The Study On Micromorphological Structure Optimization And Gasoline Desulfurization Performance Of EC/TiO₂ Membrane

Currently,considering the increasingly serious atmosphere pollution resulted from the vehicle exhaust,there is an irreversible tendency in terms of the production of low sulfur clean fuel.The membrane desulphurization by PV is considered to be an effective gasoline desulfurization technique because of its low loss of octane number and low investment.Polymeric membrane material is the PV core in the membrane separation process of gasoline.In this study,the EC/TiO₂ organic-inorganic hybrid membranes with different content of TiO₂ sol were prepared for morphologies characterization and performance test.In this study,ethyl cellulose?EC?was selected as the basis membrane material.It is quite necessary to take the chemical crosslinking modification to improve the swelling resistance of EC membrane,and take the hybrid blending method of doping inorganic nano particles to improve the pervaporation performance.According to the separation results,it was showed that the conditions of membrane preparation and PV experiment operation have great influence on separation performance.Specifically,for the model gasoline,the permeation flux of the 10% EC /TiO₂ membrane was increased to 7.58 kg·m-2·h-1 with sulfur enrichment factor of 3.13 compared to the pure EC membrane?3.73 kg·m-2·h-1,3.69?under the optimum conditions.However,the permeation flux of EC/TiO₂ membrane is four times than that of pure EC membrane when the real FCC gasoline was tested.TiO₂ nanoparticles of 10 nm were obtained by the hydrolysis of TBT.With the increasing content of TiO₂,the spherical particles were preferable to gather to form bigger particles for strengthening the effect of desulfurization,and yet the micro pores in the membrane increased which was in favor of the gasoline permeation.XRD verifies the increase of EC polymer interchain distance with TiO₂ sol injecting,and it shows that EC/TiO₂ membrane is more beneficial for gasoline permeation compared to EC membrane.The morphology of SEM demonstrated that a good stability of TiO₂ nanoparticles in EC matrix after PV desulfurization.Besides,the sorption curve of five gasoline components in EC and EC /TiO 2 membrane indicated that the permeation coefficient for thiophene?1.824×10-10 m2·s-1 and 1.911×10-10 m2·s-1?is more than toluene,cyclohexene,cyclohexane and heptane.The difference between sulfur and hydrocarbon components resulted in the removal of sulfur bearing compounds from gasoline through EC and EC/TiO₂ membrane.The permeation coefficient for thiophene in EC/TiO₂ membrane is more than it in EC membrane,which suggests that the permeation flux for thiophene in EC /TiO₂ membrane is greater than EC.The permeation coefficient ratio of thiophene and gasoline for EC/TiO₂ membrane?0.615?is lower than EC?0.649?,which il ustrated that the enrichment factor of EC/TiO₂ membrane is less than EC membrane.