Coagulation is adhesion of particles of colloidal solutions to larger, usually ending sediment. Coagulation often cause the addition to the colloidal solution of electrolytes. The minimum concentration of the electrolyte, which is observed coagulation, called the threshold of coagulation. Coagulation plays an important role in biological phenomena; it is widely used, for example in the purification of drinking water.
Cm. also Dispersed systems, Colloids, Colloidal protection.