What Factors Affect the Condensation Effect of Polyaluminium Chloride (PAC)?

  As an efficient and environmentally friendly flocculant, polymeric aluminum chloride (PAC) plays an important role in the field of water treatment. However, its coagulation effect is affected by many factors.

Factors affecting the effectiveness of PAC:

1. Coagulant type and form

PAC has two forms: solid and liquid. The dose of PAC is different based on the forms. It should be based on the specific application needs to choose the appropriate type. At the same time, the market also exists in different alumina content of PAC products, such as 26%, 28%, 30%, etc. The choice should be based on the treatment of water quality and industry requirements.

2. Product quality

The quality of PAC products will also affect their cohesive effect. If the product is deteriorated or mixed with other impurities, or there are differences between different brands of products, it may have an impact on the treatment results. Therefore, when choosing and using PAC products, you need to pay attention to their quality and stability.

3. Water temperature

Water temperature has a significant effect on the coagulation effect of PAC. When the temperature is low to a certain degree (such as -5℃), the flocculation effect will be significantly reduced. At 5℃ to 20℃, the molecular performance is stable and the coagulation ability is the best. When the water temperature is low, the hydrolysis speed is slow and incomplete, while the viscosity of water increases and the Brownian motion is weakened, leading to a reduction in the number of collisions between the flocculant colloidal particles and the impurity particles in the water, affecting the formation of flocs.

4. pH value

pH value is one of the key factors affecting the cohesive effect of PAC. The best pH value of PAC is 6-7 (Some say that the best pH value is 6-9). In this range, aluminum ions can be hydrolyzed and polymerized into polymerization of aluminum hydroxide colloid, so as to play a good coagulation effect. When the pH value is too low or too high, it will affect the hydrolysis rate of aluminum ions and the form of the product, which in turn affects the coagulation effect.

5. Dosage

The dosage of PAC directly affects its coagulation effect. Insufficient dosage may lead to incomplete coagulation, while dosage that is too large may cause the re-stabilization of colloids but reduce the coagulation effect. Therefore, it is necessary to determine the best dosage according to the water quality and treatment objectives.

6. Water quality

Water alkalinity, suspended particles, and other factors will also affect the coagulation effect of PAC. For example, high alkalinity water quality may need to add coagulants to improve coagulation; and suspended particles content is too high or too low may influence coagulation badly.