Kinetic inhibition of calcite (104) dissolution by aqueous manganese(II)

An atomic force microscopy study of calcite dissolution in saline solutions: The role of magnesium ions

“…Such a strong magnesium-surface interaction and the fact that magnesium can disrupt the surface hydration layer can lead to surface destabilization, and ultimately favor 2D nucleation of etch pits. A similar effect is suggested by Vinson et al (2007) to explain enhanced calcite dissolution in the presence of Mn 2+ , a cation with a hydration enthalpy (À1845 kJ mol À1 ) slightly smaller than that of Mg 2+ (À1921 kJ mol À1 ) but about 14% greater than that of Ca 2+ (À1592 kJ mol À1 ) (Phillips and Williams, 1965). Arvidson et al (2006) also suggest that the differences in hydration enthalpy between Mg 2+ and Ca 2+ ions may explain why enhanced etch pit nucleation occurs in the presence of the former ion.…”

“…The previous effects could be interpreted in terms of Mg 2+ adsorption (physisorption) onto defect-free calcite surfaces and subsequent competition for hydration water between this ion and the water adsorbed onto the calcite surface (Arvidson et al, 2006;Vinson et al, 2007). Molecular dynamics (MD) simulation by Kerisit and Parker (2004) has shown that Mg 2+ is able to attract water molecules from the calcite surface to retain a full coordination shell (i.e., 6 water molecules) once it adsorbs as an innersphere complex directly above a surface carbonate group.…”

Evidence and Potential Implications of Exponential Tails to Concentration Versus Time Plots for the Batch Dissolution of Calcite

“…The inhibition of calcium carbonate dissolution by minor amounts of dissolved metal and other ions has been reported at pHs of about 4 (Erga and Terjesen 1956;Terjesen et al 1961;Nestaas and Terjesen 1969;Svensson and Dreybrodt 1992;Eisenlohr et al 1999;Vinson et al 2007) and 8.9 (Lea et al 2001). Since Erga and Terjesen (1956) reported that the addition of 4 9 10 -5 M EDTA overcame lM copper inhibition in the CaCO 3 -CO 2 -H 2 O system, the effect of EDTA was investigated here.…”

“…(Note that apparent is used here to avoid having to use effective, which is already in use for a different concept.) Success in both of these would have far-reaching consequences, such as facilitating the choice between two rival views of the chemical cause of non-ideal dissolution behaviour: one depending upon the poisoning of the surface (Erga and Terjesen 1956;Terjesen et al 1961;Nestaas and Terjesen 1969;Svensson and Dreybrodt 1992;Dreybrodt et al 1996;Eisenlohr et al 1999;Lea et al 2001;Vinson et al 2007;Morse et al 2007) as dissolution continues, the other upon a change in surface morphology as dissolution continues (Northwood and Lewis 1970;Busenberg and Plummer 1986;Compton et al 1986;Dove et al 2005;Morse et al 2007;Schott et al 2009;Xu et al 2012). The accumulated preliminary evidence for the exponential tails is persuasive.…”

In situ AFM study of the interaction between calcite {101¯4} surfaces and supersaturated Mn2+–CO32− aqueous solutions

“…those which form carbonates with calcite-type structure, being the most efficient as inhibitors of calcite dissolution. Moreover, AFM observations carried out by Lea et al [31] and Vinson et al [32] indicate that the presence of small amounts of Mn 2 + in an aqueous solution can drastically reduce the step-edge migration rates and, if a sufficient amount of coj-is available in the solution, can lead to the virtual stoppage of the calcite dissolution. Such a strong effect is interpreted due to the adsorption of ions onto the surface, followed by a rapid diffusion to specific sites, which are then blocked by them.…”