Nanoparticles formed during mineral-fluid interactions

Mineral-fluid replacement reactions occur ubiquitously throughout the crust of the Earth, often resulting in the formation of nanoparticles. Recent research highlights the formation of nanoparticles¹, especially in the light of mineral/crystal growth by non-classical growth mechanisms, whereby solids form from prenucleation species or clusters within an aqueous solution from which solid nanoparticles precipitate. This is very often related to the dissolution of an existing mineral/solid phase that is coupled at the mineral-fluid interface with the precipitation of a new more stable phase². This process will occur wherever aqueous fluids can penetrate and react with constituent minerals of a rock, that is, along fractures, grain boundaries and initial or reaction-induced interconnected porosity, all potential pathways for fluid-mediated reactions. Examples given here highlight fluid pathways and subsequent nanoparticle formation, an understanding of which can be useful for potential environmental remediation strategies, such as carbon mineralization and toxic element sequestration. Recent advances in analytical techniques, such as advances in atomic force microscopy, advanced scanning and transmission microscopies, are enabling the imaging of nanoparticles. Examples presented illustrate the conditions under which nanoparticles form during the coupling of dissolution and precipitation and enable a better understanding of the mechanisms that drive fluid-mineral reactions.

References

¹Putnis C.V. and Ruiz-Agudo E. 2021. Nanoparticles formed during mineral-fluid interactions. Chem. Geol. 586, 120614.

²Ruiz-Agudo E., Putnis C.V., Putnis A. 2014. Coupled dissolution and precipitation at mineral-fluid interfaces. Chem. Geol., 383, 132-146.