%0 Journal Article
%A Pina Martínez, Carlos Manuel
%A Putnis, Cristine Veta
%A Becker, Udo
%A Biswas, Subir
%A Carrol, E.C.
%A Bosbach, Dirk
%A Putnis, Andrew
%T An atomic force microscopy and molecular simulationsstudy of the inhibition of barite growth by phosphonates
%D 2004
%@ 0039-6028
%U https://hdl.handle.net/20.500.14352/49774
%X 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 phosphonobutanetricarboxylic 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 stepsgrowing from solutions with different concentrations of each phosphonic acid. Adsorption isotherms, constructed byplotting individual monomolecular step rates versus inhibitor concentrations, indicate a Langmuir adsorption mechanismin the range of concentrations from 0.5 to 10 lmol/l. Both affinity constants calculated from adsorption isothermsand measurements of growth rates of barite monomolecular steps as a function of inhibitor concentrationallowed us to give the following ranking of inhibitor effectiveness: PBTC>NTMP>MDP>HEDPAMP. Molecularsimulations of the interaction of the phosphonic acids with barite(0 0 1) surfaces indicate that only kink sites alongmonomolecular steps can be considered as possible inhibition sites. This is in agreement with the AFM observationsand measurements.
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