MOF catches xenon and krypton

The porous organometallic skeleton (MOF), which absorbs record amounts of xenon and krypton, may offer an energy-efficient way to capture these gases during nuclear waste recycling (Angers. Chem., Int. Ed. 2022, DOI: 10.1002 / anie.202117807). Traces of radioactive xenon and krypton contaminate oxygen, nitrogen and other gases released during nuclear recycling. Expensive cryogenic distillation is commonly used to remove these isotopes and ensure that they do not enter the environment. Now researchers have found that MOF was discovered 20 years ago (J. Am. chem. Sat. 2000, DOI: 10.1021 / ja003159k) can capture more xenon and krypton than other porous materials. MOF is a lattice of copper ions bound by adamantane-tetracarboxylate-ligands. Its pores are lined by CH groups that predominantly bind the two noble gases, and some of them can shrink to fit perfectly around gas atoms, says team member Shentian Ma of the University of North Texas. The researchers tested the MOF with a mixture of oxygen and nitrogen containing 400 ppm xenon and 40 ppm krypton, a composition typical of gas released during nuclear reprocessing. At atmospheric pressure and 25 ° C the capacity of MOF on xenon was 32 mmol / kg of material, almost three times more than previous record holder, and its krypton power reached a new high of 8 mmol / kg. “In terms of overall performance, it can replace cryogenic methods,” Ma says. Now the team is trying to lower the cost of the ligand and produce MOF in pounds, potentially using a flow reactor. MOF catches xenon and krypton

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