One source of air pollution is the combustion of sulfur compounds in fuel oil. Reducing sulfur content in fuel oil has become a hot issue demanding timely solutions. Using ionic liquids (ILs) and deep eutectic solvents (DESs) to remove sulfides in fuel oil has achieved good results presently. However, since DESs are liquid and their transportation and separation are inconvenient, a new way is proposed that the DESs are loaded on the carbon nanotubes (CNTs) with large specific surface area and good chemical stability. A series of composites materials (DESs/CNTs) were prepared. Finally, they are applied to the removal of sulfides in fuel oil. This loading method, which imparts introduced unique Physico-chemical properties of the DESs to the carrier materials, preserves both advantages while overcoming some of the problems with DESs. The interaction between DESs and CNTs is mutual promotion. Therefore, this study has important theoretical significance and industrial application value. Under optimal conditions, when the reagent ChCl/p-TsOH (1 : 2) was loaded on multi-walled carbon nanotubes CNTs (OD=30-60nm) to prepare the composite material (ChCl/p-TsOH)/CNTs, the single desulfurisation rate of the composite material was 95.8%. Finally, the catalytic/oxidation mechanism was studied systematically and this work would provide a green route for the desulfurisation of fuels.

Analysis of sulfur concentration in simulated desulfurised oil was by gas chromatography. The chromatographic conditions are showed as follows: chromatogram column: HP-5; injection volume: 0.06 μL; carrier gas (N₂): 210 mL/min; H₂: 40 mL/min; air: 350 mL/min; flux: 1.6 mL/min, constant current mode; inlet temperature: 250°C; detector temperature: 250°C; column temperature: heating from 60°C to 220°C with 30°C/min increase. Th concentration was determined by standard internal method. The n-hexadecane was chosen as the standard internal solvent and concentration was 2000 ppm. The correlation coefficient was found to be 0.99941.