Purification of Air from Organic Compounds Using a Nanofiltration Composite Membrane Based on Cellulose Acetate and a Commercial OPMN-P Membrane

Nanofiltration membranes are used to separate a vapor–air mixture containing organic compounds. The membrane is obtained on a filter paper substrate by pouring with a three-component polymer solution. The surface layers are deposited onto the substrate, sequentially alternating the stages of drying of the membrane. The resulting membrane possesses hydrophilic properties; the porosity of the resulting membrane is 51%. The thickness of the membrane determined by SEM is 98 µm. The retention capacity of the membranes is studied by separating ethanol–air and gasoline–air model mixtures. The membrane permeability of an MAC3 composite membrane during separation of an ethanol–air vapor–air mixture is 11.0 m³ m⁻² h⁻¹ at 0.5 MPa. A high retention capacity of an MAC3 composite membrane is established for xylenes, toluene, and heptane; for other compounds, the efficiency is no higher than 90%. The average retention capacity of the resulting membrane is 87%. Comparative tests on the determination of the gas separation parameters under similar conditions are carried out with a commercial OPMN-P membrane.