Polyaluminium Chloride (PAC) is a widely used water treatment agent in industrial water purification applications due to its potent coagulation and flocculation properties. It is an inorganic polymer that is synthesized by the reaction of aluminum source materials, such as aluminum hydroxide or aluminum chloride, with a base, resulting in a product that effectively removes suspended solids, turbidity, and certain soluble contaminants from water.

In industrial water treatment, PAC serves several key functions:

1. Coagulation: When added to water, PAC ions neutralize the electrical charge on suspended particles, causing them to lose their repulsive forces and clump together. This process, known as coagulation, converts fine particles into larger aggregates.

2. Flocculation: After coagulation, PAC aids in forming flocs – large, visible clusters of particles that can be easily separated from the water. The polymeric structure of PAC facilitates this process by creating bridges between particles, enhancing the speed and efficiency of sedimentation or filtration.

3. Contaminant Removal: PAC is particularly effective in removing a broad spectrum of contaminants, including colloidal particles, organic matter, metals, and phosphorus compounds. It is frequently used in pre-treatment stages before reverse osmosis, ultrafiltration, or other advanced treatment processes.

4. Flexibility: The effectiveness of PAC can be adjusted depending on the specific needs of the industrial process water. Different PAC formulations exist, offering varying degrees of basicity and aluminum content to suit different water qualities and treatment goals.

5. Economic Efficiency: Compared to some other water treatment chemicals, PAC generally requires a lower dose to achieve similar treatment results. Additionally, its ability to form compact flocs can lead to reduced sludge volumes and lower disposal costs.

Polyaluminium Chloride is a versatile and cost-effective solution for a variety of industrial water treatment needs. Its adaptability to different water conditions and contaminant profiles, combined with its robust performance, makes it a preferred choice for many industries looking to treat and recycle their process water. However, the specific type and dosage of PAC required will depend on the unique characteristics of the industrial wastewater stream, and consultation with a water treatment specialist is often necessary for optimized application.