The treatment and reuse of electroplating wastewater plays a vital role in saving water resources and protecting the environment. This paper reviews the advantages and disadvantages of various electroplating wastewater treatment technologies and the application of some new materials in electroplating wastewater treatment.

01 Chemical precipitation method

Chemical precipitation method is to put chemicals into the wastewater, so that the dissolved heavy metals into insoluble compounds precipitation, and then separated from the water, so as to achieve the purpose of removing heavy metals.

Chemical precipitation method has been widely used in electroplating wastewater treatment because of its advantages of simple operation, mature technology, low cost, and removal of many heavy metals in wastewater.

1. Alkaline precipitation method

Alkaline precipitation method is to add alkaline substances such as NaOH, lime and sodium carbonate to the wastewater, so that heavy metals form hydroxide or carbonate precipitation with low solubility and are removed. This method has the advantages of low cost and simple operation, and is widely used at present.

However, the sludge production of alkaline precipitation method is large, which will produce secondary pollution, and the effluent pH is high, and the pH needs to be adjusted back. NaOH is widely used in engineering because it produces relatively less sludge and is easy to recycle.

2. Sulfide precipitation method

Sulfide precipitation method is through the addition of sulfide (such as Na2S, NariS, etc.) to form a solubility of heavy metals in the wastewater than hydroxide precipitation, the effluent pH is 7 ~ 9, no need to adjust the pH can be discharged.

However, the sulfide precipitation particles are fine, so it is necessary to add flocculant to assist precipitation, which increases the treatment cost. Sulfides also produce toxic HS gas in acidic solutions, which has limitations in practical operation.

3. Ferrite method

The ferrite method is developed according to the principle of ferrite production, so that various heavy metal ions in the wastewater form ferrite crystals to precipitate together, so as to purify the wastewater. This method is mainly by adding ferrous sulfate to wastewater, and after reduction, precipitation and flocculation, ferrite is finally formed. Because of its simple equipment, low cost, fast settling and good treatment effect, it is widely used.

The effect of pH and dosage of ferrous sulfate on the removal of heavy metal ions by ferrite method showed that the optimal flocculation pH of nickel, zinc and copper ions was 8.00 ~ 9.80, 8.00 ~ 10.50 and 10.00, respectively, and the molar ratio of ferrous ions to them was 2 ~ 8, while the optimal reduction pH of hexavalent chromium was 4.00 ~ 5.50. The best flocculation pH is 8.00 ~ 10.50, and the best feeding ratio is 20. The nickel content of the effluent is less than 0.5mg/L, the total chromium content is less than 1.0mg/L, the zinc content is less than 1.0mg/L, and the copper content is less than 0.5mg/L, which meets the requirements of Table 2 in the Discharge Standard for Electroplating Pollutants (GB21900-2008).

Limitations of chemical precipitation

With the improvement of wastewater discharge standards, the traditional single chemical precipitation method is difficult to treat electroplating wastewater economically and effectively, and is often combined with other processes.

A ferrite-carbonite (a material with physical adsorption and ion exchange function) combined process was used to treat high-concentration nickel-containing electroplating wastewater with Ni content of about 4000mg/L: The pH was controlled by ferrite method at 11.0, and the electroplating wastewater was treated in Fe/Fe. The molar ratio is O.55, the mass ratio of FeSO4·7H2O/Ni is 21, and the reaction temperature is 35℃ for 15min. The average concentration of Ni in the effluent decreases from 4212.5mg/L to 6.8mg/L, and the removal rate reaches 99.84%. Then CARBONITE was used for treatment. When CARBONITE was added at 1.5g/L, pH=6.5 and temperature 35℃ for 6h, the Ni removal rate reached 96.48% and the concentration of Ni in effluent was 0.24mg/L, meeting the "Table 2" standard in GB21900-2008.

Using advanced Fenton-chemical precipitation process to treat wastewater containing chelated heavy metals, using zero-valent iron and hydrogen peroxide to degrade chelates, and then adding alkali to precipitate heavy metal ions, not only can remove nickel ions (the removal rate is up to 98.4%), but also reduce COD chemical oxygen demand.

02 REDOX method

1. Chemical oxidation method

Chemical oxidation is particularly effective in treating electroplating wastewater containing cyanide. The cyanogen ion (CN I) in wastewater is oxidized into cyanate (CNO-), and then cyanate (CNO-) is oxidized into carbon dioxide and nitrogen, which can completely solve the problem of cyanide pollution.

