title: Studies on the formation of todorokite-type manganese oxide with different crystalline birnessites by Mg2+-templating reaction.
abstract: The formation of todorokite-type manganese oxide (TodMO) by hydrothermal soft chemical reaction (Mg2+ exchange followed by hydrothermal treatment) was studied using three kinds of Na-type birnessite (Na-BirMO) with different crystallinities. Buserite (BusMO) formation by Mg2+ exchange and TodMO formation by hydrothermal treatment progressed in a similar manner regardless of the crystallinity of the initial Na-BirMO, but the crystallinity of the synthesized TodMO depended on that of the initial Na-BirMO. Particle morphology of the synthesized TodMO was related to the crystallinity of the initial Na-BirMO. The amounts of fibrous morphology were gradually increasing, accompanied by increased crystallinity of the initial Na-BirMO. TodMO with a neat fibrous morphology was obtained using a high crystalline Na-BirMO as precursor. Most of the interlayer metal ions (Na+ and Mg2+) were extracted from Na-BirMO and BusMO by treatment with a 0.1 M HCl solution, while only 37% of Mg2+ was extracted from TodMO. Both the acid treatment and the particle morphology may be the most convenient method to distinguish TodMO from BusMO.
authors.affiliation: School of Chemistry and Materials Science of Shaanxi Normal University, Xian, Shaanxi 710062, China. zhliu@snnu.edu.cn
authors.forename: Zong-huai
authors.initials: ZH
authors.lastname: Liu
authors.forename: Liping
authors.initials: L
authors.lastname: Kang
authors.forename: Kenta
authors.initials: K
authors.lastname: Ooi
authors.forename: Yoji
authors.initials: Y
authors.lastname: Makita
authors.forename: Qi
authors.initials: Q
authors.lastname: Feng