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.