Nanoparticles and Nanofluids in Water–Rock Interactions

Resumo

The paper presents a concise review of published information on nanogeochemistry, a new field of geochemistry that deals with particles and fluids of small size (<100 nm). The properties of these particles and fluids differ from those of their larger analogues because of the greater contributions of their surface energy. The paper discusses the conditions, forms, and mechanisms of their origin and evolution and presents examples illustrating how the properties of nanoparticles and nanofluids (their solubility and stability, melting temperature, inner pressure, surface charge and adsorption, evaporation rate, and chemical reactions and transport) depend on their size. It is demonstrated that concave and convex surfaces differently affect theses properties. Nanoparticles and nanofluids are widespread in nature and can thus affect various geochemical processes. Nanoparticles can adsorb heavy metals and are the dominant mode of their transport in natural waters. Nanofluids (nanopores) control processes of diagenesis, metasomatic replacement, weathering, and gas migration in shales. Even if contained in minor concentrations, nanoparticles can principally change the behavior of macrosystems. The paper presents a review of the main research avenues pursued by nanogeochemistry.