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The adsorption behaviors and adsorption mechanism of HTO-s were systematically investigated by experiments and DFT calculations, which indicates the adsorption performance was influenced by adsorbents surface with different facets and dehydration processes. [Display omitted] • The HTO-OS with dominant (111) facet and HTO-NS with dominant (01-1) facet were synthesized. • The adsorption tests show that HTO-NS possesses faster adsorption rates and more stable recyclability than HTO-OS. • The dehydration processes of Li(H 2 O) 4 + on HTO (01-1) and (111) are partially dehydrated to form Li(H 2 O)+ and Li(H 2 O) 2 + via DFT calculations. • The study helps to better understand the effect of dehydration behavior on the Li+ adsorption in aqueous lithium resources. In this study, octahedrons assembled nanospheres Li 4 Ti 5 O 12 (LTO-OS) with dominant (111) facet and nanosheets assembled microspheres Li 4 Ti 5 O 12 (LTO-NS) with dominant (01-1) facet precursors were synthesized. Then, these corresponding H 4 Ti 5 O 12 adsorbents (HTO-OS and HTO-NS) were obtained via acid treatment and used to recover lithium from aqueous solutions. The systematic adsorption tests show that HTO-NS possesses higher adsorption uptake (35.5 mg/g) and faster adsorption rate (equilibrium time: <2 h) than HTO-OS (31.2 mg/g), owing to the role of different dehydration processes and exposed facets. With the help of DFT calculation analyses, the dehydration of Li(H 2 O) 4 + on HTO (01-1) and (111) were partially dehydrated Li(H 2 O)+ and Li(H 2 O) 2 + in the adsorption process, owing to crystal channel and surface atomic arrangement. In addition, the analysis of the adsorption mechanism indicates that the Li+ exist in the form of hydrated lithium ions in the initial adsorption solution, and the dehydration processes occur during Li(H 2 O) 4 + move to the surface of the adsorbent, then an ion exchange reaction has happened between the dehydrated Li+ and H+. These results reveal the adsorbents with different facets exposed indeed influence the surface dehydration processes and Li+ adsorption behaviors, which are favorable to better understand the interfacial interactions between adsorbents and adsorbates. [ABSTRACT FROM AUTHOR]

The adsorption behavior and mechanism of H 4 Ti 5 O 12 (1 1 0) and H 4 Ti 5 O 12 (1 1 1) were systematically investigated by experiments and theory calculations, which indicates H 4 Ti 5 O 12 (1 1 1) has more potential on Li+ recovery. [Display omitted] • The H 4 Ti 5 O 12 with (1 1 0) and (1 1 1) facets exposed were synthesized. • The adsorption uptake of H 4 Ti 5 O 12 (1 1 1) is higher than that by H 4 Ti 5 O 12 (1 1 0). • The adsorption of [Li(H 2 O) 4 ]+ on H 4 Ti 5 O 12 (1 1 1) is more stable than (1 1 0). • Li+ is easier diffused from (1 1 1) facet into Li 4 Ti 5 O 12 crystal than (1 1 0) facet. The improved adsorption capacities by increasing specific surface area methods are merely reached about 50% of H 4 Ti 5 O 12 's theoretical adsorption capacity, and the adsorption behavior and mechanism of lithium on special facets of H 4 Ti 5 O 12 remain unclear. In this study, a flower-shaped Li 4 Ti 5 O 12 and an octahedral Li 4 Ti 5 O 12 were prepared with the specific surface areas of 176.23 and 83.02 m2/g, and the corresponding adsorption behaviors of the obtained adsorbents exposed with (1 1 0) and (1 1 1) facets were investigated by using experimental and computational methods. The maximum Li+ uptake values on H 4 Ti 5 O 12 (1 1 0) and H 4 Ti 5 O 12 (1 1 1) are 26.85 mg/g and 33.56 mg/g at 45 °C in 24 mM LiCl solutions, respectively. The fifth reuse ability of H 4 Ti 5 O 12 (1 1 1) still remains 88.9% of the original's, which is higher than H 4 Ti 5 O 12 (1 1 0) (76.3%). Although with lower specific surface area, the octahedral H 4 Ti 5 O 12 have higher ions selectivity, greater adsorption capacity, and better reuse ability than flower-shaped H 4 Ti 5 O 12 , which may due to the special (1 1 1) facet exposed. Firstly, H 4 Ti 5 O 12 (1 1 1) owned small hole sizes can inhibit other ions diffusing into H 4 Ti 5 O 12 and improve the ion selectivity. Secondly, the immigration paths by the First-principles calculations revealed that the Li+ migrate onto the Li 4 Ti 5 O 12 (1 1 1) is easier to than Li 4 Ti 5 O 12 (1 1 0) through 8a-16c-8a-16c sites. At last, [Li(H 2 O) 4 ]+ can form the stable complexes and its adsorption energies on (1 1 1) are higher than on (1 1 0) facets, which may lead to larger adsorption capacity and better reuse ability. This work will help to understand the [Li(H 2 O) 4 ]+ adsorption behavior and mechanism on different crystal facets by experiments and computations. [ABSTRACT FROM AUTHOR]