Desulfurization Of Model Gasoline By Selective Adsorption Over Cu-Ce Bimetal Ion-exchanged Y Zeolite

Cu(I)-Ce(IV)-Y adsorbent was successfully prepared by the liquid-phase ion-exchange Y zeolites with combined Cu and Ce ions.The adsorbents were characterized by means of X-ray diffraction(XRD),N2-adsorption specific surface area measurements(BET),Inductively coupled plasma-atomic emission spectroscopy(ICP-AES),Scanning electron microscopy techniques(SEM),H2 temperature programmed reduction(H2-TPR),X-ray photoelectron spectroscopy(XPS),Pyridine adsorption infrared spectroscopy(Py-IR)and Fourier transform infrared(FT-IR).The adsorptive desulfurization properties of the adsorbents were studied in a fixed-bed unit through a model gasoline which made up of 1-octane solution of the refractory sulfur compounds(Such as thiophene and benzothiophene)and a certain amount of toluene,pyridine or cyclohexene.The results indicate that Cu(I)-Ce(IV)-Y not only has the high sulfur adsorption capacity similar to Cu(I)-Y but also has the high selectivity for sulfur compounds similar to Ce(IV)-Y.For each sorbent,the selectivity of adsorption of sulfur compounds from liquid solutions followed the order:benzothiophene>2,5-dimethyl thiophene>3-methyl thiophene>thiophene.The effect on the metal ion-exchanged Y zeolites for sulfur removal in the order:pyridine>cyclohexene>toluene.The high selectivity of Cu(I)-Ce(IV)-Y for sulfur removal can be attributed to the synergistic interaction between Cu+ and Ce4+.Cu(?)-Ce(?)-Y zeolite bind the organic sulfur compounds through two types of adsorption modes:?-complexation and direct coordination(S-M)interaction.The effect of different ion-exchanged Y Zeolite,ion exchange order,n(Cu)/n(Ce)ratio,ion exchange time and the calcination temperature on the adsorbent desulfurization were studied.The proper technology condition of preparation Cu(?)-Ce(?)-Y is n(Cu)/n(Ce)ratio of 1,ion exchange with Cu(NO3)2 first and then exchanged with Ce(NO3)3,ion-exchange time of 48 h,and calcination temperature of 550 ?.Static adsorption desulfurization results showed that at adsorption temperature 50 ?,model oil 20 mL,adsorben 0.2 g and adsorption for 60 min the desulfurization of BT is 99.5%.The isotherms and kinetic of Cu(?)-Ce(?)-Y were studied by a batch method at ambient conditions through model fuels,which made up of 1-octane solution of benzothiophene,and the thermodynamic parameters(?G,?H,?S)for the adsorption of BT were calculated.The results show that the isothermal equilibrium can be represented by the Langmuir model.The kinetics for the adsorption process can be described by either the Langmuir model or a pseudo-first-order model.The adsorption is spontaneous and exothermic.