Green Hydrogen Separation from Nitrogen by Mixed‐Matrix Membranes Consisting of Nanosized Sodalite Crystals

Abstract

Nanosized sodalite (Nano‐SOD) crystals were used as active filler to prepare mixed‐matrix membranes (MMMs) for promoting the H2/N2 gas‐separation performance. The Nano‐SOD crystals with extremely small crystallites (40–50 nm) were synthesized from a colloidal suspension free of organic structural directing agent and uniformly dispersed in the polyetherimide (PEI) matrix. The Nano‐SOD filler with a suitable aperture size (2.8 Å) allowed only H2 molecules to pass through and rejected the N2, thus improving the selectivity of the membranes. The high dispersion of Nano‐SOD crystals in the polymer matrix and the interactions between the inorganic and organic phases greatly improved the membrane separation performance and minimized interfacial holes. The MMMs showed a high H2 permeability (≈7155.1 Barrer at 25 °C under atmospheric pressure) and an ideal H2/N2 selectivity factor of approximately 16.9 in a single gas test. Moreover, in a gas mixture (H2/N2, 25–100 °C), the selectivity factor increased significantly to approximately 30.9. The high stability of the MMMs, which consist of highly dispersed Nano‐SOD crystals in a PEI matrix for H2/N2 separation (6 weeks continuous test), makes them an important material for ammonia synthesis applications that require and also release a large amount of H2.

Preparation of HKUST-1/PEI mixed-matrix membranes: Adsorption-diffusion coupling control of small gas molecules

“…Herein, we propose a novel homogeneous MOFs-MMMs membranes based on the combination of HKUST-1 nanocrystals and PEI. PEI, commercially known as ULTEM, is a high-performance thermoplastic polymer with imide, isopropylidene and ether groups [26,27]. It is cheap, has a good chemical and heat resistance as well as a good processability.…”

A Review on Combustion Characteristics of Ammonia as a Carbon-Free Fuel

“…It was found that ammonia started to crack when the temperature reached 473.15 K and the conversion efficiency can reach 98-99% when the temperature up to 698.15 K (Klerke et al, 2008;Lan et al, 2012). What's more, in contrast to co-firing hydrogen, using partially cracked ammonia is more economical and easier to implement (Yang et al, 2019). However, the deep insight into the combustion characteristics of NH 3 /H 2 /N 2 mixtures are limited (Mei et al, 2021;Wiseman et al, 2021).…”

Scalable crystalline porous membranes: current state and perspectives

“…64,84,85,88,190,191 ) several template free nanocrystals with SOD, FAU, RHO, CHA and EMT framework structures. 160,[192][193][194] The seeding-secondary growth method of zeolite membranes (seed dispersion, support modification and optimization strategy of mother solution) can be transferred to the preparation of MOF membranes as well. Compared with zeolite, the post-treatment step is easier for MOFs, the pores of most MOFs can be activated at mild condition (temperature below 100 o C).…”