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 N₂ 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 N₂ over VOCs such as cyclohexane. The rejection rate of the membrane reached 99.2 % with 2098 Barrer N₂ permeability at 24 °C under 4 kPa. This approach promotes development of microporous membranes for separation of condensable gases.