The Chemical Composition and Mechanism of Polyaluminium Chloride (PAC)
Polyaluminium Chloride (PAC) stands out as a highly effective coagulant in water treatment due to its unique chemical composition and the sophisticated mechanism by which it operates. NINGBO INNO PHARMCHEM CO.,LTD. provides insight into the science behind this essential chemical.
At its core, Polyaluminium Chloride is an inorganic polymer composed of aluminum, chlorine, hydrogen, and oxygen. Its general formula, [Al₂(OH)nCl₆-n]ₓ, indicates a complex polymeric structure where aluminum ions are bridged by hydroxyl groups. This polymerized structure is key to its enhanced performance compared to simple aluminum salts. The specific degree of polymerization and the ratio of hydroxyl groups to aluminum ions, often referred to as 'basicity', significantly influence PAC's efficiency. Higher basicity generally correlates with higher polymer content and a greater positive charge density, leading to more effective coagulation.
The mechanism of action of PAC in water treatment is multifaceted, involving several key processes:
1. Charge Neutralization: Similar to other coagulants, PAC introduces positively charged species into the water. These positive charges neutralize the negative surface charges of suspended colloidal particles, reducing the electrostatic repulsion that keeps them dispersed. This destabilizes the colloids, making them susceptible to aggregation.
2. Sweep Flocculation: As PAC hydrolyzes in water, it forms aluminum hydroxide precipitates, commonly known as 'flocs'. These precipitates have a large surface area and adsorb impurities. As these flocs form and grow, they entrap suspended solids, organic matter, and other contaminants, effectively sweeping them out of the water.
3. Bridging Polymerization: The long polymer chains of PAC can physically bridge between destabilized particles, forming a stronger, more robust network of flocs. This bridging action contributes to the formation of larger, faster-settling flocs.
The specific composition of PAC, including its basicity and aluminum content, determines its precise performance characteristics. Products with higher basicity tend to be more efficient in removing turbidity and organic matter, even at lower dosages. This inherent efficiency is why PAC is favored in many advanced water purification systems. Understanding these chemical underpinnings helps users appreciate why NINGBO INNO PHARMCHEM CO.,LTD.'s PAC is a leading choice for effective water treatment solutions.
Perspectives & Insights
Logic Thinker AI
“This polymerized structure is key to its enhanced performance compared to simple aluminum salts.”
Molecule Spark 2025
“The specific degree of polymerization and the ratio of hydroxyl groups to aluminum ions, often referred to as 'basicity', significantly influence PAC's efficiency.”
Alpha Pioneer 01
“Higher basicity generally correlates with higher polymer content and a greater positive charge density, leading to more effective coagulation.”