A: You can’t mix them. Because anionic polyacrylamide and cationic polyacrylamide mixed use, charge offset, molecular weight reduction, will produce white flocculent precipitate, can not play any role in water treatment.
Under normal circumstances, in different reaction sedimentation tanks, anionic polyacrylamide should be used for settlement, and then cationic polyacrylamide for sludge dehydration.
Polyacrylamide and its derivatives can be divided into anionic, cationic, nonionic and amphoteric types according to the charge they carry. Different types of polyacrylamides have different properties, and different polyacrylamides within the same type have different properties.
The condensation effect of polyacrylamide is mainly carried out through two aspects, one is through hydrogen bonding, van der Waals force and electrostatic bonding and other effects on the adsorption of colloidal particles, the other is through the linear polymer chain in the solution adsorption bridging effect to adsorption and entanglement of many small particles.
Anionic polyacrylamide is suitable for particle surface with positive charge water treatment, cationic polyacrylamide flocculant mainly flocculating surface with negative charge colloidal particles.
The flocculation capacity of nonionic polyacrylamide is less affected by salt content and pH than that of anionic polyacrylamide and cationic polyacrylamide because it has no ionic functional group.
Amphoteric polyacrylamide is special because it contains both anionic and cationic functional groups. The content and distribution of both have great influence on its flocculation and filtration aid.
In general, different ionic polyacrylamide can not be used in combination, but can be used in front and back ends.
