2025-05-13 パシフィック・ノースウェスト国立研究所（PNNL）
＜関連情報＞
- https://www.pnnl.gov/publications/crystal-morphology-controls-redox-catalyzed-mass-transfer-mineral-water-interfaces
- https://pubs.rsc.org/en/content/articlelanding/2025/en/d4en01004c
鉄(II)とシュウ酸との自己触媒的相互作用から生じるヘマタイトのファセット依存的成長と溶解 Facet-dependent growth and dissolution of hematite resulting from autocatalytic interactions with Fe(ii) and oxalic acid
Sandra D. Taylor, John B. Cliff, Thomas W. Wietsma and Kevin M. Rosso
Environmental Science:Nano Published:24 Jan 2025
DOI:https://doi.org/10.1039/D4EN01004C
Abstract
The ability to simultaneously monitor the flux of iron atoms within the solution and solid phases can provide considerable insight into mechanisms of iron oxide mineral transformations. The autocatalytic interaction between hematite and Fe(II)-oxalate has long been of interest for its environmental and industrial relevance. In this study we take advantage of iron isotopic labelling and mass-sensitive imaging at the single particle scale to determine how changes in solution composition correlate with the morphologic evolution of faceted, micrometer-sized hematite platelets. Net dissolution is confirmed through analyses of aqueous iron chemistry, as well as by quantitative atomic force microscopy. Isotopic mapping techniques show that Fe(II) readily adsorbs to (001) and (012) surfaces in the absence of oxalate, but when oxalate is present selective dissolution of the (001) surface prevails and Fe deposition via recrystallization is not observed. Comparison between particle microtopographies following reaction with Fe(II), oxalate, and Fe(II)-oxalate show substantially different behaviors, consistent with distinct mechanisms of interaction with hematite surfaces. The extensive characterization conducted on the coupled solution/solid dynamics in this system provides new insight for distinguishing crystal growth, dissolution, and recrystallization processes.
