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Aromatic sulfur compounds present in liquid fuels in the form of thiophenes are converted into sulfur oxides (SO x ) during the combustion of fuels and cause major environmental problems such as acid rain, global warming, and air pollution. The adsorptive desulfurization of four aromatic sulfur compoundsthiophene, benzothiophene, dibenzothiophene, and 4,6-dimethyl dibenzothiophenefrom n-octane was investigated in the current study over five typical metal–organic frameworks (MOFs), namely MIL-53(Cr, Al, Fe), Cu-BDC, and HKUST-1, which were successfully synthesized and characterized using XRD, FT-IR, SEM, and N2 adsorption–desorption. The results indicate that for ADS of thiophene and BT, the adsorption capacity of MOFs increases in the order MIL – 53(Fe) < Cu – BDC < HKUST – 1 < MIL – 53(Al) < MIL – 53(Cr), for DBT, it increases in the order Cu – BDC < MIL – 53(Fe) < HKUST – 1 < MIL – 53(Al) < MIL – 53(Cr), and for DMDBT, it increases in the order HKUST – 1 < Cu – BDC < MIL – 53(Fe) < MIL – 53(Al) < MIL – 53(Cr). It is evident that among the synthesized MOFs, MIL-53(Cr) demonstrated the highest adsorptive desulfurization capacity upon removing sulfur compounds from model oil due to its high surface area and suitable pore diameter, with sulfur removal performance of 29, 39, 61, and 88% for the adsorption of thiophene, benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene, respectively. Adsorption data were checked through kinetic models and isotherms, and it has been shown that the adsorption kinetics follow the pseudo-second-order kinetic model, and the adsorption isotherm is better described by the Langmuir equation.

In this study, the influence of CO 2 and CH 4 on the performance and selectivity of Co-Ru/Al 2 O 3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO 2 in the feed stream do not change the catalyst activity, but increasing the amount of CO 2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature, CO conversion will increase but there are more volatile components in the product. The effect of CO 2 on catalyst deactivation is also investigated and a mechanism is suggested to explain the negative influence of CO 2 on catalyst deactivation.