[M-IS12] 結晶成長、溶解における界面・ナノ現象

[MIS12-P05] 溶解/成長する炭酸カルシウム近傍におけるpH変化の可視化の試み

*川野 潤¹、豊福 高志²、長井 裕季子²、河田 佐知子²、板垣 璃沙¹、永井 隆哉¹ (1.北海道大学大学院 理学研究院、2.海洋研究開発機構)

キーワード：炭酸カルシウム、溶解、pH

For the investigation of the growth and dissolution of calcium carbonate, CaCO₃, it is important to understand how carbonate and bicarbonate ions behave in these processes. The pH monitoring of a solution during CaCO₃ growth or dissolution is a useful technique for this purpose, and actually in a number of the previous studies, the pH measurements of bulk solution during the growth have been performed. However, to clarify the detail process on the surface, especially the behavior of bicarbonate ions, regional change of pH just above the crystal surface should be monitored. Recently, we have started an attempt to visualize the distribution of pH around CaCO₃ crystals which inorganically grows or dissolves, by applying the method used for the research on the biogenic calcification of foraminifers. We have succeeded to detect the pH change near a dissolved calcite surface, which may provide new insights into both inorganic and biogenic formation mechanism of CaCO₃.