Effects of Co doping on the structure and physicochemical properties of hausmannite (Mn3O4) and its transformation during aging - Archive ouverte HAL Access content directly
Journal Articles Chemical Geology Year : 2021

Effects of Co doping on the structure and physicochemical properties of hausmannite (Mn3O4) and its transformation during aging

(1) , (2) , (3) , (4) , (5) , (6) , (1) , (7) , (7) , (1) , (1)
1
2
3
4
5
6
7

Abstract

Hausmannite is a common low-valence manganese oxide mineral with a distorted spinel structure in surficial sediments. Although natural Mn oxides often contain various transition metal (TM) impurities, few studies have addressed the substitution mechanisms of TMs, such as cobalt (Co), with hausmannite and induced changes in the mineral physicochemical properties. In this study, Co-doped hausmannites with final Co/Mn molar ratios of 0.05 and 0.11 were synthesized and characterized by wet chemical analysis, powder X-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (XAFS). Co-doped samples have larger crystallite sizes and smaller specific surface areas than those of the hausmannite without Co. The Co cations exist in a mixed-valence of +3 and + 2. Powder XRD and acid dissolution experiments indicate that Co incorporates into the mineral structures, and increases the mineral structural stability. Co K-edge extended X-ray adsorption fine structure (EXAFS) analysis demonstrates that Co likely substitutes for lattice Mn(III). After aging at room temperature for three years, 14.1 ± 1.9% of pure hausmannite is transformed to manganite while only 2.6 ± 0.7% of manganite appears in the aged Co-doped sample with an initial Co/Mn molar ratio of 0.10. These results provide new insights into the incorporation mechanisms of TMs into low valence Mn oxides, and the stability of these minerals in natural environments.
Fichier principal
Vignette du fichier
MS with no changes marked.pdf (1.85 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

insu-03411470 , version 1 (03-11-2021)

Identifiers

Cite

Shuang Zhang, Hui Li, Zhongkuan Wu, Jeffrey E. Post, Bruno Lanson, et al.. Effects of Co doping on the structure and physicochemical properties of hausmannite (Mn3O4) and its transformation during aging. Chemical Geology, 2021, 582, pp.120448. ⟨10.1016/j.chemgeo.2021.120448⟩. ⟨insu-03411470⟩
38 View
81 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More