Investigating the Effects of Ag, Cu, and Pd Functionalized Chabazite on the Adsorption Affinities of Noble Gases Xe, Kr, and Ar

Abstract

Separation of the noble gases from air is typically done through a cryogenic distillation process that is both energy intensive and expensive. Ag-functionalized zeolites and MOFs have a well-documented affinity for Xe and, to a lesser extent, Kr that could serve as an economical alternative to this process on a commercial scale. The mechanism driving the Ag–Xe interaction, however, is still a matter of debate, and the use of other metals in place of Ag is not as thoroughly documented. In this study, Ag, Cu, and Pd functionalized chabazite specimens were prepared, and their affinities for the noble gases Xe, Kr, and Ar were investigated and compared to each other and an unexchanged Na-chabazite. From these analyses, Ag-functionalized chabazite displayed the highest affinity for Xe among these samples, but there was not a similar affinity for Kr or Ar. From the results, a mechanism is proposed such that the strong Ag–Xe interaction contains both an underlying physical and electronic aspect related to the formation of Ag nanoclusters within the chabazite pore geometry that alters the chabazite surface state such that Xe is preferentially adsorbed.

Adsorption of radon on silver exchanged zeolites at ambient temperatures

“…There is, however, no general consensus on what physico-chemical form of silver contributes to that effect. While some authors argue that adsorption in silver exchanged zeolites predominantly occurs via interaction with metallic silver nanopaticles 16 , 17 , others have recently reported evidence that the interaction is via Ag + ions incorporated into the zeolite framework 34 – 37 . There is also no conclusive data to what extend the distribution and concentration of silver influence the adsorption properties towards noble gases.…”

Technology Development Roadmap for Volatile Radionuclide Capture and Immobilization

“…The use of HZ-PAN followed by Ag-PAN for Xe and Kr capture and separation is being investigated as an alternative to cryogenic capture and separation to reduce complexity, cost, and risk (Nguyen et al 2009;Garn and Greenhalgh 2013;Garn et al 2014;Coopersmith et al 2023;Torcivia et al 2023;Ladshaw et al 2019;Welty et al 2018).…”