Effective separation of cesium with a new silica-calix[4]biscrown material by extraction chromatography

•A novel silica-calix[4]biscrown hybrid material was prepared and characterized.•The materials exhibited strong adsorption ability and high selectivity for Cs(I).•The removal of Cs(I) was more than 99.1% in the batch adsorption and desorption cycles.•The individual separation of Cs(I) from HNO3 was achieved by extraction chromatography.•A new separation process entitled PCEC was proposed.

To separate Cs(I), a new silica-calix[4]biscrown hybrid material, 1,3-calix[4]arene-bis(naph-crown-6) (CalixBNaphC)@SiO2-P, was synthesized by impregnation in situ and immobilization of agent into the pores of the SiO2-P particles. The materials were characterized by SEM images, FT-IR spectra, nitrogen adsorption-desorption isotherms and 29Si solid-state CP/MAS NMR. The adsorption of Cs(I) and some typical metals onto CalixBNaphC@SiO2-P was investigated by examining the effect of contact time and HNO3 concentration in the range of 0.4–6.0 M. Enrichment and recovery of Cs(I) in batch experiments were performed by six adsorption and desorption cycles. The removal of Cs(I) was more than 99.1%. Based on the batch results, the chromatographic separation of Cs(I) from 3.0 M HNO3 was conducted by CalixBNaphC@SiO2-P packed column. The effective separation of Cs(I) was achieved utilizing 3.0 M HNO3 and water as eluents. A new process entitled PCEC (Partitioning of Cesium by Extraction Chromatography) for individual separation of Cs(I) was developed.

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