The Influence of Si/Al ratio on the Aromatic Adsorption from Aromatic/Alkanes Mixture by BETA Zeolite

فاقد چكيده

In this work, adsorption of benzene from benzene/n-hexane and benzene/n-heptane was studied by two types of H-BETA zeolite with Si/Al ratio 11.5 and 24.5. Benzene was adsorbed of these mixtures which have 0.5% up to 10% mole fraction of benzene by batch technique in ambient temperature, and benzene concentration in binary mixture was measured by gas chromatography (GC). H-BETA zeolite has active site in its surface, this active site which has charge of the electron interact with p electron in benzene causes the heat of adsorption to increase. Si/Al ratio detects the number of active site in zeolite surface. In the other hand, increased active sites in H-BETA zeolite decline entropy of adsorption. Therefore, free energy of mixing defines the potential of adsorption in H-BETA zeolite. As the results indicated in all mixtures, benzene was adsorbed better than n-hexane and n-heptane on H-BETA zeolite surface, and separation factors are rather than 20. H-BETA zeolite with Si/Al = 24.5 has separation factor higher than H-BETA zeolite with Si/Al= 11.5 in similar mixture. For example, the separation factor in benzene/n-hexane mixture for H-BETA zeolite with Si/Al = 24.5 is near 50, and for Si/Al =11.5 it is 20.