Commonly used oxidants include chlorine oxidants, oxygen, ozone, hydrogen peroxide and so on, of which alkaline chlorination is the most widely used. The Fenton process is used to treat electroplating wastewater containing low concentration cyanide with an initial total cyanide concentration of 2.0mg/L. The initial pH of the reaction is 3.5, and the molar ratio of H202/FeSO4 is 3.5. 1. Under the optimal conditions of H202 dosage of 5.0g/L and reaction time of 60min, the cyanide removal rate can reach 93% and the total cyanide concentration can be reduced to 0_3mg/L.

2. Chemical reduction method

Chemical reduction method is mainly used in electroplating wastewater treatment for wastewater containing hexavalent chromium. The method is to add reducing agents (such as FeSO, NaHSO3, Na2SO3, SO2, iron powder, etc.) in the wastewater to reduce hexavalent chromium to trivalent chromium, and then add lime or sodium hydroxide for precipitation separation. The ferrite method can also be classified as chemical reduction method.

The main advantages of this method are mature technology, simple operation, large processing capacity, less investment, and good results in engineering applications, but large sludge volume will produce secondary pollution. Using ferrous sulfate as reducing agent to treat 80t/d electroplating wastewater containing 7O ~ 80mg/L total chromium, the effluent total chromium is less than 1.5mg/L, and the treatment cost is 3.1 yuan /t, which has high economic benefits.

Electroplating wastewater containing 80mg/L hexavalent chromium and pH 6 ~ 7 was treated with sodium pyrosulfite as reducing agent, and the concentration of hexavalent chromium in effluent was less than 0.2mg/L.

03 Electrochemical method

Electrochemical method refers to the removal of heavy metal ions and organic pollutants in wastewater through a series of reactions such as REDOX, decomposition, precipitation and air flotation under the action of electric current.

The main advantages of this method are that the removal rate is fast, the coordination metal link can be completely broken, the heavy metal is easy to recycle, the footprint is small, the amount of sludge is small, but its plate consumption is fast, the power consumption is large, the removal effect of low concentration electroplating wastewater is not good, and it is only suitable for small and medium-sized electroplating wastewater treatment.

Electrochemical methods mainly include electrocoagulation, magnetoelectrolysis, internal electrolysis and so on.

The electrocoagulation method uses iron or aluminum plates as the anode, and produces Fe2+, Fe or Al during electrolysis. With the progress of electrolysis, the alkalicity of the solution increases, forming Fe(OH)2, Fe(OH)3 or AI(OH)3, and removing pollutants through flocculation precipitation.

Because the traditional electrocoagulation method after a long time of operation, will make the electrode plate passivation, in recent years, the high voltage pulse electrocoagulation method gradually replaces the traditional electrocoagulation method, it not only overcomes the problem of plate passivation, but also improves the current efficiency by 20% ~ 30%, reduces the electrolytic time by 30% ~ 40%, saves electric energy by 30% ~ 40%, and the sludge production is less. The removal rate of heavy metals can reach 96% ~ 99%.

The removal rates of CU20, Ni2, CN1 and COD reached 99.80%, 99.70%, 99.68% and 67.45% respectively in the treatment of electroplating wastewater from an electroplating plant by high voltage pulse electroflocculation technology.

Electrocoagulation is also commonly used in combination with other methods, using electrocoagulation and ozone oxidation to treat electroplating wastewater, using iron and aluminum as plates. The removal rates of hexavent chromium, iron, nickel, copper, zinc, lead, TOC(total organic carbon) and COD are 99.94%, 100.00%, 95.86%, 98.66%, 99.97%, 96.81%, 93.24% and 93.43%, respectively.

In recent years, internal electrolysis has attracted wide attention. The internal electrolysis method uses the principle of galvanic cell, generally adding iron powder and carbon particles to the wastewater, using the wastewater as the electrolyte medium, through the comprehensive effect of REDOX, replacement, flocculation, adsorption, co-precipitation and other reactions, it can remove a variety of heavy metal ions at one time.

