Deuterium/hydrogen permeation through different molecular sieve membranes: ZIF, LDH, zeolite

• Deuterium (D2)/hydrogen (H2) permeation was studied on MOF and zeolite membranes.
• In single gas studies on ZIF-90, ZIF-8 and NiAl–CO3-LDH, the D2 permeabilities are 3 times > H2.
• In the permeation of the binary equimolar D2/H2 mixture, no separation was found.
• This finding is explained by strong molecular D2 and H2 interactions at high pore filling.
• He and D2 do not show different permeation through ZIF-8, ZIF-90 and LDH membranes.

Different molecular sieve membranes have been evaluated in the separation of deuterium (D2)/hydrogen (H2) mixtures. Both the single gases and the binary D2/H2 mixture have been permeated at room temperature through supported Metal Organic Framework (MOF) membranes (ZIF-8 and ZIF-90) as well as through supported zeolite (SOD, LTA, FAU) and layered double hydroxide (LDH) membranes. Also the D2/H2 permeation through the non-coated bare α-Al2O3 supports, and pressed graphite discs has been studied. Since the molecular mass of D2 is twice the mass of H2, and D2 is slightly smaller than H2, D2 should show higher single component permeability than H2 because of its favored adsorption and diffusion compared with H2. For the MOF membranes (ZIF-8 and ZIF-90) as well as the LDH membrane, the single gas D2 permeabilities are indeed by the factor of 3 larger than those of H2 at room temperature. However, due to strong molecular interaction, no separation is found for the equimolar D2/H2 mixture. For comparison, we also studied the permeation of He/D2. Since these mixture components are of the same molecular mass and almost the same size, no separation can be expected and no separation has been found.

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