skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions

Abstract

The (meta)stability of low water activity sodium hydroxide/aluminate (Na +OH–/Al(OH) 4–) electrolytes dictates kinetics in the Bayer process for aluminum refining and high-level nuclear waste processing. We utilized quasi-elastic neutron scattering (QENS) and proton nuclear magnetic resonance spectroscopy ( 1H NMR) in extremely concentrated sodium aluminate solutions to investigate the picosecond (ps) to microsecond (ms) timescale motions of H-bearing species (Al(OH) 4– monomers/clusters, OH– and H 2O). In the QENS data, in contrast to typical liquids, no short-time translational diffusion was observed at 293 K, but two types of localized motions were found: (i) local backbone tumbling or a formation of large hydrated ion clusters on the order of 40–60 ps; and (ii) much slower, complex, and collective dynamics of the ensemble of H-bearing species on the order of 350–750 ps. Variable temperature, pulsed field gradient, diffusion-ordered 1H NMR was used to determine the ensemble translational motion along with relaxometry to calculate rotational correlation coefficients. The ensemble rotational correlation times were on the order of 184–300 ps from 1H NMR, which is consistent with the timescale of the QENS components. Complementary molecular dynamics simulation of NaOH solutions exhibit extensive ion networks potentially responsible for the observed dynamical coupling of watermore » with the motion of large hydrated ion clusters. Understanding these collective motions will aid in predicting the behavior of complex solutions during aluminum production and during nuclear waste processing.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3];  [3]; ORCiD logo [3]; ORCiD logo [4];  [1]; ORCiD logo [1]; ORCiD logo [3]; ORCiD logo [3]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Washington State Univ., Pullman, WA (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Washington State Univ., Pullman, WA (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1490569
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 122; Journal Issue: 50; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Graham, Trent R., Semrouni, David, Mamontov, Eugene, Ramirez-Cuesta, Anibal J., Page, Katharine, Clark, Aurora, Schenter, Gregory K., Pearce, Carolyn I., Stack, Andrew G., and Wang, Hsiu-Wen. Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions. United States: N. p., 2018. Web. doi:10.1021/acs.jpcb.8b09375.
Graham, Trent R., Semrouni, David, Mamontov, Eugene, Ramirez-Cuesta, Anibal J., Page, Katharine, Clark, Aurora, Schenter, Gregory K., Pearce, Carolyn I., Stack, Andrew G., & Wang, Hsiu-Wen. Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions. United States. doi:10.1021/acs.jpcb.8b09375.
Graham, Trent R., Semrouni, David, Mamontov, Eugene, Ramirez-Cuesta, Anibal J., Page, Katharine, Clark, Aurora, Schenter, Gregory K., Pearce, Carolyn I., Stack, Andrew G., and Wang, Hsiu-Wen. Thu . "Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions". United States. doi:10.1021/acs.jpcb.8b09375.
@article{osti_1490569,
title = {Coupled Multimodal Dynamics of Hydrogen-Containing Ion Networks in Water-Deficient, Sodium Hydroxide-Aluminate Solutions},
author = {Graham, Trent R. and Semrouni, David and Mamontov, Eugene and Ramirez-Cuesta, Anibal J. and Page, Katharine and Clark, Aurora and Schenter, Gregory K. and Pearce, Carolyn I. and Stack, Andrew G. and Wang, Hsiu-Wen},
abstractNote = {The (meta)stability of low water activity sodium hydroxide/aluminate (Na+OH–/Al(OH)4–) electrolytes dictates kinetics in the Bayer process for aluminum refining and high-level nuclear waste processing. We utilized quasi-elastic neutron scattering (QENS) and proton nuclear magnetic resonance spectroscopy (1H NMR) in extremely concentrated sodium aluminate solutions to investigate the picosecond (ps) to microsecond (ms) timescale motions of H-bearing species (Al(OH)4– monomers/clusters, OH– and H2O). In the QENS data, in contrast to typical liquids, no short-time translational diffusion was observed at 293 K, but two types of localized motions were found: (i) local backbone tumbling or a formation of large hydrated ion clusters on the order of 40–60 ps; and (ii) much slower, complex, and collective dynamics of the ensemble of H-bearing species on the order of 350–750 ps. Variable temperature, pulsed field gradient, diffusion-ordered 1H NMR was used to determine the ensemble translational motion along with relaxometry to calculate rotational correlation coefficients. The ensemble rotational correlation times were on the order of 184–300 ps from 1H NMR, which is consistent with the timescale of the QENS components. Complementary molecular dynamics simulation of NaOH solutions exhibit extensive ion networks potentially responsible for the observed dynamical coupling of water with the motion of large hydrated ion clusters. Understanding these collective motions will aid in predicting the behavior of complex solutions during aluminum production and during nuclear waste processing.},
doi = {10.1021/acs.jpcb.8b09375},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
issn = {1520-6106},
number = 50,
volume = 122,
place = {United States},
year = {2018},
month = {11}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on November 8, 2019
Publisher's Version of Record

Save / Share: