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Kinetika otapanja (100), (110) i (111) plohe fluorita u vodi praćena je potenciometrijski mjerenjem koncentracije Ca2+, F– i H+ iona u otopini ion-selektivnim elektrodama tijekom 84 dana otapanja. Tenziometrijom i mikroskopom atomskih sila praćen je utjecaj otapanja na promjenu močivosti površine i topografiju (100), (110) i (111) ploha fluorita mjerenjem kontaktnog kuta i faktora hrapavosti prije i nakon otapanja. Površinski potencijal (100), (110) i (111) plohe monokristala fluorita tijekom 24 sata otapanja mjeren je fluoritnim monokristalnim elektrodama, a elektrokinetički potencijal nanočestica fluorita tijekom 37 dana otapanja određen je mjerenjem elektroforetske pokretljivosti nanočestica fluorita. Istražen je i utjecaj H+ , OH– , F– i Ca2+ iona na elektrokinetički potencijal nanočestica fluorita. Metodama statičkog i dinamičkog raspršenja svjetlosti određen je hidrodinamički promjer i promjer giracije nanočestica fluorita. Određeni su koeficijenti brzine difuzije iona u otopinu za (100), (110) i (111) plohu te iznose: 0,005 s–1 ; 0,045 s–1 i 0,03 s–1 . Ion selective electrodes were used to study dissolution kinetics of (100), (110) and (111) fluorite crystallographic planes by measuring Ca2+, F– and H+ ion concentration in the solution. Tensiometry and atomic force microscopy were employed for measuring dissolution impact on contact angle and surface roughness of specified fluorite crystallographic planes. Surface potential change of mentioned fluorite crystallographic planes during 24 hours of dissolution was investigated using a single crystal electrode. The electrokinetic potential of fluorite nanoparticles during dissolution was determined by measuring electrophoretic mobility. The influence of H+ , OH– , F– i Ca2+ ions on the electrokinetic potential of fluorite nanoparticles was also investigated. The hydrodynamic diameter and diameter of gyration of fluorite nanoparticles were determined using static and dynamic light scattering methods. The ion diffusion rate coefficients in the solution for (100), (110) and (111) planes were obtained: 0.005 s–1 , 0.045 s–1 and 0.03 s–1 respectively. |
