Using Chaos against Calcification
How small molecules avoid unwanted precipitation
Calcite is the most stable mineral form of calcium carbonate encountered everywhere from ocean corral and oyster shells to hard water scale deposits in place such as pipes, showers, and dishwashers. When calcite precipitates from solutions of calcium carbonate the process begins with amorphous precursors. Special small molecule additives can disrupt this process and have dramatic effects on calcium carbonate precipitation.
Controlling calcium carbonate deposition
An international team of researchers from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), the Jülich Center for Neutron Science, both in Germany, the Technion-Israel Institute of Technology and Procter & Gamble unraveled how small molecule additives can stabilize amorphous precursors through specific interactions. Effective anti-scale agents bind to the amorphous precursors, masking calcium and causing substantial disorder in the arrangement of the calcium and carbonate ions, dramatically delaying the formation of mineral calcite. This research provides tools for the rational design of new anti-scale additives, which will enable the development of sustainable materials to address the challenge of calcite scale for consumers and industry.
The necessary understanding of the complex interaction mechanisms was achieved by synergizing different research approaches into a joint research consortium headed by the FAU researchers Stephan E. Wolf (Institute of Glass and Ceramics, Faculty of Engineering) and Dirk Zahn (Theoretical Chemistry, Faculty of Sciences).
The original research paper is to appear in Angewandte Chemie Int. Ed. (early view: https://onlinelibrary.wiley.com/doi/epdf/10.1002/ange.202208475). The study was ranked as a “hot paper” and is featured on the title of the upcoming issue of the journal.