Acidic electroplating wastewater treatment equipment and process based on combination of Fenton oxidation and acid-resistant nanofiltration membrane separation

Abstract

The invention belongs to the technical field of electroplating wastewater treatment, and particularly relates to acidic electroplating wastewater treatment equipment and process based on combination of Fenton oxidation and acid-resistant nanofiltration membrane separation. Considering that the acidic nickel plating wastewater not only can provide acidic conditions, but also has ferrous ions, based on this, the acidic nickel plating wastewater is used as a raw material and is mixed with the ferrous ions and hydrogen peroxide for a Fenton reaction, and then iron ions and nickel ions are separated by adopting a PP precision filter and an anti-high-turbidity ultrafiltration system. According to the method, iron ions are recycled after being reduced by an iron reduction reactor, nickel ions are separated by adopting an acid-resistant nanofiltration system, and the obtained nickel ions are subjected to electroplating and water recycling again, so that the technical defects existing in the traditional nickel plating wastewater treatment are overcome, and the utilization of the acidic nickel plating wastewater is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroplating wastewater treatment, and in particular is acidic electroplating wastewater treatment equipment and a process based on the combined use of Fenton oxidation and acid-resistant nanofiltration membrane separation. Background Art

[0002] Nickel is a scarce and expensive metal. Traditional electroplating wastewater treatment usually adopts the model of acid-base neutralization + advanced oxidation + flocculation precipitation + water reuse in membrane system, which generally has the following defects: (1) The recovery rate of heavy metals is low, and other metal ions are often mixed in, resulting in hazardous waste sludge, making it difficult to recover valuable metal ions.

[0003] (2) The traditional Fenton reaction process requires repeated adjustment of the pH value to acidity or alkalinity. In particular, the advanced oxidation process needs to be adjusted to acidity first, and then adjusted back to alkalinity after the reaction to convert the metal ions into precipitates. After flocculation and precipitation, it is converted into a large amount of worthless iron sludge, and a large amount of high-salt water is also produced.

[0004] (3) The reagent consumption is large (the dosage of Fenton reagent is >500 mg / L), and the iron sludge formed is worthless and cannot be recovered.

[0005] (4) Because the Fenton process produces a large amount of high-salt water, which increases the pressure and cost of the back-end desalination system, the treatment cost of achieving a water reuse rate of 70% is generally above 40 yuan / ton, and the construction and system costs are high. Summary of the Invention

[0006] In response to the deficiencies in the above-mentioned prior art, the present invention provides an acidic electroplating wastewater treatment device and process based on Fenton oxidation-acid-resistant nanofiltration membrane separation. Considering that acidic nickel-plating wastewater can not only provide acidic conditions but also contains ferrous ions, the present invention uses acidic nickel-plating wastewater as raw material, mixes it with ferrous ions and hydrogen peroxide to undergo Fenton reaction, then uses a PP precision filter and an anti-high turbidity ultrafiltration system to separate the iron ions from the nickel ions. The iron ions are reduced and reused in an iron reduction reactor, and the nickel ions are separated using an acid-resistant nanofiltration system. The obtained nickel ions are re-electroplated and the water is reused. This overcomes the technical defects of traditional nickel-plating wastewater treatment and realizes the utilization of acidic nickel-plating wastewater.

[0007] Based on the above technical objectives, the present invention adopts the following technical solutions: The present invention protects acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation, comprising: Nickel plating bath, used to obtain nickel-plated parts.

[0008] The rinsing tank is used to rinse the nickel-plated parts with water to remove the electrolyte on the surface of the nickel-plated parts to obtain a rinsing liquid. The rinsing liquid is collected in the rinsing tank and the pH of the rinsing liquid is about 5.5.

[0009] The Fenton reaction tank is used to carry out Fenton reaction using rinsing liquid, hydrogen peroxide and ferrous salt. The Fenton reaction is stirred at room temperature for 6h~10h to obtain iron precipitate. When the Fenton reaction is carried out, acid is used to adjust the pH to 3.5~4.5 to promote the progress of the Fenton reaction. After the Fenton reaction is completed, hydrogen peroxide is continued to be added and stirred to ensure that all ferrous ions in the rinsing liquid are oxidized into trivalent iron ions. The online redox potential (ORP) value of the solution reaches 700mV, and the change range is less than ±5mV, which is the reaction end point.

