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T. D. Khokhlova
Adsorption of acid and basic dyes on NiO–SiO2
composites
Abstract
A series of composites containing from 2.5%
to 21,0% NiO on the surface of macroporous silica is synthesized. Specific
surface area of composites measured by the thermal desorption of nitrogen
decreases with an increase in the content of NiO from 24 for the source silica
carrier up to 16 m2/g for composite, containing the most 21,0% NiO. The basic
dye - methylene blue (MB) is adsorbed in water solutions only on SiO2, but acid
blue anthraquinone (ABA) − only on the NiO. Effective specific surface
area Seff and effective diameters Deff of NiO nanoparticles are calculated from
the adsorption isotherms of the ABA on the NiO composites and on NiO
synthesized without carrier. With the rise of NiO content in the composites
Seff of the NiO nanoparticles is reduced from 76 up to 42 m2/g, and Deff
increases from 8 to 14 nm. The synthesized without carrier NiO nanoparticles
have the lowest Seff 30 m2/g and the most Deff 20 nm.
Key words: adsorption of dyes,
composite NiO–SiO2, macroporous silica, size of
nanoparticles.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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