Dear Arthur,

many thanks for posting this very interesting technical question on RG. As an organometallic chemist I'm not a proven expert in zeolite chemistry. However, I just came across a potentially useful article which might help you in your analysis. Please check this paper:

Acid Properties of Hierarchical Zeolites Y

Article Acid Properties of Hierarchical Zeolites Y

Fortunately this article has been posted by the authors as public full text on RG. Thus you can freely download it as pdf file.

I also suggest that you search the "Publications" section of RG directly for terms like "acidity of zeolites".

Good luck with your research and best wishes, Frank Edelmann

Thanks for The answer professor.

Kind regards,

first of all, what type of acidity are you interested in measuring?

for the time of catalyst stirring with your saline solution, I would say the longer is the better to allow your solution to completely react with the acidic sites of your catalyst, so overnight would be a good option in my opinion.

Mohamed M M Kashbor Thanks for the attention, I am interested to measure the Bronsted sites, so I use KCl as extract solution and standardized NaOH solution for tritration analysis

Dear Aruther

As you are intersted in Bronsted acidity, you can try an acid-base back titration using standarised agents. First of all you treat your catalyst with NaOH for an overnight and then back titrate the unreacted NaOH with an acid like HCl, and work out the calculation in mmol.g-1.

For the time as I told you an overnight at a certian temperature would be sufficient.

Good luck

for the reference values of your parent zeolites (undoped) you can calculate it using artificial stoichiometry and considering the SiO2:Al2O3 molar ratio of your zeolite.

for the last part of your question, you need to you only the filtrate in the titration, which represents the unreacted base in your case NaOH.