Separation and Purification Technology, Vol.63, No.2, 434-443, 2008
Pervaporation of benzene/cyclohexane mixtures through rhodium-loaded beta-zeolite-filled polyvinyl chloride hybrid membranes
Novel hybrid membranes were prepared by incorporating H-beta-zeolite or Rh-loaded H-P-zeolite (Rh/HP-zeolite) into polyvinyl chloride (PVC) for the pervaporative separation of benzene and cyclohexane. The membranes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to assess their morphology. The characteristics of these membranes for separating benzene/cyclohexane mixtures were investigated by varying zeolite content, feed composition and operating temperature. The results showed a typical trade-off curve; fluxes increased and selectivity decreased with the increase of benzene concentration in feed composition. The pervaporation performance for membranes filled with Rh/H-beta-zeolite was much better than that for pure PVC membrane and membranes filled with H-beta-zeolite. It might be caused by the special interaction between benzene and Rh/H-beta-zeolite found by IGC previously. And the membrane containing 7 wt.% of Rh/H-beta-zeolite showed the highest separation selectivity of benzene at all feed compositions. From the temperature-dependent permeating values, the Arrhenius activation parameters were estimated. The resulting lower apparent activation energy values for permeation flux obtained for the Rh/H-beta-zeolite-filled membranes compared to the H-beta-zeolite-filled membranes were attributed to the special interaction between Rh/H-P-zeolite and benzene. (C) 2008 Published by Elsevier B.V.
Keywords:Pervaporation;Polyvinyl chloride;Rhodium-loaded H-beta-zeolite;Permeation activation energy;Benzene/cyclohexane