Microbial catalysis, a primary pathway for the generation of Mn oxides in most of the natural environment, provides potential for material-oriented researchers to fabricate new materials. A Mn(II)-oxidizing fungi, Paraconiothyrium sp. WL-2, which was isolated from a constructed wetland in Kaminokuni, Hokkaido, Japan, was found to possess high tolerance as well as ability to oxidize high concentrations of Mn2+. Through enzymatic Mn oxidation, biogenic birnessite (BB) was produced under environmentally moderate conditions, which could be used as an ideal material for eco- and cost-effective synthesis of nanocrystalline lithium manganese oxide (LMO) by solid-state reaction for Li+ recovery. Compared with abiotic Mn oxide, the poorly crystalline BB facilitates the formation of well crystalline LMO at a relatively lower temperature. Moreover, LMOs prepared from BB show better performance on Li+ recovery compared with abiotic Mn oxides. The effects of calcination temperature on properties of LMOs and their delithiated products (HMOs) were systematically investigated by X-ray diffraction (XRD), X-ray absorption fine structure spectroscopy (XAFS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It is emphasized that changes of calcination temperature affected the crystal structure (e.g. contents of the spinel phase), the morphology, as well as the chemical composition (e.g. average oxidation states of Mn) of the product, all of which contribute to the adsorption capacity of HMOs.

Synthesis of biogenic Mn oxide and its engineering application to Li ion sieve

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.