R4: Mineral sciences of the Earth surface

[R4-05] Investigation on the crystal growth/dissolution mechanisms by using the 2-D visualization technique with fluorescent probes

*Jun Kawano¹, Makoto Yazaki¹, Takashi Toyofuku^2,3, Yukiko Nagai^2,4, Henry Teng⁵, Takaya Nagai¹ (1. Hokkaido Univ. , 2. JAMSTEC, 3. TUMSAT, 4. NMNS, 5. Tianjin Univ.)

Keywords:dissolution, diffusion, fluorescent probe , imaging, calcium carbonate

In the present study, we investigated the crystal dissolution mechanism in aqueous solution by using the visualization technique with the fluorescent probes. Temporal pH changes around the surface of a dissolving CaCO₃ crystal calculated by the Fick’s low resemble measurements when the diffusion coefficient D = 1 × 10^-6 cm²/s. This value is smaller by an order of magnitude than those for OH, which indicates that this process is a surface reaction-, rather than transport-, controlled process.