The Inhibiting Effect of Scandium Ions upon the Dissolution of Calcium Carbonate.

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.…”

How do mineral coatings affect dissolution rates? An experimental study of coupled CaCO3 dissolution—CdCO3 precipitation

“…For example, the effect of aqueous Mg 2ϩ , Ca 2ϩ , phosphates, or sulphates on calcite dissolution has been studied by Sjöberg (1978), Berner (1967Berner ( , 1975Berner ( , 1978, Berner and Morse (1974), Nancollas et al (1981), Reddy and Wang (1980), Mucci (1986), Buhmann and Dreybrodt (1987), Mucci et al (1989), Alkattan et al (2002). Several other studies have focused on the effect of transition and heavy metal adsorption on calcite dissolution (Terjesen et al, 1961;Nestaas and Terjesen, 1969;Salem et al, 1994;Gutjahr et al, 1996b). The results of these were generally interpreted using some type of reversible surface model such as the Langmuir-Volmer model (e.g., Gutjahr et al, 1996b).…”

“…These studies have focused largely on calcite because it is the most common of the carbonates; they include measurements of distribution coefficients in co-precipitation reactions (Lorens, 1981;Königsberger et al, 1991;Reeder, 1996;Tesoreiro and Pankow, 1996;Prieto et al, 1997;Fernández-González et al, 1999), the effect of metal ions on carbonate dissolution kinetics (Terjesen et al, 1961;Nestaas and Terjesen, 1969;Salem et al, 1994;Gutjahr et al, 1996b;Alkattan et al, 2002), and sorption studies (McBride, 1980;Kornicker et al, 1985;Davis et al, 1987;Fuller and Davis, 1987;Zachara et al, 1991;Stipp et al, 1992;Chiarello et al, 1997, Martin-Garin et al, 2003. A number of recent publications have focused on aqueous Cd-carbonate interaction, because the adsorption or precipitation of Cd may be an effective way to remove this contaminant from polluted water (Wang and Reardon, 2001;García-Sanchez and Álvarez-Ayuso, 2002).…”

The reactions of cadmium with calcium carbonate surfaces

“…The pH was measured by using a Radiometer Copenhagen Ion 85-Ion Analyser with a GK 2401 B combined electrode and NBS buffers. Cd and Ca determinations were made by AAS using a Perkin-Elmer 3030 spectrophotometer for metal concentrations above 0.01 pg ml-', and with a HGA 500 graphite furnace and autosampler for lower concentrations (Papadopoulos, 1985). Free metal activities were computed from the association constants for metal complexes and the Davies equation.…”