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Variability of dissolution rates at constant undersaturation.
Malvina G Orkoula1, Petros G Koutsoukos
1Department of Chemical Engineering, University of Patras, Patras, Greece.
Journal of Colloid and Interface Science
|November 18, 2005
Summary
Marble dissolution rates decrease significantly over time, even under constant conditions. This reduction is linked to surface changes, not solution chemistry or particle size, impacting weathering studies.
Area of Science:
- Geochemistry
- Materials Science
- Environmental Science
Background:
- Marble weathering is significantly influenced by dissolution processes.
- Understanding the kinetics of marble dissolution is crucial for conservation and geological studies.
Purpose of the Study:
- To investigate the dissolution kinetics of powdered Pentelic marble.
- To determine the factors influencing the rate of marble dissolution over time.
Main Methods:
- Experimental investigation of dissolution rates of powdered Pentelic marble under constant undersaturation.
- Monitoring mass loss and dissolution rate over time.
- Analysis of surface area and physical characteristics of particles.
Main Results:
- Dissolution rates decreased sharply to approximately 50% of the initial value before 5% mass loss.
- Rates stabilized at 20-25% of the initial value after 25% mass loss.
- Rate reduction correlated with decreased surface area, suggesting active site dependence, and was independent of solution undersaturation or particle characteristics.
Conclusions:
- Marble dissolution rates are not constant and decrease significantly as the process progresses.
- The reduction in dissolution rate is primarily controlled by changes in the reactive surface area and active sites, rather than solution conditions or particle properties.
- These findings are critical for accurate modeling of marble weathering and stone decay.