Coagulation or Flocculation of Dispersed Solids by Surfactants

Surfactants may be used not only to disperse solids in liquid media, but also to coagulate or flocculate solids already dispersed in liquid media. This may be accomplished with surface-active agents by a number of different mechanisms. 

Neutralization or Reduction of the Potential at the Stem Layer of the Dispersed Particles 

If the surfactant is one that has two or more hydrophilic (ionic) groups at different points in the molecule, then adsorption of the surfactant onto an oppositely charged surface may be with one hydrophilic group oriented toward the surface and with the other(s) oriented toward the aqueous phase. In this case, adsorption of the 

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