H2/D2 separation in gas chromatography through a MOF-on-MOF strategy using γ-AlOOH@Al(OH)(1,4-NDC)@ZIF-67 as the stationary phase via additive effects of chemical affinity quantum sieving and kinetic sieving

Abstract

The reaction of porous γ-Al₂O₃ particles acting as both a sacrificial template and an aluminum source with 1,4-naphthalene diacid (H₂NDC) resulted in the formation of γ-AlOOH@Al(OH)(1,4-NDC) composites, in which ZIF-67 was then loaded by the in situ crystallization method, leading to the formation of γ-AlOOH@Al(OH)(1,4-NDC)@ZIF-67 composites. The deliberately designed composite was used to separate H₂/D₂ at 77 K in a 1 m chromatographic column. The results demonstrated that the optimized composite can achieve the effective separation of H₂/D₂ in gas chromatography due to the additive effects of kinetic sieving and chemical affinity quantum sieving of Al(OH)(1,4-NDC) and ZIF-67. By optimizing chromatographic separation conditions, the resolution R reached 2.02 with the separation time t = 7.72 min. The composite also showed satisfactory repeatability and reproducibility.