Study Of Pickering Emulsion Oxidative Desulfurization System Based On Supported Polyacid Interfacial Active Material

Fuel oil desulfurization is required because the latest environmental regulations limit the sulfur content of fuel oil to less than 10 ppmw.Oxidative desulfurization is an effective and well-established technology for desulfurizing fuel oil,and it may successfully remove refractory aromatic organic sulfur under mild circumstances.To address the technical difficulties of difficult recovery of homogeneous catalysts in oxidative desulfurization and the high mass transfer resistance of conventional two-phase systems,this paper prepared amphiphilic carriers by modifying graphene oxide（GO）with hydrophobic carbon chains such as hexadecylamine（HDA）and compounding it with silica-based materials such as aminated hydrophilic magnetic silica（m Si O₂-NH₂）,SBA-15（NH₂-SBA-15）and MCM-41（NH₂-MCM-41）through the nucleophilic substitution reaction of epoxy groups with amino groups.HPW@m Si O₂/GO-HDA,HPW@SBA-15/GO-HDA,HPW@MCM-41/GO-HDA-2 and other series of loaded multi-acid interfacial activity catalysts were made by loading catalytically active substance phosphotungstic acid（HPW）through the interaction of multi-acid and amino electrons,and constructing Pickering emulsion oxidation desulfurization system by this,so as to overcome the mass transfer resistance of traditional two-phase system and realize the process recyclability.The research content is as follows:1)The physical structure and components of the catalyst were analyzed by various characterization means using HPW@m Si O₂/GO-HDA as catalyst and emulsifier.The results show that the catalyst retains the sheet structure of GO,and one side of the sheet is connected with multiple m Si O₂ core-shell microspheres,and the other side is grafted with hydrophobic carbon chains.HPW is uniformly supported on m Si O₂ and maintains the Keggin structure.The Pickering emulsion oxidative desulfurization system was constructed and the desulfurization performance was analyzed.The experimental results show that the final desulfurization rate is 99.21%under the conditions of 60 ^oC,oxygen-sulfur ratio（O/S）of 6 and catalyst dosage of 3 wt%.After the reaction,the system can be demulsification by magnetic separation to recover the catalyst.After the catalyst was recycled 5 times,the desulfurization rate still reached more than 98%,and the material maintained its original magnetism.2)HPW@SBA-15/GO-HDA was used as a catalyst and emulsifier to characterize and analyze its structure and components.The results showed that SBA-15 microspheres were grafted onto the GO side,HPW was uniformly supported on SBA-15 microspheres,and the catalyst had mesoporous structure.The Pickering emulsion oxidative desulfurization system was constructed and the desulfurization performance was analyzed.The experimental results show that under the conditions of 60 ^oC,O/S of 6 and catalyst dosage of 3 wt%,the final desulfurization rate is 99.80%,and the desulfurization performance is still above 98%after 10 cycles.3)HPW@MCM-41/GO-HDA-2 was used as catalyst and emulsifier,and the physical structure and components of the catalyst were characterized and analyzed.The results showed that MCM-41 was successfully grafted onto the GO side.With the decrease of MCM-41 mass fraction in the catalyst,the specific surface area,pore volume and HPW loading of the catalyst also decreased,and the hydrophobicity increased.The Pickering emulsion oxidative desulfurization system was constructed and the desulfurization performance was analyzed.The experimental results show that the desulfurization rate of99.65%can be achieved under the conditions of 60 ^oC,O/S of 6,catalyst dosage of 5 wt%and catalyst W element content of about 2 wt%,and the desulfurization performance is still above 98%after 5 times of recycling.