I synthesized sapo-34/zsm-5 composites via seed induced method, and some of my samples turn to gray after calcination . I calcinated all the samples at 500C and for 5 hr. Does any one know that which factors may be the reason of this problem?
many thanks in advance
Dear Nooshin,
The next link (from RG) could be useful for you:
https://www.researchgate.net/post/What_factors_make_zeolites_look_colorful_and_how_can_they_be_whitened
Best,
Fran
In addition to the factors included in the link by Francisco Manuel Marquez , it is possible that organic compounds (used as templates or incidental contaminants) were not completely oxidized during the thermal treatment, so you ended up with traces of carbonized material. Higher calcination temperature or (preferably) oxygen atmosphere and longer calcination should help if this is the problem.
If organic SDA was used, there is always a trace of carbon remaining after calcination. This gives it the Grey color. It does not take much to give zeolites color. So, good news is that slight color would likely not effect performance.
I used glucose too during the preparation of ZSM 5, after hydrothermal carbonization the color was dark brown. Ultimately I will get brown color product, is it?
- Badges
- Science topic