Research On Desulfurization Adsorption Of Model Gasoline Onto Copper/Yttrium Ion-Exchanged NaY Zeolite

Cu(I)-Y(III)-Y adsorbent was successfully prepared by the liquid-phase ion-exchange Y zeolites. The adsorbents were characterized by X-ray diffraction(XRD),Specific surface area measurements(BET), Inductively coupled plasma-atomic emission spectroscopy(ICP-AES),X-ray photoelectron spectroscopy(XPS), Thermal gravity analysis(TG-DTG), Pyridine adsorption infrared spectroscopy(Py-IR), Fourier transform infrared(FT-IR) and Scanning electron microscopy techniques(SEM). The effect of calcination temperature, ion exchange order, ion exchange concentration, n(Cu)/n(Y) ratio, ion exchange time, the weight of adsorbent, adsorption time and the adsorption temperature on the adsorbent desulfurization were studied. The proper technology condition of preparation Cu(I)-Y(III)-Y is n(Cu)/n(Y)ratio of 1, ion exchange with Cu(NO3)2 first and then exchanged with Y(NO3)3, ion-exchange concentration of 0.1 mol·L-1, ion-exchange time of 48 h, and calcination temperature of 550 oC. Static adsorption desulfurization results showed that at adsorption temperature 50 oC,weight ratio of adsorbent to oil for 0.01 g·m L-1and adsorption for 60 min, the BT uptake reach 99 %.The adsorptive desulfurization properties of the adsorbents were evaluated in a fixed-bed unit through different kinds of model gasolines which made up of 1-octane solution of refractory sulfur compounds of thiophene and benzothiophene and along with a certain amount of ortho-xylene, meta-xylene or para-xylene, respectively. Cu(I)-Y(III)-Y zeolite has a good desulfurization capacity which similar to Cu(I)-Y, and the adsorption affinity follow the order: benzothiophene > 2, 5-dimethyl thiophene > 3-methyl thiophene > thiophene.Cu(I)-Y(III)-Y adsorbent also has a high selectivity which similar to Y(III)-Y, the inhibition effect on the metal ion-exchanged Y zeolites for sulfur removal was in the order of ortho-xylene > meta-xylene > para-xylene. The strong selective adsorption capacity of Cu(I)-Y(III)-Y for organic sulfur removal can be attributed to two types of adsorption modes:π-complexation(through Cu+) and direct coordination(S-M) interaction(through Y3+).The isotherms and kinetic of Cu(I)-Y(III)-Y were studied, and the thermodynamic parameters(ΔG, ΔH) 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-second-order model. The adsorption is spontaneous and exothermic.