Treatment method and treatment system of nickel-containing wastewater produced in anodic-oxidation hole sealing

Abstract

Provided are a method and system for treating nickel-containing wastewater produced in anodic-oxidation hole sealing. The method and the system are low in equipment investment, low in treatment cost and capable of removing nickel ions in wastewater and meanwhile effectively degrading and removing organic pollutants. By adopting an efficient pretreatment technology, nickel in a strong-complexing state is subjected to complex breaking to form free-state nickel, organic matter molecule chains difficult to oxidize and degrade are broken and destroyed to form a small-molecule compound easy to treat, then the compound is further thoroughly oxidized through Fenton reaction, nickel ions in a complexing state are released, then alkali and a coagulant are added in a coagulating reaction link to remove the nickel ions in the wastewater again, most of nickel ions precipitate through flocculation and precipitation reaction, and the remaining nickel ions in supernate are absorbed again through a cationic resin exchanger. The wastewater discharge can continuously and stably reach the national first-level discharge standard, and the organic matter in the wastewater can be effectively oxidized, decomposed and removed.

Description

technical field [0001] The invention relates to a treatment method and equipment for nickel-containing wastewater, in particular to a treatment method for nickel-containing wastewater and a used treatment system for anodizing and sealing the surface of an aluminum material. Background technique [0002] Aluminum alloy materials have excellent physical, chemical, mechanical and processing properties, and are widely used in aerospace, automotive, electronics, home appliances and other fields. However, the aluminum alloy material has low hardness and poor wear resistance, and abrasion damage often occurs. Therefore, the aluminum alloy often needs to undergo corresponding surface treatment before use. [0003] The surface treatment process of aluminum alloy materials generally includes: degreasing, alkali etching, neutralization, anodizing, coloring and sealing. Anodic oxidation can form an oxide film on the surface of aluminum alloy, which can significantly improve the corrosi...

AI Technical Summary

Problems solved by technology

Once nickel ions are complexed with these complexing agents, they are very stable and cannot be removed by flocculation precipitation or ion exchange, so soluble complexed nickel can easily cause wastewater to exceed the standard

[0010] Chinese patent CN102443709 discloses a pretreatment of electroplating nickel wastewater by using acidification method to break the complexation technology. Under strong acid conditions, commonly used complexes such as citric acid, ammonia water, oxalic acid, etc. lose or weaken the ability to complex with nickel ions, thereby The metal nickel in the complex state can be freed, and this method can release nickel ions from some weaker complexing agents, but the disadvantage of this method is that it cannot release organic phosphate complexing agents such as ethylenediamine tetramine Nickel complexed by sodium methylene phosphate

Although Fenton oxidation can effectively oxidize and degrade organic pollutants in water, the degradation and release efficiency of Ni-EDTA complexation is low

Therefore, this method can only break the nickel complexes with weaker complexing ability, and the effect of breaking nickel complexes with stronger complexing ability is not obvious, and cannot achieve a sustained and stable nickel removal effect. Similarly, this method It is also easy to cause nickel emissions to exceed the standard

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