*7.2.1 Study of layered H2TiO3 LISs*

The chemical structure of layered H2TiO3 is shown in **Figure 8**. From the layered precursor Li2TiO3 a layered H2TiO3 is obtained. One can better describe as Li[Li1/3Ti2/3] O2 the crystal structure of this precursor; precisely, when metal atoms are placed in octahedral voids the structure can be represented as cubic close packed oxygen atoms. In the structure of Li2TiO3 two types of layers form Li and Ti. The first layer (Li) is inhabited only by lithium atoms, while the other layer (LiTi2) occupies Li 1/3 and

**209**

(∆G0

**Figure 8.**

*Lithium Recovery from Brines Including Seawater, Salt Lake Brine, Underground Water…*

Ti 2/3. In fact, in the structure of Li2TiO3, lithium ions in the layers make up 75% of the

*Crystal structure of Li4Ti5O12 (yellow tetrahedra represent lithium, and green octahedra represent disordered* 

Accordingly, whole lithium ions are changed by protons in the layered structure of H2TiO3. Accordingly, in early studies, some researchers believed that the structure of H2TiO3 was converted from layered Li2TiO3 by topotactic substitution of lithium ions by protons. The authors explore the composition of H2TiO3 by reviewing the variation among Li2TiO3 and H2TiO3 and modeling the XRD patterns of HxLi2−xTiO3 (0 ≤ x ≤ 2), they pointed out that a structure with a layered double hydroxide type with a sequence of 3R1 oxygen layers is more acceptable for H2TiO3, and H2TiO3 can be described as laying charge-neutral metal oxyhydroxide plates [(OH)2OTi2O(OH)2] [202]. In advanced research, requires additional experimental

In 1988, Onodera et al. first obtained Li2TiO3 [203], many kinds of research have been conducted on its electrochemical application [204–208] and in the degradation of pollutants the photocatalytic applications [209–211]. Chitrakar et al. investigated the behavior of ion exchange in salt lake brines [53]. While the rate of adsorption of lithium was relatively slow (it took 1day to reach equilibrium at room temperature),

can reach up to 32.6 mg g<sup>−</sup><sup>1</sup>

bents of lithium the greatest value is studied in an acidic solution. Besides, H2TiO3 has

it is not possible to introduce sites into the LTO adsorbent, since exchange sites have

adsorption due to the large size of the ionic radii. Although the ionic radius of Mg2+

) is four times greater than for Li (∆G0

found by Shi et al. [40]. In designing the orthogonal test, the maximum absorption of

high energy to enter the exchange nodes, since the free hydration energy for Mg

[212]. In addition, the Li-Mg separation ratio reached 102.4 on the 8th adsorption

been found to be able to efficiently absorb lithium ions from Na+

containing competitive cations in brine. With ionic radii exceeding Li+

cycle, that in salt lake brines represents the excellent separation of Li+

, that is among the adsor-

h = −475 kJ mol<sup>−</sup><sup>1</sup>

and Mg2+

, Mg2+ and Ca2+

(0.074 nm),

)

, K+

, dehydration of magnesium ions requires

at the optimal state studied by He et al. [213].

(0.138 nm) and Ca2+ (0.100 nm), which do not allow

total amount of lithium, while the surviving 25% are in layers (LiTi2) [53].

testing to confirm the well-honed structure.

*lithium and titanium) [39]. Reproduced from Ref. [39].*

(0.102 nm), K+

(0.072 nm) is close to the ionic radii of Li+

lithium by H2TiO3 reached 57.8 mg g<sup>−</sup><sup>1</sup>

at pH 6.5 the capacity of the Li+

h = −1980 kJ mol<sup>−</sup><sup>1</sup>

radii sizes Na+

*DOI: http://dx.doi.org/10.5772/intechopen.90371*

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

#### **Figure 8.**

*Thermodynamics and Energy Engineering*

capacity reaching 5.6 mmol g<sup>−</sup><sup>1</sup>

extraction-adsorption properties Li<sup>+</sup>

a high adsorption capacity of Li<sup>+</sup>

increase in absorption to 28 mg g<sup>−</sup><sup>1</sup>

l-1 solution to the crude brine.

