Solid-liquid interface hematite

Hesleitner, P. Babic, D. Kallay, N. Matijevic, E. (1987) Adsorption at solid/solution interfaces. 3. Surface charge and potential of colloidal hematite. Langmuir 3 815-820 Hesleitner, P. Kallay, N. Matijevic, E. (1991) Adsorption at solid/liquid interface. 6. The effect of methanol and ethanol on the ionic equilibrium at the hematite/water interface. Langmuir 7 178-184... 

Even though the flotation process involves three phases and three interfoces, most research work has been solely on the behavior of foe solid-liquid interface. This is in S Mte of the fact that adsoiptioa at the solid-liquid interface, as shown in Fig. 16.3-10, is of a considerably smaller magnitude than that at the solid-gas or liquid-gas interface. It is to be notisd that exceHent correlation has been obtained recoitly between surfactant adsoiption at the liquid-gas interface and flotation for the hematite-rdeate system (see Fig. 16.3-11). It is also important to note that the migration of the surfactam at the liquid-gas inteifoce is fastn- than its diffusion from bulk to the interface, as least for this system. Such a migration at the inteifoce can hdp toward faster attainment of requited surfactant adsorption density at the solid-gas interface upon the contact of the bubble with the particle. 

In brief, the investigation of ferrofluids through Raman spectroscopy permits to access the physical and chemical properties of both solid and liquid phases. Comparison between the Raman spectra obtained from liquid water and the Raman spectra obtained from the uncoated and coated nanoparticles dispersed as ferrofluid provides information about the interface nanoparticle surface-carrier liquid [63]. The onset of the hematite phase in core magnetite dispersed as magnetic fluids was followed by Raman spectroscopy, and the results showed that the laser intensity at which the phase-transition takes place was higher for nanoparticles in the colloid than that for the same core as powder samples [69]. 

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