Polyferric and ferrous sulfate belong to the same iron salt, ferrous ion belongs to divalent iron, and polyferric ion belongs to trivalent iron ion. Polyferric is a polymeric polymer iron salt. In terms of its flocculation performance, the product formed by dissolving the polymer flocculant will generate a large amount of colloidal ferric hydroxide and other multi-nuclear polymerization in addition to a large number of positively charged ions. The molecular chain structure is longer, the net catching ability is better, the flocculation effect is relatively better, and the sludge formed is more compact. Ferrous sulfate and polymeric ferric sulfate.
In addition to being used as a coagulation agent in sewage treatment, ferrous sulfate has a reducing effect on ferrous ions, which can be used to treat hexavalent chromium wastewater, dye wastewater reductive decolorization and combine with hydrogen peroxide to form a strong oxidizing Fenton process, Fenton treatment for wastewater that is difficult to treat by coagulation process.
Polyferric sulfate is mainly used for phosphorus removal, COD removal, decolorization, sulfur removal, SS removal, etc. Its phosphorus removal effect can reach about 90%, and the COD removal rate can reach more than 70%. It can be used to replace a large amount of other water in sewage treatment. Treatment of coagulants, such as ferrous sulfate, aluminum sulfate, polyaluminum chloride, etc.
Polyferric sulfate produces trivalent iron ions, while ferrous sulfate produces divalent iron ions. These two ions are very different in sewage treatment. Ferrous ions are reductive in sewage treatment. Reduction treatments such as reduction of hexavalent chromium, reduction and decolorization, etc., but ferric ions have no such function. Therefore, if it is used as a reducing agent or Fenton's reagent, the effect of ferrous sulfate is better than that of polyferric sulfate.
But if it is used as a coagulant or phosphorus removal agent, COD treatment agent, non-reducing decolorization treatment, SS treatment, more PFS is used instead of ferrous sulfate. Based on actual needs, make judgments and choices based on relevant information and experiments.