A study on the mechanism of Ca adsorption on TiO and FeO with the usage of calcium ion-selective electrode.

The paper presents the quantitative characterization of the solid/water interface applying both experimental and theoretical approaches for the system of TiO (mixture of anatase and rutile) and FeO (maghemite) with calcium ions in the pH function. The aim of the study was also to find a bonding mechanism between Ca and metal oxides surface based on the calculations from the surface complexation modeling code (GEOSURF by Sahai and Sverjensky, 1998). In order to obtain adsorption edges, a calcium ion-selective electrode (Ca-ISE) was applied for determination of Ca concentration in the suspensions.

Electrophoretic and potentiometric signatures of multistage CaCO nucleation.

Hypothesis: Calcium carbonate nucleation is often a complex and multistep process that is difficult to follow in situ. The time-resolved electrochemical and electrophoretic methods can provide a new insight into the nucleation pathway.

Experiments: Here, we used a combination of speciation calculations with time-resolved electrophoretic and potentiometric methods to monitor calcium carbonate precipitation from a slightly supersaturated solution.