Lithium (Li), as
a strategic energy source in the 21st century,
has a wide range of application prospects. As the demand for lithium
resources grows, refining lithium resources becomes increasingly important.
A novel method was proposed to directly prepare polyacrylonitrile–LiCl·2Al(OH)
3
·
n
H
2
O (PAN–Li/Al-LDH)
composites from kaolin with simple operation and low cost, showing
effective adsorption performance for the removal of Li(I) from brine
in a salt lake. Moreover, several techniques have been applied for
characterization, including X-ray diffraction, Fourier transform infrared
spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy,
and the Brunauer–Emmett–Teller method. Batch adsorption
experiments were conducted to investigate the adsorption behaviors
of PAN–Li/Al-LDHs for Li(I) in salt-lake brines, indicating
that the adsorption equilibrium could reach within 2 h, and the adsorption
kinetics for Li(I) conforms to the pseudo-second-order model. The
adsorption isotherms are consistent with those obtained by the Langmuir
model, with a maximum adsorption capacity of 5.2 mg/g. The competitive
experimental results indicated that PAN–Li/Al-LDHs exhibited
specific selectivity for Li(I) in the mixed solutions of Mg(II), Na(I),
K(I), and Ca(II) with the selectivity coefficients of 9.57, 19.38,
43.40, and 33.05, respectively. Moreover, the PAN–Li/Al-LDHs
could be reused 60 times with basically unchanged adsorption capacity,
showing excellent stability and regeneration ability. Therefore, PAN–Li/Al-LDHs
would have promising industrial application potential for the adsorption
and recovery of Li(I) from salt-lake brines.