Characterization of manganese oxide precipitates from Appalachian coal mine drainage treatment systems

摘要: The removal of Mn(II) from coal mine drainage (CMD) by chemical addition/active treatment can significantly increase costs. Passive for Mn involves promotion biological oxidative precipitation manganese oxides (MnO{sub x}). Manganese(II) was studied in three passive systems western Pennsylvania that differed based on their influent concentrations (20-150 mg/L), system construction ({+-}inoculation with patented Mn(II)-oxidizing bacteria), and bed materials (limestone vs. sandstone). occurred at pH values as low 5.0 temperatures 2 C, but enhanced circumneutral warmer temperatures. Trace metals such Zn, Ni Co were removed effectively, most cases preferentially, into the MnO{sub x} precipitates. Based synchrotron radiation X-ray diffraction K-edge extended absorption fine structure spectroscopy, predominant all sites poorly crystalline hexagonal birnessite, triclinic birnessite todorokite. surface morphology MnOx precipitates coarse 'sponge-like' composed nm-sized lathes thin sheets. scanning electron microscopy (SEM), found close proximity to both prokaryotic eukaryotic organisms. greatest efficiency one site amore » higher a total organic C (TOC) concentration (provided an upstream wetland). Biological oxidation driven heterotrophic activity likely mechanism these systems. Influent water chemistry kinetics affected relative distribution mineral assemblages CMD systems.« less