Colloids are generally ...
Published by Mark Hill
Colloids are generally highly negatively charged. This is surrounded by a Stern layer of positively charged ions. Surrounding the Stern layer is a diffuse layer of positively charged counter ions and negatively charged co-ions.
Coagulation is the process whereby the nett negative charge of the colloidal particle is neutralized by a cationic species, whether it be an inorganic cation, such as alum or ferric chloride, or a cationic polyDADMAC or similar.
Flocculation is the process whereby neutralised particles are agglomorated, either naturally or by the addition of of a flocculation aid. This is done to increase the mass of the resultant floc to enable settling.