Enhanced Adsorption and Separation of Xenon over Krypton via an Unsaturated Calcium Center in a Metal–Organic Framework

Abstract

Krypton (Kr) and xenon (Xe) are nowadays widely applied in technical and industrial fields. Separating and collecting highly pure Xe from nuclear facilities are necessary and urgent. However, the technology is limited due to the inert nature of Xe and other interferential factors. In this work, a calcium-based metal–organic framework, Ca-SINAP-1, which comprises a three-dimensional microporous framework with a suitable pore width, was researched for xenon and krypton separation through both experimental and theoretical methods. Ca-SINAP-1, synthesized in solvothermal and gamma ray conditions, features accessible open-metal sites, exhibits a high Xe/Kr selectivity of 10.32, and owns a Xe adsorption capacity of 2.87 mmol/g at room temperature (1.0 bar). Particularly, its excellent chemical stability (from pH 2 to 13) and thermal stability (up to 550 °C), as well as radiation-resistance (up to 400 kGy β irradiations), render this material a promising candidate for radioactive inert gases treatment.

Creating Optimal Pockets in a Clathrochelate-Based Metal–Organic Framework for Gas Adsorption and Separation: Experimental and Computational Studies

“…Adsorbents based on porous MOFs have emerged as the front-runners for the purification of various gas mixtures by virtue of their high tunability. , Nonetheless, the adsorption and separation of Xe from Kr by MOFs still remain unsolved challenges, since both Xe capacity and separation selectivity have to be addressed. Previous works mostly focused on the introduction of open metal sites (OMSs) that can distinguish Xe versus Kr based on their difference in polarizability (40.44 × 10 –25 cm 3 for Xe and 24.84 × 10 –25 cm 3 for Kr). − …”

Constructing Cationic Metal–Organic Framework Materials Based on Pyrimidyl as a Functional Group for Perrhenate/Pertechnetate Sorption

“…With a burgeoning class of porous materials with large specific surface areas, easy modification, and high stability, MOFs have been widely used in gas storage, luminescence, catalysis, separation, and biomedicine. − Besides these applications, MOFs can also be applied in the nuclear fuel cycle, such as in metal-ion extraction, I 2 sorption, and Kr/Xe capture. − Nevertheless, major MOFs based on metal ions (e.g., Zr IV ) and carboxylic acid exhibit great water stability but lack effective sorption sites or a capacity for anion pollutants . Virtually, designing MOFs for anion capture is a cumbersome task and requires careful consideration of the environment needed .…”

A microporous Ce-based MOF with the octahedron cage for highly selective adsorption towards xenon over krypton

“…[21][22][23][24][25] Furthermore, studies on the selectivity of Xe/Kr with MOFs under irradiation conditions have emerged with the development of nuclear energy. [26][27][28][29][30][31][32][33][34][35][36][37][38][39] Thallapally et al proposed a concept of a two-bed radioactive off-gas treatment with Ni/DOBDC and FMOF-Cu. 40,41 Sameh et al synthesized a SIFSIX-3-M (Cu, Zn, Co, Fe, Ni) series.…”