Atomistic simulations of nucleation and growth of CaCO₃ with the influence of inhibitors: A review

Abstract

Calcium carbonate (CaCO3) is a crucial mineral with great scientific relevance in biomineralization and geoscience. However, excessive precipitation of CaCO3 is posing a threat to industrial production and the aquatic environment. The utilization of chemical inhibitors is typically considered an economical and successful route for addressing the scaling issues, while the underlying mechanism is still debated and needs to be further investigated. In this context, a deep understanding of the crystallization process of CaCO3 and how the inhibitors interact with CaCO3 nuclei and crystals are of great significance in evaluating the performance of scale inhibitors. In recent years, with the rapid development of computing facilities, computer simulations have provided an atomic‐level perspective on the kinetics and thermodynamics of possible association events in CaCO3 solutions as well as the predictions of nucleation pathway and growth mechanism of CaCO3 crystals as a complement to experiment. This review surveys several computational methods and their achievements in this field with a focus on analyzing the functional mechanisms of different types of inhibitors. A general discussion of the current challenges and future directions in applying atomistic simulations to the discovery, design, and development of more effective water‐scale inhibitors is also discussed.

Modulating ion-binding at macromolecular interfaces during (bio)mineralization: A snapshot review for calcium carbonate and calcium phosphate systems

“…While electrostatics play a role in drawing cations near the macromolecule, the intensity and longevity of the interaction are typically stabilized by entropic effects [28][29][30]. CaCO 3 (and other Ca mineral) ion pair formation is also water/entropy motivated [31][32][33]. Therefore, ion and macromolecule hydration must both be accounted for when considering binding mechanisms and polymer design.…”

“…Error estimation and limited experimental data also contribute. The issue becomes impressively complex as other ions and interfaces are introduced to the system [33,[105][106][107]. Further, scaling up from the atomic level to bulk solution expounds uncertainty and error.…”

The solubility product controls the rate of calcite dissolution in pure water and seawater

“…9,17 Under seawater conditions carbonate ion is known to form ion pairs 18 most notably with Mg, Ca and Na cations, 17,19 resulting in merely 8% of the total carbonate existing as free ions. 17 It is evident that the ionic composition of seawater plays an integral role in the calcium carbonate chemistry not only at the heterogeneous calcite–water interface 20,21 but also chemically in the solution phase. Note that more recent studies observed the recession/growth of pristine surface and kink sites of calcite surfaces using atomic force microscopes allows mechanistic insights into particle dissolution/crystallisation at the nanoscale level with or without calcite dissolution/growth inhibitors to be inferred.…”