PNNL

Abstract

Atomic force microscopy (AFM) has been used to study dissolution of the cleaved CaCO3(1014) surface in clean and impurity containing aqueous environments. In the clean solution, dissolution was found to occur by retreat of steps and creation of rhombohedral pits on a surface. Dissolution is anisotropic with two different step velocities differing by a factor of 2.3, resulting from different atomic step structures. Dissolution is partially changed after adding impurities in the solution via rounding of the fastest dissolution corner of rhombohedral pits and slowing down the step velocity in that direciton. The role of impurity on dissolution is discussed in terms of preferential adsorption of impurities on kink sites.