Pina Martínez, Carlos Manuel and Putnis, Cristine Veta and Becker, Udo and Biswas, Subir and Carrol, E.C. and Bosbach, Dirk and Putnis, Andrew (2004) An atomic force microscopy and molecular simulations study of the inhibition of barite growth by phosphonates. Surface science, 553 . pp. 61-74. ISSN 0039-6028
Official URL: http://www.elsevier.com/locate/susc
The effect of five phosphonic acids (hydroxyethylene diphosphonic acid, HEDP; nitro trimethyl phosphonic acid, NTMP; methylene diphosphonic acid, MDP; amino methylene phosphonic acid, AMP; and sodium phosphonobutane tricarboxylic acid, PBTC) on the growth of the barite(0 0 1) face has been investigated using atomic force microscopy (AFM). Experimental data have been obtained by in situ measurements of the velocities of barite monomolecular steps growing from solutions with different concentrations of each phosphonic acid. Adsorption isotherms, constructed by plotting individual monomolecular step rates versus inhibitor concentrations, indicate a Langmuir adsorption mechanism in the range of concentrations from 0.5 to 10 lmol/l. Both affinity constants calculated from adsorption isotherms and measurements of growth rates of barite monomolecular steps as a function of inhibitor concentration allowed us to give the following ranking of inhibitor effectiveness: PBTC>NTMP>MDP>HEDPAMP. Molecular simulations of the interaction of the phosphonic acids with barite(0 0 1) surfaces indicate that only kink sites along monomolecular steps can be considered as possible inhibition sites. This is in agreement with the AFM observations and measurements.
|Uncontrolled Keywords:||Adsorption isotherms; Atomic force microscopy; Computer simulations; Growth; Crystallization|
|Subjects:||Sciences > Geology > Mineralogy|
|Deposited On:||02 Dec 2011 12:36|
|Last Modified:||02 Dec 2011 12:36|
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