Preparation of adsorbent CeO₂/NaF and its adsorption performance for MoF₆

Background: The fluoride volatility process has been developed to recover uranium from spent nuclear fuel. And the fluoride adsorption technique is usually applied in the purification and collection of UF₆ during the fluoride volatility process. Purpose: This study aims to investigate the characteristics and sorption performance of a novel sorbent CeO₂/NaF synthesized by doping NaF with CeF₃. Methods: With polymer sodium carboxymethyl cellulose (CMC) as a binder and pore-forming agent, CeF₃ and NaF was mixed according to a mass ratio of 4:9:62, and then water were added (the ratio of CMC to water is 1:6). The porous CeO₂/NaF adsorbent particles were prepared by a mixing, molding and sintering process. The characteristics and adsorption performance of the adsorbent particles were analyzed and characterized. Results: Specific surface area of CeO₂/NaF was (0.84±0.04)m²·g^-1, which was twice of NaF sorbent made under the same process. Porosity was 42.2%, which was larger than that of NaF sorbent. The initial adsorption rate of MoF₆ on CeO₂/NaF was much higher than that of NaF sorbent. The temperature zone for desorption of MoF₆ from CeO₂/NaF ranged from 150 ℃ to 300 ℃, while there were two desorption zones for desorption of MoF₆ from NaF sorbent, which varied from 100 ℃ to 300 ℃ and 350 ℃ to 400 ℃, respectively. This phenomenon showed that CeO₂ might stabilize Mo⁶⁺ in MoF₆. Conclusion: The physical properties of NaF could be changed by doping with CeO₂, and its adsorption performance was also improved. (authors)