Polyacrylamide (PAM) is a water-soluble macromolecule polymer, insoluble in most organic solvents, with good flocculation, which can reduce friction resistance between liquids. According to ionic characteristics, PAM can be divided into four types: non-ionic, anionic, cationic and amphoteric.

Characteristic

1. Flocculation. PAM can make suspended matter flocculate by electroneutralization.

2. Adhesiveness. It can be bonded by physical chemistry, etc.

3. Thickener. Thickening can be achieved under neutral and acidic conditions, and PAM with PH above 10 is easy to hydrolyze.

Matters needing attention

Cautions for the use of cationic polyacrylamide:

1. Floc size: too small flocs will affect the drainage speed, too large flocs will restrain more water and reduce the mud biscuit degree. The size of flocs can be adjusted by selecting the molecular weight of polyacrylamide.

2. Sludge characteristics: The first point is to understand the source, characteristics and composition of sludge and its proportion. According to different properties, sludge can be divided into organic and inorganic sludge. Cationic polyacrylamide is used to dispose of organic sludge, relative anionic polyacrylamide flocculant is used for inorganic sludge, cationic polyacrylamide is used when alkalinity is strong, and anionic polyacrylamide is not suitable when acidity is strong, and the sludge with high solid content usually uses a large amount of polyacrylamide.

3. Floc strength: Flocs should be stable and not broken under shear action. The improvement of molecular weight of polyacrylamide or the selection of suitable molecular structure will help to improve the floc stability.

4. Ionicity of polyacrylamide: For dewatered sludge, flocculants with different ionicity can be selected through small-scale tests to select the best suitable polyacrylamide, so that the best flocculant effect can be obtained, the dosage can be minimized and the cost can be saved.

5. Dissolution of polyacrylamide: Only when it dissolves well can it give full play to flocculation. Sometimes the dissolution rate needs to be accelerated, and the concentration of polyacrylamide solution can be improved.

Can polyacrylamide and polyaluminium chloride be used at the same time?

In fact, in the ordinary treatment of sewage, some sewage, the use of a single flocculant is not effective, must be combined with two kinds of use, the use of inorganic flocculant PAC and polyacrylamide composite flocculant to treat sewage will achieve better results, but when adding agents, attention should be paid to the order, the order is incorrect, but also can not achieve results.

The sequential method for adding polyacrylamide and other flocculants is as follows:

When using composite flocculant, attention must be paid to the sequence of adding and the interval of adding. The combination of PAC and PAM is to let PAC complete neutralization charge/colloid destabilization to form fine flocs, and further increase floc volume is conducive to full precipitation. Because the reaction time of PAC is very short, strong mixing is needed after adding PAM. The action time of PAM is long. The mixing attention is first strong and then weak - first strong is to mix evenly and then weak is to avoid destroying flocs! Polyacrylamide belongs to flocculant, polyaluminium chloride belongs to coagulant, generally adding coagulant and polyacrylamide first, but for the sake of safety, it is suggested that we determine the order of adding through experimental results! The dosing point, dosage, time and mixing strength need to be determined experimentally. Keep in mind that they should not be used together, otherwise the effect will be affected and the cost of use will be increased.