**7.2 About LTO-type LISs**

the industry, avoiding water pollution.

*7.2.1 Study of layered H2TiO3 LISs*

LiNi0.5Mn1.5O4 and LiTi0.5Mn1.5O4 spinels do not exhibit satisfactory Li<sup>+</sup>

for Li<sup>+</sup>

and adsorption properties because of substantial cell contraction or expansion. By Chitrakar et al. Sb-doped LMO spinel was synthesized for the first time [186]. Samples received Li1.16Sb(V)0.29Mn(III)0.77Mn(IV)0.77O4 was a well-crystallized spinel-type structure, in the following order of affinity K < Na ≪ Li and exchange

composite oxides with various Sb/Mn molar ratios by solid-state reactions obtained by Ma et al. [187]. Studies have shown that the molar ratio Sb/Mn of composite oxides Li-Sb-Mn is a decisive factor in the identification of their structure and

spinel oxide Li-Sb-Mn with a molar ratio Sb/Mn of 0.05 showed in lithium solution

property of iron-doped lithium manganese oxides Li1.33FexMn1.67-xO4 (x = 0.15, 0.30 and 0.40) in Bolivian brine was studied [38]. Studies have shown that the adsorbent with a Fe/Mn ratio of 0.1, obtained by calcining the precursor at 450°C, has the highest extractability of lithium with HCl solution. Finally, from crude brine at

33.23 mg g<sup>−</sup><sup>1</sup>

a final pH of 2.0, the adsorbent showed lithium absorption of 18.1 mg g<sup>−</sup><sup>1</sup>

Study of the description of the LMO-doped spinels, it is obvious that doping modifications can effectively improve the adsorption properties of lithium. Nevertheless, little attention has been paid to refining LIS compared with the great progress of ion-doped manganese oxide spinels in the field of electrochemistry. At present, just several studies of LISs doped with a single metal have been studied. Lithium adsorption property of multicharged ions doped LISs, including several cation-doped, several anion-doped and cation-anion-doped LISs in aqueous solution, still an untouched area for research. Early research of numerous ion-doped LiMn2O4 showed high capacity retention, high discharge capacity, and lithium ion batteries good cycling performance. This is due to the fact that multiple ions doped LiMn2O4, have increased structural stability [188–197]. Besides, as cathodes, co-doping has a synergistic effect on increasing the cyclic durability of materials, which can for single ion-doped LiMn2O4 discourage all factors responsible for capacity loss [198–201]. Similarly, it has been convincingly shown that multiple ion doping has a beneficial effect on improving the regeneration efficiency and absorption capacity of lithium LISs in aqueous solutions. Prospective studies should focus on the synergistic effects of different ions on the reductive properties of lithium.

There are currently two categories of LTO-type LISs: layered structure H2TiO3 and spinel structure H4Ti5O12. Albeit the amount of LTO-type LISs is confined, there is great potential to develop these green lithium adsorbents for application in

The chemical structure of layered H2TiO3 is shown in **Figure 8**. From the layered precursor Li2TiO3 a layered H2TiO3 is obtained. One can better describe as Li[Li1/3Ti2/3] O2 the crystal structure of this precursor; precisely, when metal atoms are placed in octahedral voids the structure can be represented as cubic close packed oxygen atoms. In the structure of Li2TiO3 two types of layers form Li and Ti. The first layer (Li) is inhabited only by lithium atoms, while the other layer (LiTi2) occupies Li 1/3 and

extraction

with an

NaOH

. In a subsequent study, a series of Li-Sb-Mn

. By Chitrakar et al. the ion-exchange

. Hereinafter, the acid-treated composite

at a final pH of 7.2 after adding 1 mol L<sup>−</sup><sup>1</sup>

**208**

*Crystal structure of Li4Ti5O12 (yellow tetrahedra represent lithium, and green octahedra represent disordered lithium and titanium) [39]. Reproduced from Ref. [39].*

Ti 2/3. In fact, in the structure of Li2TiO3, lithium ions in the layers make up 75% of the total amount of lithium, while the surviving 25% are in layers (LiTi2) [53].

