Selective Separation of Zr(IV) from Simulated High-Level Liquid Wastes by Zeolites

ABSTRACT

Effectively separating Zr(IV) from strong acidic and radioactive solutions is crucial for spent fuel reprocessing plants, but it remains a challenging task. This study investigated the adsorption of Zr(IV) in HNO₃ solutions using zeolites as adsorbents. The zeolites were characterized by X-ray diffraction (XRD)，scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The effects of adsorption time, HNO₃ concentration, the initial concentration of Zr(IV), zeolites dosage, and temperature on the Zr(IV) adsorption behaviors were investigated. The results demonstrated that HY zeolite had a higher adsorption capacity for Zr(IV) than H-SSZ-13 zeolite. The adsorption capacity of HY zeolite was influenced by its Si/Al ratio, which determined the density of adsorption sites. The optimal HY zeolite (HY-25) exhibited a maximum adsorption capacity of 30.438 mg/g in 3 M HNO₃ solution. Furthermore, the adsorption isotherms and kinetics of Zr(IV) adsorption were investigated. The adsorption of Zr(IV) on zeolites was endothermic and spontaneous, in accordance with the Freundlich’s isotherm model and pseudo-second-order kinetic model. In a simulated strong acidic solution of Zr(IV) and 10 co-existing cations (Ag⁺, Ba²⁺, Cs⁺, Ce³⁺, Eu³⁺, Fe³⁺, La³⁺, Nd³⁺, Sm³⁺, Sr²⁺), HY-25 exhibited good selective adsorption of Zr(IV), indicating its potential application in the treatment of high-level radioactive liquid waste.

KEYWORDS:

• Adsorption
• high level liquid waste
• zeolite
• Zr(IV)

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/07366299.2023.2231493

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [U1867206]; Lingchuang Foundation of China National Nuclear Corporation [LC202309000703]; Continuous-Support Basic Scientific Research Project [BJ22002903]; Presidential Foundation of China Institute of Atomic Energy [YZ202212001003].