Polarity of Aluminium oxide
Jan 3,2024
Polarity of Aluminium oxide
Activated alumina is amorphous or crystalline alumina, which has been partially or completly dehydrated and has a large surface area per unit mass. Activated alumina is made from hydrated alumina, namely, Al2O3.nH2O, where n = 1~3, by calcining to get n closeto 0.5. It is a white or tan-colored material of chalky appearance. Stable crystalline forms are usually not thought of as adsorbents because they have very low surface areas. However, transitional forms, such as gamma and beta alumina, have high surface areas, typically between 200 and 400 m2/g. They contain pores with diameters largely in the range 2–5 nm. Being extremely hydrophilic materials, they find application mainly in the removal of water from acid, gas, or organic solvent streams.
Activated alumina has a high polarity which is suitable for mixtures of saturated and unsaturated hydrocarbons. To avoid tailing peaks for unsaturated components, some controlled surface deactivation is necessary. Aluminium oxide is a polar column chromatography adsorbent that can be separated by polar interactions. Therefore, the mobile phase used must be a non-polar solvent. Silica gel and alumina are both polar adsorbents, but silica gel is less polar than alumina.
Surface facetting and polarity of alumina
Atomic-resolution electron microscopic images of ruby show (0001) polar surface facets developing under electron irradiation. Attempts to understand the “dark-line” contrasts associated with the surface atom profiles, following comparison of the experimental images with computer modelling, leads to the realization that aluminium atom and oxygen atom surface terminations may be distinguished. Hence surface polarity, as well as details of surface step structure and mobility, may be determined. Positive surface polarity is preferred.
References:
[1] L.A. BURSILL, David J S, Peng Ju Lin. Surface facetting and polarity of alumina[J]. Ultramicroscopy, 1987. DOI:10.1016/0304-3991(87)90166-5.
- Related articles
- Related Qustion
1-Butanol is a vital chemical platform used as feedstock in the plastic industry, plasticizers, paints, binders, and food extractants.....
Jan 3,2024Organic SolventsGlycerin is FDA-approved for the treatment of constipation. The use of glycerin as a suppository or rectal enema may reduce constipation in adults and children at least 2 years of age.....
Jan 3,2024APIALUMINUM OXIDE
1302-74-5You may like
- ALUMINUM OXIDE
-
- $0.00 / 1KG
- 2024-08-17
- CAS:1302-74-5
- Min. Order: 1KG
- Purity: 99.0%
- Supply Ability: 10000KG
- ALUMINUM OXIDE
-
- $10.00 / 1KG
- 2021-10-19
- CAS:1302-74-5
- Min. Order: 1KG
- Purity: 99%
- Supply Ability: 20 tons
- ALUMINUM OXIDE
-
- $15.00 / 1KG
- 2021-07-10
- CAS:1302-74-5
- Min. Order: 1KG
- Purity: 99%+ HPLC
- Supply Ability: Monthly supply of 1 ton