[0010] The solid-liquid separation system consists of a PP precision filter and an anti-high turbidity ultrafiltration system, which is used to separate iron precipitates. After the Fenton reaction, ferrous salts are oxidized to ferric salts and precipitated to form iron precipitates. Nickel ions do not react and remain in the solution. Therefore, solid-liquid separation is achieved by using PP precision filters and anti-high turbidity ultrafiltration systems, and then nickel and iron separation is achieved; filtration through PP precision filters and anti-high turbidity ultrafiltration systems ensures that all iron precipitates are separated.

[0011] The nickel plating tank, the rinsing tank, the Fenton reaction tank, the PP precision filter and the anti-high turbidity ultrafiltration system are sequentially connected through pipelines.

[0012] The acidic dissolution tank is used to collect and dissolve iron precipitates. Acidic solution is used to dissolve the iron precipitates and form a solution. The acidic dissolution tank is connected to the PP precision filter and the anti-high turbidity ultrafiltration system through pipes. The iron precipitates separated by the PP precision filter and the anti-high turbidity ultrafiltration system enter the acidic dissolution tank respectively.

[0013] The iron reduction reactor is used to reduce the ferric iron in the iron precipitate to ferrous iron. The iron reduction reactor is set between the acid dissolution tank and the Fenton reaction tank through a pipeline. The reduced ferrous iron enters the Fenton reaction tank for continued use.

[0014] The acid-resistant nanofiltration system is used to separate nickel ions and water. It is connected to the anti-high turbidity ultrafiltration system through a pipe. The acid-resistant nanofiltration system is also connected to the nickel plating pool and the rinsing pool through two pipes respectively. The collected nickel ions are reused as replenishment for the nickel plating pool, and the water is reused to the rinsing pool to continue rinsing the nickel-plated parts.

[0015] Preferably, in the Fenton reaction tank, after adding ferrous salt and 30% hydrogen peroxide by mass to the rinse liquid, the pH is adjusted to 3.5-4.5 with acid, the molar ratio of 30% hydrogen peroxide by mass to ferrous salt is 1:1-5, and the mass ratio of hydrogen peroxide to COD of the rinse liquid is 0.1-0.2:100.

[0016] Preferably, the anti-high turbidity ultrafiltration system is provided with an anti-high turbidity ultrafiltration membrane, the anti-high turbidity ultrafiltration membrane is a polyethersulfone ultrafiltration membrane, and the pore size of the anti-high turbidity ultrafiltration membrane is 10nm~20nm.

[0017] Preferably, the operating pressure of the acid-resistant nanofiltration system is 1.0 MPa to 4.0 MPa, and an acid-resistant nanofiltration membrane is provided in the acid-resistant nanofiltration system, and the nickel ion retention rate of the acid-resistant nanofiltration membrane is ≥98%.

[0018] Preferably, acid solution is used to adjust the pH in the acidic dissolution tank to 1-2 to facilitate the dissolution of iron precipitates.

[0019] Preferably, the pipeline between the anti-high turbidity ultrafiltration system and the acid-resistant nanofiltration system is connected to the PP precision filter and is provided with a backwash tank.

[0020] Preferably, a concentrated liquid pool is provided on the pipeline between the acid-resistant nanofiltration system and the nickel plating pool, and the concentrated liquid pool is convenient for storing nickel concentrate.

[0021] Preferably, a recycled water production pool is provided on the pipeline between the acid-resistant nanofiltration system and the rinsing pool, and the recycled water production pool is convenient for storing water.

[0022] The present invention also provides a process for treating acidic electroplating wastewater, which uses the above-mentioned acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation, and comprises the following steps: Electroplating is performed in a nickel plating tank to obtain nickel-plated parts, which are then transported to a rinsing tank and rinsed with water to remove electrolyte on the surface of the nickel-plated parts and obtain a rinsing solution.

[0023] In the Fenton reaction tank, the rinse liquid, hydrogen peroxide and ferrous salt are mixed, and the pH is adjusted to 3.5~4.5 with acid. After 6h~10h of Fenton reaction, the COD value of the rinse liquid is reduced to less than 200mg / L.

[0024] After the Fenton reaction is completed, hydrogen peroxide is continued to be added to the Fenton reaction tank and stirred for 2h~4h to ensure that all ferrous ions in the rinse liquid are oxidized to trivalent ferrous ions, the online redox potential (ORP) value reaches 700mV, and the variation range is less than ±5mV, to obtain iron precipitate.

