Reaction mechanisms for barite dissolution and growth

Stack, Andrew G.

关键词: Reaction Mechanisms;   

DOI  :  10.2172/1107642
RP-ID  :  DOE-GATECH-15901-3
PID  :  OSTI ID: 1107642

学科分类：地球科学(综合)

美国|英语

来源: SciTech Connect

【 摘 要 】

In Stack and Rustad (2007), the reactive flux method (Rey and Hynes, 1996) and molecular dynamics (MD) were used to simulate the {001} barite-water interface structure and water exchange rate of aqueous barium ions and barium surface species. Atomic-level mineralwater interfacial structure and kinetics are being studied with increasing precision due to advances in spectroscopic methods at synchrotron x-ray sources as well as improved computational capacity. Better characterization of these interfaces in turn is leading to advances in the understanding of many macroscopic geochemical properties. Overall the barite-water interfacial structure was found to compare well to that estimated using X-ray reflectivity (XRR) measurements (Fenter et al., 2001), but there was an important difference: the MD predicted an intricate water structure present at the interface with one major peak and several minor peaks whereas the XRR found only a single layer of water. This discrepancy is thought to result from a limited resolution in the Fenter et al. (2001) study as well as over-coordination of surface sulfates by the MD model.