|
MOR |
Mordenite |
Si(90), Al(10) |
Contributed by Wha Seung Ahn
Verified by G. Price, by K. Satya Narayana Reddy, and by Yan Sun
Type Material Na5[Al5Si43O96] : w H2O
Method G. J. Kim, W. S. Alin [1]
Batch Composition 6 Na2O : Al2O3 : 30 SiO2 : 780 H2O
Source Materials
distilled water
sodium hydroxide (Junsei Co., 95% NaOH)
sodium aluminate (Junsei Co., 32.6% Na2O, 35.7% Al2O3)
silica powder (Zeosil from Kofran Co., 91.8% SiO2, 8.2% H2O)a
Batch Preparation (for 56 g dry product)
(1) [40 g water + 19 g sodium hydroxide], stir until dissolved
(2) [(1) + 14.3 g sodium aluminate], stir until dissolved
(3) [(2) + 645 g water], mix
(4) [(3) + 98.2 g silica], stir for 30 minutes
Crystallization
Vessel: Teflon-lined stainless steel autoclave
Incubation: noneb
Temperature: 170¡C
Time: 24 hours c
Product Recovery
(1) Filter and wash to pH < 10
(2) Dry at 100¡C
(3) Yield: near 100% on Al2O3
Product Characterization
XRD: 100% mordenite, characteristic peaks at d = 3.45, 3.97, 9.02, 3.27 and 3.21 Å competing phases: quartz, analcime, gismondine
Elemental Analysis: Na2O : Al2O3: 17.2 SiO2
Crystal Size and Habit: irregular spherical to prismatic, ~ 5 um d
Click here to view XRD pattern
Reference
[1] G. J. Kim, W. S. Ahn, Zeolites 11(1991) 745
Notes
a. Sodium silicate can also be used as a silica source, but crystallization rates are lower.
b. Incubation is not required when using silica powder as SiO2 source; aging at room temperature resulted in larger crystals but lower crystallization rates.
c. Seeding with 5 wt% mordenite in the reaction batch substantially improved the crystallization rate.
d. Typically needle-shaped crystals, but siliceous crystals can be plate or flat prismatic shape.