Construction Of New Desulfurization System Of Fuel Based On Janus Emulsion

Janus emulsification is the phenomenon that the functional surfaces of Janus material have affinities on both of immiscible two phases.The Janus emulsion can be easily demulsified because of the utilization of the solid emulsifier,which was totally different from the conventional micro-emulsion.Explicitly,the emulsifier can also be recovered via the simple separation of the solidified Janus material,for example using centrifugation.In this dissertation,a series of ionic liquids(ILs)based Janus nanosheets with dual functions of emulsifiers and catalysts were synthesized,and they were applied to the oxidative desulfurization system for the first time to realize the ultra-deep desulfurization of model oil.Janus microspheres with a paraffin-in-water core/shell structure were synthesized using three kinds of silane reagents as precursors by the sol-gel process.The imidazolin based Janus nanosheets were then compounded after the paraffin core was dissolved and further crushed using an ultrasonic cell crusher.The [BMIM]Cl based Janus nanosheets were synthesized via a selective reaction between n-chlorobutane and imidazolin based Janus nanosheets,which possessed a functional included interface with one side being the ILs and the other side being the phenyl function groups.The catalytic anion of [HSO4]-,[SiW12O40]4-,[PMo12O40]3-and [PW12O40]3-can be selectively loaded onto the specific surface of the IL,leading to the immobilization of catalysts on the Janus nanosheets.Their morphologies and surface properties were characterized using SEM,EDS,FT-IR and XPS spectra.It is noteworthy that the separated two sides of the catalytic nanosheet were still modified with polar IL and non-polar phenyl function group respectively,demonstrating that the catalytic nanosheets preserved their original Janus structures efficiently.The amphipathy of catalytic Janus nanosheets with two immiscible solutions of the desulfurization system,such as IL of [BMIM]BF4 and the model oil of n-octane was analyzed.It can be observed that all of the Janus nanosheets could be uniformly dispersed in [BMIM]BF4 or n-octane to form a homogeneous milky-white solutions.Moreover,both of these two homogeneous suspensions were stable even after the storage for several weeks,indicating that the Janus nanosheets exhibited good amphipathic character toward the two necessary solvents for desulfurization.The well-distributed emulsion droplets can be clearly observed by the optical micrographs.The as prepared catalytic Janus nanosheets were introduced to the oxidative desulfurization system for the first time.The results showed that [BMIM]3PMo12O40 based Janus nanosheet was the best catalyst.The optimum conditions were determined as follows: the amount of catalyst was 30 mg,O/S = 5,T = 50 ?.Based on that,the desulfurization performance of [BMIM]3PMo12O40based Janus nanosheets was investigated.The results showed that the sulfur removal of dibenzothiophene(DBT)reached 100%,the sulfur removal efficiency of DBT could still reach 99.8% after the catalytic nanosheets have been recycled at least six times.