Effect of ultrasonication and chelating agents on the dispersion of NiMo catalysts on carbon for Hydrodesulphurization

The effectiveness of the ultrasonication (US) and chelating agents in the dispersion of NiMo supported on activated carbon were examined. Accordingly, NiMo catalysts supported on carbon were prepared through co-impregnation of the support using US or the addition of chelating agents namely citric acid (CA) or ethylenediaminetetraacetic acid (EDTA) to facilitate the dispersion of the metals on the support. A surface area analyzer was used to provide the BET surface area measurements. Fourier-transform infrared spectroscopy (FTIR) and a powder X-ray diffractometer were used for the characterization of the structure of the prepared materials. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis of the morphology and surfaces of the mapping of the prepared material was obtained to get insight into the metal dispersion on the support. Results revealed a uniform dispersion of the nickel and molybdenum particles on carbon, especially in the case of using EDTA as a dispersion agent. Hydrodesulphurization of dibenzothiophene on the prepared catalysts was tested in a high-pressure batch reactor 1000 »ppm dibenzothiophene in decalin as a model fuel. The results indicated that the chelating agents have a positive impact on hydrodesulphurization (HDS) efficacy and the EDTA has more effect than others. 97 % HDS was achieved using NiMo/AC(EDTA) while 94 % and 92 % were obtained using NiMo/AC(CA) and NiMo/AC(US), compared to 89 % without the use of US and chelating agents.