The apparent activation energy and pre-exponential kinetic factor for heterogeneous calcium carbonate nucleation on quartz

Journal Article · Wed Sep 19 00:00:00 EDT 2018 · Communications Chemistry

DOI:https://doi.org/10.1038/s42004-018-0056-5· OSTI ID:1470578

Li, Qingyun; Jun, Young-Shin

Abstract Nucleation occurs widely in materials synthesis and natural environments. However, in the nucleation rate equation, values for the apparent activation energy ( E _a ) and the pre-exponential kinetic factor ( A ) are thus far unknown because real-time nanoscale observations are difficult to perform. Here we experimentally determine E _a and A using heterogeneous calcium carbonate nucleation on quartz as a model system. Nucleation rates are measured with in situ grazing incidence small-angle X-ray scattering and ex situ atomic force microscopy, and the experiments are conducted with a fixed supersaturation of IAP/ K _sp (calc)  = 10 ^1.65 at 12, 25, and 31 °C. E _a is calculated as 45 ± 7 kJ mol ⁻¹ , and A is 10 ^{12.0 ± 1.1} nuclei μm ⁻²  min ⁻¹ , or 10 ^{2.9 ± 1.3}  mol m ⁻²  min ⁻¹ . Increasing the temperature shortens the induction time, but does not change nucleus sizes. These parameter values are critical for predicting and controlling the nucleation of materials.

• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-05CH11231; AC02-06CH11357
• OSTI ID: 1470578
• Journal Information: Communications Chemistry, Journal Name: Communications Chemistry Vol. 1 Journal Issue: 1; ISSN 2399-3669
• Publisher: Nature Publishing Group
• Country of Publication: United Kingdom
• Language: English