Dynamic Quantum Molecular Sieving Separation of D₂ from H₂–D₂ Mixture with Nanoporous Materials

Abstract

Quantum molecular sieving separability of D(2) from an H(2)-D(2) mixture was measured at 77 K for activated carbon fiber, carbon molecular sieve, zeolite and single wall carbon nanotube using a flow method. The amount of adsorbed D(2) was evidently larger than H(2) for all samples. The maximum adsorption ratio difference between D(2) and H(2) was 40% for zeolite (MS13X), yielding a selectivity for D(2) with respect to H(2) of 3.05.

Adsorption dynamics of hydrogen and deuterium in a carbon molecular sieve bed at 77K

“…On the other hand, the specific surface area of various microporous adsorbents was compared by using the N 2 BET method [24][25][26]. Furthermore, the surface area and the pore size of CMS were measured by the N 2 BET method in the hydrogen isotope study [21,37]. In this study, Fig.…”

“…3, the CMS can give rise to more serious diffusion restrictions. At low temperatures and small pore dimensions on the order of de Broglie wavelengths, kinetic quantum effects on pore diffusion are significant [13,18,19,21,22,48,49]. When the pore size of the adsorbents was small, the successive adsorption stage, after initial surface diffusion and pore diffusion, was governed by quantum sieving stemming from different zero-point energies, and the translational and rotational confinements of the hydrogen isotope molecules.…”

“…In addition, it was reported that the dynamic quantum molecular sieving effect in various activated carbon fibers (ACFs), carbon molecular sieves (CMS5A), SWCNTs and zeolites (MS4A, MS5A, MS13X, RHO and H-ZSM-11) contributed to the separation of a H 2 -D 2 mixture, The range of separation factors was from 1.47 to 3.05, showing the separation factor of 1.60 at 5 min in CMS5A [21]. The separation of H 2 and HD, as well as H 2 and D 2 , in practical carbon molecular sieve (Tekeda 3 Å) with a pore size distribution of 0.63-1.0 nm was investigated using path integral simulation [22].…”

“…In addition, structural nanomaterials with uniform pore size distribution were commonly discussed in most experimental and theoretical studies [6,9,[12][13][14][17][18][19][21][22][23][24][25][26]. However, few of hydrogen isotope separation studies were found for adsorbents with wide pore size distribution even though many pelletized adsorbents used in industries have a wide pore size distribution.…”

“…Breakthrough curves of H2 and D2 on CMS bed at different flow rates. (Blank symbol: H2, The comparison of the breakthrough curves among three adsorbents under the total flow rate of 129.8 cm3/min and total pressure of 400.0 kPa (Data of zeolite 5A and Y from reference[21]…”