One of the most common crystal habits of the thermodynamically stable polymorph of calcium carbonate, calcite, is the rhombohedral one, which exposes {10.4} faces. When calcite is precipitated in the presence of Li+ ions, dominantly {00.1} faces appear together with the {10.4}, thus generating truncated rhombohedrons. This well-known phenomenon is explored in this work, with the aim of obtaining calcite crystals with smooth {00.1} faces. In order to achieve this objective, the formation of calcite was examined in precipitation systems with different c(Ca2+)/c(Li+) ratios and by performing an initial high-power sonication. At the optimal conditions, a precipitate consisting of thin, tabular {001} calcite crystals and very low content of incorporated Li+ has been obtained. The adsorption properties of the tabular crystals, in which the energetically unstable {00.1} faces represent almost all of the exposed surface, were tested with model dye molecules, calcein and crystal violet, and compared to predominantly rhombohedral crystals. It was found that the {00.1} crystals showed a lower adsorption capability when compared to the {10.4} crystals for calcein, while the adsorption of crystal violet was similar for both crystal morphologies. The obtained results open new routes for the usage of calcite as adsorbing substrates and are relevant for the understanding of biomineralization processes in which the {00.1} faces often interact with organic macromolecules.

Synthesis and Adsorbing Properties of Tabular {001} Calcite Crystals

Magnabosco, Giulia;Fermani, Simona;Falini, Giuseppe;
2019

Abstract

One of the most common crystal habits of the thermodynamically stable polymorph of calcium carbonate, calcite, is the rhombohedral one, which exposes {10.4} faces. When calcite is precipitated in the presence of Li+ ions, dominantly {00.1} faces appear together with the {10.4}, thus generating truncated rhombohedrons. This well-known phenomenon is explored in this work, with the aim of obtaining calcite crystals with smooth {00.1} faces. In order to achieve this objective, the formation of calcite was examined in precipitation systems with different c(Ca2+)/c(Li+) ratios and by performing an initial high-power sonication. At the optimal conditions, a precipitate consisting of thin, tabular {001} calcite crystals and very low content of incorporated Li+ has been obtained. The adsorption properties of the tabular crystals, in which the energetically unstable {00.1} faces represent almost all of the exposed surface, were tested with model dye molecules, calcein and crystal violet, and compared to predominantly rhombohedral crystals. It was found that the {00.1} crystals showed a lower adsorption capability when compared to the {10.4} crystals for calcein, while the adsorption of crystal violet was similar for both crystal morphologies. The obtained results open new routes for the usage of calcite as adsorbing substrates and are relevant for the understanding of biomineralization processes in which the {00.1} faces often interact with organic macromolecules.
Matijaković, Nives; Magnabosco, Giulia; Scarpino, Francesco; Fermani, Simona; Falini, Giuseppe; Kralj, Damir
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/653959
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 6
social impact