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A combined in situ AFM and SEM study of the interaction between celestite (001) surfaces and carbonate-bearing aqueous solutions

Sánchez Pastor, Sánchez and Pina Martínez, Carlos Manuel and Fernández Díaz, Lourdes (2007) A combined in situ AFM and SEM study of the interaction between celestite (001) surfaces and carbonate-bearing aqueous solutions. Surface science, 601 . pp. 2973-2982. ISSN 0039-6028

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Abstract

In this paper, we present in situ atomic force microscopy (AFM) observations of the interaction between celestite (SrSO4) (001) surfaces
and Na2CO3 aqueous solutions. The observations indicate that the interaction is characterized by a rapid alteration (carbonatation)
and dissolution of the original surface, shortly followed by the formation of a new phase. EDX analyses indicate that the new phase is
strontianite (SrCO3). Its crystallization involves the formation and spreading of islands of about 2.75 nm in height, which chiefly occurs
on the step edges of the dissolving celestite substrate. The thickness of the islands remains almost constant during their spreading, which
occurs mainly parallel to the celestite [010] direction. As a result of the progressive coalescence of the islands, a fairly homogeneous epitaxial
layer forms on the celestite (001) face. At the initial stages, the formation of islands on the celestite (001) faces enhances dissolution,
indicating the existence of a coupling between dissolution and crystallization reactions. Our measurements on series of AFM
images provided quantitative information about coupled dissolution-growth rates on a nanoscale. The effect of the coupled reactions
on the celestite (001) surface on a microscopic scale was also studied by scanning electron microscopy (SEM).

Item Type:Article
Uncontrolled Keywords:Dissolution–crystallization; Celestite; Strontianite; Atomic force microscopy; Scanning electron microscopy
Subjects:Sciences > Geology > Mineralogy
ID Code:13934
Deposited On:02 Dec 2011 10:55
Last Modified:02 Dec 2011 10:55

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