Kinetics of Calcite Dissolution as Affected by Carbon Dioxide Partial Pressure
1985
Amrhein, C. | Jurinak, J. J. | Moore, W. M.
Research was conducted to determine the effect of CO₂ on the kinetics of soil mineral dissolution. It was found that in soils or overburden materials in which CaCO₃ is the dominant weatherable mineral, the kinetics of dissolution was not a simple diffusion controlled or first-order reaction. In these calcareous systems, the transfer of atmospheric CO₂ to solution was an important rate limiting step in the kinetics of dissolution. At higher PCO₂ values the dissolution of calcite was modeled by three simultaneous reactions on the surface of the calcite. It is postulated that the CO₂ attack consists of an adsorption of CO₂(aq) on the calcite surface followed by hydrolysis of the CO₂ to H₂CO₃. The hydrolysis is apparently catalyzed by the calcite surface because the aqueous hydrolysis, CO₂(aq) + H₂O → H₂CO₃, occurs too slowly for the observed rate of reaction.
显示更多 [+] 显示较少 [-]