Electrophoretic Mobility of Nonuniformly Charged Spherical Particles with Polarization of the Double Layer

In spite of the increased use of streaming current detectors (SCDs) as a means of monitoring and/or controlling coagulant dosage, knowledge regarding fundamental workings is incomplete. This paper provides an initial attempt at predicting and verifying functioning compared to electrophoretic mobility. The instrument's components -- the sensor and the signal processor -- are first described. Equations modelling electro-double layer behavior in its sensor are then developed. Simplifying assumptions include the use of a capacitance model of the double layer and a triangular velocity profile for fluid within the sensor's annulus. More complex modelling approaches are also suggested which incorporate the Gouy-Chapman electro-double layer model and an exact solution for the velocity profile. Experimental results confirm predictions of the simplified model under conditions of low potential. A monotonic relationship exists between streaming current electrophoretic mobility, which is required for its use as a control parameter. Deviations from model predictions are suggested to be due to charge characteristics of the sensor surfaces themselves.

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Diffuse double layer interaction between two spherical particles with constant surface charge density in an electrolyte solution

Colloid & Polymer Science ◽

10.1007/bf01775682 ◽

1975 ◽

Vol 253 (2) ◽

pp. 158-163 ◽

Cited By ~ 6

Author(s):

Hiroyuki Ohshima

Keyword(s):

Charge Density ◽

Surface Charge ◽

Double Layer ◽

Electrolyte Solution ◽

Surface Charge Density ◽

Spherical Particles ◽

Diffuse Double Layer ◽

Layer Interaction

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Electrophoretic mobility of spherical particles in bounded domain

Journal of Colloid and Interface Science ◽

10.1016/j.jcis.2015.08.039 ◽

2016 ◽

Vol 461 ◽

pp. 32-38 ◽

Cited By ~ 3

Author(s):

Yu-Wei Liu ◽

Sumita Pennathur ◽

Carl D. Meinhart

Keyword(s):

Electrophoretic Mobility ◽

Bounded Domain ◽

Spherical Particles

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The electroviscous effect for suspensions of solid spherical particles

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1950.0155 ◽

1950 ◽

Vol 203 (1075) ◽

pp. 533-551 ◽

Cited By ~ 152

Keyword(s):

Theoretical Analysis ◽

Surface Charge ◽

General Formula ◽

Double Layer ◽

Effective Viscosity ◽

Theoretical Work ◽

Spherical Particles ◽

Electroviscous Effect ◽

Electrokinetic Phenomenon ◽

Ionic Double Layer

In this paper a theoretical analysis is made of the electrokinetic phenomenon known as the ‘electroviscous effect’. A general formula is given for the effective viscosity of a suspension of solid, spherical, charged non-conducting particles in an electrolyte. The increase of the effective viscosity due to the surface charge and the ionic double layer surrounding the particles is determined by a modification of Einstein’s method for the calculation of the viscosity of solid suspensions. The effective viscosity may be expressed in the form η = η 0 {1+2.5 (v/V) (1+Ʃ ∞ r -1 a r Q r )}, where η 0 is the viscosity of the electrolyte, v the volume of suspension in volume V of solution and Qe is the charge on each particle. It is shown that a 1 = 0 and a 2 is determined explicitly. It is found that the electroviscous contribution to η, for a given charge Q , tends to increase as the thickness of the double layer increases. When the thickness of the double layer is small compared with the radius of the particle the effect vanishes. A comparison with previous theoretical work is made, and it is shown that much improved agreement with experiment is obtained.

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