Kinetics of heterocoagulation. Part.2—The effect of the discreteness of surface charge

Absolute Aggregation Rate Constants of Hematite Particles in Aqueous Suspensions: A Comparison of Two Different Surface Morphologies

“…Equation [13] introduces the correction These features hint toward an approximately symmetrical factor for hydrodynamic interaction B(h) and the interaction ion binding process (53). The total site density G 0 Å 8 nm 02 potential between two particles V (h).…”

“…have a distribution of surface potentials (13,18,19). The where p(c d ,c Љ d ) is the joint probability distribution of suraggregation rate of a pair of spheres with surface potentials face potentials of the encountering particles.…”

“…For a given c d and c Љ d can be still calculated from Eq. [13] but the potential distribution this expression can be evaluated nuelectrostatic potential entering Eq. [16] must be generalized merically.…”

“…The origin of these discrepancies is still not enthe PZC the rate constants are rather well predicted by the tirely clear, but the most likely explanation for the observed classical DLVO theory. Below the PZC, however, it is necessary deviations must be sought in surface heterogeneities or partito assume a distribution in the surface potentials with a coeffi-cle roughness (13,14). Such heterogeneity effects on the cient of variation around 30% to account for the observed behav-aggregation rate constants are rather difficult to assess theoior.…”

The Stability Behavior of Sol-Emulsion Systems

“…stant-potential while the other was one of constant surface charge density. Kihara and Matijevic ( 3 ) and Kihara et al ( 4 ) replaced computed values of the surface potential with experimentally measured zeta potentials in the HHF model Titanium dioxide (Titandioxid P25, Degussa Corp., Teterboro, NJ) was used as the pigment, and mineral oil (Aldapplied to the water-borne hematite -glass system ( both constant-potential surfaces ) and obtained computed stabil-rich Chemical Co., Milwaukee, WI) was used in the formation of the emulsion droplets. Titanium dioxide is a conveity ratios which were found to be only in rough qualitative agreement with values obtained independently using nient pigment since it has a point of zero charge (pzc) near the midpoint of the pH range; for the material used it was 6.3 (7).…”