January 8, 2019
Journal Article

27Al Pulsed Field Gradient, Diffusion-NMR Spectroscopy of Solvation Dynamics and Ion Pairing in Alkaline Aluminate Solutions

Trenton Graham
Kee Han
Mateusz Dembowski
Anthony Krzysko
Xin Zhang
Jian Hu
Aurora Clark
Carolyn Pearce
Pulsed field gradient diffusion ordered nuclear magnetic resonance spectroscopy (DOSY-NMR) was successfully applied to the 27Al nucleus in concentrated electrolytes to investigate the diffusion of aluminate [Al(OH)4-] in simulant high-level nuclear waste (3M NaOH) between 25 and 85°C. The temperature dependent diffusion coefficients obtained from 1H, 23Na and 27Al PFG-NMR were well fit by a Vogel-Fulcher-Tammann model and a power law equation. Comparison of 27Al diffusion coefficients of 0.1 M Al(OH)4- in 3M sodium hydroxide, 3M potassium hydroxide (KOH) and 25 wt % tetramethylammonium hydroxide (TMAOH) at room temperature varied in agreement with expected changes in viscosity. 27Al DOSY-NMR studies extend an established methodology to a previously unexplored nucleus, and demonstrate the advantages of this technique for exploring ion transport, speciation and solution structure in concentrated electrolytes.

Revised: January 8, 2019 | Published: December 6, 2018

Graham T.R., K. Han, M. Dembowski, A. Krzysko, X. Zhang, J.Z. Hu, and S.B. Clark, et al. 2018. "27Al Pulsed Field Gradient, Diffusion-NMR Spectroscopy of Solvation Dynamics and Ion Pairing in Alkaline Aluminate Solutions." Journal of Physical Chemistry B 122, no. 48:10907-10912. PNNL-SA-138291. doi:10.1021/acs.jpcb.8b10145