Pathways of birnessite formation in alkali medium
- 1 September 2005
- journal article
- Published by Springer Science and Business Media LLC in Science in China Series D Earth Sciences
- Vol. 48 (9), 1438-1451
- https://doi.org/10.1360/03yd0280
Abstract
Birnessite is a common weathering and oxidation product of manganese-bearing rocks. An O2 oxidation procedure of Mn(OH)2 in the alkali medium has been used to synthesize birnessite. Fast and powder X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), energy dispersed X-ray analysis (EDAX), infrared spectroscopy (IR) techniques and chemical composition analysis, Eh-pH equilibrium diagram approaches were employed to investigate the reaction process and pathways of birnessite formation. Results showed that the process of the birnessite formation could be divided into four stages: (1) formation stage for hausmannite and feitknechtite, (2) stage of transformation of hausmannite and feitknechtite to buserite, (3) buserite crystal growing stage, and (4) stage of conversion of buserite into birnessite. Mn(OH)2 was mainly present as amorphous state only for a short initial time of oxidation reaction. In the oxidation process, buserite formed following two pathways by recrystallization after dissolution of the intermediates, and the transformations of the minerals de-pended on the Eh determined by the dissolved O2 concentration on their surfaces. The results are fundamental in further exploration on the mechanism of birnessite formation in the alkali medium. A great practical significance would also be expected with respect to the areas of material sciences.Keywords
This publication has 23 references indexed in Scilit:
- Manganese Oxides and HydroxidesPublished by Wiley ,2018
- Preparative Parameters and Framework Dopant Effects in the Synthesis of Layer-Structure Birnessite by Air OxidationChemistry of Materials, 2002
- Trace Elements in Manganese‐Iron Nodules from a Chinese AlfisolSoil Science Society of America Journal, 2002
- Oxidation of Chromium(III) to (VI) by Manganese OxidesSoil Science Society of America Journal, 2002
- Manganese Oxide Octahedral Molecular Sieves: Preparation, Characterization, and ApplicationsScience, 1993
- Transformation of Hausmannite into Birnessite in Alkaline MediaClays and Clay Minerals, 1988
- Ion Exchange, Thermal Transformations, and Oxidizing Properties of BirnessiteClays and Clay Minerals, 1986
- Transformation of Synthetic Birnessite to Cryptomelane: An Electron Microscopic StudyClays and Clay Minerals, 1986
- Oxidative power of Mn(IV) and Fe(III) oxides with respect to As(III) in terrestrial and aquatic environmentsNature, 1981
- The synthesis of birnessite, cryptomelane, and some other oxides and hydroxides of manganeseMineralogical Magazine, 1971