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Title: Kinetic model of impurity poisoning during growth of calcite

Abstract

The central role of the organic component in biologically controlled mineralization is widely recognized. These proteins are characterized by a high proportion of acidic amino acid residues, especially aspartate, Asp. At the same time, biomineralization takes place in the presence of a number of naturally-occurring, inorganic impurities, particularly Mg and Sr. In an attempt to decipher the controls on calcite growth imposed by both classes of modifiers, we have used in situ AFM to investigate the dependence of growth morphology and step kinetics on calcite in the presence of Sr{sup 2+}, as well as a wide suite of Aspartic acid-bearing polypeptides. In each case, we observe a distinct and step-specific modification. Most importantly, we find that the step speed exhibits a characteristic dependence on impurity concentration not predicted by existing crystal growth models. While all of the impurities clearly induce appearance of a 'dead zone,' neither the width of that dead zone nor the dependence of step speed on activity or impurity content can be explained by invoking the Gibbs-Thomson effect, which is the basis for the Cabrera-Vermilyea model of impurity poisoning. Common kink-blocking models also fail to explain the observed dependencies. Here we propose a kinetic model of inhibitionmore » based on a 'cooperative' effect of impurity adsorption at adjacent kink sites. The model is in qualitative agreement with the experimental results in that it predicts a non-linear dependence of dead zone width on impurity concentration, as well as a sharp drop in step speed above a certain impurity content. However, a detailed model of impurity adsorption kinetics that give quantitative agreement with the data has yet to be developed.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
15014168
Report Number(s):
UCRL-CONF-204243
TRN: US200805%%432
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Presented at: 19th American Conference on Crystal Growth and Epitaxy West, Fallen Leaf Lake, CA, United States, Jun 12 - Jun 15, 2004
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMINO ACIDS; CALCITE; CRYSTAL GROWTH; EPITAXY; KINETICS; POISONING

Citation Formats

DeYoreo, J, Wasylenki, L, Dove, P, Wilson, D, and Han, N. Kinetic model of impurity poisoning during growth of calcite. United States: N. p., 2004. Web.
DeYoreo, J, Wasylenki, L, Dove, P, Wilson, D, & Han, N. Kinetic model of impurity poisoning during growth of calcite. United States.
DeYoreo, J, Wasylenki, L, Dove, P, Wilson, D, and Han, N. 2004. "Kinetic model of impurity poisoning during growth of calcite". United States. https://www.osti.gov/servlets/purl/15014168.
@article{osti_15014168,
title = {Kinetic model of impurity poisoning during growth of calcite},
author = {DeYoreo, J and Wasylenki, L and Dove, P and Wilson, D and Han, N},
abstractNote = {The central role of the organic component in biologically controlled mineralization is widely recognized. These proteins are characterized by a high proportion of acidic amino acid residues, especially aspartate, Asp. At the same time, biomineralization takes place in the presence of a number of naturally-occurring, inorganic impurities, particularly Mg and Sr. In an attempt to decipher the controls on calcite growth imposed by both classes of modifiers, we have used in situ AFM to investigate the dependence of growth morphology and step kinetics on calcite in the presence of Sr{sup 2+}, as well as a wide suite of Aspartic acid-bearing polypeptides. In each case, we observe a distinct and step-specific modification. Most importantly, we find that the step speed exhibits a characteristic dependence on impurity concentration not predicted by existing crystal growth models. While all of the impurities clearly induce appearance of a 'dead zone,' neither the width of that dead zone nor the dependence of step speed on activity or impurity content can be explained by invoking the Gibbs-Thomson effect, which is the basis for the Cabrera-Vermilyea model of impurity poisoning. Common kink-blocking models also fail to explain the observed dependencies. Here we propose a kinetic model of inhibition based on a 'cooperative' effect of impurity adsorption at adjacent kink sites. The model is in qualitative agreement with the experimental results in that it predicts a non-linear dependence of dead zone width on impurity concentration, as well as a sharp drop in step speed above a certain impurity content. However, a detailed model of impurity adsorption kinetics that give quantitative agreement with the data has yet to be developed.},
doi = {},
url = {https://www.osti.gov/biblio/15014168}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 18 00:00:00 EDT 2004},
month = {Tue May 18 00:00:00 EDT 2004}
}

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