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.

What are the properties of high-purity PACL based on bauxite & calcium aluminate?

Properties of the high-purity PACl (samples A–C) prepared with bauxite and calcium aluminate in comparison with a conventional PACl. The basicity of high-purity PACl can be maintained at about 92% after the adjustment by calcium aluminate (Table 3), it has exceeded the national and international standards of PACl.

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).

Does high-purity PACL reduce operating cost?

On the other hand, when the dose was greater than 4 mg L −1 as Al, the high-purity PACl showed great UV 254 -absorbance removal capacity; which was even much greater at high does (e.g., 10 mg L −1). Relative low dose requirement of high-purity PACl indicates the potential of the reduction of operating cost.

What is the difference between high-purity PACL and conventional PACL?

The preparation process of high-purity PACl and conventional PACl is different as stated previously, where raw materials used and the operating conditions are different. As shown in Table 5, Al (OH) 3 is relatively expensive than bauxite but sulfydryl/PAM polymer is cheaper.

Does high-purity PACL remove turbidity?

Samples taken from the Huangpu River were used to evaluate the coagulation performance of high-purity PACl in comparison with conventional PACl. The results demonstrate that for the whole dose range studied, high-purity PACls removed more turbidity than conventional PACl.