Effective Removal of Cesium by New Functionalized 1,3-Alternate Calixcrown Materials Immobilized on a Silica Carrier

ABSTRACT

Removal of Cs isotopes, one of the heat generators present in used fuel/reprocessing waste, is one of the most challenging obstacles in the disposal of these materials. For this purpose, a new silica-calix[4]crown material, CBisC6@SiO₂, has been prepared. The material was created coupling a symmetric calixcrown derivative CBisC6 into the pores and channels of the SiO₂-P particles through vacuum hybridization and immobilization. SEM, ²⁹Si solid-state CP/MAS NMR, N₂ adsorption-desorption isotherms, TGA-DSC and XPS were used to characterize the structure of the final material. The adsorption of Cs and some representative metals onto CBisC6@SiO₂ has been investigated in the range of 0.4 to 6.0 M HNO₃. CBisC6@SiO₂ showed strong adsorption ability and selectivity for Cs over all of others except for Rb in 3.0 M HNO₃. The adsorption mechanism of Cs was verified using XRD and FT-IR spectra. The separation of Cs from other waste materials by CBisC6@SiO₂ was performed through six adsorption-desorption cycles. The removal efficiency of Cs was 99.5%, while other fission products were weakly absorbed except for Rb with the removal efficiency of 85.3%. A nearly quantitative removal of Cs by CBisC6@SiO₂ was achieved.

KEYWORDS:

• Adsorption
• removal
• calixcrown derivative
• silica adsorbent
• cesium

Disclosure Statement

The authors declare no known financial or personal conflicts of interest associated with this publication.

Additional information

Funding

This work was financially supported by National Natural Science Foundation of China (No. U1832124) and Natural Science Foundation of Zhejiang Province (No. LY17B060004).