The Li(H2O)n dehydration behavior influences the Li+ ion adsorption on H4Ti5O12 with different facets exposed

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. • 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.