| VOCs(volatile organic compounds) are dangerous by-products in many chemicalprocesses. Composite hollow fiber membrane separation is widely applied toseparation VOCs from air. Here, some membranes were made, n-heptane recoveryprocess from the N2 was studied and the effects of some factors on separationperformance were discussed.Firstly, the silicone rubber / polysulfone hollow fiber composite membranes wereprepared by dip-coating method. Some penetrating behaviors of n-heptane through thecomposite membranes were studied. The effects of some factors, includingconcentration of the PDMS, catalyst and cross-linker, on gas separation performanceof composite membranes also were discussed. The structure of silicone rubber, hollowmembranes and hollow fiber composite membranes were analyzed by SEM and IRmethods. The membrane of silicon oil/PS-1, having the best performance of them, hasthe flux of n-heptane 1.17E-07 mol/(m2.s.Pa), and the separation factor 113.Secondly, the heating treatment was applied to enhance the separationperformance of some membrane. The effects of some factors, including thetemperature of heat treatment and the time of heat treatment, were discussed. Thestructure of the membranes before and after the heating treatment were analyzed bySEM and IR. And the membrane of RTV-107/PS-2 got the best performance under theheat treatment of 353.2K and 10 minute heating;the membrane of RTV-107/PVDFgot the best performance under the treatment of 393.2K and 12 minute heating.Finally, the influences of feed flow rate, feed pressure, and the concentration ofn-heptane in permeate gas on gas permeability and selectivity of hollow fibercomposite membranes were studied and the reasonable operating conditions weredecided. The membrane RTV-107/PVDF, having the best performance of all, has theflux of n-heptane 2.16E-06 mol/(m2.s.Pa) and the separation factor 482.39.
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