Rozalen(eの頭に´),M.L., Huertas,F.J., Brady,P.V., Cama,J., Garcia(iの頭は´)-Palma,S. and Linares,J.(2008): Experimental study of the effect of pH on the kinetics of montmorillonite dissolution at 25℃. Geochimica et Cosmochimica Acta, 72, 4224-4253.

『25℃におけるモンモリロナイト溶解のカイネティックスに与えるpHの影響についての実験的研究』


Abstract
 The effect of pH on the kinetics of smectite (K-montmorillonite) dissolution was investigated at 25℃ in batch and stirred flow-through reactors over the pH range of 1-13.5, in KNO3 solutions. Dissolution rates were obtained based on the release of Si and Al at steady-state under far from equilibrium conditions. Dissolution was non-stoichiometric between pH 5 and 10, due to adsorption/precipitation of Al. Dissolution rates computed from batch and flow-through experiments were consistent, irrespective of the Si and Al concentrations. Sample pre-treatment and the interlayer cation do not affect the steady-state dissolution rate or stoichiometry of cation release. The rate dependence on pH can be described by:
 R (mol m-2 s-1) = 10-12.30aH+0.40 + 10-14.37 + 10-13.05aOH-0.27
The experimental results are consistent with a dissolution mechanism involving inward movement of a dissolution front from crystal edges. Consequently, normalization of the dissolution rates should take into account the reactive surface located on the smectite edges.』

1. Introduction
2. Materials and methods
 2.1. Characterization of the montmorillonite
 2.2. Experimental design
  2.2.1. Flow-through experiments
  2.2.2. Batch experiments
 2.3. Kinetics calculations
3. Results
 3.1. Flow-through experiments
 3.2. Batch experiments
4. Discussion
 4.1. Initial dissolution and sample preconditioning
 4.2. Stoichiometry
 4.3. saturation state of the solutions
 4.4. Dissolution rates
 4.5. Surface area and reactivity
5. Conclusions
Acknowledgements
Appendix A
Appendix B
References



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