[0025] The iron precipitate is coarsely filtered using a PP precision filter to obtain concentrated solution I and filtrate I. The filtrate I is further finely filtered using an anti-high turbidity ultrafiltration system to obtain concentrated solution II and filtrate II. Both concentrated solution I and concentrated solution II are iron precipitates, and nickel ions are dissolved in filtrate II. The concentrated solution in the figure represents concentrated solution II, and the filtrate in the figure represents filtrate II. A portion of filtrate II is refluxed into the backwash tank, and the PP precision filter is backwashed to obtain backwash liquid. The backwash liquid, concentrated solution I and concentrated solution II are mixed and transported to the acidic dissolution tank to recover the iron ions.

[0026] Another part of the filtrate II enters the acid-resistant nanofiltration system, which uses the acid-resistant nanofiltration system to separate nickel ions in the filtrate II. The nickel ions are recycled to the nickel plating pool 1 through the concentrated liquid pool, and the water is recycled to the rinsing pool through the recycled water production pool.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. The pH of the rinse liquid of the present invention is about 5.5, which is adjusted to 3.5-4.5 by acid solution. The rinse liquid contains a small amount of ferrous ions. The consumption of ferrous salt and acid solution is reduced by the self-replenishment mechanism of ferrous salt (the replenishment amount is 50 mg / L-150 mg / L). After the addition of hydrogen peroxide, the Fenton reaction is carried out to degrade organic matter in the rinse liquid.

[0028] 2. The present invention adopts high turbidity resistance ultrafiltration membrane (molecular weight cut-off 5000-10000Da) + acid-resistant nanofiltration membrane (retention rate Ni 2+ ≥98%) combined process to achieve the separate recovery of iron precipitates and nickel ions.

[0029] 3. The present invention uses an anti-high turbidity ultrafiltration membrane to separate iron precipitates and nickel ions. The obtained iron precipitates enter an acidic dissolution tank with a pH of 1 to 2 for dissolution. Then, after reduction in an iron reduction reactor, the iron ions are reduced to ferrous ions and used as a circulating iron source for cyclic Fenton treatment. The filtrate after separation by the anti-high turbidity ultrafiltration membrane is separated by an acid-resistant nanofiltration system to obtain Ni 2+ Concentrate (Ni 2+ The pH value of the produced water is about 5.5, which is recycled as rinsing water after nickel plating.

[0030] 4. Compared with the existing technology which adopts the mode of acid-base neutralization + advanced oxidation + flocculation precipitation + membrane system, the advantages of the present invention are: (1) the process of the present invention is carried out under acidic conditions, without the need for acid-base alternating adjustment, without the generation of high brine, and then without the need to set up a desalination system, thus reducing costs; (2) the process of the present invention has a high nickel ion recovery rate, Ni 2+The concentration is ≥12 g / L, and the metal ions in the process of the present invention are recycled, overcoming the problems caused by hazardous waste sludge; (3) Since the rinsing liquid is acidic and contains iron ions, the present invention utilizes the acidic environment and iron ions in the rinsing liquid to reduce the dosage of the reagent and thus reduce the cost; In summary, the present invention overcomes the technical defects of the prior art acid-base neutralization + advanced oxidation + flocculation precipitation + membrane system model. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a process flow chart of the acidic electroplating wastewater treatment equipment based on the combined use of Fenton oxidation and acid-resistant nanofiltration membrane separation of the present invention.

[0032] 1. Nickel plating tank; 2. Rinsing tank; 3. Fenton reaction tank; 4. PP precision filter; 5. Anti-high turbidity ultrafiltration system; 6. Acidic dissolution tank; 7. Iron reduction reactor; 8. Acid-resistant nanofiltration system; 9. Concentrate tank; 10. Recycled water tank; 11. Backwash tank. DETAILED DESCRIPTION

[0033] The following is a detailed description of the technical solutions in the embodiments of the present invention, using preferred embodiments and accompanying drawings in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The present invention protects acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation, comprising: Nickel plating pool 1, used for obtaining nickel-plated parts.

[0035] The rinsing tank 2 is used to rinse the nickel-plated parts with water to remove the electrolyte on the surface of the nickel-plated parts to obtain a rinsing liquid.

[0036] The Fenton reaction tank 3 is used to use the rinsing liquid, hydrogen peroxide and ferrous salt to perform Fenton reaction and obtain iron precipitate.

