Fabrication of homochiral metal-organic framework membrane for enantioseparation of racemic diols

Chiral metal-organic frameworks (MOFs) used to discriminate chiral enantiomers are of great practical significance. In this study, a novel homochiral [Ni₂(L-asp)₂(bipy)] membrane was fabricated on a porous ceramic support and used for enantioselective separation of racemic diols. High-energy ball milling was applied to decrease the size of MOF crystals to achieve homogeneous seed suspensions. A high-quality homochiral membrane was obtained after optimizing the preparation process. Under the concentration-driven permeation process, racemic 2-methyl-2,4-pentanediol (MPD) was readily separated by the as-prepared membrane. At 30°C, an enantiomeric excess value of 35.5±2.5% was obtained at a feed concentration of 1.0 mmol L^-1. The chiral separation of racemic MPD via the membrane followed a preferential sorption mechanism.