Preparation Of Ag-Ce Bimetal Ion-exchanged And Micro-mesoporous Y Zeolite And Its Adsorption Desulfurization Performance

Micro-mesoporous AgCeY（meso-AgCeY）adsorbent was successfully prepared by the liquid-phase Ag,Ce ions exchange and sequential dealumination-desilication Y zeolites.The adsorbents were characterized by X-ray diffraction（XRD）,N2 sorption（BET）,X-ray photoelectron spectroscopy（XPS）,Pyridine adsorption infrared spectroscopy（Py-IR）,Fourier transform infrared spectrum（FT-IR）,Scanning electron microscope（SEM）and Transmission electron microscope（TEM）.The effect of different preparation conditions on the adsorbent desulfurization were studied by static adsorption experiment with different sulfur（toluene/ cyclohexene）contained model gasoline.The desulfurization properties were evaluated in a fixed-bed unit through different amount of toluene or cyclohexene contained model gasolines.Adsorbent regeneration,isotherm,kinetic and thermodynamic of meso-AgCeY were studied.The result shows that:（1）The proper preparation conditions of meso-NaY are that: the concentration of EDTA is 0.2 mol·L^-1,EDTA treatment time is 6 h,the concentration of NaOH is 0.8 mol·L^-1,NaOH treatment time is 30 min.（2）The proper ions exchange conditions are that: the n（Ce）/n（Ag）ratio is 7.5,Ce ion exchange time is 24 h,calcination temperature is 500℃.（3）The proper adsorption conditions are that: adsorption time is 20 min,adsorption temperature is 50 ℃.（4）With the gradually increasing the content of toluene,the selective adsorption capability of the two adsorbents are decreased,but when the content of toluene increase to 16.6 vol.%,the meso-AgCeY still keep its adsorption capability while the AgCeY almost lost its adsorption capability.Same with toluene,with the gradually increasing the content of cyclohexene,the selective adsorption capability of the two adsorbents are decreased,but when the content of toluene increase to 15.8 vol.%,the meso-AgCeY still keep its adsorption capability while the AgCeY almost lost its adsorption capability.The higher desulfurization performance of meso-AgCeY possibly cause the weakened micropore filling effect depressed the non-selective adsorption of toluene and cyclohexene.（5）After five times of regeneration,the adsorption capability of adsorbent only decreased 6.3%.The regeneration method of adsorbent is washed thoroughly with anhydrous ethanol and dried and calcined.（6）The isothermal equilibrium of adsortption 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.