Why is polyaluminum chloride a good coagulant for water treatment?

Polyaluminum chloride (PAC) is highly effective coagulant for water treatment over conventional coagulants because of low dosage requirement, shorter flocculation time, smaller amount of sludge, high efficiency and low aluminum residual in treated water .

What is the molecular formula of poly-aluminum chloride?

One of the major pre-polymerized coagulants, poly-aluminum chloride (PACl) is used broadly for water and wastewater treatment. PACl contains different amounts of hydroxyl, and the molecular formula of PACl is [Al m (OH) n (H 2 O) x]·Cl 3m−n (n ≤ 3 m).

Can polyaluminum chloride be used in water treatment?

In this study, synthesis and speciation of polyaluminum chloride (PAC) for application in water treatment was investigated using a colorimetric speciation method. It was possible to produce stable preparations of PAC solutions in which a relatively stable cationic polymer predominated.

What is high-purity poly-aluminum chloride (PACL)?

Poly-aluminum chloride (PACl) is one of the common coagulants for water and wastewater treatment. A new Chinese national standard of PACl has been implemented, where the concentration of insoluble substances, iron and heavy metals is to be controlled strictly, then researches on the preparation of high-purity PACl are needed.

How do you determine alkalinity of polyaluminium chloride?

The alkalinity of polyaluminium chloride is determined by the quotient of the number of moles OHto Al 3+ in a coagulant, referred to as the alkalinity ratio (r), which is approached as a coagulant polymerisation degree measure. … …

Why does polyaluminium chloride contain more polymerised aluminium?

Controlled initial hydrolysis of aluminium salts occurring during the production of polyaluminium chloride causes that they contain more polymerised aluminium forms with a high positive charge than those generated during rapid and uncontrolled hydrolysis of aluminium sulphate (VI) [22, 23].