Manganese ionic strength dependence

Surface Complex Formation. Metal ions form both outer and inner sphere complexes with solid surfaces, e.g. hydrous oxides of iron, manganese, and aluminium. In addition, metal ions, attracted to charged surfaces, may be held in a diffuse layer, which, depending upon ionic strength, extends several nanometres from the surface into solution. 

Several members of the domain Bacteria have a capacity to form Mn(IV) oxides by oxidizing Mn(II), which some deposit on their cells, sheaths or appendages, or in the case of marine Bacillus sp. strain SG-1 on the surface of the spores this organism forms (see Ehrlich, 1999). In most cases the mineral type of the manganese oxide formed has not been well characterized. In the case of the free spores of Bacillus sp. strain SG-1, the nature of the mineral formed varies depending on culture conditions, such as Mn(II) concentration, ionic strength and temperature, under which the mineral was formed, and on mineral aging (Mandernack et al., 1995). The initial product of the Mn(II) oxidation by the spores is poorly crystallized. 

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