The solid acid properties of aluminosilicates are well know. My question is: how are the number of active sites calculated in such zeolites? Does it require simulation? Can it be estimated from amount of aluminium?
Edit: I have found FTIR methods thanks to keyword prompts from answers below - see:Article Acidity and basicity of zeolites: A fundamental approach
It might be useful if you use the gravimetric method or NH3-TPD to analyze the acidity of zeolite. I hope it helps.
If you need to calculate the number of acid sites of zeolite, you can use the sorption of bases such as NH3, pyridine, etc. Using thermoprogrammed desorption of bases, you can calculate the total number of acid sites and their strength. In this case, the higher the desorption temperature, the stronger the centers. Using pyridine adsorption with IR control, you can know the nature of acid sites (Bronsted or Lewis acid sites). Very useful is the Hammett titration method for the calculation of the number and strength of zeolites.
In general, you can calculate the number of acid sites theoretically coming from the number of aluminum atoms in zeolite, but take into consideration that native sodium in your sample cannot be exchanged fully on hydrogen.
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