Possibilities and Limits of Texture Properties Characterization
A series of microporous-mesoporous mechanical mixtures of zeolite NaY and γ-alumina was used for testing the applicability of the modified (three-parameter) BET isotherm equation. Nitrogen adsorption isotherms (77 K) of NaY+ γ-alumina samples were analyzed by this equation and the results compared with the independent textural information obtained from t-plots (with the standard isotherm of nonporous α-alumina and the standard isotherms of Lecloux-Pirard). It appeared that the use of the modified BET equation as same as the standard t-plot method provided good micropore volumes and mesopore surface areas contrary to the incorrect results of the classic BET equation.
KeywordsAdsorption isotherm microporous-mesoporous samples modified BET equation t-plots
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