Why is the use of cationic polyacrylamide not effective

Release time:

Jan 17,2024

Cationic polyacrylamide is one of the water treatment chemicals commonly used in sewage treatment. However, some customers have reported that the use of cationic polyacrylamide is not effective. So why is this?

First, we must determine whether the selection of polyacrylamide is correct, and secondly, we must ensure that the properties of sewage and sludge have not changed. If there is no error in these two points, then you can see if it is caused by the following situations:

1. The main factor that determines the solubility of cationic polyacrylamide is the dissolution time. The solubility of cationic polyacrylamide also directly affects the use effect. When dissolving cationic polyacrylamide, attention should be paid to using stirring and heating measures to add the product evenly and slowly into the container to avoid agglomeration. The solution should be prepared at an appropriate temperature, otherwise it will cause polymer degradation and affect the use effect. When dissolving cationic polyacrylamide, high-speed stirring or strong mechanical shearing in the solution will break the macromolecular structure of PAM. Therefore, when configuring the PAM solution, the stirring speed should be reasonably controlled to prevent the decrease in molecular weight and flocculation performance.

2. Cationic polyacrylamide powder can be stored in a dry and cool place for more than two years, but after being formulated into a solution, the storage time is limited. Therefore, the appropriate storage method should be selected according to the form of polyacrylamide.

3. Add a very small amount of iron compounds or iron powder to the PAM solution and stir slightly to disperse it. The viscosity and flocculation performance of the polypropylene solution will be greatly reduced. This is why the cationic polyacrylamide solution must be prepared in enamel, galvanizing, Causes are carried out in aluminum or plastic buckets. Cationic polyacrylamide is more sensitive to iron ions, calcium ions and magnesium ions than anionic cationic polyacrylamide. Iron ions are catalysts that cause chemical degradation of cationic polyacrylamide. Therefore, when preparing, transferring and storing cationic polyacrylamide solutions, stainless steel, plastic, glass fiber reinforced plastic or carbon steel containers coated with resin should be used as much as possible to avoid iron ions entering and the solution contacting the equipment.

4. The higher the concentration of cationic polyacrylamide, the longer the storage time. However, 3% to 5% solutions cannot directly treat sewage and must be diluted before use.

5. Cationic polyacrylamide is very sensitive to high temperatures. Under high temperature conditions, the viscosity of the solution will drop rapidly, and products with higher molecular weights will drop more. Therefore, when dissolving cationic polyacrylamide, it should be carried out at room temperature of 25°C. When the temperature is higher than 50°C, the flocculation performance of the product begins to decrease to varying degrees.

6. Whether the water in which cationic polyacrylamide is dissolved is clean tap water. If it is not clean tap water, then the cationic polyacrylamide will react chemically with impurities in the water when it is dissolved, thus affecting its use effect.