Molecular-scale understanding of crystallographic controlled anisotropic dissolution of albite in sulfate solution

Full understanding of the anisotropic interfacial reactions between albite (NaAlSi3O8) and sulfate-rich solutions is crucial for predicting the stability of minerals in both natural and engineered systems. However, the regulatory role of mineral surface orientation on reaction pathways at the atomic scale remains unclear. This study employs reactive molecular dynamics (ReaxFF MD) simulations to systematically investigate the kinetic behaviors of the interfacial reactions between albite (100), (010), and (001) surfaces and sulfate solution. The results reveal significant anisotropic effects among the different surfaces: the (001) surface exhibits the highest reactivity due to its high surface energy, which leads to the surface structural disordering as well as the leaching of Na+ mediated by ion exchange and sulfate coordination. In contrast, the (100) surface maintains structural stability through a dense hydrogen bond network and Na+ shielding effects, while the (010) surface structure facilitates the formation of silanols, inhibiting ion migration.