[0037] The solid-liquid separation system is composed of a PP precision filter 4 and an anti-high turbidity ultrafiltration system 5, and is used to separate the iron precipitate.

[0038] The nickel plating tank 1, the rinsing tank 2, the Fenton reaction tank 3, the PP precision filter 4 and the anti-high turbidity ultrafiltration system 5 are sequentially connected through pipelines.

[0039] The acidic dissolution tank 6 is used to collect and dissolve the iron precipitate. The acidic dissolution tank 6 is connected to the PP precision filter 4 and the anti-high turbidity ultrafiltration system 5 through pipelines.

[0040] The iron reduction reactor 7 is used to reduce the ferric iron in the iron precipitate to ferrous iron. The iron reduction reactor 7 is arranged between the acidic dissolution tank 6 and the Fenton reaction tank 3 through a pipeline.

[0041] The acid-resistant nanofiltration system 8 is used to separate nickel ions. It is connected to the anti-high turbidity ultrafiltration system 5 through a pipeline, and the acid-resistant nanofiltration system 8 is also connected to the nickel plating pool 1 and the rinsing pool 2 through two pipelines respectively.

[0042] The concentrated liquid pool 9 is arranged in the pipeline between the acid-resistant nanofiltration system 8 and the nickel plating pool 1 .

[0043] The recycled water production pool 10 is arranged on the pipeline between the acid-resistant nanofiltration system 8 and the rinsing pool 2 .

[0044] The backwash tank 11 is arranged between the pipeline between the anti-high turbidity ultrafiltration system 5 and the acid-resistant nanofiltration system 8 and the PP precision filter 4.

[0045] The following acid electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation is used to treat acid electroplating wastewater, as shown below: Example 1 A process for treating acidic electroplating wastewater comprises the following steps: A nickel plating operation is performed in a nickel plating tank 1 to obtain a nickel-plated part; in a rinsing tank 2, the nickel-plated part is rinsed with water to remove the electrolyte on the surface of the nickel-plated part to obtain a rinsing liquid, the pH of which is about 5.5; the rinsing liquid is collected and then overflowed into a Fenton reaction tank 3, the pH of the Fenton reaction tank 3 is first adjusted to 3.5 with a 20% mass fraction dilute sulfuric acid aqueous solution, and then the COD of the rinsing liquid is measured, and then 30% mass fraction hydrogen peroxide and ferrous sulfate are weighed according to a molar ratio of 1:3, and the pH of the hydrogen peroxide is 20%. The amount of addition is determined according to 0.1 wt% of the COD content in the rinse liquid. Hydrogen peroxide and ferrous sulfate are added together to the Fenton reaction tank 3 and stirred at room temperature for 8 hours for Fenton reaction. At this time, the COD of the rinse liquid is reduced to 189 mg / L. 30% hydrogen peroxide is continued to be added and stirred. When the redox potential in the rinse liquid rises to above 700 mV and the variation range is less than ±5 mV, stirring is continued for 2 hours to ensure that all ferrous ions in the rinse liquid are oxidized to trivalent iron ions, and the reaction is stopped; a treated liquid is obtained.

[0046] The treated liquid is pumped into the PP precision filter 4 and the anti-high turbidity ultrafiltration system 5 in sequence. The anti-high turbidity ultrafiltration system 5 is provided with an anti-high turbidity ultrafiltration membrane. The anti-high turbidity ultrafiltration membrane is an external pressure polyethersulfone hollow fiber ultrafiltration membrane with an average pore size of 10 nm. The treated liquid is separated into a filtrate and a concentrated liquid by the anti-high turbidity ultrafiltration system 5. The filtrate is a green, clear and transparent solution. A part of the filtrate is used to backwash the PP precision filter 4 to obtain a backwash liquid; the backwash liquid and the concentrated liquid are jointly transported to the acidic dissolution tank 6.

[0047] In the acidic dissolution tank 6, sulfuric acid is used to adjust the pH to 1.5 and the temperature is raised to 40°C to accelerate the dissolution of the iron sludge. After dissolution, it is pumped into the iron reduction reactor 7, where the trivalent iron is reduced to divalent iron to obtain a new ferrous solution, which is transported to the Fenton reaction tank 3 and recycled as the iron source of the Fenton reaction tank 3.

