Polymeric ferric sulfate (PFS) is an inorganic macromolecule that is highly efficient and has a steady chemical characteristic that dissolves with water. It is a red brown transparent viscous liquid, solid is light yellow amorphous powder or resin particles. It is high polymeric compound, and the molecular structure is huge, with strong adsorption ability. It is also good coagulation performance, alumem ustum close-grained, sedimentation velocity quickly. Polymeric ferric sulfate (PFS) has good characteristic of bridge and net. It is produced flocs speed, fast settling. Polymeric ferric sulfate can achieve ideal purification effect for different types and areas source water. Polymeric ferric sulfate can discolor, remove smell, dehydrate, remove oil, sterilize, remove heavy metal, radioelement and carcinogen easily, with strong ability removing COD and BOD.
Polymeric ferric sulfate also been used to treat municipal and industrial waste waters to help remove, by flocculation, suspended organic waste matter. There is currently considerable interest in the more widespread application of polymeric ferric sulfate as coagulants. Because of its relative efficiency, polymeric ferric sulfate may need less chemical addition. It can have a greater removal capacity and may reduce the volumes of waste concentrates that require disposal or further treatments.
There are many methods to produce polymeric ferric sulfate (PFS) in liquid or solid forms. For liquid PFS, direct oxidation of ferrous sulfate by strong oxidizers, such as NaClO3, H2O2 and HNO3, is carried out following partially hydrolyzing or polymerization to produce polymeric ferric sulfate. One of the direct oxidation methods is catalytic oxidation, where oxygen or air is used to oxidize Fe2+ to Fe3+. Catalysts, such as NOx from NaNO2 and HNO3 are needed. Alternatively, biological oxidation is available where iron-sulfur bacteria acts as the oxidant to oxidize ferrous to ferric ions and polymeric ferric sulfate is formed by partially polymerization as detailed above. Solid PFS can be produced by drying solution PFS with cylinder or spray drier or by direct synthesis with ferrous sulfate, nitric acid and water.
Waste Water Treatment
Polymeric ferric sulfate is suitable for phosphorus removal of life sewage wastewater treatment plant or improving the hydrophobicity of sludge. Polymeric ferric sulfate can replace the use of aluminum salt. It can be used to remove the residual aluminum pollution of tap water during its treatment. Polymeric ferric sulfate is also used to sludge press mud. It will have excellent effect with used with few of polyacrylamide. Polymeric ferric sulfate (PFS) is widely used for industries wastewater treatment of printing and dyeing, paper making, electroplating, circuit board, food processing, pharmacy, fertilizer, pesticide etc.