**Table 2.**

*Recovery of lithium from seawater by various processes.*

*Lithium Recovery from Brines Including Seawater, Salt Lake Brine, Underground Water… DOI: http://dx.doi.org/10.5772/intechopen.90371*

#### **5.2 Ion exchange and sorption method for extracting lithium from seawater**

Although various mega-industries are interested in extracting lithium from seawater in the present decade, extracting lithium from seawater has become increasingly attractive to researchers over several years through ion exchange and sorption. Several alternative methods of lithium extraction from seawater using ion-exchange after solar evaporation and fractional crystallization of NaCl, KCl and CaSO4 are also proposed. According to this method, organic and inorganic sorbents are similar to the compounds used to extract lithium. Reports explaining this method are discussed below. Obtained by treating a Dowex-1 type microporous anion exchanger with a lithium-selective aluminum-containing resin with a saturated solution of ammonia, AlCl3, and finally a solution of lithium halide before heating to produce a composite matrix of the microcrystalline resin LiX·2Al(OH)3 is an example of such products that have been patented in the United States [66, 116, 117]. High selectivity for lithium extraction was synthesized with sorbents based on antimony, tin, dioxides based on titanium and zirconium [118], mixed oxides of titanium and iron, titanium and chromium, titanium arsenate and magnesium and thorium [66]. To extract lithium from seawater, only manganese oxide-based cation exchange yields effective results in a wide range of lithium-selective ion exchange materials. Russian scientists use manganese oxide and mixed oxides of manganese and aluminum, known as ISM-1 and ISMA-1, respectively, to reduce lithium [66, 119]. For Li<sup>+</sup> in mixtures of alkali metal and alkali metal ions, the H2TiO3 ion exchanger resulted in high selectivity. Achieving the exchange capacity of Li+ was 25–34 mg g<sup>−</sup><sup>1</sup> . High selectivity for lithium cations by synthetic inorganic materials of titanium (IV) antimonate cation exchanger (TiSbA) ion exchange has been reported by Abe et al. Recovery of lithium cations from hydrothermal water as well as seawater can be successfully applied. Using the periodic method, the effect of K<sup>+</sup> , Mg2+ and Ca2+ cations on the adsorption of lithium cations on TiSbA has been reported by Abe et al. They showed that lithium adsorption decreases significantly with increasing concentrations of K<sup>+</sup> , Mg2+ and Ca2+ cations. Lithium from the sea and hydrothermal water is enriched through TiSbA columns. To separate lithium cations from seawater and hydrothermal water TiSbA exchanger potentially be reused. With HNO3 solution as the eluent, the adsorbed lithium can be eluted [120].

Selective extraction of lithium from seawater using two sequential ion exchange processes has been reported by Nishihama et al. [100]. By bench chromatographic operation with adsorbent k-MnO2, lithium was concentrated from seawater, which has a 33% lithium recovery efficiency. A combination of ion exchange using resin and solvent impregnated resin is carried out lithium purification from the concentrated liquor of the reference unit. The cleaning process consists of the removal of divalent metal ions with a strong acid cation exchange resin accompanied by the removal of Na+ and K+ with b-diketone/TOPO impregnated resin; finally, the reduction of Li+ as Li2CO3 precipitates using a saturated solution (NH4) <sup>2</sup><sup>−</sup>CO3. According to the method, the concede was 56%, and the cleanness was 99.9% [100]. Takeuchi reported on a new method of extracting lithium from seawater, also supported [101]. At a temperature of 50°C, almost 70% for lithium ion recovery is achieved in a periodic mode with a high selectivity of the Al(OH)3 layer [101].

Several authors have reported that the extraction of lithium from seawater by sorption/desorption is a fairly common process, which is discussed below [108]. Many studies based on manganese oxide sorbate are used for the sorption/desorption of lithium from seawater. Japanese scientists have developed a sorbet based on hydrated c-oxides of manganese and mixed oxide of manganese and magnesium [102, 103]. By Ooi et al. lithium extraction from seawater using manganese oxide ion sieve (HMnO) was investigated. Maximum (7.8 mg g<sup>−</sup><sup>1</sup> ) absorption of lithium

*Thermodynamics and Energy Engineering*

MgCl2 and MnCl2 (10 and 100 mmol/dm3

Seawater Adsorption (HMnO) ion-sieve

Seawater Liquid-liquid

Seawater Liquid-liquid

Seawater Membrane

Seawater Membrane

Seawater Membrane

Seawater Membrane

Seawater Membrane

Seawater Membrane

Seawater Membrane

Seawater Membrane

extraction

extraction

process

process

process

process

process

process

process

process

*Recovery of lithium from seawater by various processes.*

seawater and terrestrial hydromineral resources are very similar [66]. To extract lithium from seawater, various reagents such as potassium, iron sulfates and aluminum hydroxides, are successfully used to co-precipitate lithium [66, 96]. To obtain lithium concentrate, the dissolution of the co-precipitate after an ion exchange process is used. A hydrometallurgical process for extracting lithium from seawater using an adsorption process with a manganese oxide adsorbent followed by a deposition process reported by Um and Hirato [99]. By this method, at a temperature of (25–90°C), MgCl2 and CaCl2 from seawater were precipitated as Mg(OH)2 and Ca(OH)2. Using the NaOH, pH was managed between 7 and 14 with an initial concentration of CaCl2,

recovered through carbonation using Na2CO3 by neutralization using HCl [99].

