In situ heterogeneous nucleation of CaCO3 on quartz was investigated at different salinities. The salinities (represented by ionic strengths) were tuned with NaCl and ranged from 0.15 M to 0.85 M. Through analyses of nucleation rates at different supersaturations, we obtained the effective interfacial energy (α) controlling the nucleation process for each salinity. Using the thermodynamic parameters for calcite, α was ~10 mJ/m2 lower for high salinity systems than for low ones, due to the lower water-CaCO3 and CaCO3-quartz interfacial energies in high salinity systems. On the other hand, the kinetic factor in the nucleation rate equation was lower in high salinity systems, and this reduction can account for observed nucleation rates an order of magnitude slower than rates predicted solely by thermodynamic (i.e., interfacial energy) variations. New information provided by this study can help predict and improve system operations such as membrane fouling control, pipeline scaling control, mineral trapping of pollutants, and material synthesis.

Heterogeneous calcium carbonate nucleation in saline solution:  Thermodynamic and kinetic contributions

251st National Meeting (2016)

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