Preparation and characterization of lithium-ion sieve with attapulgite

Extracting lithium from liquid lithium resources has emerged as a research hotspot. Attapulgite (ATP), a layered materials with unique pore structure, exhibits certain ion exchange properties, and is a suitable candidate for preparing lithium-ion sieves. In this study, high value lithium-ion sieve was prepared by high temperature synthesis method using inexpensive ATP. The prepared lithium-ion sieve H-ATP-3 calcined at 400 °C was achieved optimal adsorption efficiency, which was consistent with Langmuir and pseudo-second-order model and the maximum adsorption capacity reached 29.18 mg·g−1. After 5 cycles, the adsorption capacity only decreased to 26.46 mg·g−1, still reaching 90.68 %. In the simulated Mg2+ and Li+ ion solution, the adsorption capacity was 5.689 mg·g−1 and 28.66 mg·g−1, respectively. H-ATP-3 possessed excellent selective adsorption, stability and recycling properties. During adsorption, Li+ reacted with H-ATP-3, which formed Li4SiO4, Li2SiO3 and LiAlSi2O6, forming the Li+ memory pore. After Li+ adsorption, the specific surface area decreased from 185.50 to 15.14 m2/g, indicating Li+ entered ion sieve and filled the pore. Moreover, the -OH and interlayer water in H-ATP-3 exchanged with Li+. The synthesis method is relatively simple, and has high selectivity, effectively recovering Li+ and expanding the market application prospect of attapulgite resources.