(microporous)

Cyclohexane and tri-octyloxyphosphine

and TOPO

adsorbent

membrane

crystallization

Thenoyltrifluoroacetone (TTA)

Mixed matrix nanofiber as a flow-through membrane

Inorganic adsorbent containing polymeric membrane

Inorganic adsorbent containing polymeric membrane

Recyclable composite nanofiber

Li ionic superconductor functioning as a Li separation

Membrane distillation and

Mixed matrix nanofiber as a flow-through membrane

Seawater Adsorption k-MnO2 Sorption [103] Seawater Adsorption MnO2 Sorption [104] Seawater Adsorption HMnO Sorption [105] Seawater Adsorption Nanostructure MnO2 ion-sieve Sorption [18] Seawater Adsorption MnO2 adsorbent Sorption [106] Seawater Adsorption H1.6Mn1.6O4 Sorption [48]

**Resources Process Reagents Mechanism Reference** Seawater Precipitation Na2CO3 + HCl Precipitation [99] Seawater Adsorption k-MnO2 adsorbent Sorption [100] Seawater Adsorption Al(OH)3 layer Sorption [101]

). Followed by the second stage Li2CO3 was

Sorption [102]

Adsorption [102]

Adsorption [103]

Adsorption [109]

Adsorption [110]

Dialysis [111]

Adsorption [115]

Ionic liquid membrane Electrodialysis [112, 113]

Osmotic and vacuum configuration [101, 107]

[108]

[114]

**198**

**Table 2.**

HMnO from seawater was achieved [102]. A study using ISMA-1 sorbents to extract lithium from seawater shows the following information: (1) The Li+ cation distribution ratio is 4 × 104 . (2) Sorbents are easily regenerated by nitric acid. (3) They exhibit a high capacity for lithium cations of about 20 mg/m. (4) Lithium concentrates containing up to 1 g L<sup>−</sup><sup>1</sup> of lithium can be achieved under optimal conditions. A two stage scheme for obtaining Li2CO3 from seawater using this information of a pilot plant with a capacity of 3 m3 of seawater per hour has been developed and presented [66]. ISMA-1 sorbents provide higher chemical stability, but manganese oxide degradation associated with ion exchange remains the most serious drawback for their large-scale application in the lithium reduction process. A Japanese researcher developed a composite material by introducing a fine powder k-MnO2 with spinel structure into polyvinyl chloride to improve the kinetic properties of manganese oxide sorbents [121]. Sorbents ISM and ISM-1, synthesized in Russia, are also a composite material obtained using a polymer binder [66, 119]. In Korea, it has also been reported to recover lithium from seawater using an ion exchange type of manganese oxide adsorbent. To recover dissolved lithium in seawater a highly efficient ion exchange adsorbent was prepared according to their method. A highly efficient ion exchange type adsorbate was synthesized as a result of the solid state reaction of Li2CO3 and MgCO3. The ion sieve is formed after treatment of seawater with adsorbate, which is reduced by acid treatment. The lithium-ion sieve was produced by 3 cycles of 0.5 m HCl treatment with 24 h/cycle stringing, which shows 25.7 mg L<sup>−</sup><sup>1</sup> lithium absorption from artificial seawater [98]. Extraction of lithium from seawater by manganese oxide ion-sieve reported by Liu et al. The most promising method of industrial application was considered to be the extraction of lithium from seawater by adsorption using manganese oxide-ion sieves [104]. The sorption properties of HMnO in seawater and wastewater have been studied by Park et al. [105]. Lithium recovery from lake Urmia by the MnO2 ion sieve, where more than 90% lithium recovery can be achieved, was reported by Zandevakili et al. [122]. Wajima et al. studied the adsorption behavior of lithium from seawater using the adsorbent manganese oxide [106]. In studies using a pseudo-second-order kinetic model, a higher adsorption Kinetics of lithium cations in seawater was observed [106]. Reduction of lithium from seawater using manganese oxide adsorbent synthesized from Li1.6Mn1.6O4 precursor studied by Chitrakar et al. Manganese oxide adsorbent LiMnO2 was synthesized from H1.6Mn1.6O4 at 400°C by hydrothermal and reflux method. H1.6Mn1.6O4 was synthesized from precursor Li1.6Mn1.6O4. The sufficiently effective adsorbent can absorb lithium up to 40 mg g<sup>−</sup><sup>1</sup> from seawater [48].
