(12,13) developed different methods for orientation-controlled monolayer assembly of zeolite crystals via covalent linkers or hand rubbing, which facilitate b-oriented MFI zeolite membrane formation by secondary growth. (11) Thus, b-oriented MFI zeolite membranes with straight and short channels are highly desired to maximize permeance (throughput) and separation factor (selectivity) simultaneously. The diffusion coefficient along the straight channel is approximately three times higher than that on the channel perpendicular to this direction. (6) Given the different molecular size and affinity, microporous zeolite membranes should be able to separate the smaller CO 2 molecules from the bigger Xe molecules (3.3 Å vs 4.1 Å) based on a kinetically controlled process.Ĭrystals of the archetype all-silica MFI zeolite exhibit hexagonal platelet morphologies with distinct surfaces, the (100) and (010) faces, and a third surface ( x0 z) with a variable Miller index. In the case of waste anesthetic gas, Xe (50–60% concentration) would be retrieved by selective removal of CO 2.
(3) To make Xe less costly, equilibrium-based adsorption processes using metal–organic frameworks, (3) zeolites, (4) or porous organic cages (5) were explored to capture Xe directly from the air or discharged Xe-containing gas waste. (1) However, its broad application is significantly impeded by the extremely high price of Xe (5000 $/kg) (2) associated with the low abundance in the Earth’s atmosphere (0.087 ppmv) and energy-intensive cryogenic distillation used in its production.
Xenon (Xe) is considered as an attractive and better anesthetic than the standard ones used currently (such as N 2O and fluoroethers) in clinical medicine because of the low risk of hypoxia, not being a neurotoxin, and the absence of “memory” effects in nerve cells.
0 kommentar(er)
