Removal of refractory organic sulfur compounds in fossil fuels using MOF sorbents

The stringent new regulations to lower sulfur content in fossil fuels require new economic and
efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such
compounds is very costly and requires high operating temperature and pressure. Adsorption is a
non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild
conditions and it can be potentially used in industrial desulfurization. Intensive research has been
conducted in materials development to increase their desulfurization activity; however, even the
highest activity obtained is still insufficient to fulfil the industrial requirements. To improve the
adsorption capacity and sorbent regeneration, more work is needed in areas such as increasing
specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature,
and development of new porous substrates for desulfurization of a broader range of sulfur
compounds. This work comprehensively describes the adsorption of organo-sulfur compounds
present in liquid fuels on metal-organic framework (MOF) compounds. It has been demonstrated that
the extent of dibenzothiophene (DBT) adsorption at temperatures close to ambient (304 K) is much
higher on MOF systems than on the benchmarked Y-type zeolite and activated carbons. In addition, the
DBT adsorption capacity depends strongly on the MOF type as illustrated by the much higher extent of
adsorption observed on the Cu-(C300) and Al-containing (A100) MOF systems than on the Fe-containing
(F300) MOF counterpart.