Preparation of the Porous Supports With SiO 2 -ZrO 2 -Na 2 O Composition
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PREPARATION OF THE POROUS SUPPORTS WITH SiO2-ZrO2-Na20 COMPOSITION. Y. TSURITA AND K. WADA Research Center, Mitsubishi Kasei Corporation, ku, Yokohama City, 227 JAPAN
1000 Kamoshida-chou,
Midori-
ABSTRACT A new method for preparation of porous mixed oxide with SiO -ZrO -Na 0 composition was investigated by heating the sol-gel derived SiO2 microsphere gel in the presence of ZrOClp and NaCI. Surface of the -products was composed of sponge-like structure, similar to the porous glasses manufactured by the phase separation method. Their pore volumes ranged from 1.0 to 1.5
cc/g(pore radius 100-lO00A) and their pore peak tops of about 45o-600A in radius.
distributions were
sharp,
with
INTRODUCTION Porous glasses containing ZrO2 are of considerable technological interest due to their high resistant property to the alkaline solution. In recent years, two methods were reported to prepare these glasses. Eguchi et al. (1) have shown the preparation of Si0 -Zr02based porous glasses from SiO -ZrO -B 0 -CaO-Na 0 mother glasses by The p~hase-separation method.
Nog~mi
[•]
•r~pared a~other Si02 -ZrO2 porous glass through the sol-gel route.
The amount of ZrO2 could be easily controlled with this method. However, it was difficult To obtain the porous glasses with pore size larger than 50A in radius. We have reported recently that a new method for preparation of SiO ZrO2 -Na.O0 porous glass through heating SiO2 -ZrO2 gel in the presence of NaCl [3].'In this study, we will report the prepar-ation of porous supports with SI2-ZO-aO 2 composition and NaCl.
by means of heating Si02
gel together with ZrOCl
2
EXPERIMENTAL Sample Preparation Partial
hydrolysis
of tetraethoxysilane,
of tetraethoxysilane
136.3g of ethanol,
was
performed
43.2g of water,
by
mixing
500g
and 18.7g of 0.1N-
HCI ethanolic solution and refluxing at 60°C for 30 minutes. This solution was heated at 120°C for 2 hours and 150°C for 1 hour under Ar atomosphere to remove volatile material. 44.5mi of the resultant solution, mixed with 7.5 ml of cyclohexane and 22.5mi of t-amylalcohol, was added dropwise into an aqueous solution, which was composed of 433.9g of water, 13.5g of ethanol and 3.4g of Tween 20(Polyethylenesorbitane monolaurate), under stirring at about 970rpm, to form an O/W emulsion. Then, 58.5mi of 17h ammoniac aquous solution was added during 40 minutes, and stirred for 5 hours and let stood over night. A white gel was formed immediately at addition of ammoniac solution. The supernant solution was removed by decantation, the gel was washed with ethanol, collected by filtration and dried at 120°C for 5 hours. Zirconium oxychloride 0.40g together with 0.29g of sodium chloride, was dissolved in 5ml of water. This solution was added to the dried gel 1.0g described above and dried at 120°C for 5 hours. The impregnated gel was heated to 600'C at a rate of 2°C/min., and kept under stream of air for 3 hours and heated again at the designated temperature for 5 hours in the furnace. The calcined sample was washed twice with water and with hot w
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