Nucleation of nanoparticles is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces that provide remarkable reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, and a better understanding of nucleation of nanoparticles will enable a sustainable synthetic process in engineered systems. In this talk, I will introduce our recent in situ kinetic study of the heterogeneous nucleation of calcium carbonate on quartz in aqueous systems. To investigate the size and total particle volume of heterogeneously formed CaCO3 nanoparticles in situ and in real-time, we utilized grazing incidence small-angle X-ray scattering (GISAXS). Using this technique, we analyzed the nucleation rates and obtained interfacial energies (thermodynamic information) between nuclei and surfaces and their nucleation kinetic factor. To support and complement our findings, atomic force microscopy (AFM) was also utilized. The findings, significantly enhanced by in situ observations, can lead to a more accurate quantitative prediction of the behaviors of nanoparticles in the environment and enable better control of the physico-chemical properties of nanoparticles and their occurrence in engineered systems.

In situ detection of heterogeneous nucleation of CaCO3 nanoparticles at environmental interfaces

256th National Meeting (2018)

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