Getenet, Melese and Rieder, Julian and Kellermeier, Matthias and Kunz, Werner and Garcia-Ruiz, Juan Manuel (2021) Tubular Structures of Calcium Carbonate: Formation, Characterization, and Implications in Natural Mineral Environments. CHEMISTRY-A EUROPEAN JOURNAL, 27 (65). pp. 16135-16144. ISSN 0947-6539, 1521-3765
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Chemical gardens are self-assembled tubular precipitates formed by a combination of osmosis, buoyancy, and chemical reaction, and thought to be capable of catalyzing prebiotic condensation reactions. In many cases, the tube wall is a bilayer structure with the properties of a diaphragm and/or a membrane. The interest in silica gardens as microreactors for materials science has increased over the past decade because of their ability to create long-lasting electrochemical potential. In this study, we have grown single macroscopic tubes based on calcium carbonate and monitored their time-dependent behavior by in situ measurements of pH, ionic concentrations inside and outside the tubular membranes, and electrochemical potential differences. Furthermore, we have characterized the composition and structure of the tubular membranes by using ex situ X-ray diffraction, infrared and Raman spectroscopy, as well as scanning electron microscopy. Based on the collected data, we propose a physicochemical mechanism for the formation and ripening of these peculiar CaCO3 structures and compare the results to those of other chemical garden systems. We find that the wall of the macroscopic calcium carbonate tubes is a bilayer of texturally distinct but compositionally similar calcite showing high crystallinity. The resulting high density of the material prevents macroscopic calcium carbonate gardens from developing significant electrochemical potential differences. In the light of these observations, possible implications in materials science and prebiotic (geo)chemistry are discussed.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CHEMICAL GARDENS; SILICA GARDEN; PRECIPITATION; GROWTH; MECHANISM; SYSTEM; TUBES; RAMAN; CRYSTALLIZATION; DIFFUSION; calcium carbonate; chemical gardens; electrochemical potential; membranes; prebiotic chemistry |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Werner Kunz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 08 Sep 2022 06:16 |
| Last Modified: | 08 Sep 2022 06:16 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47526 |
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