Inhibiting Effects of Trace Amounts of Lanthanum Ion on the Dissolution of Calcite: A Comparative Study on Calcium Carbonate Polymorphs

A significant inhibiting effect was observed on the dissolution of calcite by addition of 5 μM lanthanum ion to the solution, whereas no inhibition was observed both for aragonite and vaterite under the same conditions. In situ AFM (atomic force microscopy) images suggested that micro-precipitates depositing at the step site of calcite inhibited the dissolution in the lanthanum-doped solution. The solubility-calculation for the given solution was consistent with lanthanum carbonate being the micro-precipitate.