Accordingly, whole lithium ions are changed by protons in the layered structure of H2TiO3. Accordingly, in early studies, some researchers believed that the structure of H2TiO3 was converted from layered Li2TiO3 by topotactic substitution of lithium ions by protons. The authors explore the composition of H2TiO3 by reviewing the variation among Li2TiO3 and H2TiO3 and modeling the XRD patterns of HxLi2−xTiO3 (0 ≤ x ≤ 2), they pointed out that a structure with a layered double hydroxide type with a sequence of 3R1 oxygen layers is more acceptable for H2TiO3, and H2TiO3 can be described as laying charge-neutral metal oxyhydroxide plates [(OH)2OTi2O(OH)2] [202]. In advanced research, requires additional experimental testing to confirm the well-honed structure.

In 1988, Onodera et al. first obtained Li2TiO3 [203], many kinds of research have been conducted on its electrochemical application [204–208] and in the degradation of pollutants the photocatalytic applications [209–211]. Chitrakar et al. investigated the behavior of ion exchange in salt lake brines [53]. While the rate of adsorption of lithium was relatively slow (it took 1day to reach equilibrium at room temperature), at pH 6.5 the capacity of the Li+ can reach up to 32.6 mg g<sup>−</sup><sup>1</sup> , that is among the adsorbents of lithium the greatest value is studied in an acidic solution. Besides, H2TiO3 has been found to be able to efficiently absorb lithium ions from Na+ , K+ , Mg2+ and Ca2+ containing competitive cations in brine. With ionic radii exceeding Li+ (0.074 nm), it is not possible to introduce sites into the LTO adsorbent, since exchange sites have radii sizes Na+ (0.102 nm), K+ (0.138 nm) and Ca2+ (0.100 nm), which do not allow adsorption due to the large size of the ionic radii. Although the ionic radius of Mg2+ (0.072 nm) is close to the ionic radii of Li+ , dehydration of magnesium ions requires high energy to enter the exchange nodes, since the free hydration energy for Mg (∆G0 h = −1980 kJ mol<sup>−</sup><sup>1</sup> ) is four times greater than for Li (∆G0 h = −475 kJ mol<sup>−</sup><sup>1</sup> ) [212]. In addition, the Li-Mg separation ratio reached 102.4 on the 8th adsorption cycle, that in salt lake brines represents the excellent separation of Li+ and Mg2+ found by Shi et al. [40]. In designing the orthogonal test, the maximum absorption of lithium by H2TiO3 reached 57.8 mg g<sup>−</sup><sup>1</sup> at the optimal state studied by He et al. [213].

#### **Figure 9.**

*Schematic representation in spinel manganese oxides by the composite mechanism (a) Li+ extraction reactions and (b) Li<sup>+</sup> insertion reactions.*

#### *7.2.2 Study of spinel titanium oxides*

The LTO-type LISs represent the different types of spinel titanium oxides that are derived from spinel precursors Li4Ti5O12. In the field of lithium-ion batteries, spinel Li4Ti5O12 is seen as one of the most promising future anode candidates for large-scale lithium-ion batteries used for hybrid electric vehicles or power electric vehicles. Through high efficient due to high potential during charge and discharge of about 1.55 V (vs. Li/Li+ ), good cycle property and good heat resistance and security [214– 216]. There is great potential for the development of spinel Li4Ti5O12 in the extraction of lithium from aqueous solutions. High capacity lithium has on LIS (H4Ti5O12) and due to stronger Ti–O bond cycling performance is better than that of manganese-type LISs. Withal, Li4Ti5O12 has an identical chemical structure like Li4Mn5O12 (**Figure 9**).

Nevertheless, as far as we know, there are currently very limited reports on the property of extracting lithium from H4Ti5O12. A three-dimensionally ordered precursor to nano Li4Ti5O12 using colloidal PMMA crystal matrices developed by Dong et al. [217]. High selectivity for Li<sup>+</sup> , 56.81 mg g<sup>−</sup><sup>1</sup> showed corresponding ion sieve and good stability to acid. LISs H4Ti5O12 with nanotube morphology synthesized by an ordinary two-stage hydrothermal process presented a lithium capacity of 39.43 mg g<sup>−</sup><sup>1</sup> in a 120 mg L<sup>−</sup><sup>1</sup> in lithium solution reported by Moazeni et al. [39].

