The Coagulation Mechanisms of Polymeric Aluminum Chloride (PAC)

Polyaluminium chloride (PAC, also written PACl) coagulation should not be explained as one fixed mechanism for every grade and water source. Research reports that pH, coagulant dosage and aluminium species influence the coagulation behavior.

Charge Neutralization

Positively charged aluminium species can contribute to destabilizing negatively charged particles. The importance of this pathway depends on the species present and the treatment conditions; it is not a universal performance guarantee.

Sweep Flocculation

Where aluminium hydroxide precipitation occurs, particles can be captured within the precipitate. The contribution of this pathway depends on the operating conditions and should not be assumed from the PAC product name alone.

Double-Layer Compression: A General Framework

Double-layer compression is discussed in general colloid-destabilization theory. Its inclusion in that framework does not establish that it is the dominant mechanism for a particular PAC grade or application.

Adsorption and Bridging: Avoid a Universal Chain Description

Adsorption and bridging also appear in general coagulation descriptions. Do not infer that every high-basicity PAC product behaves as a long-chain organic Flocculant. A mechanism statement needs evidence relevant to the actual aluminium species and test system.

Information to Record in a PAC Trial

• Exact grade specification and available supplier documentation.
• Representative water composition and the required treatment indicators.
• pH, dose, mixing and separation conditions used in the comparison.
• Measured results and any residual or downstream indicators required for the project.

Discuss Grade Selection with Lanyao

Share your application, sample analysis and operating conditions. Request candidate-grade documents, SDS, available COA and sample availability before agreeing a trial.

Research Background

Coagulation behavior of Polyaluminum Chloride: Effects of pH and coagulant dosage and Mechanism of natural organic matter removal by polyaluminum chloride provide research context. Their findings are not certification or a performance claim for a Lanyao grade.