Critical zeta potential and the Hamaker constant of oxides in water

Properties of Commercial Nanoparticles that Affect Their Removal During Water Treatment

“…4.2, the primary particle size is nanoscale, on the order of 5-25 nm, but the aggregated form is far greater in size and may not be considered a nanoparticle by the operational definition cutoff of 100 nm. Similar phenomenon is observed with commercial TiO 2 nanoparticles (10) and other commercial nanoparticles (11)(12)(13)(14)(15)(16), which showed that such so-called nanoparticles were aggregates composed of primary nanoparticles with sizes less than 100 nm. We believe that commercial metal and metal oxide nanoparticles aggregate during their manufacturing processes, but that they can be manufactured as discrete nanoparticles by adding functional groups to the surface (e.g., citrate).…”

Assessment of ζ-potential in TiO2 aqueous suspensions: A comparative study based on thermodynamic and rheological methods

“…Table 2 summarizes the ζ crit and the D 0 distance estimated to various ionic strengths. The values of these two parameters between 100 and 1 mM KCl range from 44.45 to 51.32 mV and from 1.35 to 3.84 nm, which are consistent with other values reported: 47 mV for 200 mM KCl suspensions [30] or 49 mV (ionic strength410 mM 1:1 electrolyte) [16], when conductivity is not too low or anomalous surface conductance becomes important. In both cases, the ESA electroacustic theory of ζ-potential was utilized.…”

Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

“…The Hamaker constant for a given system is notoriously difficult to obtain experimentally. 50 are indicated in the literature, for example, 0.7 × 10 20 J and 3.8 × 10 20 J. 30,51 As a result, the Hamaker constant used in this work was chosen instead on the basis of a qualitative analysis of the experimental silica suspensions.…”