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Sorption of iron‐cyanide complexes on goethite
Author(s) -
Rennert T.,
Mansfeldt T.
Publication year - 2001
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.2001.t01-1-00368.x
Subject(s) - sorption , ferricyanide , goethite , ferrocyanide , chemistry , ionic strength , inorganic chemistry , cyanide , desorption , adsorption , inner sphere electron transfer , hematite , precipitation , ion , mineralogy , organic chemistry , electrode , aqueous solution , physics , meteorology
Summary Iron‐cyanide complexes are present in soils on sites of former gas plants and coke ovens. We have studied the sorption of the complexes ferricyanide, [Fe(CN) 6 ] 3– , and ferrocyanide, [Fe(CN) 6 ] 4– , on goethite in batch experiments, including the effects of concentration, time, ionic strength, pH, and the extent of reversibility. The sorption of ferricyanide showed features of both outer‐sphere and inner‐sphere complexation: its extent decreased with increasing pH; it depended on ionic strength; it was quickly and completely reversible; and it induced a change in surface electric potential. In contrast, sorption of ferrocyanide depended on pH to a lesser extent and was not affected by ionic strength at different pHs. The desorption was slower and incomplete. For ferrocyanide we conclude that sorption involves inner‐sphere complexation and precipitation of a Berlin‐Blue‐like phase on the goethite surface.