This method does not require electrical energy, has low treatment cost and less sludge. The removal of COD and copper ions from simulated electroplating wastewater by iron-carbon microelectrolysis method was studied by static test. The removal rates reached 59.01% and 95.49%, respectively. However, the operation results of the continuous flow study using the micro-electrolytic reaction column show that the COD removal rate of the micro-electrolytic effluent after 14 days is only 10% ~ 15%, and the copper removal rate is reduced to 45% ~ 50%. It can be seen that the filler needs to be replaced or regenerated regularly.

04 Membrane separation technology

Membrane separation technology mainly includes microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), liquid membrane (Lv), etc., using the selective permeability of membranes to separate and remove pollutants.

This method has good removal effect, can realize heavy metal recycling and water reuse, covers a small area, no secondary pollution, is a promising technology, but the membrane cost is high, easy to be polluted.

The application and effect of membrane technology in the treatment of electroplating wastewater were analyzed. The results showed that the water quality of electroplating wastewater after treatment reached the discharge standard by combining the conventional wastewater treatment process with membrane bioreactor (MBR). After the treatment of electroplating wastewater by UF purification, RO and NF membrane, the water quality reached the reuse water standard. The conductivity of RO and NF produced water was lower than 100gS/cm and 1000gS/cm, and the COD was about 5mg/L and 10mg/L, respectively. After nickel plating rinsing wastewater passes through RO membrane, nickel concentration is more than 25 times, nickel recovery is realized, and the quality of RO produced water meets the reuse standard.

The analysis of investment and operation cost shows that the equipment cost of RO concentrated nickel can be recovered after more than one year of operation.

Liquid film method is not a traditional solid phase film, but a thin layer of emulsion particles suspended in the liquid, is a new type of separation technology similar to solvent extraction, including film production, separation, purification and demulsification process.

Dr. NormanN.Li, a Chinese-American, invented the emulsion membrane separation technology, which has the advantages of both extraction and penetration, combining the two steps of extraction and de-extraction. The emulsion liquid membrane method also has the characteristics of high mass transfer efficiency, good selectivity, small secondary pollution, energy saving and less investment in infrastructure, and has a good effect on the treatment and recycling of heavy metals in electroplating wastewater.

05 Ion exchange method

Ion exchange method is the use of ion exchange agents to exchange and separate harmful substances in wastewater, commonly used ion exchange agents are humic acid substances, zeolite, ion exchange resin, ion exchange fiber and so on. The operation of ion exchange includes four steps: exchange, backwash, regeneration and cleaning.

This method has the characteristics of simple operation, recycling heavy metals, low secondary pollution, but the cost of ion exchanger is high and the consumption of regenerant is large.

The treatment conditions and recovery methods of nickel containing wastewater by strong acid ion exchange resin were studied. The results showed that pH 6 ~ 7 was favorable for the removal of nickel ions by strong acidic cation exchange resin. The optimal temperature for nickel removal by ion exchange is 30℃ and the optimal flow rate is 15BV/h(that is, l5 times the volume of the resin bed per hour). The optimal desorption agent was 10% hydrochloric acid, and the flow rate of desorption solution was 2BV/h. The first 4.6BV desorption solution can be used to prepare plating bath solution, and the average mass concentration of nickel ion is 18.8g/L.

Mei.1ingKong et al. studied the adsorption capacity of CHS-L resin on cr(VI) and found that at low concentration of Cr(VI), the exchange adsorption rate of resin was controlled by liquid film diffusion and chemical reaction. The optimum adsorption pH of CHS-1 resin for Cr(VI) is 2 ~ 3, and its saturation adsorption capacity is 347.22mg/g at 298K. Chs-1 resin can be eluted with 5% sodium hydroxide solution and 5% sodium chloride solution, and the adsorption capacity of CHS-1 resin has no obvious decrease after regeneration.

The magnetic weak acid cation exchange resin NDMC-1 was prepared by copolymerization of 1-Fe203 with methyl acrylate using titanate coupling agent and hydrolysis under alkaline condition.

06 Evaporation enrichment method

Evaporation enrichment method is to vaporize electroplating wastewater by heating, so that the liquid can be concentrated to achieve the effect of reuse. It is generally suitable for treating wastewater containing chromium, copper, silver, nickel and other heavy metals with high concentration, and it consumes a lot of energy and is uneconomical when treating heavy metal wastewater with low concentration.

In the treatment of electroplating wastewater, the evaporation enrichment method is often used together with other methods to achieve closed cycle, such as atmospheric pressure evaporator combined with counter-current rinsing system. Evaporation enrichment method is simple to operate, mature technology, can realize recycling, but the concentrated dry solid disposal cost is large, restricting its application, currently generally only as an auxiliary treatment means.

