TY - JOUR

T1 - Probing the effects of polymers on the early stages of calcium carbonate formation by stoichiometric co-titration

AU - Schodder, Philipp I.

AU - Gindele, Maxim B.

AU - Ott, Andreas

AU - Rückel, Markus

AU - Ettl, Roland

AU - Boyko, Volodymyr

AU - Kellermeier, Matthias

N1 - Funding Information: The authors thank Elisabeth Wagner and Peter Stengel (BASF SE) for their continuous support during the experimental phase of the work, Bernd Hinrichsen (BASF SE) for conducting XRD analyses, Meik Ranft (BASF SE) for performing rheological studies, Thorsten Wieczorek and Matthias Werner (BASF SE) for help with cryo-TEM analyses, as well as Heike Weber and Matthias Arndt (BASF SE) for valuable discussions.

PY - 2022/3/17

Y1 - 2022/3/17

N2 - Potentiometric titrations are a powerful tool to study the early stages of the precipitation of minerals such as calcium carbonate and were used among others for the discovery and characterisation of key precursors like prenucleation clusters. Here we present a modified procedure for conducting such titration experiments, in which the reactants (i.e. calcium and (bi)carbonate ions) are added simultaneously in stoichiometric amounts, while both the amount of free calcium and the optical transmission of the solution are monitored online. Complementarily, the species occurring at distinct stages of the crystallisation process were studied using cryogenic transmission electron microscopy. This novel routine was applied to investigate CaCO3 nucleation in the absence and presence of polymeric additives with different chemical functionalities. The obtained results provide new insights into the critical steps underlying nucleation and subsequent ripening, such as the role of liquid mineral-rich phases and their transformation into solid particles. The studied polymers proved to interfere at multiple stages along the complex mineralisation pathway of calcium carbonate, with both the degree and mode of interaction depending on the chosen polymer chemistry. In this way, the methodology developed in this work allows the mechanisms of antiscalants - or crystallisation modifiers in general - to be elucidated at an advanced level of detail.

AB - Potentiometric titrations are a powerful tool to study the early stages of the precipitation of minerals such as calcium carbonate and were used among others for the discovery and characterisation of key precursors like prenucleation clusters. Here we present a modified procedure for conducting such titration experiments, in which the reactants (i.e. calcium and (bi)carbonate ions) are added simultaneously in stoichiometric amounts, while both the amount of free calcium and the optical transmission of the solution are monitored online. Complementarily, the species occurring at distinct stages of the crystallisation process were studied using cryogenic transmission electron microscopy. This novel routine was applied to investigate CaCO3 nucleation in the absence and presence of polymeric additives with different chemical functionalities. The obtained results provide new insights into the critical steps underlying nucleation and subsequent ripening, such as the role of liquid mineral-rich phases and their transformation into solid particles. The studied polymers proved to interfere at multiple stages along the complex mineralisation pathway of calcium carbonate, with both the degree and mode of interaction depending on the chosen polymer chemistry. In this way, the methodology developed in this work allows the mechanisms of antiscalants - or crystallisation modifiers in general - to be elucidated at an advanced level of detail.

UR - http://www.scopus.com/inward/record.url?scp=85128117937&partnerID=8YFLogxK

U2 - 10.1039/d1cp05606a

DO - 10.1039/d1cp05606a

M3 - Article

AN - SCOPUS:85128117937

VL - 24

SP - 9978

EP - 9989

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 17

ER -