An atomic force microscopy and molecular simulations study of the inhibition of barite growth by phosphonates

The effect of cation:anion ratio in solution on the mechanism of barite growth at constant supersaturation: Role of the desolvation process on the growth kinetics

“…Nevertheless we noticed that two dimensional nucleation is a very surface dependent process, as for the same r and X conditions we observed surfaces on which massive and continuous 2D nucleation occurred as well as surfaces on which islands were not nucleated during the time of the experiment. As growth rates measured on our (0 0 1) barite faces are quite low compared with literature data Pina et al, 2004;Sanchez-Pastor et al, 2006) it is possible that the influence of impurities or defects which could facilitate nucleation was relatively low for crystals used in our experiments. Summarizing our observations we can conclude that for r < 0.24 crystal growth is controlled mainly by advancement of preexisting steps.…”

Interaction between Epsomite Crystals and Organic Additives

“…Adsorption at kinks leads to a plateau in the effectiveness of the inhibitor vs concentration. 40 This is not observed in the case of epsomite, where a continuous increase in G.I. values with increasing additive concentration is observed, even at values as high as 0.1 M. Adsorption on terraces is not ruled out in the case of the large polyacrylate molecules.…”

“…54 Note also that additives that bind simultaneously at two surface sites will be much more effective at blocking step growth than a single ion molecule. 36 At least two functional groups were thus required for modeling phosphonate adsorption onto epsomite (bidentate adsorption) as in Pina et al 40 and Ruiz-Agudo et al In order to compare the effects of the different additives tested, critical supersaturation data were normalized with respect to the control critical supersaturation by using percentage of growth inhibition (G.I.). 55 The latter is calculated using the formula:…”

Molecular simulations and critical pH studies for the interactions between 2-phosphonobutane-1,2,4-tricarboxylic acid and calcite surfaces in circular cooling water systems

“…At these pH values, PBTC exists as an anion. In this study, PBTC 2− ions were adsorbed on the calcite surfaces [18]. The molecular simulation studies were performed using the COMPASS force field [19,20], which enabled the accurate and simultaneous prediction of chemical properties (structure, conformation, vibration, etc.)…”