How to deal with excessive heavy metals in industrial wastewater?

At present, the treatment methods of heavy metal wastewater treatment can be roughly divided into three categories: chemical treatment, physical treatment and biological treatment. Due to its effect, cost and ease of operation, chemical treatment has become the main method for the treatment of heavy metals at home and abroad.

Heavy metal capture (chelating) agent treatment.

This method mainly uses a heavy metal chelator group that can form a complex with heavy metal ions, which can react with a variety of total heavy metal ions in water at the same time to form a water-insoluble metal complex, thereby forming a precipitate.

At present, there are many groups that can be chelated with heavy metals, including hydroxyl groups, amine groups, sulfhydryl groups and dithioamino groups. Dithioamides have attracted the attention of researchers at home and abroad because of the complex precipitation with strong coordination ability with a variety of heavy metal ions.

At present, the research focus of heavy metal scavengers is mainly in two aspects: first, the monomer containing chelating agent groups is prepared by polyaddition, polycondensation, stepwise polymerization or ring-opening polymerization; On the other hand, the polymer heavy metal scavenger is synthesized by introducing side groups containing chelating functions through chemical reactions with natural polymers as the matrix. Commonly used polymer carriers are polystyrene, polyvinyl chloride, starch, polypolysaccharides, etc.

Compared with inorganic heavy metal removers, heavy traps have attracted much attention because of their obvious effect on the removal of complexed heavy metal ions, and are widely used in the treatment of various types of difficult-to-treat wastewater.

Neutralization and precipitation method.

Principle: Alkaline substances are added to the wastewater, so that the heavy metals are removed by forming hydroxide precipitates with little solubility.

Sulfide precipitation method.

Principle: Sodium sulfide and other sulfiding agents are added to make the heavy metal ions form a heavy gold sulfide precipitate with a small solubility product and be removed.

Pharmaceutical precipitation method.

Principle: The method is mainly to inject heavy metal scavenger into the wastewater, a chemical product that can be strongly chelated with heavy metal ions, using grafting synthesis process, the chelating group on the branch chain can form insoluble matter with chelating heavy metals and precipitate.

It is very necessary to take chemical precipitation to remove heavy metal ions, because if heavy metal ions are discharged into the ground, they will definitely pollute the groundwater, which is a terrible thing.

Heavy metal contaminated water can be treated by:

1.Eco heavy metal wastewater chemical precipitation method: the heavy metal ions in the polluted water are reacted with the precipitant to form insoluble precipitates, and then the heavy metal ions are removed by precipitation and separation.

2.Eco wastewater treatment adsorption method: the adsorbent is used to adsorb the heavy metal ions in the polluted water to its surface, and then the heavy metal ions are removed by the removal of the adsorbent.

3.Ion exchange method: the heavy metal ions in the polluted water are exchanged with the ions in the ion exchange resin, and then the heavy metal ions are removed by the removal method of the resin.

4.Membrane separation method: a special membrane material is used to separate heavy metal ions in contaminated water from water.

5.Biotechnology law: the use of microorganisms or plants and other organisms to absorb, transform or degrade heavy metals. Different treatment methods are suitable for different types of heavy metal contaminated water, so the appropriate treatment method should be selected according to the specific situation.

Heavy metal wastewater refers to the wastewater containing heavy metals discharged from the industrial production processes such as mining and metallurgy, machinery manufacturing, chemical industry, electronics, and instrumentation. Heavy metal (such as cadmium, nickel, mercury, zinc, etc.) wastewater is one of the most polluting industrial wastewater and the most harmful to human beings, and its water quality and quantity are related to the production process.

The heavy metals in wastewater generally cannot be decomposed and destroyed, but can only transfer their location and transform their physical and chemical forms. The treatment method is to first reform the production process, and use no or less toxic heavy metals.

In the production site on-site treatment (such as not discharged from the production workshop) often use chemical precipitation method, ion exchange method, etc., and the heavy metals in the treated water can be discharged or reused if they are lower than the discharge standard. The formation of new heavy metal concentrate products as far as possible to use or harmless treatment.

The treatment of heavy metal wastewater requires the use of professional technology and Eco heavy metal sewage treatment instruments, and the following are some possible treatment methods:

Electrolysis: The electrolysis reaction is used to reduce or oxidize heavy metal ions into metals or oxides on the electrode, so as to achieve the purpose of removing heavy metal ions.

Membrane separation method: the use of semi-permeable membranes to separate heavy metal ions in wastewater, this method is suitable for wastewater treatment with low ion concentration.

Biological method: the use of microorganisms to bioadsorb or biodegrade heavy metal ions, so as to remove heavy metal ions. This method is suitable for situations where the concentration of heavy metals in wastewater is low.

These treatment methods can also be combined, such as electrolysis to remove most of the heavy metal ions in the wastewater, and then membrane separation to remove the residual heavy metal ions. Choose the appropriate treatment method according to the specific situation to achieve efficient, safe and environmentally friendly treatment results.

1) Chemical precipitation: adding chemicals to wastewater can be applied to a wide range of pH conditions, and is not affected by the concentration of heavy metal ions.

2) Solvent extraction: The different solubility of contaminants in water and organic solvents is used for separation.

3) Electrolysis: a common method for treating cyanide-containing wastewater, decomposing and precipitating cyanide by electrolysis and oxidation.

Hope it helps.

Precipitation method, electrolysis method, redox method, new membrane separation treatment technology, high-efficiency ion exchange technology, biological purification treatment technology.