Poor water treatment effect? It is highly likely that the reaction of polyaluminium chloride (PAC) is not sufficient

The water purification efficiency of polymeric flocculants is not achieved simply by mixing, but relies on three closely interconnected core reactions: hydrolysis, electric neutralization, and bridging flocculation. Many cases of poor water treatment results stem from the insufficient progression of these reactions. Understanding the mechanism of action of PAC is essential to precisely control the usage conditions and maximize the water purification effect. 1. The “three-step core reaction” of PAC water purification: the complete process from dissolution to clarification After being introduced into the water body, PAC achieves water purification through three synergistic and progressive reactions, each step being indispensable: 1. Step 1: Rapid hydrolysis to generate highly active polymers PAC itself is a pre-hydrolyzed form of polymer, containing a large number of positively charged hydroxyl complex ions (such as [Al₂(OH)₅]⁺, [Al₈(OH)₂₀]⁴⁺, etc.). Once introduced into water, these highly reactive ions will quickly react further with water molecules, forming larger inorganic polymer molecules in a short period of time. Compared to traditional aluminum salts such as aluminum sulfate, the hydrolysis process of PAC is mild and does not significantly deplete the alkalinity of the water body, which also allows it to have a wider range of pH adaptability and function efficiently even in neutral water quality. 2. Step 2: Electro-neutralization, breaking the colloidal stable state Suspended colloidal particles in water (such as clay, bacteria, organic impurities, etc.) mostly carry negative charges. The property of like charges repelling each other allows them to remain stably suspended for a long time and resist natural sedimentation, which is the core reason for water turbidity. The polynuclear hydroxyl cations generated by the hydrolysis of PAC carry strong positive charges and will actively adsorb onto the surface of negatively charged colloids like a “magnet,” precisely neutralizing their surface charges. When the “repulsive barrier” of colloidal particles is weakened or eliminated, the van der Waals attraction between particles begins to dominate, laying the foundation for subsequent aggregation. 3. Step 3: Bridge netting and capturing to form dense floc sedimentation After the completion of electro-neutralization, the long-chain high molecular polymers formed by PAC will initiate the “bridging adsorption” effect: multiple active adsorption sites on its molecular chains can simultaneously “capture” multiple destabilized microflocculants, connecting them like bridges to form larger flocculated particles (i.e., “alum flocs”). At the same time, these long-chain polymers will also act like a “three-dimensional net”, actively netting and capturing the remaining fine suspended solids in the water during the sedimentation process, bringing all impurities to the bottom of the water and ultimately achieving water clarification. II. In these scenarios, PAC can best leverage its advantages Based on the aforementioned unique reaction mechanism, PAC performs particularly well in the following water quality and operating conditions. Choosing the right scenario can achieve twice the result with half the effort: 1. Treatment of water bodies with high turbidity and complex composition For industrial wastewater containing a large amount of organic matter, colloidal particles, and suspended solids, or high turbidity river water during the flood season, PAC’s strong electric neutralization ability can quickly break the colloidal stability, and then form dense alum through bridging action, resulting in fast sedimentation speed and good solid-liquid separation effect. It can effectively solve the problem of “difficult to clarify” in water bodies. 2. Processes with high requirements for floc strength The alumen ustum formed by PAC is not only bulky but also has a tough structure, making it difficult to disperse during subsequent hydraulic impact in the sedimentation tank or filtration process. It can maintain its shape stably and complete solid-liquid separation, making it particularly suitable for water treatment scenarios involving subsequent supporting processes such as filtration and pressure filtration, ensuring stable treatment effects. 3. Situations where the pH value of raw water fluctuates significantly Traditional coagulants are sensitive to the pH value of water bodies, requiring frequent acid-base adjustments to ensure effectiveness. However, PAC exhibits stronger adaptability to changes in pH and temperature, capable of stably completing hydrolysis and neutralization reactions within a wide range of pH from 5.0 to 9.0. This significantly reduces the consumption of acid-base regulators and lowers treatment costs. summary The core of PAC‘s water purification effect lies in the full synergy of three steps: hydrolysis, electric neutralization, and bridging flocculation. When the water treatment effect is poor, it is advisable to first check whether the dosage of PAC is reasonable, whether the pH of the water body is suitable, and whether the stirring intensity is sufficient (to ensure that the reaction proceeds fully). Only by ensuring that this series of reactions are fully implemented can the efficacy of PAC be maximized. Mastering its mechanism of action and adjusting the usage conditions according to the actual water quality can achieve efficient and stable water treatment effects. The main products of flocculant manufacturer Xinhuan Water Treatment are: White polyaluminium chloride (food grade), drinking grade polyaluminium chloride, industrial grade polyaluminium chloride, anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide, petroleum recycling polyacrylamide, oil recovery polyacrylamide, polyacrylamide, polymer flocculant polymer flocculation coagulant, polymeric ferrous sulphate, polymerized iron and aluminium chloride, and other water treatment chemicals. Welcome customers to write to us to negotiate business! Tel/WhatsApp：86 19139972558 Email：Sunny@xhwtm.com Contact:Sunny