Naslov
The effect of water on pH-dependent charge at metal oxide/aqueous electrolyte interface

Autori
Preočanin, Tajana ; Kallay, Nikola ; Lutzenkirchen, Johannes

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The International Symposium on Electrokinetic Phenomena 2014 (ELKIN 11) / Beunis, Fulip ; Neyts, Kristiaan ; Strubbe, Filip ; Brans, Toon ; Schreuer, Caspar - Ghent : University Ghent, 2014, 85-85

Skup
The International Symposium on Electrokinetic Phenomena 2014 (ELKIN 11)

Mjesto i datum
Gent, Belgija, 20.05.2014. - 23.05.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
air/water interface ; electrokinetic potential ; surface potential ; surface charging

Sažetak
For development application of surface complexation models and analysis of the surface reac-tions the properties of individual surface planes should be measured. The surface of colloids and nanoparticles consists of different crystallographic planes. Therefore, from measurements of surface charge density and electrokinetic potential of particles only the average surface properties could be evaluated. Construction of single crystal metal oxide and silver halides electrodes enables measurements of inner surface potential of defined crystal planes. While streaming potential (or streaming current) measurements provide the electrokinetic zeta- potential of defined crystal plane. The comparison and analysis of those two measured potentials leads to interesting and surprising findings. For some metal oxide crystal planes the measured Ψ0(pH) function is nonlinear with a broad zero- potential region around the point of zero potential. This result could be interpreted by surface complexation model and is in accordance with predictions of the Multi-site Complexa-tion Model (MUSIC). In such a case electrokinetic streaming potential measurements of the particular crystal plane provides the clear isoelectric point and higher values of the zeta poten-tial with respect to measured inner surface potentials (Figure 1.). This unexpected behavior could be explained by considering pH dependent charging of the interfacial water layer af-fecting electrokinetic behavior but not the surface potential. Additionally the surface and zeta- potential measurements on AgCl and AgBr single crystals and colloid particles show that the zeta- potential exhibits pH-dependence, while the surface potential does not.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA