20.500.12556/RUL-188603 Kalorimetrične raziskave vezave različnih ionov na nabito površino nanodelcev TiO₂ Calorimetric study of the binding of various ions on the charged surface of TiO₂ nanoparticles Zanimalo nas je, kako se različni ioni vežejo na nabito površino nanodelcev TiO2. Z metodo izotermne titracijske kalorimetrije (ITC) smo pri različnih vrednostih pH izmerili nekatere termodinamske parametre pri procesu vezave ionov različnih soli na nabito površino nanodelcev in agregacije nanodelcev. Uporabili smo soli NaCl, KCl in NaBr. Za NaCl smo preučevali vrednosti pH 2, pH 4,80 in pH 10, za KCl pH 10 ter za NaBr pH 4,86. Največji toplotni efekt smo izmerili pri titraciji z NaBr, sledili so KCl, nato NaCl pri pH 4,80, NaCl s pH 2 in nazadnje NaCl pri pH 10. Integrirani signal ITC smo dodatno analizirali z modelnimi funkcijami ter določili termodinamske parametre ∆H⊖, ∆S⊖, ∆G⊖, K_b in \tau. Eksperimentalne rezultate smo želeli podpreti s simulacijami Monte Carlo pri konstantnem pH v okviru grobozrnatega modela v NVT ansamblu. Pri primerjavi sistemov s KCl in NaCl smo dobili rezultate simulacij, ki so se kvalitativno ujemali z meritvami ITC, medtem ko pri sistemu z NaBr rezultati simulacij niso pojasnili eksperimentalnih meritev. Pri primerjavi sistemov, ki so vsebovali NaCl, pa so rezultati simulacij nasprotovali rezultatom meritev. Predlagali smo več možnih interpretacij takšnih rezultatov, ki temeljijo predvsem na hidrataciji in dehidrataciji ionov ter površine nanodelcev, na elektrostatskem senčenju oziroma spremembi efektivnega naboja nanodelcev ter na omejitvah uporabljenega modela. Zaključimo lahko, da je izbrani model primeren predvsem za primerjavo ionov, pri katerih se radiji hidratiranih ionov dovolj razlikujejo in katerih vrednost pH je čim bolj oddaljena od točke ničelnega naboja. We investigated the binding of different ions to the charged surface of TiO₂ nanoparticles. Using isothermal titration calorimetry (ITC), we measured selected thermodynamic parameters of the binding of ions from different salts to charged nanoparticle surfaces and the aggregation of nanoparticles at different pH values. The salts NaCl, KCl, and NaBr were investigated. For NaCl, pH values of 2; 4,80; and 10 were studied, while KCl was investigated at pH 10 and NaBr at a pH of 4,86. The largest thermal effect was measured for NaBr, followed by KCl, NaCl at pH 4,80, NaCl at pH 2, and finally NaCl at pH 10. The integrated ITC signal was additionally analyzed using model functions to determine the thermodynamic parameters ∆H⊖, ∆S⊖, ∆G⊖, K_b and \tau. The experimental results were further investigated using constant-pH Monte Carlo simulations within a coarse-grained model in the NVT ensemble. When comparing the NaCl and KCl systems, the simulation results qualitatively agreed with the trends observed in the ITC measurements, whereas for the NaBr system, the simulations could not reproduce the experimental measurements. In comparisons among the NaCl systems, however, the simulation results were inconsistent with the experimental measurements. Several possible interpretations of these findings were proposed, primarily based on the hydration and dehydration of ions and nanoparticle surfaces, electrostatic screening and changes in the effective nanoparticle charge, as well as limitations of the applied model. We conclude that the selected model is primarily suitable for comparing ions whose hydrated-ion radii differ sufficiently and for systems in which the pH is as far as possible from the point of zero charge of the nanoparticles. koloidna kemija vezava ionov izotermna titracijska kalorimetrija modeliranje koloidnega sistema Monte Carlo simulacije pri konstantnem pH colloidal chemistry ion binding isothermal titration calorimetry colloidal system modeling constant-pH Monte Carlo simulation true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-09-24 11:10:03 2026-09-24 11:10:12 2026-11-06 10:55:52 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 25888 304210435 Basic_Jan_-_Kalorimetricne_raziskave_vezave_razlicnih_ionov_na_nabito_povrsino_nanodelcev_TiO₂.pdf Basic_Jan_-_Kalorimetricne_raziskave_vezave_razlicnih_ionov_na_nabito_povrsino_nanodelcev_TiO₂.pdf 1 D94B74ECAD1DF6B6329BA42680ACDBAA ee3dec1da31da234a4c71a669147c63f704a58570214819afe980903cbc3928f ae133109-b7f7-11f1-8bc5-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=248876 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0