Extraction desulphurization of fuels using ZIF-8-based porous liquid

Porous ionic liquids (PILs), coupling the permanent porosity of porous solids with the good solubility and liquid fluidity of ionic liquids, have been successfully synthesized and offer great opportunities in the development of adsorption and separation. In this study, series of zeolitic imidazolate framework-8 based PILs (ZIF-8-PILs) are constructed and used for extractive desulfurization of fuels. Effects of extraction time, temperature, mass ratio of PILs to model oil and initial sulfur concentration on desulfurization are investigated. ZIF-8-based N-butylpyridinium bis(trifluoromethanesulfonyl)imide PILs (ZIF-8/[Bpy][NTf2]) exhibits encouragingly high performance with the removal efficiencies of thiophene (TH) and benzothiophene (BT) of 72.41% and 80.87% under optimum extraction conditions. After extraction, PILs can be facilely recovered and reused with steady removal efficiencies. The stable liquid porous structure of ZIF-8-PILs plays a dominant role for the excellent extractive desulfurization performance, and the synergistic effects of electrostatic interaction, hydrogen bonding and pi-complexation interaction among ILs, ZIF-8 and sulfur compounds are also closely relevant to the high removal efficiency. The results of this work show that PILs are a new and promising extractant for fuel extraction desulfurization process.