[0048] The other part of the filtrate separated by the anti-high turbidity ultrafiltration system 5 is pumped into the acid-resistant nanofiltration system 8. The acid-resistant nanofiltration system 8 is provided with an acid-resistant nanofiltration membrane. The acid-resistant nanofiltration membrane uses a flat-plate acid-resistant nanofiltration membrane. The flat-plate acid-resistant nanofiltration membrane can be stably used in acids with a mass fraction of less than 20%. The operating pressure is 1.5 MPa and the water flux per unit membrane area is 17 L / m 2 h. The acid-resistant nanofiltration system 8 has a nickel ion retention rate of >98%, which is collected in a concentrated liquid pool and replenished to the nickel plating pool 1 via a variable frequency pump for reuse. The produced water after separation by the acid-resistant nanofiltration system 8 is a nickel-removal solution with a pH of 4.0, which is collected in a reused produced water pool and replenished with external pure water. After being evenly mixed, it is recycled as rinsing water for nickel-plated parts.

[0049] Example 2 A process for treating acidic electroplating wastewater comprises the following steps: A nickel plating operation is performed in a nickel plating tank 1 to obtain a nickel-plated part; in a rinsing tank 2, the nickel-plated part is rinsed with water to remove the electrolyte on the surface of the nickel-plated part to obtain a rinsing liquid, the pH of which is about 5.5; the rinsing liquid is collected and then overflowed into a Fenton reaction tank 3, the pH of the Fenton reaction tank 3 is first adjusted to 4.5 with a 20% by mass dilute sulfuric acid aqueous solution, the COD of the rinsing liquid is then measured, and then 30% by mass hydrogen peroxide and ferrous sulfate are mixed at a molar ratio of 1:1. :1 weighing, the amount of hydrogen peroxide added is judged according to 0.15wt% of the COD content in the rinse liquid, hydrogen peroxide and ferrous sulfate are added together into a Fenton reaction tank 3, stirred at room temperature for 6h to carry out Fenton reaction, 30% hydrogen peroxide is continued to be added and stirred, when the redox potential in the rinse liquid rises to above 700mV and the variation range is less than ±5mV, stirring is continued for 3h to ensure that all ferrous ions in the rinse liquid are oxidized to ferric ions, and the reaction is stopped; and a treated liquid is obtained.

[0050] The treated liquid is pumped into the PP precision filter 4 and the anti-high turbidity ultrafiltration system 5 in sequence. The anti-high turbidity ultrafiltration system 5 is provided with an anti-high turbidity ultrafiltration membrane. The anti-high turbidity ultrafiltration membrane is an external pressure polyethersulfone hollow fiber ultrafiltration membrane with an average pore size of 15 nm. The treated liquid is separated into a filtrate and a concentrated liquid by the anti-high turbidity ultrafiltration system 5. The filtrate is a green, clear and transparent solution. A part of the filtrate is used to backwash the PP precision filter 4 to obtain a backwash liquid; the backwash liquid and the concentrated liquid are jointly transported to the acid dissolution tank 6.

[0051] In the acidic dissolution tank 6, sulfuric acid is used to adjust the pH to 1 and the temperature is raised to 40°C to accelerate the dissolution of the iron sludge. After dissolution, it is pumped into the iron reduction reactor 7, where the trivalent iron is reduced to divalent iron to obtain a new ferrous solution, which is transported to the Fenton reaction tank 3 and recycled as the iron source of the Fenton reaction tank 3.

[0052] Another part of the filtrate separated by the anti-high turbidity ultrafiltration system 5 is pumped into the acid-resistant nanofiltration system 8. The acid-resistant nanofiltration system 8 is provided with an acid-resistant nanofiltration membrane. The acid-resistant nanofiltration membrane is a flat-plate acid-resistant nanofiltration membrane. The flat-plate acid-resistant nanofiltration membrane can be stably used in acids with a mass fraction of less than 20%. The operating pressure is 1MPa. The retention rate of nickel ions by the acid-resistant nanofiltration system 8 is greater than 98%, and it is collected into the concentrated liquid pool and replenished to the nickel plating pool 1 for reuse through a variable frequency pump. The produced water after separation by the acid-resistant nanofiltration system 8 is a nickel-removal solution with a pH of 5.0, which is collected into the reused water production pool and replenished with external pure water. After mixing evenly, it is recycled as water for rinsing nickel-plated parts.

