May I determine the Si/Al ratio if I quantify these elements using ICP AES data from the precursor material and if I start the synthesis and control the cristalographic profile using DRX?
Dear Arthur Vasconcelos
How are you? Hoping you are fine.
You can determine Si/Al ratio by both techniques ICP-AES and XRD data, but the more accurate is ICP-AES because the technique principle (Which use absorption/emision principles with external standards)
With XRD also you could determine this relationship, but I am not sure about accuracy (please check this reference:
Breck, D. W. .; Flanigengem, E. M. . Molecular Sieves. In Society of Chemical Industry; London, 1968; p 47.)
Using XRD for calculating Si/Al ratio you need first to calculate the number of aluminum atoms towards the next equation:
Nal=115.2(Ao-24.191)
where Ao=is the unit cell (considering the standard peaks, this value will depende on the type of your sample)
After calculation of Nal, you can determine Si/Al using next equation:
Si/Al=192-Nal/Nal
You could try by both techniques and compared it with respect to theoretical value.
If you have any doubt you could contact me.
Regards,
Julián.
Thank you Julián E. Sánchez-Velandia , I saw this method for the calculus, this method requires a DRX analysis to obtain the parameter a0. Do you know something about the use of elements percentages from ICP AES results for Si/Al calculation?
with regards
Dear Arthur Vasconcelos ! Tudo bem? Yes, I know how to calculate Si/Al ratio from the percentages given by ICP-AES.
First, measure the percentage of Si and Al in your sample, and after, transform it in molar values, finally divided those values to obtain SI/Al.
But, take into account that this value will be general, I mean... It will be include Al framework and extraframework.
If you would like to determine the aluminum of framework and extraframework you will need more sophisticated technique such as NMR of solids.
Regards,
Julián.
Please look at the following below links which may help you in your analysis:
https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=903425
Thanks