07 Biological treatment technology

Biological treatment method is the use of microorganisms or plants to purify pollutants, the method has low operating cost, less sludge, no secondary pollution, and is the best choice for low concentration electroplating wastewater with large water volume. Biological methods mainly include biological flocculation, biological adsorption, biochemical method and phytoremediation method.

1. Biological flocculation method

Bioflocculation is a method to purify water by flocculating and precipitating microorganisms or metabolites produced by microorganisms. Microbial flocculants are a kind of metabolites produced by microorganisms and secreted to the outside of the cell, with flocculating activity, which can make colloidal suspensions in water coagulate and precipitate each other.

Compared with inorganic flocculants and synthetic organic flocculants, biological flocculants have the advantages of safety, non-toxicity, good flocculation effect and no secondary pollution in wastewater treatment, but they are not easy to save and the production cost is high, which limits their practical application. At present, most biological flocculants are still in the stage of exploration and research.

Biological flocculants can be divided into the following three categories:

(1) Direct use of microbial cells as flocculants, such as some bacteria, actinomyces, fungi, yeast, etc.

(2) Microbial cell wall extracts were used as flocculants. The flocculating substances produced by microorganisms are glycoprotein, mucopolysaccharide, protein and other macromolecular substances, such as saccharan of yeast cell wall, ⅳ-acetylglucosamine, and polysaccharide of filamentous fungi cell wall can be used as good biological flocculants.

(3) Flocculants using microbial cell metabolites. The main metabolites are polysaccharides, proteins, lipids and their complexes.

The biological flocculants reported in recent years are mainly polysaccharides and proteins, the former are ZS-7, ZL-P, H12, DP. 152, the latter has MBF-W6, NOC - l and so on. Tao Ying et al] studied the flocculation and adsorption of cr(Ⅳ) by using the flocculant prepared by Pseudomonas GX4-1 extracellular polymer.

The results show that the removal rate of Or(Ⅳ) can reach 51% under suitable conditions. The biological flocculant V-polyglutamic acid (T-PGA) prepared by Bacillus subtilis NX-2 was studied for the treatment of electroplating wastewater. The experimental results showed that T-PGA could effectively remove heavy metal ions such as Cr3+ and Ni.

2. Biological adsorption method

Biological adsorption method is to use the chemical structure or composition characteristics of the organism itself to adsorb heavy metals in water, and then through solid-liquid separation to separate heavy metals from water.

Organisms and their derivatives that can separate heavy metals from solutions are called biosorbents. Biological adsorbents are mainly biomass, bacteria, yeast, mold, algae and so on. The method has the advantages of low cost, fast adsorption and resolution rate, easy recovery of heavy metals, selectivity and broad prospect.

The effect of various factors on the adsorption of Cd in electroplating wastewater was studied. The results showed that the removal rate of cadmium in wastewater was more than 93% under the conditions of pH 8, dosage of adsorbent 10g/L(wet weight), stirring revolution 800r/min and adsorption time 10min.

The cells of Bacillus subtilis adsorbed with cadmium were enlarged, brightened and adhered to each other. Cd2+ was adsorbed by ion exchange with sodium on the cell surface.

Chitosan is a kind of natural high molecular polysaccharide, which is obtained by deacetylation of chitin extracted from Marine crustaceans. It can effectively remove heavy metal ions from electroplating wastewater.

Chitosan microspheres composed of magnetic silica nanoparticles were prepared by emulsification crosslinking method, and then modified with quaternary ammonium groups of ethylenediamine and glycine trimethyl chlorination. The resulting bioadsorbent has high acid resistance and magnetic response.

It is used to remove cr(VI) in acidic wastewater, with a maximum adsorption capacity of 233.1mg/g at a pH of 2.5 and a temperature of 25 ° C, and an equilibrium time of 40 to 120min[depending on the initial Cr(VI) concentration. The adsorbent was regenerated with a mixture of 0.3mol/LNaOH and 0.3mol/LNaC1, and the desorption rate reached 95.6%, so the bioadsorbent has a high repeatability.

3. Biochemical methods

Biochemical method refers to the direct chemical reaction of microorganisms with heavy metals in wastewater, so that heavy metal ions are converted into insoluble substances and removed.

