1、 Polyferric sulfate

The higher the content of PFS, the more polynuclear hydroxylated complexes will be formed in the hydrolysis process, which can neutralize more colloidal charges of pollutants, and has strong adsorption bridging and net precipitation. The pH value of 1% aqueous solution of the product is closely related to the content of total iron (with trivalent iron). The higher the content of trivalent iron, the more hydrogen ions hydrolyzed, the lower the pH value of total iron solution.

2、 Basicity of polyferric sulfate

Its level depends on the amount of hydroxyl content in the product, high basicity is unstable, but too low will affect the use effect of the product. The lower the basicity of PFS, the less the number of polynuclear complexes, the higher the charge density and the smaller the molecular weight; the higher the basicity, the more the number of polynuclear complexes and the smaller the charge density.

Electro neutralization and adsorption bridging work together to remove colloidal pollutants in water body, while adsorption electro neutralization and precipitation net capture are important means of coagulation. Therefore, the effect of products should not be judged simply by the level of basicity.

Trivalent iron pre hydrolyzed products form polynuclear complexes such as [Fe3 (H2O) 6 (OH) 3] 6 + through bridging between hydroxyl groups. At high basicity, the equilibrium moves to the direction of Fe (OH) 3, which weakens the adsorption capacity of the products, but also enhances the bridging and net trapping. The basicity of PFS is n / 6 × 100%. The higher the basicity of PFS, the higher the value of N, the higher the degree of polymerization of PFS.