THE MIGRATION CHEMISTRY OF COBALT
The geochemical behaviour and the general properties as well as the chemistry of cobalt has been reviewed with special emphasis on factors which may be of importance in controlling the environmental behaviour of this element. Under geochemical conditions, cobalt exists exclusively in the divalent state as Co(II), since non-complexed Co(III) is quickly reduced. Co(II) has an exceptionally strong affinity for manganese oxide minerals and will become bound, to some extent irreversibly, to these minerals. Co(II) can in addition be bound by ion exchange to clay minerals and to humic acid. This bounding is, however, considerably weaker. At pH above neutrality cobalt is also immobilized by forming insoluble carbonates. Cobalt is a prolific complexing agent and Co(II), which is the dominant species in nature, is capable of forming complexes with naturally occurring ligands. In the presence of inorganic ligands at their usual geochemical concentration, complexed Co(II) species will exist only to a minor extent, but in the presence of the low molecular acids of the soil organic matter, the possibility of complexation increases, although free Co(II) is still the dominant species. The Co(II) complexes may be neutral or negatively charged and are thus capable of migration. Artificial chelating agents such as those of the EDTA family very easily yield mobile neutral or negatively charged cobalt complexes.
Bibliographic Reference: EUROPEAN APPLIED RESEARCH REPORTS + NUCLEAR SCIENCE AND TECHNOLOGY SECTION, VOL. 7 (1985), NO. 1, PP. 23-86, (EUR 9781 EN).
Availability: Can be ordered online
Record Number: 1989124112900 / Last updated on: 1987-01-01
Available languages: en