Facile synthesis of Fe-based metal-organic frameworks from Fe 2 O 3 nanoparticles and their application for CO 2 /N 2 separation.

A facile approach was employed to fabricate MIL-100(Fe) materials from Fe 2 O 3 nanoparticles through a conventional hydrothermal reaction without the presence of HF and HNO 3 . Effects of trimesic acid content in the reaction system on the quality and CO 2 /N 2 separation performance of the as-prepared MIL-100(Fe) samples were investigated. Using 1.80 g of trimesic acid in the reaction system yielded the sample M-100Fe@Fe 2 O 3 #1.80, which proved to be the optimal sample. This choice struck a balance between the amount of required trimesic acid and the quality of the resulting material, resulting in a high yield of 81% and an impressive BET surface area of 1365.4 m 2 ·g -1 . At 25 °C and 1 bar, M-100Fe@Fe 2 O 3 #1.80 showed a CO 2 adsorption capacity of 1.10 mmol·g -1 and an IAST-predicted CO 2 /N 2 selectivity of 18, outperforming conventional adsorbents in CO 2 /N 2 separation. Importantly, this route opens a new approach to utilizing Fe 2 O 3 -based waste materials from the iron and steel industry in manufacturing Fe-based MIL-100 materials.