Removal of organic sulfur compounds from diesel by adsorption on carbon materials

Removal of organic sulfur compounds from diesel by adsorption on different carbon materials, including activated carbons (ACs), carbon aerogels, carbon nanotubes, and AC cloths, was reviewed. The effect of the textural and surface chemistry property of carbon on desulfurization performance, carbon surface modification, adsorption mechanism, and adsorbent regeneration and the effect of other components, including aromatics, additives, nitrogen compounds, and moisture, on adsorptive desulfurization of diesel fuel were also discussed in detail. Carbon materials showed very high selectivity for removing the dibenzothiophenes, especially for 4,6-dimethyldibenzothiophene, which is very difficult with hydrodesulfurization and other adsorbents. Both the textural and chemical properties of AC have an important impact on the adsorption of DBTs. Adsorption selectivity and capacity can be enhanced further by carbon surface modification. Considering the effect of diffusion hindrance and regeneration, mesoporous carbon is more suitable than microporous carbon with pore size <2 nm. It is necessary to eliminate the inhibiting effect of fuel additive and nitrogen compounds on the DBTs before carbon materials are used for desulfurization of real diesel fuel. In the end, some useful suggestions are also made.