Neutron Spectroscopic and Thermochemical Characterization of Lithium–Aluminum-Layered Double Hydroxide Chloride: Implications for Lithium Recovery

Abstract

Lithium−aluminum-layered double hydroxide chloride (LDH) has been recently demonstrated to be a promising sorbent material for selective lithium extraction and recovery from geothermal brine. In this research, LDH samples synthesized from two different starting materials (alumina and gibbsite) and with two post-drying conditions (ambient-dried and oven-dried) as well as and Fe-doped LDH are studied using neutron vibrational spectroscopy. The results reveal differences in the ordering of interlayer water molecules. Thermochemical measurements of LDHs show that a higher interlayer ordering of water is directly related to the stability of gibbsite-and alumina-derived LDH. This corroborates with the previous work on increasing the stabilization of LDH via partial substitution of aluminum with iron. These findings on the properties of LDH have implications on their lithium extraction abilities and subsequent recovery.

Cryogenic heat capacity measurements and thermodynamic analysis of lithium aluminum layered double hydroxides (LDHs) with intercalated chloride

“…The reported enthalpies are based on dissolution enthalpies measured in our previous work (ΔH dissol ) (Wu et al, 2019a;Wu et al, 2019b). Because the dissolution enthalpy of liquid water in 5 N HCl solution is small, it was neglected in our previous calculations.…”

“…Keeping in view the compositional flexibility of the Al(OH) 3 based LDHs, [Li-Al] LDHs with variable Li/Al ratios can be envisaged. When the Li/Al ratio is > 0.5, a layer of composition [Li 1+x Al 2-x (OH) 6 ] (1-2x)+ can be formulated, where the layer charge is lower than that found in the Synthesis and characterization (including powder x-ray diffraction, inductively coupled plasma-optical emission spectroscopy, differential scanning calorimetry, and thermogravimetry measurements) of these LDHs were performed previously (Wu et al, 2019a;Wu et al, 2019b).…”

“…This suggests there may be a secondary phase of LiCl present. Therefore, we remeasured this sample using powder X-ray diffraction (PXRD) to check for the presence of an LiCl secondary phase (PXRD measurements have previously been performed on all samples (Wu et al, 2019a;Wu et al, 2019b) (Shi et al, 2011;Shi et al, 2010). Approximately mg of each sample was enclosed in a copper cup (0.025 mm thick, 99.999% purity from Alfa Aesar).…”

Selective Lithium Adsorption of Silicon Oxide Coated Lithium Aluminum Layered Double Hydroxide Nanocrystals and Their Regeneration

“…Generally, Al(OH) 3 prepared by lithium desorption needs a high concentration of LiCl to readsorb lithium. [8][9][10][11][12]39] Previous in-situ XRD analyses reported that Al-(OH) 3 partly adsorbed lithium in a 4 M LiCl solution for 4 hours [11] but rarely adsorbed lithium in 1 M LiCl solution. [39] Selective adsorption of lithium ions.…”

“…[LiAl 2 (OH) 6 ] + (X À ) • yH 2 O (LiAl 2 -LDH) is considered one of the best representative hosts for lithium recovery from aqueous resources, such as brine and seawater, due to its promising characteristics of high chemical stability against lithium adsorption/ desorption in the aqueous phase and octahedral voids capable of accommodating lithium ions. [1][2][3][4][5][6][7][8][9] Typically, LiMnO x , Li 2 TiO 3 , and LiAl 2 -LDH have been used as sorbents for extraction of lithium from aqueous resources, [10] and LiAl 2 -LDH is a potential candidate for large-scale applications. Separation of lithium ions through precipitation of LiAl 2 -LDH powder has been accomplished by addition of aluminum salt in brine and reaction of aluminum ions with lithium ions.…”