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 degrees 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 m(2)/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.

Automated summary

In this study, a high-performance lithium-ion sieve was prepared using inexpensive attapulgite. The sieve exhibited excellent adsorption efficiency, selectivity, and recycling properties. The formation of a lithium ion memory pore and the filling of pores by lithium ions were observed during the adsorption process. The study provides a new approach to the market application of attapulgite resources.