The solution of some minor element oxides by decomposing plant materials

Oxides of several trace elements are dissolved by the action of anaerobically fermenting plant material and, less effectively, by sterile aqueous extracts of undecomposed plant material. The dissolved metals seem to be in complex form and in true solution, not colloidally dispersed. The solutions are stable to atmospheric oxidation, but in the presence of ferrous iron aeration causes coprecipitation of the trace elements with ferric oxide. The order of ease of coprecipitation appears to be Mo, V > Zn > Cu > Co > Ni. Sorption on ferric oxide is appreciable under certain conditions. Copper and nickel are irreversibly sorbed from fermentation solutions by plant fibres. RESP-4503