Growth modification of seeded calcite using carboxylic acids: atomistic simulations

U Aschauer, D Spagnoli, P Bowen, Stephen Parker

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

Molecular dynamics simulations were used to investigate possible explanations for experimentally observed differences in the growth modification of calcite particles by two organic additives, polyacrylic acid (PAA) and polyaspartic acid (p-ASP) The more rigid backbone of p-ASP was found to inhibit the formation of stable complexes with counter-ions in solution, resulting in a higher availability of p-ASP compared to PAA for surface adsorption Furthermore the presence of nitrogen on the p-ASP backbone yields favorable electrostatic interactions with the surface, resulting in negative adsorption energies, in an upright (brush conformation). This leads to a more rapid binding and longer residence times at calcite surfaces compared to PAA, which adsorbed in a flat (pancake) configuration with positive adsorption energies The PAA adsorption occurring despite this positive energy difference can be attributed to the disruption of the ordered water layer seen in the simulations and hence a significant entropic contribution to the adsorption free energy These findings help explain the stronger inhibiting effect on calcite growth observed by p-ASP compared to PAA and can be used as guidelines in the design of additives leading to even more marked growth modifying effects
Original languageEnglish
Pages (from-to)226-231
Number of pages6
JournalJournal of Colloid and Interface Science
Volume346
Issue number1
DOIs
Publication statusPublished - 1 Jun 2010

Keywords

  • atomistic simulation
  • polycarboxylic acids
  • calcium carbonate
  • adsorption
  • calcite

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