4 CONCLUSIONS
In summary, we have reported an ultra-microporous aluminum-based MOF with unique porous walls constructed from benzene rings with a suitable pore size to capture CH4 from a CH4/N2 mixture. The framework material exhibited a high CH4 uptake (33.7 cm3/g) along with satisfactory CH4/N2 selectivity (6.0). Benefiting from a thermodynamic-kinetic synergistic separation effect, this MOF shows excellent separation performance for CH4/N2 mixtures under dynamic conditions, which is comparable to that of a previously reported benchmark CH4/N2 adsorbent (Al-CDC), as demonstrated by our breakthrough experiments. Meanwhile, the CH4 breakthrough uptake of MIL-120Al (19.6 cm3/g) is also higher than most of the previously reported water stable materials. More importantly, further PSA simulations indicated that after a one-step enrichment, pristine 50% methane can be enriched to 86%, and the CH4 recovery and productivity can reach up to 80% and 1.54 mol/h/Kg, respectively. When combined with the good enrichment effect of the PSA simulation, the stable structure, easily scaled-up production, and regenerability of MIL-120Al demonstrate its promising potential as an adsorbent for CH4/N2 separation. This work not only presents a efficient performance adsorbent for low-concentration CMM enrichment, but also provides useful guidance for the design and preparation of novel CH4/N2 separate adsorbents.