Electrokinetically Enhanced Sedimentation of Colloidal Contaminants

An Analysis of Electrophoresis of Concentrated Suspensions of Colloidal Particles

“…[1], as ␣ 3 0 and for a* ӷ 1. This is confirmed for a suspension of particles with a* ϭ 104, as shown in Fig.…”

“…Sauer and Davis (1) found that the coal/clay suspension obtained from a lake formerly used to store the effluent from a coal-washing plant near Centralia, Washington, could be clarified electrophoretically using modest potentials and low power consumption. The colloidal contaminants were found to be negatively charged at the nearly neutral pH of the lake water, and the major cation in the surrounding electrolyte solution was sodium.…”

“…He analyzed the motion of a single sphere in a fluid of infinite extent with an unpolarized, infinitesimally thin double layer. His wellknown expression for electrophoretic mobility, U/E*, is U E* ϭ ⑀ r ⑀ 0 * , [1] in which U is the electrophoretic velocity, E* is the applied electric field, ⑀ r is the dielectric constant of the electrolyte solution, ⑀ 0 is the permittivity of free space, * is the zeta potential, and is the fluid viscosity. The thickness of the double layer, Ϫ1 , where is the Debye-Hückel parameter, is given by…”

“…Particle-particle interactions become increasingly significant as the number density of particles in a suspension in- 1 To whom correspondence should be addressed.…”

Gravity settling characteristics of Cryptosporidium parvum oocysts in aqueous suspension using in situ static light scattering

“…Several experimental approaches have been used to measure the settling velocities in the past. Traditionally, three methods have been employed to measure settling velocities [12][13][14][15]: (1) measuring fall velocity of the liquid-particle interface (valid only for highly concentrated suspension with well defined interface); (2) measuring change in number concentration of particles with time above a fixed plane (applicable for large, optically observable particles) and; (3) measuring an average settling velocity of a marked particle in presence of other particles in the bulk of suspension. The laser light scattering method used in this study is inherently non-intrusive and can be used for extremely dilute suspensions with volume fractions as low as 10 −5 .…”