Synthesis and Adsorption Properties of Li_1.6Mn_1.6O₄ Spinel

Abstract

Orthorhombic-LiMnO 2 , spinel-type Li 1.6 Mn 1.6 O 4 , and spinel MnO 2 •0.5H 2 O were synthesized via a combination of hydrothermal synthesis and solid-phase reaction. o-LiMnO 2 with different stacking fault concentrations were synthesized by controlled hydrothermal reaction using a KMnO 4 , MnCl 2 , and LiOH mixed solution. Spinel-type Li 1.6 Mn 1.6 O 4 precursor was prepared via heat treatment of o-LiMnO 2 . The effects of hydrothermal and solid-phase reaction on the structure and ionexchange properties were examined with powder X-ray diffraction, scanning electron microscopy, and Li + selective adsorption measurements. The results showed that stacking fault concentration of o-LiMnO 2 affects the adsorption properties of Li 1.6 Mn 1.6 O 4 . Li + adsorption capacity reached 6.06 mmol•g −1 at equilibrium. Distribution coefficients of metal ions were in the order Li + ≫ Na + > Mg 2+ > K + > Ca 2+ and were significant for Li + extraction from low grade brine. The equilibrium uptake of Li + from salt lake brine remained at 3.62 mmol•g −1 after six cycles.

Lithium recovery from brine using a λ-MnO2/activated carbon hybrid supercapacitor system

“…In addition, manganese ions in the adsorbent are dissolved out during regeneration, restricting the reuse of the adsorbents (Nishihama et al, 2011;Shi et al, 2011). Recently, in order to improve the adsorption process, several trials were reported by introducing better fabrication methods (Xiao et al, 2012(Xiao et al, , 2013, proposing a new desorption method (Ryu et al, 2013a), applying reducing agents (Intaranont et al, 2014), or using a novel adsorbent (Chitrakar et al, 2014). …”

Lithium ion recovery from brine using granulated polyacrylamide–MnO 2 ion-sieve

“…MnO 2 ion-sieves are the potential adsorbent materials for Li + recovery from brines because of low toxicity, low cost, and high Li + selectivity [11,12]. A series of MnO 2 ion-sieves have been synthesized from lithium manganese oxides with different Li/Mn molar ratios, namely LiMn 2 O 4 , Li 4 Mn 5 O 12 , and Li 1.6 Mn 1.6 O 4 [13][14][15][16][17][18]. However, The adsorbent materials with the powder form cannot be used directly in salt lakes because of the physical loss during postadsorption retrieval [10,19,20].…”

A Facile Synthesis of Hexagonal Spinel λ-MnO2 Ion-Sieves for Highly Selective Li+ Adsorption

“…The lithium reserves in China are the world's second-largest, which are primarily distributed in the salt lakes of Qinghai and Tibet [4]. However, the ratio of magnesium to lithium in the salty brine is extremely high, making it difficult to extract and recover lithium using conventional separation technologies [5,6]. Compared with precipitation and solvent extraction methods, ion-sieve adsorption has many technical merits, such as excellent selectivity and relatively low cost [7,8], which is considered to be the most promising environmentally benign technology for extracting lithium from salt lakes [9,10].…”