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Title: Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO 4) – Malinkoite (NaBSiO 4) Join

Abstract

The dissolution kinetics of five glasses along the NaAlSiO 4-NaBSiO 4 join were used to evaluate how the structural variations associated with boron-aluminum substitution affect the rate of dissolution. The composition of each glass varied inversely in mol% of Al 2O 3 (5 to 25 mol%) and B 2O 3 (20 to 0 mol%) with Na 2O (25 mol%) and SiO 2 (50 mol%) making up the remaining amount, in every case Na/(Al+B) = 1.0. Single-pass flow-through experiments (SPFT) were conducted under dilute conditions as a function of solution pH (from 7.0 to 12.0) and temperature (from 23° to 90°C). Analysis by 27Al and 29Si MAS-NMR suggests Al (~98% [4]Al) and Si atoms (~100% [4]Si) occupy a tetrahedral coordination whereas, B atoms occupy both tetrahedral ([4]B) and trigonal ( [3]B) coordination. The distribution of [3]B fractionated between [3]B(ring) and [3]B(non-ring) moieties, with the [3]B(ring)/ [3]B(non-ring) ratio increases with the B/Al ratio. The MAS-NMR results also indicated an increase in the fraction of [4]B with an increase in the B/Al ratio. But despite the changes in the B/Al ratio and B coordination, the 29Si spectra maintain a chemical shift between -88 to -84 ppm for each glass. Unlike the 29Si spectra,more » the 27Al resonances shift to more positive values with an increase in the B/Al ratio which suggests mixing between the [4]Al and [3]B sites, assuming avoidance between tetrahedral trivalent cations ( [4]Al-O- [4]B avoidance). Raman spectroscopy was use to augment the results collected from MAS-NMR and demonstrated that NeB4 (glass sample with the highest B content) was glass-glass phase separated (e.g., heterogeneous glass). Results from SPFT experiments suggest a forward rate of reaction and pH power law coefficients,η, that are independent of B/Al under these neutral to alkaline test conditions for all homogeneous glasses. The temperature dependence shows an order of magnitude increase in the dissolution rate with a 67°C increase in temperature and suggests dissolution is controlled by a surface-mediated reaction, evident by the activation energy, E a, being between 44±8 and 48±7 kJ/mol. Forward dissolution rates, based on Na and Si release, for homogeneous glasses are independent of the B/Al ratio, whereas dissolution rates based on Al and B release are not. Dissolution rates based on B release increase with an increase in the fraction of [3]B(ring). Finally in accord with previous studies, the data discussed in this manuscript suggest rupture of the Al-O and Si-O bond as the rate-limiting step controlling the dissolution of these glasses.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
974934
Report Number(s):
PNNL-SA-61097
Journal ID: ISSN 0016-7037; GCACAK; 14592; KP1301020; TRN: US201007%%893
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 74; Journal Issue: 9; Journal ID: ISSN 0016-7037
Publisher:
The Geochemical Society; The Meteoritical Society
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; ACTIVATION ENERGY; ATOMS; AVOIDANCE; CATIONS; CHEMICAL SHIFT; DISSOLUTION; DISTRIBUTION; GLASS; KINETICS; RAMAN SPECTROSCOPY; RUPTURES; SPECTRA; TEMPERATURE DEPENDENCE; Environmental Molecular Sciences Laboratory

Citation Formats

Pierce, Eric M, Reed, Lunde R, Shaw, Wendy J, McGrail, B Peter, Icenhower, Jonathan P, Windisch, Charles F, Cordova, Elsa A, and Broady, Johnathan W. Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO4) – Malinkoite (NaBSiO4) Join. United States: N. p., 2010. Web. doi:10.1016/j.gca.2009.09.006.
Pierce, Eric M, Reed, Lunde R, Shaw, Wendy J, McGrail, B Peter, Icenhower, Jonathan P, Windisch, Charles F, Cordova, Elsa A, & Broady, Johnathan W. Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO4) – Malinkoite (NaBSiO4) Join. United States. https://doi.org/10.1016/j.gca.2009.09.006
Pierce, Eric M, Reed, Lunde R, Shaw, Wendy J, McGrail, B Peter, Icenhower, Jonathan P, Windisch, Charles F, Cordova, Elsa A, and Broady, Johnathan W. Sat . "Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO4) – Malinkoite (NaBSiO4) Join". United States. https://doi.org/10.1016/j.gca.2009.09.006.
@article{osti_974934,
title = {Experimental Determination of the Effect of the Ratio of B/Al on Glass Dissolution along the Nepheline (NaAlSiO4) – Malinkoite (NaBSiO4) Join},
author = {Pierce, Eric M and Reed, Lunde R and Shaw, Wendy J and McGrail, B Peter and Icenhower, Jonathan P and Windisch, Charles F and Cordova, Elsa A and Broady, Johnathan W},
abstractNote = {The dissolution kinetics of five glasses along the NaAlSiO4-NaBSiO4 join were used to evaluate how the structural variations associated with boron-aluminum substitution affect the rate of dissolution. The composition of each glass varied inversely in mol% of Al2O3 (5 to 25 mol%) and B2O3 (20 to 0 mol%) with Na2O (25 mol%) and SiO2 (50 mol%) making up the remaining amount, in every case Na/(Al+B) = 1.0. Single-pass flow-through experiments (SPFT) were conducted under dilute conditions as a function of solution pH (from 7.0 to 12.0) and temperature (from 23° to 90°C). Analysis by 27Al and 29Si MAS-NMR suggests Al (~98% [4]Al) and Si atoms (~100% [4]Si) occupy a tetrahedral coordination whereas, B atoms occupy both tetrahedral ([4]B) and trigonal ([3]B) coordination. The distribution of [3]B fractionated between [3]B(ring) and [3]B(non-ring) moieties, with the [3]B(ring)/[3]B(non-ring) ratio increases with the B/Al ratio. The MAS-NMR results also indicated an increase in the fraction of [4]B with an increase in the B/Al ratio. But despite the changes in the B/Al ratio and B coordination, the 29Si spectra maintain a chemical shift between -88 to -84 ppm for each glass. Unlike the 29Si spectra, the 27Al resonances shift to more positive values with an increase in the B/Al ratio which suggests mixing between the [4]Al and [3]B sites, assuming avoidance between tetrahedral trivalent cations ([4]Al-O-[4]B avoidance). Raman spectroscopy was use to augment the results collected from MAS-NMR and demonstrated that NeB4 (glass sample with the highest B content) was glass-glass phase separated (e.g., heterogeneous glass). Results from SPFT experiments suggest a forward rate of reaction and pH power law coefficients,η, that are independent of B/Al under these neutral to alkaline test conditions for all homogeneous glasses. The temperature dependence shows an order of magnitude increase in the dissolution rate with a 67°C increase in temperature and suggests dissolution is controlled by a surface-mediated reaction, evident by the activation energy, Ea, being between 44±8 and 48±7 kJ/mol. Forward dissolution rates, based on Na and Si release, for homogeneous glasses are independent of the B/Al ratio, whereas dissolution rates based on Al and B release are not. Dissolution rates based on B release increase with an increase in the fraction of [3]B(ring). Finally in accord with previous studies, the data discussed in this manuscript suggest rupture of the Al-O and Si-O bond as the rate-limiting step controlling the dissolution of these glasses.},
doi = {10.1016/j.gca.2009.09.006},
url = {https://www.osti.gov/biblio/974934}, journal = {Geochimica et Cosmochimica Acta},
issn = {0016-7037},
number = 9,
volume = 74,
place = {United States},
year = {2010},
month = {3}
}