Effect of pH value on PFS and the suitable pH value of PFS
Effect of pH value on polyferric sulfate
PFS is a new type of inorganic polymer. Compared with other water treatment coagulants, its excellent flocculation performance makes it more effective in decolorization, COD, chroma and turbidity removal. PFS and PAC have been recognized by the market. The pH value range of PFS is wide, ranging from 4 to 11, and the suitable range is 6-9. In the appropriate pH range, coagulant can play a greater role in coagulation.
When the pH value of wastewater changes, PFS will also be affected to a certain extent. When the pH value of wastewater is too acidic (pH < 3) or alkalinity is too strong (pH < 11), PFS will be inhibited in the process of hydrolysis and can not be fully hydrolyzed, which will affect the flocculation effect. Therefore, when the above situation occurs, it is usually necessary to add alkali or acid to adjust to the appropriate pH range.
More suitable pH value for coagulation reaction of PFS
Polyferric sulfate is an acid polymer. Generally, the pH value of 3% aqueous solution of PFS is about 2.3, that is, pH is between 2-3. In particular, when the pH value of sulfuric acid is higher than 4, it is easy to polymerize iron in the process of sulfuric acid hydrolysis. On the contrary, when the pH value of PFS is lower than 2, the basicity of PFS is relatively low, which will increase the dosage of alkali agent (such as lime) in the wastewater treatment process, thus greatly increasing the treatment cost.