Mechanisms of Barium Sulfate Dissolution through the Lens of Kinetic Monte Carlo Simulations.

The prediction of crystalline matter dissolution kinetics is one of the main focuses in environmental science, civil engineering, chemical kinetics, synthesis, drug delivery, and other scientific and industrial fields. Our ability to predict the temporal dynamics of material fluxes is crucial for designing crystalline materials and controlling the behavior of chemical systems for various applications. The critical question is, do these dynamics have deterministic or stochastic features, or should we expect a constant, oscillatory, or completely random temporal behavior from a predefined crystalline structure? Our study is dedicated to barium sulfate (barite), which is considered one of the primary backfilling materials for nuclear waste repositories. We developed a new parametrized Kinetic Monte Carlo (kMC) model, which allows us to simulate the temporal evolution of the system. We have found that material flux oscillates quasiperiodically over time, indicating the presence of deterministic and stochastic components. This raises the question of whether it can be predicted in principle. Our observations cover the mechanistic and kinetic behavior of the Barite-water system and can be applied to studies of other solid-liquid interfaces.