Preparation And Desulfurization Performance Study Of PEG Based Mixed Matrix Membrane

The sulfur dioxide?SO_X?produced after the combustion of organic sulfur in gasoline directly emits severe air pollution and threatens the living environment of human beings.China's oil sources are relatively single,Fluid Catalytic Cracking?FCC?gasoline accounting for about80%of the oil market.Therefore,removing the organic sulfur in FCC gasoline and production clean gasoline is imminent.Pervaporation is a new separation technology,which has the advantages of mild operating conditions,low energy consumption,high separation efficiency and desulfurization capability,no loss of octane number,and the like when used for desulfurization.One of the critical factors of PV desulfurization process is the membrane material.Mixed matrix membranes?MMMs?combine the advantages of organic membranes with inorganic membranes to provide synergistic effects.However,due to the problems of agglomeration of inorganic particles and interfacial defects,the traditional mixed matrix membrane can not achieve the desired separation effect.In this paper,water-soluble polyethylene glycol?PEG?is selected as the organic film matrix,and SiO₂ and ZIF-8 directly dispersed in water without drying.The method of blending?water-based process?is adopted to prepare SiO₂-PEG/PVDF MMMs and ZIF-8-PEG/PVDF MMMs respectively,which improved the desulfurization performance of PEG membranes.First of all,in this article ZIF-8 nanoparticles were prepared by the method of aqueous phase synthesis.ZIF-8-PEG/PVDF MMMs was prepared by mixing ZIF-8 aqueous dispersion with PEG aqueous solution.The structure and properties of ZIF-8 particles were characterized by Scanning electron microscopy?SEM?,Fourier Transform infrared spectroscopy?FT-IR?,X-ray diffraction?XRD?and nitrogen adsorption.The surface composition and structural morphology of all ZIF-8-PEG/PVDF MMMs were systematically investigated by FT-IR and SEM.Moreover,effect of ZIF-8 particle loading,operating temperature,and feed sulfur content on separation performance of ZIF-8-PEG/PVDF MMMS were investigated.Experiments show that the ZIF-8 particle loading is 4%and the ZIF-8-PEG/PVDF MMMs has the best pervaporation performance.When the feed concentration was 200 ppm and the operating temperature was 75°C,the permeation flux of 4%ZIF-8-PEG/PVDF MMMs reached 1.96 kg/?m²·h?,and the sulfur enrichment factor was 8.93,which increased by 397%and 18.75%versus pristine PEG membrane,respectively.Then,SiO₂-PEG/PVDF mixed matrix membrane was prepared by the water-based process.The Si O₂ particles were characterized by transmission electron microscopy?TEM?.The surface composition and structural morphology of all SiO₂-PEG/PVDF MMMs were systematically investigated by SEM,FT-IR and X-ray photoelectron diffraction?XPS?.The effects of particle size,loading and operating temperature of SiO₂ particles on the pervaporation performance of SiO₂-PEG/PVDF mixed matrix membranes were investigated.The results showed that the permeability of the SiO₂-PEG/PVDF mixed matrix membrane was significantly higher than that of the pure PEG membrane.When the loading of Si O₂particles was 1%,the feed concentration was 200 ppm,and the temperature was 75°C,the permeation flux was 4.0 kg/?m²·h?,and the sulfur enrichment factor was 8.93,which increased by 915%and 18.75%versus pristine PEG membrane,respectively.