Abstract:
It is the first time that zero-valent zinc(ZVZ), sodium bentonite(Na-bent) supported zero-valent zinc(ZVZ/Na-bent) and AlCl
3 solution pillars modified Na-bent supported zero valent zinc(ZVZ/Al/Na-bent) were prepared in our experiment. The effects on removing U(Ⅵ) from aqueous solution of ZVZ, Na-bent, ZVZ/Na-bent and ZVZ/Al/Na-bent were studied. The U(Ⅵ) adsorption mechanism of above four adsorbents was investigated by
X-ray powder diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS). The results show that ZVZ has a layered stack structure, which can be significantly eliminated by doping bentonite. The maximum adsorption capacity of uranium by ZVZ/Na-bent and ZVZ/Al/Na-bent are about 250 mg/g, while the adsorption capacity of ZVZ can be as high as 505 mg/g. All of the adsorption processes of the four adsorbents have positive Δ
S, Δ
H and negative Δ
G, which are agreed well with the Langmuir model. The removal mechanism of U(Ⅵ) is mainly chemical reduction, hydrolytic precipitation and ion exchange.