Ferric chloride is a kind of compound, which will be hydrolyzed when dissolved in water. Iron ion in ferric chloride will combine with hydroxyl ion in water to form ferric hydroxide colloid which is slightly soluble in water. Ferric hydroxide colloid has good flocculation effect, and the water purification principle of ferric chloride is also realized through these.

Ferric chloride can be used as flocculant or coagulant in water treatment, no matter what kind of use, it has very good effect. Ferric chloride is easily soluble in water, so the hydrolysis speed is fast, and the formed ferric hydroxide can adsorb the suspended solid particles in the sewage, so as to achieve the effect of water purification. Ferric chloride contains a lot of iron ions, which can react with various sulfides in sewage to produce insoluble precipitation, so as to achieve the effect of sulfide removal.

Ferric chloride in ferric chloride has strong oxidizability, so ferric chloride can achieve some other functions in wastewater treatment by oxidizability, such as decolorization, deodorization, oil removal, phosphorus removal, COD removal, etc.

Ferric chloride can replace many other water purification agents in the wastewater treatment line, and has excellent flocculation effect. At the same time, it has the advantages of dense alum and fast sedimentation. The amount of sewage sludge treated by ferric chloride is small, which can greatly save the sludge treatment cost, etc.