Влияние рН на седиментационные свойства наночастиц анатаза и рутила

Abstract

The colloidal behaviour of engineered nanoparticles is greatly influenced by the composition of the dispersion medium. The aim of this study was to determine the influence of the pH on the sedimentation of TiO2 nanoparticles by means of spectrophotometry. We examined anatase and rutile nanoparticles with average size of 18 and 83 nm, respectively. The sedimentation was parametrized by the semi-empirical model equation (R2 > 0.9). It was found that both nanoparticles settled in 10 mM NaCl, while anatase suspensions were more stable than rutile ones. In acidic medium nanoparticles had the highest stability while in alkaline medium - the lowest one. For instance, there were 76, 72 and 47 % of anatase particles left in water at pH 3, 7 and 11 in 180 min. The concentration of residual nanoparticles at infinite time at the pH = 11 was 0 % compared to more than 40 % at pH ≤ 7