Hi all,
Attached are SEM images of different types of zeolites (3A, 4A, 5A and 13X in that order). How do we interpret these images?
I would like to see the differences in the cage structure/ framework of A and X types, the homogeneity of the pore size distribution which is characteristic of zeolites, location of the cations added in the crystal lattice and adsorbed gases in the pores. If SEM is not a suitable technique, will TEM be helpful?
And also we have around 1.5% carbon in the sample obtained from SEM- EDX analysis. Is it because of coverage of active sites with coke or some CO2 adsorption?
I would be very thankful to the insights provided.
Hi
I have some points
a) The particles are irregular which exhibits poor equilibrium
b) in fourth sample particle size is less.
C) the particles are poly amorphous. More crystall domains are put together.
If you go for lattice and crystall paramters better go for TEM.
Best
I am in no way expert in zeolites, but...
You should ignore %C obtained with EDS, most probably it's an artifact. And discard any quantitative results from EDS and stick to qualitative EDS.
Also I think your present pictures are of not much use. All we can see is some powdered, agglomerated, damaged mineral. You may want to think about other, more appropriate way for your task of specimen preparation (in some relevant papers).
Thank you Arunprakash and Vladimir. As per your suggestions, I understand that the next course of action must be proper sample preparation for SEM and TEM analysis.
Also I was told by SEM operator that since zeolite is an insulator, it was covered with a layer of conducting material by sputter coating and high intensity of electron beam was focused on it. Might this be a possible reason for the damage?
Is there any other diagnostic that would be useful in my case?
Hi
Actually the images are in giod form no doubt. Ol thank the operator. The nature of sample is like irregular and polymorphism.
Bettrr go for TEM. It will say
Saoe, size, crystaline nature, d spacing, grain size and even chemical composition (edax).
Try TEM in CECRI karikudi
Good luck
Any doubts regarding this pl feel free to text.
Best Arunprakash Vincent
Thank you so much...We will get a TEM done. In perfectly crystalline material like zeolite, I am still not able to understand why it is irregular. Also does crushing of sample for analysis results in irregularity? Can we analyse the beads (3mm size) as it is rather than crushing it to powder form?
Of course you should not crash your specimen. The worst thing to do, actually. Your beads are small enough for SEM, so you can study their surface and you can crack in half some of them to observe inner structure.
TEM specimen preparation is much more challenging, your lab should have proper equipment for materials specimen preparation.
Anyway, you will not get answer on your question about " location of the cations added in the crystal lattice and adsorbed gases in the pores" with the help on conventional electron microscopy.
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