|
|||||
|
|
Reaction pathways for quartz dissolution determined by statistical and graphical analysis of macroscopic experimental data |
|
| Authors: | Barry R Bickmore Justin C Wheeler Kathryn L Nagy |
| Institution: | a Department of Geological Sciences, Brigham Young University, Provo, UT 84602, USA b Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA c Department of Earth and Environmental Sciences, University of Illinois at Chicago (MC-186), 845 West Taylor Street, Chicago, IL 60607-7059, USA d Center for Statistical Consultation and Collaborative Research, Department of Statistics, Brigham Young University, Provo, UT 84602, USA |
| Abstract: | In light of recent work on the reactivity of specific sites on large (hydr)oxo-molecules and the evolution of surface topography during dissolution, we examined the ability to extract molecular-scale reaction pathways from macroscopic dissolution and surface charge measurements of powdered minerals using an approach that involved regression of multiple datasets and statistical graphical analysis of model fits. The test case (far-from-equilibrium quartz dissolution from 25 to 300 °C, pH 1-12, in solutions with Na+] ? 0.5 M) avoids the objections to this goal raised in these recent studies. The strategy was used to assess several mechanistic rate laws, and was more powerful in distinguishing between models than the statistical approaches employed previously. The best-fit model included three mechanisms—two involving hydrolysis of Si centers by H2O next to neutral (>Si-OH0) and deprotonated (>Si-O−) silanol groups, and one involving hydrolysis of Si centers by OH−. The model rate law is |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ | |