BET test results before and after modification of molecular sieve powder
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Friends, I’ve recently noticed a strange phenomenon: a type of HZSM-5 molecular sieve powder, after being modified with an alkali, was sent for a full BET analysis. The results are strange: why did the specific surface area, total pore volume, and average pore size all increase? Because some of the micropores merged during the modification process, the amount of mesoporous regions increased, in other words, the number of macroporous regions increased. So, in this case, it is understandable that both the total pore volume and the average pore size of the molecular sieve powder increase. However, in this case, it would logically make sense for the specific surface area of the molecular sieve powder to decrease, since the total number of micropores decreases while the number of mesopores and macropores increases! But why has the total specific surface area also increased? For example, it increased from the original 200 m2/g to 210 m2/g. What could be the reason for this? Does anyone know? :victory:
Is the molecular sieve you mentioned used to absorb leaked gases or moisture in a vacuum environment?
No: it is used as a catalyst, for catalyzing chemical reactions.