ISSN:
1573-4854
Keywords:
alumina
;
hexagonal structure
;
anions
;
alumina mesophase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Aluminium-based dodecyl sulfate mesophases were synthesized by the homogeneous precipitation from a mixture of aluminium nitrate, sodium dodecyl sulfate, urea and water with or without five kinds of additional anions. The addition of monovalent Cl-, CH3COO- and HCOO- anions yielded a hexagonal mesophase, whereas F- anions induced a different mesophase. The crystallinities of these mesophases increased in the following order: NO3 - and Cl-〉CH3 COO-〉HCOO-〉F-, corresponding to the reverse order of affinity for Al3+. The resulting mesophases were also largely affected in morphology by the anion species added to form worm-like shaped particles for NO3 - and/or Cl- anions, and widely varying shapes of particles for the others. On calcination, these mesophases were transformed into α-alumina particles with macro pores having the specific surface area of ca. 20 m2ċg-1. On the other hand, the addition of divalent SO4 2- anions or the single use of aluminium sulfate led to a mesophase with a structural period as long as 6 nm, which was deorganized into a layered phase with an interlayer spacing of 1.4 nm.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009697421580
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