Sorption of Co 2 Ions on the Biogenic Mn

This study investigates the sorption of Co²⁺ ions on biogenic manganese oxides produced by the Mn-oxidizing fungus Paraconiothyrium sp. WL-2, which shows high tolerance to Mn²⁺ ions and can oxidize substantial quantities of Mn²⁺, leading to the formation of insoluble Mn(III, IV) oxides. The biogenic Mn oxides were analyzed using various characterization techniques including X-ray diffraction, FT-Infrared spectroscopy, and scanning electron microscopy, comparing them to synthetic Mn oxides. Results indicate that the biogenic Mn oxide displays poor crystallization as birnessite, enhanced porosity, and a higher proportion of weakly bound Mn(II) on its surface relative to synthetic counterparts. Notably, Co(II) ions were effectively sorbed and incorporated into the biogenic Mn oxide structure, achieving a sorption efficiency that was 5.6 times greater than that of the synthetic oxide. This finding highlights the preference for Mn(IV) to act as an oxidant over Mn(II) in biogenic environments, thereby activating geochemical cycles involving Mn and other elements, underscoring the ecological significance of the biogenic Mn oxides.