Measuring mineral dissolution kinetics using on-line flow-through time resolved analysis (FT-TRA) : an exploratory study with forsterite
department or school: Earth, Ocean and Atmospheric Sciences, Department of
department or school: Science, Faculty of
data provider: DSpace
identifier citation: B. De Baere et al. / Chemical Geology 413 (2015) 107–118
rights copyright: Elsevier
creator: De Baere, Bart
creator: François, Roger
creator: Mayer, K. Ulrich
issued: 2015-10-24T02:34:14
issued: 2015-09
description: We explore the applicability of on-line flow-through time-resolved analysis (FT-TRA) to measure mineral dissolution rates, determine dissolution rate parameters, and monitor dissolution stoichiometry under both constant and transient eluent conditions. A custom-built automated flow-through system is used to subject mineral samples to controlled eluent flows of constant or varying composition, and the dissolution products aremeasured online with a quadrupole ICP–MS. Because forsterite dissolution has been extensively studied, this mineral provides an ideal benchmark to test the approach. FT-TRA has several advantages compared to the mixed-flow reactors conventionally used to measure mineral dissolution. The mineral dissolution regime (surface vs transport-controlled) can be readily established prior to conducting dissolution experiments, which is important if the goal of the experiment is to determine dissolution rate parameters. Because of the small volume (25 μL) of the flow-through reactor, the time to reach steady state concentration in the effluent is shorter and is limited by the intrinsic properties of the mineral, instead of the residence time of the effluent in the reactor. For minerals reaching steady-state dissolution rapidly, dissolution rate parameters (rate constant(s) and reaction order(s)) are established in a fewhours, allowing for replications, statistical analysis of the results, and investigation of the underlying causes of variability. The experimental set-up can be adapted for minerals that require longer periods of time to reach steady-state dissolution. In addition, FTTRA lends itself particularlywell for detailed monitoring of dissolution rates and dissolution stoichiometry under transient conditions. For forsterite dissolution under acidic conditions, preferential release ofMg when pH transits to lower values, and preferential release of Siwhen pH transits to higher values is clearly documented and can be interpreted as indicating changes in…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/54819
note: ngs07 MReceived in revised form 22 August 2015Accepted 26 August 2015Available online 2 September 2015Keywords:Mineral dissolutionDissolution rateForsteriteFlow-through dissolutionStoichiometryExfoliationtransient eluent con-ion kinetics have beenudies (Rimstidt et al.,s the results obtainedChemical Geology 413 (2015) 107–118Contents lists available at ScienceDirectChemicall seble of rapidly generating data on mineral dissolution rates would bebeneficial to study the factors underpinning the variability of this pro-cess and to better constrain random errors. Likewise, methods provid-with the new approach. In addition, its dissolution rate below pH 6 isrelatively rapid and controlled by the activity of protons, resulting in asimple linear relationship between the logarithm of the surface normal-solution rates measured in different laboratories can differ by severalorders of magnitude (e.g. Rimstidt et al., 2012), and this problem iscompounded by the fact thatmethods used tomeasuremineral dissolu-tion rates tend to be labor intensive and time consuming.Methods capa-lution rate and stoichiometry under constant andditions. Forsteritewas chosen because its dissolutwell characterized in a number of laboratory st2012), providing a robust benchmark to assesAccurate determination of mineral dissolution rates over a widerange of conditions (pH, temperature, pCO2, etc.) is essential to investi-gate a wide variety of environmental processes. However, mineral dis-controlling mineral dissolution. This study uses forsterite to explorethe applicability of “flow-through time resolved analysis” (FT-TRA)with on-line measurement of dissolution products by inductivelycoupled plasmamass spectrometry (ICP–MS) tomeasuremineral disso-ing information on dissolution rate and sto⁎ Corresponding author.E-mail addresses: b.debaere@alumni.ubc.ca (B. De Bae(R. François), umayer@eos.ubc.ca (K.U. Mayer).http://dx.doi.org/10.1016/j.chemgeo.2015.08.0240009-2541/© 2015 Elsevier B.V. All rights reserved…
has type: Article
is shown at: 10.14288/1.0220729
language: eng
peer review status: Reviewed
provider: Vancouver : University of British Columbia Library
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Faculty
subject: Mineral dissolution
subject: Dissolution rate
subject: Forsterite
subject: Flow-through dissolution
subject: Stoichiometry
subject: Exfoliation
subject: Leached layer
type: Text
identifier URI: http://hdl.handle.net/2429/54819