Correlation between Wettability and Dissolution of Calcite in Ion-Free Water

Calcite, a prevalent mineral in the earth's crust, plays a pivotal role in various geological and industrial processes, including carbon sequestration, water treatment, and enhanced oil recovery. Understanding how wettability (a crucial surface property influenced by the interaction between calcite and surrounding fluids) affects calcite's dissolution is essential for optimizing these processes. We conducted a series of experiments to study the wettability and its relation to calcite dissolution of an atomically flat calcite surface under deionized water. This system provides a simple environment that allows us to study the wettability alteration in the absence of external ions except the one generated during the dissolution process. Using macroscopic, microscopic, and nanoscopic analytical techniques, we observed that surface evolution progresses from the initial formation of chemical heterogeneities to the gradual growth of a surface water layer strongly bonded to the calcite surface on the time scale of hours as the system reaches an equilibrium state. We also show that the surface evolution is directly related to the calcite dissolution, and it depends on the degree of solution saturation. This research not only sheds light on fundamental aspects of calcite behavior in aqueous solutions but also establishes a foundation for future studies aiming to manipulate mineral surfaces for enhanced performance in their respective applications.