Polyaluminum Chloride (PAC)-also known simply as "Poly-aluminum"-is a water-soluble inorganic polymer situated chemically between AlCl3 and Al(OH)3. Its general chemical formula is [Al2(OH)nCl6-n]m, where *m* represents the degree of polymerization and *n* indicates the degree of basicity (neutrality) of the PAC product. When *n* falls within the range of 1 to 5, the substance consists of highly charged polymeric ring-chain structures featuring a Keggin-type configuration; these structures exert potent electrical neutralization and bridging effects on colloidal particles and suspended solids present in water. Furthermore, PAC is highly effective at removing toxic substances and heavy metal ions. Characterized by its chemical stability, it serves as a modern, advanced water purification material and coagulant, finding widespread application in the purification and treatment of drinking water, industrial wastewater, and municipal sewage.
Polyaluminum Chloride is broadly categorized into two types: one for drinking water applications and another for industrial water applications, each adhering to distinct regulatory standards. In terms of appearance, the product ranges in color from yellow or pale yellow to dark brown or dark gray; it is available in two physical forms: liquid and solid. This product exhibits strong bridging and adsorption capabilities; during the hydrolysis process, it simultaneously facilitates various physicochemical reactions, including coagulation, adsorption, and precipitation. The fundamental distinction between Polyaluminum Chloride and traditional inorganic coagulants lies in their molecular structures: traditional inorganic coagulants are typically low-molecular-weight crystalline salts, whereas the structure of Polyaluminum Chloride comprises a diverse array of polynuclear hydroxyl complexes with variable morphologies. Consequently, it facilitates rapid flocculation and sedimentation, operates effectively across a wide pH range, is non-corrosive to piping and equipment, and delivers demonstrably superior water purification results-effectively removing color, suspended solids (SS), COD, BOD, and heavy metal ions such as arsenic and mercury from water. As such, this product is extensively utilized across the fields of drinking water treatment, industrial water management, and wastewater treatment.
