Synthesis And Application Of Poly(Ionio Liquids) Membranes In Desulfurization Of Model Gasoline

The sulfur oxides emitted during fuel combustion are one of the main components that cause environmental pollution,and deep desulfurization is the key to efficient and clean use of fuel.Membrane separation is a"green"separation technology,but there is a"trade-off"effect.In order to break this effect and improve the separation performance,according to the design characteristics of ionic liquids,this thesis designs and synthesizes 4 kinds of polyionic liquids,which are blended with polyvinyl alcohol(PVA)to prepare hybrid membranes for simulating gasoline desulfurization experiments,The specific content is as follows:(1)Designed and synthesized 1-methyl-3-octylimidazole polyvinylsulfonate([Omim]Pss),N-octylpyridine polyvinylsulfonate([Opy]Pss),N-octylpyrrole polyvinylsulfonate Salt([Opr]Pss),N-octyltetrahydropyrrole polyvinylsulfonate([Othp]Pss)functionalized ionic liquid;The structure of the synthesized target functionalized ionic liquid was confirmed by infrared and nuclear magnetic methods.(2)Using polyvinyl alcohol(PVA)as the membrane base fluid,the prepared functionalized ionic liquid and PVA are prepared by blending method[Omim]Pss/PVA,[Opy]Pss/PVA,[Othy]Pss/PVA,[Opr]Pss/PVA hybrid membrane material;Based on the characterization of the hybrid membrane material,a simulated gasoline desulfurization experiment was carried out.The result shows:[Omim]Pss/PVA,[Opy]Pss/PVA,[Opr]Pss/PVA,[Othy]Pss/PVA the one-time removal rate of dibenzothiophene in dibenzothiophene-n-octane simulated oil respectively 75.3%,72.5%,68.4%,67.2%;[Omim]Pss/PVA hybrid membrane has the best desulfurization effect,this is because the symmetry of the imidazole ring is the worst compared to the other three,so the polarizability of the cation is the strongest,and the stronger the complexation with the thiophene sulfide,so the desulfurization effect is the best.The pyridine ring has relatively poor symmetry compared with the pyrrole ring and the tetrahydropyrrole ring,so the polarization of the cation is relatively strong.[Opy]Pss/PVA hybrid membrane has better desulfurization effect than[Opr]Pss/PVA and[Othy]Pss/PVA hybrid membrane.The one-time removal rate of benzothiophene in the p-benzothiophene-n-octane simulated oil is 70.8%,70.5%,63.5%,and 62.3%respectively;The one-time removal rates of thiophene in the thiophene-n-octane simulated oil were 61.5%,60.2%,59.6%,and57.4%,respectively.The desulfurization efficiency of the three simulated oils is in order of dibenzothiophene,benzothiophene,thiophene,which is related to the electron cloud density of sulfur atoms of different sulfides,and the electron cloud density is in order of dibenzothiophene,benzothiophene,For thiophene,the greater the electron cloud density,the stronger the?-?force,the better the desulfurization effect.The desulfurization effect of the four membrane materials did not change significantly during the five consecutive reuse processes.(3)Further introduce Cu²⁺into[Omim]Pss and[Opy]Pss polyfunctionalized ionic liquids,and prepare the corresponding Cu²⁺-[Omim]Pss/PVA and Cu²⁺-[Opy]Pss/PVA hybrid membranes to simulate gasoline desulfurization by blending Experiment to study the desulfurization performance of the copper-containing polyfunctionalized ionic liquid/polyvinyl alcohol hybrid membrane.The results show that Cu²⁺is introduced on the basis of the ratio of bromide salt and sodium polystyrene sulfonate at 2:1,and the hybrid films of Cu²⁺-[Omim]Pss/PVA and Cu²⁺-[Opy]Pss/PVA are p-dibenzothiophene,respectively.The desulfurization rate of n-octane and benzothiophene-n-octane simulated oil reached 84.6%and 83.5%.The lone electron of the sulfur atom on the thiophene ring easily interacts directly with the metal ions with high polarizability through S-Cu²⁺,which strengthens the interaction between the thiophene ring and the vaporization membrane,and effectively improves its selective removal ability of thiophene sulfides.