Adsorption characteristics of dichlorodifluoromethane (freon-12) over Pd-supported on SiO2 and AlF3 matrices prepared by sol-gel method

作者：Hina R^*; Arafa I

来源：Acta Chimica Slovenica, 2004, 51(4): 729-742.

• freon-12
• adsorption thermodynamics
• sol-gel
• Pd-supported on silica and aluminumfluoride
• SEM

0.5% Pd supported on SiO2 and AlF3 matrices were prepared by sol-gel method. The morphology, surface porosity (BET surface area, pore volume & pore diameter) and total surface acidity of these catalysts were investigated using scanning electron microscopy (SEM), N-2 adsorption isotherm and gas-phase pyridine adsorption, respectively. It was found that the BET specific surface area and total pore volume of 0.5% Pd/SiO2 are larger than those of 0.5% Pd/AlF3 whereas the total surface acidity was higher in the case of 0.5% Pd/AlF3 catalyst. The gas-phase adsorption process of dichlorodifluoromethane (freon-12) over the prepared catalysts was investigated at 0, 31, 55 and 180degreesC. The fraction of sites (theta) occupied by freon-12 at these conditions, were calculated from Langmuir adsorption isotherm. Thermodynamic analysis of freon-12 adsorption data at equilibrium (K-ads, DeltaG(ads), DeltaH(ads) and DeltaS(ads)) indicates that the adsorption of freon-12 over 0.5% Pd/AlF3 was more favorable than that on 0.5% Pd/SiO2.

• 出版日期2004