Microporous Polyamide Membranes for Molecular Sieving of Nitrogen from Volatile Organic Compounds

Microporous polymer membranes continue to receive tremendous attention for energy‐efficient gas separation processes owing to their high separation performances. A new network microporous polyamide membrane with good molecular‐sieving performance for the separation of N 2 from a volatile organic compound (VOC) mixture is described. Triple‐substituted triptycene was used as the main monomer to form a fisherman's net‐shaped polymer, which readily forms a composite membrane by solution casting. This membrane exhibited outstanding separation performance and good stability for the molecular‐sieving separation of N 2 over VOCs such as cyclohexane. The rejection rate of the membrane reached 99.2 % with 2098 Barrer N 2 permeability at 24 °C under 4 kPa. This approach promotes development of microporous membranes for separation of condensable gases.