Structure and ordering of water and ions at the quartz/water interface play a key role in ions adsorption and subsequent heterogeneous nucleation of crystals. Here, we will first show preliminary results on <i>in situ </i>nucleation study of barite (BaSO<sub>4</sub>) in flow-through silica tubes by optical microscopy. We will investigate the effect of solution chemistry (saturation index, pH, and cation to anion ratio) on the heterogeneous nucleation kinetics of barite crystals. Previous work has shown that ion adsorption [1], or perhaps ion pair formation [2], are key parameters affecting the rate of heterogeneous nucleation. However, current computational models show discrepancies on quartz/water interfacial structures as predicted by X-ray reflectivity, limiting their predictive capabilities to understand nucleation reaction mechanisms [3-4]. We will further investigate the molecular-scale quartz/water structures by density functional tight biding (DFTB) calculations. DFTB uses pre-calculated parameters from DFT calculations to enable simulations of systems in larger sizes and longer time-scales. The combination of experimental and computational methods will provide new insights into the mechanism of heterogenous nucleation at the quartz/water interface.

Understanding interfacial structure and nucleation at the quartz/water interface by optical microscopy and DFTB simulations

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.