Removal of organically bound sulfur from oil shale by iron(III)-ion generated–regenerated from pyrite by the action of Acidithiobacillus ferrooxidans — Research on a model system

Abstract

Oil shale is one of the alternative sources of hydrocarbon fuels (“synthetic petroleum”) but is characterized by increased sulfur and nitrogen contents, which represent even greater ecological problems in its use compared to classical fuels. Acidithiobacillus ferrooxidans ( At. f.) is capable of oxidizing pyrite to iron(III)-ions, providing a strong oxidation agent at low pH. We have used this oxidizing agent for the oxidation of the sulfur present in dibenzothiophene (DBT), as a substrate model to demonstrate its potential to oxidize organically bound sulfur in oil shale. An HCl-concentrate of oil shale was used as the hydrocarbon matrix. Acidithiobacillus ferrooxidans has already been shown to oxidize the pyritic sulfur component, thereby potentially providing a complete sulfur removal system. By applying GC-MS, we established that DBT transformation occurred by oxidation or elimination of sulfur. The products obtained were more soluble in water than the parent compounds, which reduced the concentration of organic sulfur.