Superior liquid fuel desulfurization through emulsification solvent extraction using polymeric-based eutectic solvents

The addition of surfactants to solvents results in the formation of well-defined assemblies which contribute to increasing contact area available for mass transfer. In this work, the idea of emulsification solvent extraction was exploited for fuel desulfurization. The extractive desulfurization of two sulfuric compounds was investigated using deep eutectic solvents comprising the quaternary ammonium salt tetrabutylammonium bromide (TBAB) and polyethylene glycol (PEG). The surfactants Triton X-100 and Sodium dodecyl sulfate (SDS) were used as emulsifying agents. Using a mixture of 1:1 volumetric ratio of solvent to fuel, and at room temperature, the extraction efficiency of DBT and thiophene reached 82.40% and 62.16% respectively. With the addition of a surfactant, the removal of DBT and thiophene reached 84.20% and 70.90% respectively. A further enhancement was achieved by the addition of different types of polymers and glycols. With a 50% added PEG 400, the extraction efficiency of the two sulfuric compounds reached 91.47% and 80.89% respectively. To the best of the author's knowledge, the results attained in this work are the highest single stage reported extraction-based sulfur removal within a mixing time of 30 min and at room temperature conditions.