Synthesis of granulated Li/Al-LDHs adsorbent and application for recovery of Li from synthetic and real salt lake brines

Powder Li/Al-layered double hydroxides (LDHs) of Li2Al4(CO3)(OH)12·3H2O were hydrothermally synthesized in one pot with sodium alginate as a structure modifier and granulated by crosslinked sodium alginate. The powder and granulated Li/Al-LDHs lithium adsorbents were characterized by FT-IR spectroscopy, XRD, SEM, TEM, XPS, and porosity. The adsorption-desorption performance of the granulated Li/Al-LDHs adsorbents was evaluated. Adsorption isotherm, adsorption kinetics, adsorption thermodynamics were investigated. The effects of solution pH, temperature, and the electrolytes (NaCl, Na2SO4, MgCl2, and KCl) on lithium adsorption, and the dissolution of granulated Li/Al-LDHs adsorbents after cyclic adsorption-desorption were also investigated. The granulated Li/Al-LDHs adsorbed 14.5 mg/g of lithium from the brine of East Taigener Salt Lake with a lithium concentration of 1400 mg/L. The granulation of powder Li/Al-LDHs by crosslinked alginate greatly reduced the dissolution of powder Li/Al-LDHs. The granulated Li/Al-LDHs adsorbents prepared in this report are promising materials for Li+ extraction from salt lake brines.