Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9781749 | Journal of Physics and Chemistry of Solids | 2005 | 7 Pages |
Abstract
The oxidation of (Ni,Fe)(OH)2 suspensions in the presence of SO32â and SO42â anions can lead whether to the SO3-form or to the SO4-form of the Ni(II)-Fe(III) layered double hydroxides (LDHs). The hydroxysulphite, like the corresponding Fe(II)-Fe(III) compound, is characterised by a M(III)/M(II) ratio of 1/3 and forms from the initial hydroxide. If P=[Fe]/[Ni]=1/3, the end product is then Ni6IIFe2III(OH)16SO3·nH2O. If P>1/3, the SO3-LDH still contains Fe(II) and the oxidation process goes on. The SO3-LDH tends to transform into a mixture of ferrihydrite and SO4-LDH. The hydroxysulphate, like the corresponding Fe(II)-Fe(III) compound, is characterised by a M(III)/M(II) ratio of 1/2 and obeys to the composition Ni4IIFe2III(OH)12SO4·nH2O. The formation of the SO4-LDH is favoured by the oxidation of SO32â into SO42â anions, whereas the formation of ferrihydrite is the process that takes place if the initial anions are stable, e.g. Clâ.
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Authors
Philippe Refait, Mustapha Abdelmoula, Lilian Simon, Jean-Marie R. Génin,