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O: Fachverband Oberflächenphysik

O 36: Focus Session: Mineral-water interfaces II

O 36.4: Hauptvortrag

Dienstag, 10. März 2026, 11:30–12:00, HSZ/0403

Living Interfaces: Dissolution and Precipitation Processes at Mineral-Brine Interfaces Revealed by AFM — •Igor Siretanu, Vincenzo Alagia, Saravana Kumar, Shilpa Mohanakumar, Max Nederstigt, Chinmay Shukla, Michel Duits, and Frieder Mugele — Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

Mineral-brine interfaces are dynamic systems where dissolution and precipitation govern reactivity and morphology. Using in-situ Atomic Force Microscopy (AFM), we examine olivine ([Mg,Fe]2SiO4) and calcite. Olivine, a candidate for carbon mineralization, shows etch-pit-mediated surface retraction with morphology strongly dependent on solution chemistry. In H2SO4, pits are larger and deeper than in HCl, while oxalic acid induces anisotropic complexation, forming rectangular pits and stepped terraces aligned with crystallographic directions. These changes accelerate step retreat and Mg release, offering mechanistic insight into dissolution kinetics relevant for CO2 sequestration. At calcite-water interfaces near equilibrium, AFM force spectroscopy reveals two regimes: (A) DLVO-type forces with low surface potentials (<5 mV) and (B) long-range viscoelastic repulsion from a soft interfacial layer formed by coupled dissolution-precipitation. This dynamic interphase explains inconsistencies in reported surface forces and highlights how solution composition, crystallography, and transient phases control mineral reactivity, with implications for geochemistry, biomineralization, and carbon capture.

Keywords: Atomic Force Microscopy; Calcite interfaces; Olivine dissolution; Mineral–brine interactions; Carbon mineralization