Using Molecular Modelling to Understand and Predict the Impact of Organic Additives as Crystal Growth Modifiers

Abstract

Empirical molecular modelling was used to investigate the impact of organic additives on crystal morphology and inhibition. The replacement energy was found to correlate reasonably well with the degree of inhibition as determined from conductivity data. The replacement energy was also able to predict the barium sulfate face on which additive adsorption was most likely. While the ability of the organic functional groups to sit in the vacant sulfate lattice positions (the so-called ‘lattice matching’ criteria) appears intuitively sensible, it was found that this is not a sufficient criterion to predict real behaviour. A better criterion is the overall replacement energy as it takes into consideration the number of Ba–Oorganic interactions and whether the adsorption process overall is energetically favourable (by including the hydration energy of the ions). Thus, the replacement energy can successfully predict the effect of organic molecules on the crystal growth modification of barium sulfate.

Density-Functional Theory Investigation of Barite Scale Inhibition Using Phosphonate and Carboxyl-Based Inhibitors

“…The 001 surface is the most stable based on growth morphology while the 210 surface is the most stable based on equilibrium morphology 39 the former is the most commonly observed surface and hence used in this work. 31,40 A supercell of 3 × 3 × 1 was created as the slab that consists of four layers (438 atoms) using a relaxed structure of barite (mp-3164) from the materials project database. 38,41 The choice of this number of layer was to compromise between the computational costs of running a system with a large number of atoms while having a system large enough to represent the bulk.…”

“…Both the 001 and 210 surfaces have the lowest surface energies. The 001 surface is the most stable based on growth morphology while the 210 surface is the most stable based on equilibrium morphology the former is the most commonly observed surface and hence used in this work. , …”

PhysChem 2019: RACI Australian Conference on Physical Chemistry, Perth, 11–14 February 2019

“…Franca Jones and Andrew Rohl of Curtin University apply empirical molecular modelling to unravel the effect of organic additives on the inhibition of crystallisation, and the resulting crystal morphology, in their paper 'Using Molecular Modelling to Understand and Predict the Impact of Organic Additives as Crystal Growth Modifiers'. [8] Conductivity data allowed them to determine that the replacement energy correlated well with degree of inhibition, and that this energy can also predict the effect of organic molecules on crystal growth modification.…”