Xenon Recovery by DD3R Zeolite Membranes: Application in Anaesthetics

Abstract

Xe is only produced by cryogenic distillation of air, and its availability is limited by the extremely low abundance. Therefore, Xe recovery after usage is the only way to guarantee sufficient supply and broad application. Herein we demonstrate DD3R zeolite as a benchmark membrane material for CO2/Xe separation. The CO2 permeance after an optimized membrane synthesis is one order magnitude higher than for conventional membranes and is less susceptible to water vapour. The overall membrane performance is dominated by diffusivity selectivity of CO2 over Xe in DD3R zeolite membranes, whereby rigidity of the zeolite structure plays a key role. For relevant anaesthetic composition (<5 % CO2) and condition (humid), CO2 permeance and CO2/Xe selectivity stabilized at 2.0×10−8 mol m−2 s−1 Pa−1 and 67, respectively, during long‐term operation (>320 h). This endows DD3R zeolite membranes great potential for on‐stream CO2 removal from the Xe‐based closed‐circuit anesthesia system. The large cost reduction of up to 4 orders of magnitude by membrane Xe‐recycling (>99+%) allows the use of the precious Xe as anaesthetics gas a viable general option in surgery.

High‐Silica CHA Zeolite Membrane with Ultra‐High Selectivity and Irradiation Stability for Krypton/Xenon Separation

“…To get more insight in the separation mechanism, single gas permeation of CO 2 , N 2 , Kr, CH 4 and Xe was measured for membrane M2 (Figure 3 a and Figure S4a) and described by a Maxwell‐Stefan formulation [15a, 34] . Together with the adsorption parameters derived from single‐site Langmuir fitting (Table S2), the temperature‐dependent diffusivity was estimated (Figure 3 b).…”

“…[12] Alternatively,k inetic control (diffusion selectivity) can easily dominate over thermodynamic control in membrane gas separation, evidenced by the separation of H 2 / CO 2 , [13] N 2 /CH 4 [14] and CO 2 /Xe. [15] However,K r/Xe membrane separation is challenging because the kinetic diameter difference between Kr (0.36 nm) and Xe (0.396 nm) is less than 0.04 nm and Xe is preferentially adsorbed over Kr (competitive adsorption control). Polycrystalline membranes featuring aw ell-defined pore structure are the most promising for Kr/Xe separation in view of working capacity (permeance) and efficiency (selectivity).…”

Interfacial Thermal Conductivity and Its Anisotropy

“…We investigated three working fluids confined within copper walls [5]. This special design also facilitated the equilibration by increasing interfacial surface area, which had been documented in our previous studies [28][29][30][31], and proved effective in investigating solid-fluid interfacial thermal conductivities [2][3][4]. Figure 1 shows a schematic Processes 2020, 8,27 3 of 18 sketch of a system set-up with a size of 130.14 × 65.07 × 28.92 Å in the x, y, z dimensions, respectively, that contains a liquid between solid walls.…”

Comparative study on different strategies for synthesizing all-silica DD3R zeolite crystals with a uniform morphology and size

“…Additionally, DD3R membranes have an excellent separation performance for CO 2 /CH 4 and CO 2 /N 2 mixtures. [11][12][13][14][15][16][17][18][19][20][21] Most recently, Wang et al 22 reported that a DD3R membrane showed great potential for on-stream CO 2 removal from the Xe-based closed-circuit anesthesia system.…”