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摘要
In the presence of aspartic acid (Asp), the calcite (104) face shows distinct dissolution pit morphology, presumably resulting from the surface reaction between calcite and Asp. However, the specific nature of this interaction and the influence of solution hydrodynamics remain unclear. To this end, we have followed the calcite (104) surface dissolution using in situ fluid cell atomic force microscopy (AFM). The results showed that at pH 4.5 and in 100 mM Asp the surface reactions were controlled by diffusion under static conditions and that trapezoidal etch pits were formed. In contrast, elliptical etch pits were rapidly developed upon flowing due to the increased transfer of Asp to the [010] step edge dissolution of Asp-surface complexes away from the step edge. The occurrence of the [010], [46 (1) over bar], and [(4) over bar 11] steps of trapezoidal etch pits was attributed to the stabilization of the (001), ((1) over bar 12), and (0 (1) over bar1) faces by Asp through bridging between the two carboxyl groups and two adjacent Ca atoms, with the alpha-NH3+ group forming a hydrogen bond with the oxygen of the H2O from the bulk solution and the surface CO3 groups from the ((1) over bar 12) and (0 (1) over bar1) faces. The mirror images of the etch pits formed in n-Asp and L-Asp solutions resulted from the enantio-specific interaction, supporting the tripodal contact of Asp with the crystal surface. Thus, the etch pit morphology is affected by Asp concentration, mass transfer, and specific surface reaction.
- 出版日期2012-5
- 单位中国石油大学（华东）
