Abstract:
Nano bimetallic oxides have broad application prospects as fluoride removal agents. La
2O
3-CeO
2 nanofibers were fabricated via electrospinning-calcination method using Ce(NO
3)
3·6H
2O and La(NO
3)
3·6H
2O as raw materials and polyacrylonitrile (PAN) as template. TEM, SEM-EDS, BET, FTIR and XRD were employed to verify the morphology and structure of La
2O
3-CeO
2 nanofibers. The defluoridation properties of La
2O
3-CeO
2 nanofibers were discussed under batch mode, and the effects of adsorbate (F
−) initial concentration, pH, contact time, La
2O
3-CeO
2 nanofibers dose and coexisting anions on the defluoridation were explored. The results illustrate that the specific surface area of La
2O
3-CeO
2 adsorbent is 31.04 m
2·g
−1. The La
2O
3-CeO
2 nanofibers exhibit the best defluoridation performance at pH of 3, and the adsorption capacity of La
2O
3-CeO
2 nanofibers climbs up with rise of the initial concentration of F
−. The pseudo-second-order kinetic and Langmuir isotherm model (
R2>0.99) simulate the defluoridation process of La
2O
3-CeO
2 nanofibers better, and the maximum uptake of F
− by La
2O
3-CeO
2 nanofibers is 111.98 mg·g
−1 at 45℃. Thermodynamic studies suggest that the defluoridation process of La
2O
3-CeO
2 nanofibers is a spontaneous (Δ
G0<0), entropy increase (Δ
S0=56.63 J·mol
−1·K
−1) and endothermic (Δ
H0=9.90 kJ·mol
−1) process.