Preparation And Desulfurization Performance Of Magnetic Molecular Sieve Catalytic Material

At present,China attaches great importance to environmental protection,especially in terms of air pollution control.Therefore,our country pays more attention to the quality of domestic fuel.Starting from January 1,2018,China will fully implement the national five fuel standard,that is,sulfur content in fuel should not exceed 10 ppm.The traditional hydrodesulfurization has been unable to meet the requirements.Because of mild reaction conditions,low investment cost of raw materials and equipment,oxidative desulfurization can be well removed for thiophene organic sulfur compounds,which has attracted wide attention of scholars.As a good oxygen carrier,Schiff base complexes can effectively activate molecular oxygen.As an excellent carrier,Y zeolite can effectively avoid the two polymerization of Schiff base complexes.Magnetic carrier technology(MCT)and magnetized bed technology are becoming more and more mature,which makes magnetic separation technology widely used in industrial catalysis.Based on the above characteristics,the magnetic molecular sieves 0.05-Fe304/NaY(N2)was prepared by using 0.05 mol/L Fe2(S04)3 solution andNaY molecular sieves for ion exchange.The magnetic and adsorption properties of the magnetic molecular sieves were good.At 25 degrees centigrade,the saturation magnetization is 9.154 emu/g and the coercivity is 143 Oe.The Fe304 particles were distributed evenly in the sodalite cage of the molecular sieve.At 100 degrees centigrade,nitrogen atmosphere,0.05 g magnetic molecular sieves are adsorption desulfurized for 25 mL octane simulated fuel which DBT concentration is 500 ppm.After 150 minutes,the desulfurization efficiency can reach 42.76%.Using the magnetic molecular sieve as the carrier,the Schiff base cobalt complex Co(Salen)is fixed in the super cage of magnetic molecular sieve by the method of "ship in the bottle",and the magnetic high efficiency desulfurization catalyst,0.05-Fe3O4/Co(Salen)/NaY(N2),is prepared.The structural characteristics and internal morphology of the DBT were characterized by SEM,TEM,XRF,VSM,BET,XRD,XPS,FTIR and H2-TPR.The oxidative desulfurization properties of the catalysts were tested.The results show that the Co(Salen)complex and Fe3O4 particles are loaded in the super cage and the sodalite cage of the molecular sieves respectively,and the magnetic load does not affect the oxidation desulfurization effect of Co(Salen).At 100 degrees centigrade,oxygen atmosphere,0.05 g catalyst are oxidative desulfurized for 25mL octane simulated fuel which DBT concentration is 300 ppm.After 180 minutes,the desulfurization efficiency can reach 66.94%.By the test of chemiluminescence,it was concluded that the main active oxygen species of oxidation DBT to become dibenzothiophene sulfone(DBT02)should be superoxide anion radical(·O2-).