Homogeneous membranes based on fullerene‐polyphenylene oxide compositions containing up to 2 wt% fullerene C₆₀ were prepared. The effect of fullerene addition on PPO transport properties was studied in gas separation and pervaporation processes. Permeability coefficients of H₂, O₂, N₂, CH₄, and CO₂ were measured; a correlation between gas transport properties and membrane free volume was established. Pervaporation properties were studied for the system with ethyl acetate synthesis reaction: quaternary system ethanol—acetic acid—water—ethyl acetate and some constituent binary and ternary mixtures. Pervaporation in binary systems, ethanol–water and ethyl acetate–water was considered with the use of the data on sorption capacities and interaction parameters. In pervaporation of a quaternary reacting mixture, the permeate containing essentially ethyl acetate was obtained. Results show that membranes with fullerene additives exhibit improved transport properties.