Naslov
Structure and chemistry of the calcite-water- interface

Autori
Heberling, Frank ; Klačić, Tin ; Preočanin, Tajana ; Eng, Peter ; Lützenkirchen, Johannes

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Geophysical Research Abstracts / - , 2019

Skup
EGU General Assembly 2019

Mjesto i datum
Beč, Austrija, 07.04.2019. - 12.04.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
calcite ; electrokinetic potential ; inner surface potential ; surface complexation model

Sažetak
Calcite is the most stable polymorph of CaCO3 at ambient conditions. It is ubiquitous in natural systems and controls to a large degree the geochemistry of terrestrial soils and sediments, but also of lacustrine- and seawater. Due to the reactivity of its surface, calcite has impact on the mobility of nutrients and contaminants in subsurface environments. Electrostatic phenomena at the calcite-water- interface provide a link between surface chemistry on the one hand side and hydrogeophysical methods like streaming potential or induced polarization measurements on the other hand side. In this study we present an updated view of the structure of the calcite(104)-water interface on the basis of a new extended crystal truncation rod data set, which allows to resolve previous ambiguities with respect to the coordination sphere around the surface Ca-ions and the relaxation of surface carbonate groups. On the basis of resonant surface diffraction data we investigate the interaction between calcite and weakly / non adsorbing Rb+ alkali metal cations. The structural aspects will be related to a newly developed electrostatic surface complexation model (SCM), describing the calcite-water-interface chemistry. For the first time, direct information on the inner surface potential of calcite, as measured with a calcite single crystal electrode, is included in the data constraining the calcite SCM, besides zeta potential data. Potential links between the calcite SCM and hydrogeophysical measurements will be highlighted.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Kemija

POVEZANOST RADA