Mechanism of lithium adsorption by AlLi-LDH with Al–O octahedral ring
Yongpan Tian, Cheng-cheng WANG, Fan Zhang, Liang Xu, Zhuo Zhao, Bihai Tong
Abstract
Aluminum–lithium layered double hydroxide (AlLi-LDH) was synthesized using a co-precipitation method for Li + adsorption. AlLi-LDH crystallized in space group of P 32 or C 2/ m , where the microstructure had regular spherical shapes with diameters of 5–10 μm. The space group of AlLi-LDH only belonged to P 32 after Li + adsorption. The Li + adsorption from a solution with a Li + concentration of 95.4 mg/L reached 8.98 mg/g after 1 h. The adsorption amount increased to 16.50 mg/g after 48 h, where the Li + adsorption capacity determined by applying the second-order adsorption model was 17.57 mg/g. The Mg 2+ /Li + separation coefficient was 29536 when the mass ratio of Mg 2+ to Li + was 1067. The interaction strength of Li–O was weaker for AlLi-LDH in the P 32, where the interaction occurs via the electrostatic effect. The Li + adsorption and desorption occurred more readily in AlLi-LDH belonging to P 32 space group.