### **8. Conclusions**

Lithium is one of the rarest metals with various applications and the demand for lithium will increase with the ever-increasing use of electric and electronic devices and hybrid electric vehicles.

Therefore, the search for ways to obtain lithium from water sources suitable for the production of lithium compounds is a serious and very important problem.

Various methods have been given in the literature for lithium recovery from brines, seawater and geothermal water: including precipitation, solvent extraction, selective membrane separation, liquid-liquid extraction, ion exchange adsorption, electro dialysis and so on.

**211**

*Lithium Recovery from Brines Including Seawater, Salt Lake Brine, Underground Water…*

The recovery of lithium by the absorption method shows promising results for future production. Because of the adsorption method, evaporation, crystallization process can be avoided. That is why it is necessary to develop and recommend a technically and economically feasible, environmentally friendly and sustainable

Scientists and manufacturers are faced with the task to solve several problems: the ion sieve has a relatively low ion exchange capacity and weak stability; lithium

positions; low stability during cycling; the appearance of secondary waste in the

To solve this problem, scientists of the world have carried out many scientific works to improve the stability of sorbents, increase the absorption capacity, selectivity, acceleration of sorption time, for this purpose, many methods were used, including organic chemicals, synergies, binders, various composites. But none of them makes it possible to industrialize the method of lithium adsorption. That is why there is still a goal to find ways to improve the method of lithium adsorption. Lithium adsorption extraction may be an alternative option to meet future demand,

The authors gratefully acknowledge partial financial supports from the National Natural Science Foundation of China (U1607123 and 21773170), the Key Projects of Natural Science Foundation of Tianjin (18JCZDJC10040), the Major Special Projects of Tibet Autonomous Region (XZ201801-GB-01) and the Yangtze Scholars

1 College of Marine and Environmental Science, Tianjin University of Science and

2 College of Chemical Engineering and Materials Science, Tianjin University of

3 Central Laboratory of Geological Mineral Exploration and Development Bureau

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Ji Duo3

and Tianlong Deng1,2\*

and Innovative Research Team of the Chinese University (IRT\_17R81).

; dissolution of sorbents. Weight loss was observed in almost all com-

, the theoretical adsorption capacity

*DOI: http://dx.doi.org/10.5772/intechopen.90371*

absorption reaches from 16 to 26–28 mg g<sup>−</sup><sup>1</sup>

regeneration of acids; the process takes a long time.

energy sustainability, environment and circular economy.

Samadiy Murodjon1,2, Xiaoping Yu1,2, Mingli Li3

Science and Technology, TEDA, Tianjin, P.R. China

\*Address all correspondence to: tldeng@tust.edu.cn

of Tibet Autonomous Region, Tibet, P.R. China

provided the original work is properly cited.

Technology, TEDA, Tianjin, P.R. China

process.

is 54 mg g<sup>−</sup><sup>1</sup>

**Acknowledgements**

**Author details**

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

The recovery of lithium by the absorption method shows promising results for future production. Because of the adsorption method, evaporation, crystallization process can be avoided. That is why it is necessary to develop and recommend a technically and economically feasible, environmentally friendly and sustainable process.

Scientists and manufacturers are faced with the task to solve several problems: the ion sieve has a relatively low ion exchange capacity and weak stability; lithium absorption reaches from 16 to 26–28 mg g<sup>−</sup><sup>1</sup> , the theoretical adsorption capacity is 54 mg g<sup>−</sup><sup>1</sup> ; dissolution of sorbents. Weight loss was observed in almost all compositions; low stability during cycling; the appearance of secondary waste in the regeneration of acids; the process takes a long time.

To solve this problem, scientists of the world have carried out many scientific works to improve the stability of sorbents, increase the absorption capacity, selectivity, acceleration of sorption time, for this purpose, many methods were used, including organic chemicals, synergies, binders, various composites. But none of them makes it possible to industrialize the method of lithium adsorption. That is why there is still a goal to find ways to improve the method of lithium adsorption. Lithium adsorption extraction may be an alternative option to meet future demand, energy sustainability, environment and circular economy.