Three strains of bacteria were screened and isolated from electroplating wastewater, which could efficiently degrade the free cyanogen root. Under the best conditions, 80mg/L of CN was removed to 0.22mg/L. Studies have found that there are many microorganisms that can reduce cr(VI) to low-toxicity cr(III), such as achromobacter, soil bacteria, Bacillus, desulphurvibrio, Enterobacter, micrococcus, thiobacillus, pseudomonas, etc. In addition to Escherichia coli, Bacillus, thiobacillus, pseudomonas, etc., Cr(VI) can be reduced under aerobic conditions. Most of the remaining strains can only reduce cr(VI) under anaerobic conditions.

R.s. axman et al. found that Streptomyces griseus could reduce cr(VI) to cr(III) within 24 ~ 48h, and could significantly absorb and remove cr(III). Li Fu, Wu Qianjing and others from Chengdu Institute of Biology, Chinese Academy of Sciences isolated and screened 35 strains from electroplating sludge, wastewater and sewage iron pipes, and obtained SR series of composite functional bacteria, which has the effect of efficiently removing Cr(VI) and other heavy metals, and carried out engineering application on this basis, and achieved good results.

4. Phytoremediation

Phytoremediation is the use of plants absorption, precipitation, enrichment and other functions to treat heavy metals and organic matter in electroplating wastewater, to achieve the purpose of sewage treatment and ecological restoration.

The method has less disturbance to the environment, is beneficial to the improvement of the environment, and the treatment cost is low. Constructed wetland plays an important role in this respect and is a promising treatment method.

Poa lii is a metal-rich aquatic plant, which has great potential in removing heavy metals from water. The content of chromium, copper and nickel electroplating wastewater was reduced by 84.4%, 97.1% and 943%, respectively. When the hydraulic load is less than 0.3m/(m2·d1), the concentration of heavy metals in the effluent meets the requirements of the discharge standard for electroplating pollutants. When the concentration of chromium, copper and nickel in the influent is 5, 10 and 8mg/L, the discharge can still meet the standards.

It can be seen that it is feasible to treat electroplating wastewater of medium and low concentration with Leucogramma. The mass balance shows that chromium, copper and nickel are mostly retained in the sediments of the constructed wetland system.

08 Adsorption method

Adsorption method is to use porous materials with large surface area to adsorb heavy metals and organic pollutants in electroplating wastewater, so as to achieve the effect of sewage treatment.

Activated carbon is the earliest and most widely used adsorbent, which can adsorb a variety of heavy metals and has a large adsorption capacity, but activated carbon is expensive, has a short service life, and requires regeneration and regeneration costs are not low. Some natural cheap materials, such as zeolite, olivine, kaolin, diatomite, etc., also have good adsorption capacity, but for various reasons, almost no engineering applications.

The adsorption capacity of nickel, copper and zinc by zeolite is 5.9, 4.8 and 2.7mg/g respectively under static conditions. Magnetic biochar was used to remove Cr(vI) from electroplating wastewater.

The removal rate of cr(VI) was 97.11% after separation by external magnetic field. After the magnetic separation of 10rain, the turbidity decreased from 4075NTU to 21.8NTU. It was also confirmed that magnetic biochar retained its original magnetic separation properties after adsorption. In recent years, some new adsorbent materials have been developed, such as biological adsorbent and nanomaterial adsorbent mentioned in this paper.

Nanotechnology refers to the research and application of atomic and molecular phenomena at the scale of 1 ~ 100nm, and the science and technology developed from this is interdisciplinary, and the basic research and application are closely linked. Nanoparticles have higher catalytic activity because of the nano effect that conventional particles do not have.

The surface effect of nanomaterials makes them have high surface activity, high surface energy and high specific surface area, so nanomaterials show great potential in preparing high performance adsorbents. Rayleigh et al. quickly synthesized titanate nanotubes (TNTs) by a mild hydrothermal method in one step and applied them to the adsorption of Pb(II), cd(II) and Cr(III) heavy metal ions in water.

The results show that at pH=5, the equilibrium adsorption capacities of Pb(II), Cd(II) and Cr(III) at initial concentrations of 200, 100 and 50mg/L on TNTs are 513.04, 212.46 and 66.35mg/L, respectively, and the adsorption performance is better than that of traditional adsorption materials. As a new treatment technology of high efficiency, energy saving and environmental protection, nanotechnology has been widely recognized by people and has great development potential.

