Influence of Ionic strength on calcium carbonate (CaCO3) polymorphism

TL;DR

This study investigates how ionic strength, modulated by different cations and concentrations, influences the polymorphism of calcium carbonate, revealing that higher ionic strength favors vaterite formation.

Contribution

It is the first to systematically analyze the effect of ionic strength on CaCO3 polymorphism using various cations and concentrations.

Findings

Higher ionic strength increases vaterite percentage.

Ionic strength significantly influences CaCO3 polymorph selection.

Different cations affect the crystalline structure of CaCO3.

Abstract

CaCO3 crystals' physical properties, such as polymorphism and hence the reflectivity and stability, are critical factors of their qualities in industrial applications. Factors such as additives and substrates that influence CaCO3 polymorphism have been intensively studied. However, the effects of ionic strength created by varying additives are seldom paid attention to. This study is analyzing how ionic strength of the growth solution influences the crystalline structure of CaCO3, by applying growth solutions containing different types of cations of varying concentrations, K+, Na+, and NH4+. This study reveals that the ionic strength plays a significant role in polymorph selection in the way that the percentage of vaterite among the precipitates increases with the concentration of ionic strength.