Highly uniform molybdenum oxide loaded N-CNT as a remarkably active and selective nanocatalyst for H2S selective oxidation

Ghasemy, E ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.scitotenv.2019.134819
  3. Publisher: Elsevier B.V , 2020
  4. Abstract:
  5. Selective oxidation of H2S to elemental sulfur is a low cost and highly efficient process for sulfur removal from H2S-containing hydrocarbon streams in medium scale (i.e. 0.2–10 ton sulfur/day) for environmental protection and prevention of emitting toxic gases to the atmosphere. In this research, in order to prepare a highly active and selective nanocatalyst for selective oxidation of hydrogen sulfide, for the first time, molybdenum oxides were loaded uniformly over nitrogen- doped carbon nanotubes through incipient wetness impregnation. Different metal loadings including 5, 10, and 15 wt% Mo were considered in the synthesis procedure to achieve the optimized performance and provide complete environmental protection. The Mox/N-CNT nanocatalysts were thoroughly characterized via TEM, FE-SEM, XPS, N2 adsorption/desorption, and XRD techniques. The characterization methods confirmed that the Mo oxides nanoparticles were successfully distributed over the N-CNT support uniformly in nanoscale in which there was no sign of agglomeration. The catalytic experiments on Mox/N-CNT were performed in temperature range of 190–230 °C in which the feed gas was composed of 3000 ppm H2S and 1500 ppm O2. The results showed that the Mox/N-CNT samples were highly active at all considered temperatures providing the H2S conversion of almost 100% from which almost no H2S was emitted. Furthermore, by loading the Mo oxide over the N-CNT support, selectivity toward elemental sulfur was increased significantly at high temperatures (i.e. above 190 °C) suggesting that the progress of side reactions on the nanocatalyst has been minimized. The best result was obtained with the sample containing 15 wt% Mo at 230 °C providing the H2S conversion of 100% and selectivity of 89.7%. According to these results, Mo oxide/N-CNT is introduced as a potential candidate for catalytic H2S removal processes toward environmental protection in industrial plants. © 2019 Elsevier B.V
  6. Keywords:
  7. Elemental sulfur ; Hydrogen sulfide ; Molybdenum oxides ; Nitrogen-doped CNT ; Carbon nanotubes ; Doping (additives) ; Environmental protection ; Industrial plants ; Nanocatalysts ; Oxidation ; Sulfur compounds ; Sulfur determination ; Characterization methods ; Incipientwetness impregnation ; Nitrogen doped carbon nanotubes ; Nitrogen-doped ; Optimized performance ; Selective oxidation ; Selective oxidation of H2S ; Molybdenum oxide ; Carbon nanotube ; Unclassified drug ; Adsorption ; Catalyst ; Concentration (composition) ; Molybdenum ; Nanoparticle ; Nitrogen ; Sulfur ; X-ray diffraction ; Article ; Chemical reaction ; Desorption ; Field emission scanning electron microscopy ; Hydrogen sulfide removal ; Nanoanalysis ; Nanocatalyst ; Priority journal ; Synthesis ; Temperature measurement ; Transmission electron microscopy ; X ray photoemission spectroscopy
  8. Source: Science of the Total Environment ; Volume 711 , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0048969719348107