Preparation of granular titanium-type lithium-ion sieves and recyclability assessment for lithium recovery from brines with different pH value

Titanium-type lithium-ion sieves with stronger Ti-O bond have the advantages of stable structure, good acid resistance and excellent Li+ adsorption performance, being the promising adsorption materials for lithium recovery from brine. In this work, an improved solid-phase reaction method is adopted to prepare the monodispersed Li2TiO3 nanocrystals, where the solid-phase reaction between anatase TiO2 and Li2CO3 takes place in the LiCl molten-salt medium. After immersing Li2TiO3 nanocrystals with diluted HCl, the obtained titanium type ion sieves (H2TiO3 powders) have smaller crystal size and higher special surface area, which makes H2TiO3 ion sieves with an excellent Li+ adsorption performance, stable structure and low synthesis cost when compared with titanium type ion sieves prepared by the traditional solid-phased reaction without the addition of LiCl molten-salt medium. Furthermore, polyvinyl butyral (PVB) polymers with both hydrophilic and hydrophobic properties, are used to shape H2TiO3 powders into granular lithium-ion sieves (PVB-H2TiO3 composite materials). Li+ adsorption and desorption performances are investigated, and the recyclability of granular lithium-ion sieves is evaluated for lithium recovery from three kinds of Li+ contained solutions with different pH value and compositions of coexisting cations.