The goal of coagulation is to make the colloidal system unstable by introducing chemicals that may eliminate the forces that are present on the surface of colloidal particles suspended in water in order to neutralise the negatively charged particles and allow them to agglomerate into flocs. Such chemicals are referred to as coagulants.
Ferric chloride (FeCl3) is one of the coagulants that is widely utilised. When 162 mg of ferric chloride (FeCl3) dissolve in one litre of water, 55.8 mg/L of ferric ions (Fe3+) and 106.5 mg/L of chloride ions (Cl-) are formed as a result of the easy dissolution of ferric chloride in water.
Anhydrous iron(III) chloride
The coagulation process are impacted by pH, as the pH value lowers when dosages of iron chloride are added because the creation of iron hydroxide flocculants removes the hydroxide ions.
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Rapid mixing is necessary after adding coagulant dosages to the water because inefficient processing might result from sluggish mixing.
Agglomeration is a process that aggregates tiny bodies suspended in aqueous medium into bigger blocks to hasten the settling process. Brownian motion causes the colloidal particles to first form particles with dimensions of about 0.1 micron after they have been released from their charge as a result of coagulation. These particles then begin to gather in larger groups under the influence of external mechanical movement (quiet moving), or of adhesion with coagulants.
