Abstract
Gas adsorption properties of mesoporous γ-Al 2 O 3 prepared by the selective leaching method were investigated using various adsorbate gases. The mesoporous γ-Al 2 O 3 was prepared by calcining kaolinite to form a microtexture of fine γ-Al 2 O 3 grains dispersed in a matrix of amorphous SiO 2 followed by selective leaching of amorphous SiO 2 from the microtexture. The mesopores were formed inside the pseudomorphic hexagonal platy particles of kaolinite. The specific surface area, total pore volume and pore size measured at 77 K using N 2 gas were ca. 240 m 2 g –1 , 0.7 ml g –1 and 6 nm, respectively. The gas adsorption isotherms of polar molecules such as water, methanol and butan-1-ol showed type IV isotherms (IUPAC classification) while those of non-polar molecules such as cyclohexane showed type V isotherms. The γ-Al 2 O 3 was therefore recognized as having hydrophilic surface characteristics. The onset of adsorption of these gases in the low relative pressure (P/P 0 ) region was methanol>water>butan-1-ol>cyclohexane, this order corresponding to the affinity between the adsorbate gas and surface of the γ-Al 2 O 3 and also reflecting the steric effect of adsorbate gas. The fractal dimension obtained from the BET monolayer adsorption capacity plot was 2.1, indicating a smooth surface. The gas adsorption properties of the γ-Al 2 O 3 are discussed and compared with commercial γ-Al 2 O 3 and Al 2 O 3 -SiO 2 gel.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
