Catalytic oxidation of isopropyl mercaptan over nano catalyst of tungsten oxide supported multiwall carbon nanotubes

Abstract

Catalytic oxidation of isopropyl mercaptan with the purpose of its removal from a gas stream containing n-hexane, He and O2, has been investigated in this work. Multiwall carbon nanotubes (MWNTs) decorated with tungsten oxide nano particles were selected to catalyze mercaptan oxidation process. The catalysts were synthesized and characterized by XRD, SEM, TEM, BET, and ICP tests. Moreover, the effects of operating parameters of temperature, catalyst loading, Gas Hour Space Velocity (GHSV) and oxygen-to-IPM molar ratio have been investigated in the range 100 to 300°C, 7 to 15wt.%, 2000 to 4000h−1, 15 to 25, respectively. Based on experimental data, mercaptan content of outlet stream was correlated with the four previously mentioned key factors and their quadratic and cubic interactions by use of central composite design of experiments. The results revealed that comparing other parameters temperature had the upmost influence in changing the mercaptan content of outlet stream. Furthermore, nano tungsten oxide loading significantly affected the results. In addition, it was reported that at optimum operating condition: 246°C, catalyst loading: 11.5wt.%, GHSV: 2587h−1 and oxygen-to-IPM molar ratio: 21, mercaptan conversion to products was near 100% even 220min after beginning of reaction.