Abstract
Feldspar dissolution rates were measured in flow-through reactors, over a pH range of 3-7, oxalic acid concentration of 0-8 m M, and feldspar compositional range of An0-An76. Dissolution rates in O and l m M concentrations of oxalic acid increased linearly with increasing mole percent anorthite in the solid. Dissolution was nonstoichiometric in oxalic acid, due to a preferential release of Al at steady state, 1 m M concentrations of oxalic acid increased dissolution rates by a factor of 2-5 at pH 3 and 2-15 at pH 5-6. At pH 5-6 the rate enhancement due to oxalic acid may increase with increasing anorthite content of the feldspar. The ligand-promoted rate, RL, defined as the observed total rate in oxalic acid minus the proton-promoted rate, Rt - RH, was estimated as 10-12.8(aHOx-+ aOx2)0.75, suggesting that both HC2O-4 (bioxalate) and C2O2-4 (oxalate) play a role in the dissolution mechanism.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 79-89 |
| Number of pages | 11 |
| Journal | Chemical Geology |
| Volume | 132 |
| Issue number | 1-4 SPEC. ISS. |
| State | Published - Oct 30 1996 |
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All Science Journal Classification (ASJC) codes
- Geology
- Geochemistry and Petrology
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Rates of feldspar dissolution at pH 3-7 with 0-8 m M oxalic acid. / Stillings, Lisa L.; Drever, James I.; Brantley, Susan L.; Sun, Yanting; Oxburgh, Rachael.
In: Chemical Geology, Vol. 132, No. 1-4 SPEC. ISS., 30.10.1996, p. 79-89.Research output: Contribution to journal › Article
TY - JOUR
T1 - Rates of feldspar dissolution at pH 3-7 with 0-8 m M oxalic acid
AU - Stillings, Lisa L.
AU - Drever, James I.
AU - Brantley, Susan L.
AU - Sun, Yanting
AU - Oxburgh, Rachael
PY - 1996/10/30
Y1 - 1996/10/30
N2 - Feldspar dissolution rates were measured in flow-through reactors, over a pH range of 3-7, oxalic acid concentration of 0-8 m M, and feldspar compositional range of An0-An76. Dissolution rates in O and l m M concentrations of oxalic acid increased linearly with increasing mole percent anorthite in the solid. Dissolution was nonstoichiometric in oxalic acid, due to a preferential release of Al at steady state, 1 m M concentrations of oxalic acid increased dissolution rates by a factor of 2-5 at pH 3 and 2-15 at pH 5-6. At pH 5-6 the rate enhancement due to oxalic acid may increase with increasing anorthite content of the feldspar. The ligand-promoted rate, RL, defined as the observed total rate in oxalic acid minus the proton-promoted rate, Rt - RH, was estimated as 10-12.8(aHOx-+ aOx2)0.75, suggesting that both HC2O-4 (bioxalate) and C2O2-4 (oxalate) play a role in the dissolution mechanism.
AB - Feldspar dissolution rates were measured in flow-through reactors, over a pH range of 3-7, oxalic acid concentration of 0-8 m M, and feldspar compositional range of An0-An76. Dissolution rates in O and l m M concentrations of oxalic acid increased linearly with increasing mole percent anorthite in the solid. Dissolution was nonstoichiometric in oxalic acid, due to a preferential release of Al at steady state, 1 m M concentrations of oxalic acid increased dissolution rates by a factor of 2-5 at pH 3 and 2-15 at pH 5-6. At pH 5-6 the rate enhancement due to oxalic acid may increase with increasing anorthite content of the feldspar. The ligand-promoted rate, RL, defined as the observed total rate in oxalic acid minus the proton-promoted rate, Rt - RH, was estimated as 10-12.8(aHOx-+ aOx2)0.75, suggesting that both HC2O-4 (bioxalate) and C2O2-4 (oxalate) play a role in the dissolution mechanism.
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UR - http://www.scopus.com/inward/citedby.url?scp=0030423865&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0030423865
VL - 132
SP - 79
EP - 89
JO - Chemical Geology
JF - Chemical Geology
SN - 0009-2541
IS - 1-4 SPEC. ISS.
ER -