Distribution of the Cu ions in the CuHY zeolite and its performance of desulfurization

The CuHY zeolites' absorbents with different Cu loadings were prepared via isovolumic impregnation method, and characterized via X-ray diffraction(XRD), BET surface area measurement and NH(3) temperature-programmed desorption(NH(3)-TPD) techniques. The CuHY zeolites absorbents' performance of desulfurization was investigated in the model diseles containing dibenzothiophene (DBT). The crystalline structure of Cu8HY zeolite and the Cu(2+) cations distribution in the cages of the Y zeolite was determined via powder XRD with Rietveld method. The results show that the frameworks of the Y zeolites were retained after Cu(2+) cations entered the cages of the Y zeolites, the amounts of strong acid sites increased slightly and the amounts of mid-strong acid sites decreased slightly in the CuHY zeolite. At the same time, one part of Cu(2+) cations entering the cages of Y zeolite, and situated at the sites S(I) in the beta cages, while another part of Cu(2+) cations situated at sites S(III) in the supereages and coordinated with water molecules in the supercages. The Cu(2+) cations situating at sites S(III) in the supereages can adsorb DBT molecules in the model diseles and become the centers of desulfurization. However, naphthalene molecules will resulting the competitive adsorption with DBT molecules if there are naphthalene molecules in the model diseles.