Izvorni znanstveni članak
Preparation of Nano-Size Al-Promoted Sulfated Zirconia and the Impact of Calcination Temperature on Its Catalytic Activity
B. R. Vahid
; Department of Chemical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
N. Saghatoleslami
; Department of Chemical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
H. Nayebzadeh
; Department of Chemical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
A. Maskooki
; Department of Food Technology, Khorasan Research Institute for Food Science and Technology, Mashhad, Iran
Sažetak
Solvent-free technique was employed in this work in order to assess the influence of the calcination temperature on the activity of Al-promoted sulfated zirconia. The catalyst was analyzed by XRD and IR-spectrum method, and catalytic activity was examined
by esterification reaction of oleic acid. XRD analysis revealed that a decline in the percentage of tetragonal phases of zirconia was observed by increasing the calcination temperature from 500 to 900 °C. In addition, a reduction of sulfate groups as SO42– on zirconia
surface was observed. As a consequence, a decline in Brønsted sites with calcinationtemperature enhancement also prevailed. Therefore, the size of Al-promoted sulfated zirconia particles was increased accordingly. On the other hand, with the aluminum sulfate loading, the amount of sulfate ions on Al-promoted sulfated zirconia surface was enhanced and a reduction in particle size of Al2O3/S-ZrO2 was also observed, as compared to non-promoted. The result of this study revealed that an increase of sulfate and alumina groups causes a raise in the acidity of catalyst. Furthermore, the calcined Al-promoted and non-promoted sulfated zirconia would convert 96.10 % and 89.36 % of oleic acid to biodiesel, respectively. Therefore, Al2O3/S-ZrO2 as a catalyst exhibits a higher activity
than S-ZrO2.
Ključne riječi
Sulfated zirconia; alumina; solvent-free; calcination; esterification
Hrčak ID:
83946
URI
Datum izdavanja:
4.7.2012.
Posjeta: 984 *