Synthesis of robust MIL-140A series membranes for efficient butane isomer separation

Developing advanced membrane materials, represented by MOF membranes, is crucial for the efficient separation of butane isomers, which are important petrochemical industrial raw materials. However, this area has received limited attention to date. In this work, MIL-140A series membranes were successfully prepared on α-Al 2 O 3 ceramic substrates by metal precursor induction method, and were attempted for the separation of butane isomers. The developed MOF membranes exhibit impressive performance in separating n-butane/isobutane mixtures, which is attributed to their appropriate sieve apertures and preferential adsorption of n-butane. This mechanism can be described as size-based sieving assisted by preferential adsorption. Owing to its smaller sieve aperture, the performance of MIL-140A-NH 2 membrane was superior to that of the MIL-140A membrane, showing a n-butane permeance of 136 GPU and an ideal selectivity of 25.4. The excellent separation performance was maintained under varying testing conditions, including operating temperature, operating pressure, feed composition, and testing duration. This work provides a useful reference for the development of membranes for industrial separation of butane isomers.