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Can polyaluminum chloride be used when arsenic content in drinking water exceeds the standard

Coagulation is a widely used arsenic removal method in industrial production and treatment of drinking water, and can well make industrial sewage meet the discharge standard and drinking water meet the drinking standard. The common coagulants are iron salts: such as ferric chloride, ferrous sulfate and ferric chloride; Aluminum salt: such as aluminum sulfate, basic aluminum chloride, polyaluminum chloride, etc.

The research shows that the arsenic removal effect of iron salt is better than that of aluminum salt, and the removal effect of as is significantly better than that of as (III). Therefore, in the process of arsenic removal, the treated water is often pre oxidized, oxidized from trivalent as to pentavalent as (V), and then coagulated. In order to improve the oxidation effect, sometimes a catalyst is added for oxidation.

The process of arsenic removal by coagulation can be summarized into the following three aspects:

1. precipitation, hydrolyzed metal ions and arsenate ions form precipitation;

2. coprecipitation: in the coagulant hydrolysis polymerization precipitation process, arsenic is precipitated with the hydrolysate through adsorption, encapsulation, closure (or complexation):

3. adsorption: arsenic is adsorbed on the surface of insoluble hydrolysate formed by coagulant polyaluminum chloride. The latter two mechanisms may be more important, because in the treatment of arsenic removal from drinking water, generally ph>5.5, it is not easy to form precipitation coagulation method under this condition. The method requires a large amount of polyaluminum chloride, resulting in a large amount of arsenic containing waste residue that can not be used, and the treatment is difficult. Long-term accumulation is easy to cause secondary pollution, Therefore, the application of this method is limited.

Thank you for your attentionHenan aierfuke Chemical Co., Ltd：Focus on water treatment, only for the healthy world! Our company is committed toPolyaluminium chloride、Polyferric sulfateThe R & D, manufacturing and sales of series of water purification materials are willing to create success with our customers and friends.