Sedimentation potential Dorn effect

The streaming potential (Dorn effect) relates to a movement of liquid that generates electric potential, and electroosmosis occurs when a direct electric potential causes movement of the liquid. The sedimentation potential relates to sedimentation (directed movement) of charged particles that generates electric potential, and electrophoresis occurs when a direct electric potential causes a movement of charged particles. 

Dorn effect Dorn potential, and - sedimentation potential... 

A noticeable deviation of sedimentation potentials from Smoluchowski s formula takes place at large siuface concentration variation along the bubble surface. Before considering experimental data, it has to be pointed out that the validity of Smoluchowski s formula for the description of the Dorn effect at large Peclet numbers applies only to solid spherical particles. In particular, the correctness of conclusions of some papers (Dukhin, 1964 Dukhin Buikov, 1965 Derjaguin Dukhin, 1967, 1971) is experimentally confirmed by Usui et al. (1980). Sedimentation potential for four sizes of glass balls appears to be the same. Since the radii of the particles under consideration are approximately 50, 150, 250, and 350 pm, the absence of any effect of Peclet and Reynolds numbers on the sedimentation potential could be demonstrated. 

Sedimentation Potential The potential difference at zero current caused by the sedimentation of dispersed species. This mechanism of potential difference generation is known as the Dorn effect accordingly, the sedimentation potential is sometimes referred to as the Dorn potential. The sedimentation may occur under gravitational or centrifugal fields. The potential difference per unit length in a sedimentation potential cell is the sedimentation field strength. 

The reverse of electrophoresis occurs when small particles are allowed to fall through a liquid under the influence of gravity. A difference of potential is observed between two electrodes placed at different levels, and its magnitude again depends on the magnitude of the zeta potential. This phenomenon is known as the sedimentation potential or as the Dorn effect, after the German physicist Friedrich Ernst Dorn (1848-1916), who discovered it in 1880. 

Sedimentation Potential (Dorn effect) In this case the particles are allowed to settle or rise through a fluid under the influence of gravity (or using a centrifugal force) - When the particles move they leave behind their ionic atmosphere and this creates a potential difference in the direction of motion which can be measured using electrodes and an electrometer. 

The four possible types of electrokinetic phenomena are streaming (current) potential (electric potential generated by fluid movement relative to another phase), sedimentation potential or Dorn phenomenon or Dom effect (due to dispersed particles motion relative to the fluid caused by sedimentation) and electrophoresis and electro-osmosis (movement of two phases is caused by an external potential difference). 

Electrophoresis - solid particles caused to move through a stationary liquid Sedimentation potential - potential produced by the free fall of particles through a liquid (the Dorn effect)... 

Electrophoresis (q.v.) Electro-osmosis (q.v.) charged particles through liquid liquid past stationary solid Sedimentation potential or Dorn effect (q.v.) Streaming potential (q.v.)... 

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