Hydrogen isotopes separation in Ag(I) exchanged ZSM-5 zeolite through strong chemical affinity quantum sieving

Abstract Zeolites have been considered to be viable candidates for hydrogen isotopes separation in a technological scale due to the well-defined channel, low cost and good thermal and radiation stability. Here, we report a strategy to separate hydrogen isotopes using Ag(I) exchanged ZSM-5(Ag(I)-ZSM-5) zeolite based on strong chemical affinity quantum sieving (CAQS) effect. The thermal desorption spectra (TDS) results reveal that the hydrogen isotope separation on Ag(I)-ZSM-5 zeolite can be achieved at and above liquid nitrogen temperature with a D2/H2 selectivity of 8.7 at 77 K. In addition, 95.1% of deuterium can be enriched through three adsorption/desorption cycles from a mixture with a deuterium concentration of 2.5%. Structural characterization and density functional theory calculations reveal that the high hydrogen isotope selectivity of Ag(I)-ZSM-5 zeolite can be attributed to the strong chemical affinity on Ag(I) site with a large hydrogen isotope effect. Moreover, the hydrogen isotope selectivities (including S (D2/DH), S (T2/D2), S (T2/TD) and S (T2/TH)) on Ag(I)-ZSM-5 are predicted under difference temperatures. Control of the chemical affinity quantum sieving effect of active sites in pore interiors of easily scalable zeolites has unlocked their potential in challenging hydrogen isotopes separation.