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Title: Intermediate Species in the Crystallization of Sodium Aluminate Hydroxy Hydrates

Abstract

In highly alkaline “water-in-salt” Na 2O/Al 2O 3/H 2O solutions where the monomeric Al(OH) 4 - anion dominates, isolation of transitional species that seed crystallization of sodium aluminate salt hydrates has been challenging. For example, discrimination of dimeric [e.g., Al 2O(OH) 6 2-] from species via 27Al nuclear magnetic resonance (NMR) spectroscopy is limited via fast interconversion through hydrolysis and condensation reactions. Despite this, using magic-angle spinning NMR ( 27Al MAS NMR) at high magnetic field strengths (14.1 and 20.0 T) on crystals of nonasodium bis(hexahydroxyaluminate) trihydroxide hexahydrate [NSA, Na 9[Al(OH) 6] 2·3(OH)·6(H 2O)], we observed a 27Al resonance consistent with Na 2Al 2O(OH) 6. This tetrahedral dimeric species was also identified in the mother liquor by Raman spectroscopy while remaining expectedly unresolved by high-field liquid-state 27Al NMR. Its substantial abundance in the mother liquor and as either an interstitial or an adsorbate on precipitated solids suggest that it plays a crucial role in NSA crystallization. Here, our detailed characterization, which includes single-pulse 27Al MAS NMR, nutation 27Al MAS NMR, and multiple quantum 27Al MAS NMR, provides new molecular insights into how aluminate transitions from tetrahedral in solution to octahedral in solid. This understanding could ultimately lead to better predictionsmore » of aluminum phase change behavior in caustic sodium hydroxide with wide-ranging technological and environmental implications.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [2]; ORCiD logo [3]; ORCiD logo [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Washington State Univ., Pullman, WA (United States)
  3. Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1633402
Report Number(s):
PNNL-SA-150266
Journal ID: ISSN 1932-7447
Grant/Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 124; Journal Issue: 23; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
NMR; Sodium Aluminate; Crystallization; Ions; Sodium; Nuclear magnetic resonance spectroscopy; Resonance structures

Citation Formats

Graham, Trent R., Dembowski, Mateusz, Hu, Jian Zhi, Jaegers, Nicholas R., Zhang, Xin, Clark, Sue B., Pearce, Carolyn I., and Rosso, Kevin M. Intermediate Species in the Crystallization of Sodium Aluminate Hydroxy Hydrates. United States: N. p., 2020. Web. doi:10.1021/acs.jpcc.0c00205.
Graham, Trent R., Dembowski, Mateusz, Hu, Jian Zhi, Jaegers, Nicholas R., Zhang, Xin, Clark, Sue B., Pearce, Carolyn I., & Rosso, Kevin M. Intermediate Species in the Crystallization of Sodium Aluminate Hydroxy Hydrates. United States. doi:10.1021/acs.jpcc.0c00205.
Graham, Trent R., Dembowski, Mateusz, Hu, Jian Zhi, Jaegers, Nicholas R., Zhang, Xin, Clark, Sue B., Pearce, Carolyn I., and Rosso, Kevin M. Wed . "Intermediate Species in the Crystallization of Sodium Aluminate Hydroxy Hydrates". United States. doi:10.1021/acs.jpcc.0c00205.
@article{osti_1633402,
title = {Intermediate Species in the Crystallization of Sodium Aluminate Hydroxy Hydrates},
author = {Graham, Trent R. and Dembowski, Mateusz and Hu, Jian Zhi and Jaegers, Nicholas R. and Zhang, Xin and Clark, Sue B. and Pearce, Carolyn I. and Rosso, Kevin M.},
abstractNote = {In highly alkaline “water-in-salt” Na2O/Al2O3/H2O solutions where the monomeric Al(OH)4- anion dominates, isolation of transitional species that seed crystallization of sodium aluminate salt hydrates has been challenging. For example, discrimination of dimeric [e.g., Al2O(OH)62-] from species via 27Al nuclear magnetic resonance (NMR) spectroscopy is limited via fast interconversion through hydrolysis and condensation reactions. Despite this, using magic-angle spinning NMR (27Al MAS NMR) at high magnetic field strengths (14.1 and 20.0 T) on crystals of nonasodium bis(hexahydroxyaluminate) trihydroxide hexahydrate [NSA, Na9[Al(OH)6]2·3(OH)·6(H2O)], we observed a 27Al resonance consistent with Na2Al2O(OH)6. This tetrahedral dimeric species was also identified in the mother liquor by Raman spectroscopy while remaining expectedly unresolved by high-field liquid-state 27Al NMR. Its substantial abundance in the mother liquor and as either an interstitial or an adsorbate on precipitated solids suggest that it plays a crucial role in NSA crystallization. Here, our detailed characterization, which includes single-pulse 27Al MAS NMR, nutation 27Al MAS NMR, and multiple quantum 27Al MAS NMR, provides new molecular insights into how aluminate transitions from tetrahedral in solution to octahedral in solid. This understanding could ultimately lead to better predictions of aluminum phase change behavior in caustic sodium hydroxide with wide-ranging technological and environmental implications.},
doi = {10.1021/acs.jpcc.0c00205},
journal = {Journal of Physical Chemistry. C},
issn = {1932-7447},
number = 23,
volume = 124,
place = {United States},
year = {2020},
month = {4}
}

Journal Article:
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