Preparation of Pt-ZSM-5 zeolite membrane catalysts for the isomerization of linear alkane

A ZSM-5 supported membrane was synthesized by the secondary growth method. The Pt-ZSM5 membrane was prepared by the impregnation method. This membrane was characterized by a single gas permeation step at room temperature. The isomerization of n-pentane was selected as a probe reaction for evaluating the catalytic performance of the membrane. In particular, the effects of the space velocity and the time on stream were considered. After the catalytic tests, the membrane was characterized by Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), and X-Ray Diffraction (XRD). N2 permeance for the membrane, after calcination, was equal to 2.9 x 10(-7) mol/m(2).s.Pa, indicating the coverage of the larger support pores by the zeolite crystals. This result was also confirmed by the SEM investigation. In addition, XRD analysis showed that the ZSM-5 was the desired zeolite type. During the catalytic tests, the reduction of the nC(5) conversion and the increase of the iC(5) selectivity with Weight Hourly Space Velocity (WHSV) were observed. The nC(5) conversion decreased from 2.5 to less than 0.5, with an enhancement in WHSV, while the selectivity increased from 30 to over 70. On the other hand, its conversion on catalyst enhanced from 10% to approximately 38% with an increase in the reaction temperature from 250 to 450 degrees C. (C) 2020 Sharif University of Technology. All rights reserved.