Electrochemical treatment system and electrochemical treatment method for treating nickel-containing wastewater

Abstract

The invention discloses an electrochemical treatment system and electrochemical treatment method for treating nickel-containing wastewater. According to the system, a dimensional stable anode is used as an anode, cathode and anode chambers are separated by a cation exchange membrane, complexing-state nickel ions in the nickel-containing wastewater are subjected to decomplexation to release free-state nickel ions under the oxidization effect of the dimensional stable anode and the free-state nickel ions penetrate through the cation exchange membrane to enter the cathode chamber to be reduced into elementary nickel. The electrochemical treatment system and electrochemical treatment method, disclosed by the invention, can be used for treating complexing-state nickel ions, also can be used for removing organic pollutants in the nickel-containing wastewater to some extent, and are simple in process, efficient, energy-saving and environmentally friendly.

Description

technical field [0001] The invention belongs to the field of industrial wastewater treatment. Background technique [0002] A large amount of nickel-containing wastewater is produced in industry, in which nickel mainly exists in the form of nickel ions, mainly divided into free nickel ions and complexed nickel ions, of which complexed nickel ions are mainly Ni 2+ With various organic acids or organic acid radicals, CN - 、SCN - , EDTA substances, ammonia or complexes formed by amine substances. In view of the toxicity of nickel ions, nickel-containing wastewater needs to be treated before it can be discharged. [0003] The existing nickel-containing wastewater treatment methods include precipitation method, ion exchange method, electrodeposition method and so on. Among them, the precipitation method is to add alkali or carbonate to precipitate nickel ions into nickel hydroxide or nickel carbonate, resulting in a large amount of sludge precipitation, and in order to recove...

AI Technical Summary

Problems solved by technology

Among them, the precipitation method is to add alkali or carbonate to precipitate nickel ions into nickel hydroxide or nickel carbonate, resulting in a large amount of sludge precipitation, and in order to recover metal nickel from the precipitation product, cumbersome follow-up procedures are required

The ion exchange method can only deal with free nickel ions, but is powerless to complex nickel ions

And other organic pollutants in nickel-containing wastewater often block the ion exchange membrane or ion exchange resin, and have to be shut down frequently for cleaning

Electrodeposition is also difficult to deal with complexed nickel ions, because of the strong complexation of ligands in complexed nickel ions, it is difficult for nickel ions to accept electrons and be reduced, not to mention some complexed nickel ions, such as Ni(CN) 4- or Ni(SCN) 4- , has become an anion, and cannot reach the cathode at all under the action of an electric field, let alone be reduced

In addition, organic pollutant sludge is often deposited on the cathode, resulting in a decrease in cathode current efficiency

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