crystal facet [3]. Your task will be to evaluate the mineral’s response to different electrolytes and temperatures. Fluid exchange, injection of additives and temperature ramps will serve as ‘control knobs’ to learn more about the mechanisms that govern the evolution of the facet architecture.
Learning Objectives
Outside of the common objectives for a BSc project, you will learn how to perform AFM experiments and use complementary techniques (Raman Spectroscopy, and/or Scanning Electron Microscopy) to study a mineral interface. Data analysis and interpretation will involve the use of relevant software (MATLAB, Python, Gwyddion, Vesta.exe) to examine etch pits changes and the correlation to the material’s structure.
H2SO4 HCl H2SO4+OA
[1]: E.H. Oelkers et al., Chemical Geology 2018 (review on olivine dissolution)
[2]: X. Li et al., Applied Surface Science 2021 (AFM to analyse olivine dissolution)
Daily supervision: Vincenzo Alagia
Promotor: Igor Sîretanu