The mechanisms of crystal growth inhibition by organic and inorganic inhibitors

Abstract

Understanding mineral growth mechanism is a key to understanding biomineralisation, fossilisation and diagenesis. The presence of trace compounds affect the growth and dissolution rates and the form of the crystals produced. Organisms use ions and organic molecules to control the growth of hard parts by inhibition and enhancement. Calcite growth in the presence of Mg2+ is a good example. Its inhibiting role in biomineralisation is well known, but the controlling mechanisms are still debated. Here, we use a microkinetic model for a series of inorganic and organic inhibitors of calcite growth. With one, single, nonempirical parameter per inhibitor, i.e. its adsorption energy, we can quantitatively reproduce the experimental data and unambiguously establish the inhibition mechanism(s) for each inhibitor. Our results provide molecular scale insight into the processes of crystal growth and biomineralisation, and open the door for logical design of mineral growth inhibitors through computational methods.

Temperature dependence of calcite dissolution kinetics in seawater

“…The speciation of the calcite surface is well understood in dilute solutions (Van Cappellen et al, 1993;Pokrovsky, 1998b;Pokrovsky and Schott, 2002;Pokrovsky et al, 2005;Wolthers et al, 2008;Pokrovsky et al, 2009;Schott et al, 2009), and significant work has been done to relate these species to dissolution and precipitation kinetics (Chou et al, 1989;Arakaki and Mucci, 1995;Pokrovsky and Schott, 2002;Pokrovsky et al, 2005;Pokrovsky et al, 2009;Wolthers et al, 2012). Surface speciation models have only recently begun to include interactions with individual major seawater ions such as S and Mg 2+ (Song et al, 2017;Dobberschütz et al, 2018, and references therein), and these models have yet to be applied to the kinetics of seawater dissolution. Our measurements imply that a complete understanding of a dissolution rate law for calcite in seawater will require a surface energetic framework that incorporates the chemical complexation of the solution and mineral surface.…”

Heterogeneous Nucleation and Growth of CaCO3 on Calcite (104) and Aragonite (110) Surfaces: Implications for the Formation of Abiogenic Carbonate Cements in the Ocean

“…These abiogenic CaCO 3 minerals, composed of aragonite and high-magnesium calcite in shoal-shallow marine environments [4][5][6], typically form either as heterogeneously precipitated primary marine cements or through post-depositional and diagenetic reactions [1]. In order to further understand the lack of abiogenic CaCO 3 in the modern ocean, many efforts have been conducted to ascertain factors which affect the precipitation of abiogenic CaCO 3 [7][8][9][10][11].…”

“…Divalent metal cations, such as Mg 2+ , Ba 2+ and Sr 2+ , inhibit calcite growth by step pining, incorporation or kink blocking [18][19][20][21]. Similarly, soluble organic molecules (such as humate, fulvate, citrate and polyfunctional aromatic acids) inhibit the precipitation of aragonite by the modification of functional groups in these additives [11,22,23].…”

The impact of Mg2+ ions on equilibration of Mg-Ca carbonates in groundwater and brines

“…The calcite growth rate decreases in presence of Mg 2+ and SO 2− 4 (Pokrovsky, 2001;Pokrovsky et al, 2005Pokrovsky et al, , 2009aGledhill and Morse, 2006;Nielsen et al, 2016), which both enhances the hydrophilic character of the calcite surface and weakens the adsorption of organic compounds (Generosi et al, 2016;Andersson et al, 2016). Besides inorganic components, also organic components inhibit growth of calcite such as citrate (Montanari et al, 2017), alginate (Lakshtanov et al, 2014) and acetate (Dobberschütz et al, 2018).…”