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

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 15 wt.%, 2000 to 4000 h− 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: 11.5 wt.%, GHSV: 2587 h− 1 and oxygen-to-IPM molar ratio: 21, mercaptan conversion to products was near 100% even 220 min after beginning of reaction.

► W supported carbon nanotubes as catalyst to catalyze isopropyl mercaptan oxidation.
► Optimizing operational conditions and their interactions by design of experiments.
► Temperature and catalyst loading have the upmost effects in catalytic oxidation process.
► At optimized conditions mercaptan conversion was sustained 100% within 220 min.
► Process selectivity for sulfur compounds not hydrocarbons.