09 Photocatalytic technology

The photocatalytic treatment technology has the characteristics of low selectivity, high treatment efficiency, complete degradation products and no secondary pollution.

The core of photocatalysis is photocatalyst, commonly used are TiO2, ZnO, WO3, SrTiO3, SnO2 and Fe2O3. TiO2 has many characteristics such as good chemical stability, non-toxicity, oxidation and reduction. TiO: When exposed to a certain energy of light, an electron transition occurs, resulting in an electron-hole pair.

Photogenerated electrons can directly reduce metal ions in electroplating wastewater, and holes can oxidize water molecules into OH free radicals with strong oxidation, thus oxidizing many difficult to degrade organic matter into inorganic substances such as COz, H: 0, which is considered to be one of the most promising and effective water treatment methods.

The photocatalytic reaction of copper complex wastewater was carried out with suspended TiO2 as catalyst under the action of ultraviolet light. The results show that when TiO2 dosage is 2g/L and wastewater pH=4, the removal rates of Cu(II) and COD in 120mg/LEDTA complexed copper wastewater are 96.56% and 57.67%, respectively, after 60mL/min air reaction of 40rain under 300W high-pressure mercury lamp irradiation. A project example of treating electroplating wastewater with "physicochemical, photocatalysis and film" was carried out. The COD removal rate of effluent reached more than 70%, and TiO2 photocatalyst could be reused.

The introduction of membrane method can greatly improve the water quality, make the water quality after treatment meet the standard of recycled water, improve the resource utilization rate of electroplating wastewater, the reuse rate reaches more than 85%, and greatly save the cost. However, there are many limitations in the practical application of photocatalysis technology, such as the low adsorption rate of heavy metal ions on the surface of the photocatalyst, the immature carrier of the catalyst, and the treatment effect is greatly reduced when encountering wastewater with large chroma, and so on. However, photocatalysis technology as a high efficiency, energy saving, clean treatment technology, will have great application prospects.

10 Heavy metal catcher

Heavy metal catcher is also called heavy metal chelating agent, which can produce strong chelating cooperation with most of the heavy metal ions in the wastewater, and the generated polymer chelating salt is insoluble in water, and heavy metal ions in the wastewater can be removed by separation.

The concentration of residual heavy metal ions in heavy metal wastewater treated by heavy metal catcher can mostly meet the national discharge standard. Dithiocarbamate heavy metal ion collector XMT was used to investigate the trapping effect of different factors on Cu. The removal rate of Cu was above 99%, and the concentration of Cu in effluent was less than 0.05mg/L, which was far lower than the "Table 3" standard of GB21900-2008.

Three kinds of commercial heavy metal collector were selected for synchronous deep treatment of Cu2+, Zn2+ and Ni in electroplating wastewater. It was found that trisodium trithiocyanate (TMT) had the most significant removal effect on Cu, and the dosage was small and the effect was stable, but the removal effect on Ni was poor. Methyl-substituted sodium dithiocarcarbamate (represented by Me2DTC) has the strongest applicability, has a good removal effect on the three heavy metal ions, can meet the GB21900-2008 "Table 3" emission standard, and the treatment effect is the best when DH=9.70. As for ethyl-substituted sodium dithiocarbamate (Et2DTC), the removal effect of Ni is not good.

Heavy metal catcher has great practicability because of its high efficiency, low energy and relatively low processing cost.

peroration

The composition of electroplating wastewater is complex, so it should be treated in different sections as far as possible. In the selection of treatment methods, the advantages and disadvantages of various methods should be fully considered, the comprehensive application of various water treatment technologies should be strengthened, and the combination process should be formed to enhance strengths and avoid weaknesses.

Heavy metals have great recycling value and high toxicity, so the recycling process of heavy metals should be used more in the electroplating wastewater treatment process to reduce emissions as much as possible.

Based on the large sludge output of chemical precipitation method, high energy consumption of electrochemical method, high cost of membrane components of membrane separation technology and easy to be polluted and many other problems, the existing electroplating wastewater treatment technology should be improved in the direction of energy saving, high efficiency and no secondary pollution.

At the same time, it can be combined with computer technology to realize intelligent control. It can also be combined with materials science, biology and other disciplines to develop new materials that are more suitable for treating electroplating wastewater.