Guest editorial
- 作者：Jü ; rg Schweizer ; Mohammed Naaim ; Florence Naaim
- 关键词：Dolomite dissolution rates ; CO2 sequestration ; Kinetics ; Weathering
- 刊名：Cold Regions Science and Technology
- 出版年：2007
- 期刊代码：14_0165232x
- 类别：ear
- 出版时间：November 2007
- 卷：50
- 期：1-3
- 页码：1-2
- 文件大小：84 K
摘要
Steady-state dissolution rates of Haute Vallée de l'Aude dolomite were measured as a function of chemical affinity and aqueous solution composition in mixed-flow reactors at 80 °C. Experiments were performed in HCl–NaHCO3 bearing aqueous solutions with in-situ pH ranging from 6.36 to 7.17. Rates are found to be a strong function of aqueous carbonate concentrations at far-from-equilibrium conditions. Measured rates can be described using the dissolution mechanism of Pokrovsky and Schott [Pokrovsky, O.S., Schott, J., 2001. Kinetics and mechanism of dolomite dissolution in neutral to alkaline solutions revisited. Am. J. Sci., 301, 597–626] where rates are controlled by the detachment of the > MgOH2+ species at the dolomite surface. Within this mechanism, dolomite dissolution rates can be described using
where r refers to the overall BET surface area normalized dolomite dissolution rate at both near and far-from-equilibrium conditions, kMg+ designates a rate constant equal to 4.0 × 10− 12 mol cm− 2 s− 1, KCa
and KCO3 denote equilibrium constants equal to 3.5 × 10− 5 and 4.5 × 10− 5, respectively, ai refers to the activity of the subscripted aqueous species, A corresponds to the chemical affinity of the dissolving dolomite, R represents the gas constant, T symbolizes absolute temperature and n designates a stoichiometric coefficient equal to 1.9.
and KCO3 denote equilibrium constants equal to 3.5 × 10− 5 and 4.5 × 10− 5, respectively, ai refers to the activity of the subscripted aqueous species, A corresponds to the chemical affinity of the dissolving dolomite, R represents the gas constant, T symbolizes absolute temperature and n designates a stoichiometric coefficient equal to 1.9.