Potential Separation of SF₆ from Air Using Chabazite Zeolite Membranes

Abstract

Chabazite zeolite membranes were synthesized by the secondary growth method. Chabazite powders were obtained by decomposition of zeolite Y and subsequent ion exchange to produce a fully exchanged potassium chabazite. The synthesized powders were used as seeds for membrane synthesis. Chabazite membranes were prepared via hydrothermal synthesis on porous a-alumina disks as supports. The effects of synthesis parameters including synthesis temperature and synthesis time on the chabazite zeolite membranes were investigated. The synthesized powders and membranes were characterized and the separation performance of the synthesized membranes were evaluated by separation of N 2 /SF 6 and O 2 /SF 6 gas mixtures. Gas permeation results are discussed in terms of optimum synthesis temperature and time.

Gas-Permeable Carbon Molecular Sieve Membranes Fabricated from a Norbornene-Functionalized Polyimide–Polyhedral Oligomeric Silsesquioxane Composite

“…In this study, ideal N 2 /SF 6 separation (kinetic diameters of N 2 and SF 6 : 0.364 and 0.55 nm, respectively) was adopted as an indicator to assess the performance of the carbon-POSS membrane calcined at 700 °C. A tradeoff plot was constructed to compare the performance of the carbon-POSS membranes fabricated at different temperatures (200–800 °C) to that of previously reported membranes such as those containing organosilica, , aminosilica, zeolites, − and polymers − (Figure ; see Table S1 for more details). The results suggest that the carbon-POSS membranes fabricated at 700 °C surpass their counterparts fabricated at other temperatures and compete favorably with state-of-the-art membranes while exhibiting reproducible N 2 permeance and ideal N 2 /SF 6 selectivity values of 10 –6 mol m –2 s –1 Pa –1 and 100–200, respectively.…”

Tritiated Sulfur Hexafluoride Disposition Strategies

“…Membranes are typically polymeric materials, but nanoporous zeolite-on-alumina membranes and other inorganic membranes have been reported. 33,61,62 These materials have not been evaluated for purification of SF6 from its decomposition byproducts, but for separations from atmospheric gasses such as N2, O2, and CO2. Polymeric materials are easily decomposed during exposure to tritium.…”

Synthesis of chabazite/polymer composite membrane for CO2/N2 separation

“…Li et al [27] synthesized chabazite membrane in the presence of potassium cation. The seeds for secondary growth of these membranes was prepared by the conversion of micron-sized zeolite Y-type crystal [25][26][27][28][29][30], or from zeolite T [28]. Different substrates have been used for the growth of CHA membranes, such as mullite [27], porous α-Al 2 O 3 [25,29,30], and stainless steel [28].…”