Electrical gradient water flow

RJ Naftalin, S Tripathi. Passive water flows driven across isolated rabbit ileum by osmotic, hydrostatic and electrical gradients. I Physiol 360 27-50, 1985. 

During water flow in clays driven by a hydraulic pressure gradient in absence of electrical shorting, a streaming potential gradient, V(—E), tends to be induced. In this condition the streaming current I will be zero. From (2) it then follows that under non-shorted conditions... 

In 1809, Reuss observed the electrokinetic phenomena when a direct current (DC) was applied to a clay-water mixture. Water moved through the capillary toward the cathode under the electric field. When the electric potential was removed, the flow of water immediately stopped. In 1861, Quincke found that the electric potential difference across a membrane resulted from streaming potential. Helmholtz first treated electroosmotic phenomena analytically in 1879, and provided a mathematical basis. Smoluchowski (1914) later modified it to also apply to electrophoretic velocity, also known as the Helmholtz-Smoluchowski (H-S) theory. The H-S theory describes under an apphed electric potential the migration velocity of one phase of material dispersed in another phase. The electroosmotic velocity of a fluid of certain viscosity and dielectric constant through a surface-charged porous medium of zeta or electrokinetic potential (0, under an electric gradient, E, is given by the H-S equation as follows ... 

It is much more difficult to describe the relationship of the bulk field gradients, easily recognised in the flow of water in clouds and of oxygen in the ozone layer described in Section 3.4, to that of the gradients controlling the chemical flow in cell liquids. The effects of electric fields due to charge distribution in various parts of the cell is an obvious possibility. 

In the absence of gradients of salt concentration and temperature, flows of water and electric current in bentonite clay are coupled through a set of linear phenomenological equations, derived from the theory of irreversible thermodynamics (Katchalsky and Curran, 1967), making use of Onsager s Reciprocal Relations (Groenevelt, 1971) ... 

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