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Phosphate Adsorption by Aluminous Hematites of Different Shapes
Author(s) -
Barron V.,
Herruzo M.,
Torrent J.
Publication year - 1988
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1988.03615995005200030009x
Subject(s) - adsorption , phosphate , chemistry , soil water , materials science , analytical chemistry (journal) , mineralogy , inorganic chemistry , geology , soil science , chromatography , organic chemistry
The phosphate adsorption capacity of 43 synthetic hematites having widely different shapes, specific surface areas and Al 2 O 3 mole fractions ranged between 0.19 and 3.33 µmol P m −2 , with a mean value of 0.97 µmol P m −2 . There was a significant decrease in the adsorption capacity when the diameter/thickness ratio of the particles increased; this agrees with the hypothesis that, because of the distribution and type of surface hydroxyls, the basal faces of hematites are not able to adsorb phosphate, in contrast with some of the nonbasal faces. The low adsorption capacity of the hematites studied here, as compared to many natural and synthetic goethites, gives a reason why, as reported in the literature, red (hematitic) soils adsorb less phosphate than similar yellow (goethitic) soils.