[0053] Example 3 A process for treating acidic electroplating wastewater comprises the following steps: A nickel plating operation is performed in a nickel plating tank 1 to obtain a nickel-plated part; in a rinsing tank 2, the nickel-plated part is rinsed with water to remove the electrolyte on the surface of the nickel-plated part to obtain a rinsing liquid, and the pH of the rinsing liquid is about 5.5; after the rinsing liquid is collected, it is converged into a Fenton reaction tank 3 by overflow, and the pH of the Fenton reaction tank 3 is first adjusted to 4.0 with a 20% mass fraction dilute hydrochloric acid aqueous solution, and then the COD of the rinsing liquid is measured, and then 30% mass fraction hydrogen peroxide and ferrous sulfate are mixed at a molar ratio of 1: 5. Weighing, the amount of hydrogen peroxide added is determined according to 0.2 wt% of the COD content in the rinse liquid, hydrogen peroxide and ferrous sulfate are added together into the Fenton reaction tank 3, stirred at room temperature for 10 hours to perform the Fenton reaction, and 30% hydrogen peroxide is continued to be added and stirred. When the redox potential in the rinse liquid rises to above 700 mV and the variation range is less than ±5 mV, stirring is continued for 2.5 hours to ensure that all ferrous ions in the rinse liquid are oxidized to ferric ions, and the reaction is stopped; and a treated liquid is obtained.

[0054] The treated liquid is pumped into the PP precision filter 4 and the anti-high turbidity ultrafiltration system 5 in sequence. The anti-high turbidity ultrafiltration system 5 is provided with an anti-high turbidity ultrafiltration membrane. The anti-high turbidity ultrafiltration membrane is an external pressure polyethersulfone hollow fiber ultrafiltration membrane with an average pore size of 20 nm. The treated liquid is separated into a filtrate and a concentrated liquid by the anti-high turbidity ultrafiltration system 5. The filtrate is a green, clear and transparent solution. A part of the filtrate is used to backwash the PP precision filter 4 to obtain a backwash liquid; the backwash liquid and the concentrated liquid are jointly transported to the acid dissolution tank 6.

[0055] In the acidic dissolution tank 6, sulfuric acid is used to adjust the pH to 2 and the temperature is raised to 40°C to accelerate the dissolution of the iron sludge. After dissolution, it is pumped into the iron reduction reactor 7, where the trivalent iron is reduced to divalent iron to obtain a new ferrous solution, which is transported to the Fenton reaction tank 3 and recycled as the iron source of the Fenton reaction tank 3.

[0056] The other part of the filtrate separated by the anti-high turbidity ultrafiltration system 5 is pumped into the acid-resistant nanofiltration system 8. The acid-resistant nanofiltration system 8 is provided with an acid-resistant nanofiltration membrane. The acid-resistant nanofiltration membrane is a flat-plate acid-resistant nanofiltration membrane. The flat-plate acid-resistant nanofiltration membrane can be stably used in acids with a mass fraction of less than 20%. The operating pressure is 4MPa. The retention rate of nickel ions by the acid-resistant nanofiltration system 8 is greater than 98%, and it is collected into the concentrated liquid pool and replenished to the nickel plating pool 1 for reuse through a variable frequency pump. The produced water after separation by the acid-resistant nanofiltration system 8 is a nickel-removal solution with a pH of 5.5, which is collected into the reused water production pool and replenished with external pure water. After mixing evenly, it is recycled as water for rinsing nickel-plated parts.

[0057] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. Acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation, characterized in that: include: A nickel plating pool (1) for obtaining nickel-plated parts; A rinsing tank (2) is used to rinse the nickel-plated part with water to remove the electrolyte on the surface of the nickel-plated part to obtain a rinsing liquid; A Fenton reaction tank (3) is used to perform a Fenton reaction using the rinse solution, hydrogen peroxide and ferrous salt to obtain an iron precipitate; A solid-liquid separation system, comprising a PP precision filter (4) and an anti-high turbidity ultrafiltration system (5), for separating the iron precipitate; The nickel plating tank (1), the rinsing tank (2), the Fenton reaction tank (3), the PP precision filter (4) and the anti-high turbidity ultrafiltration system (5) are sequentially connected through pipelines; an acidic dissolution tank (6) for collecting and dissolving the iron precipitate, wherein the acidic dissolution tank (6) is connected to the PP precision filter (4) and the anti-high turbidity ultrafiltration system (5) respectively through pipelines; An iron reduction reactor (7) for reducing ferric iron in the iron precipitate to ferrous iron, wherein the iron reduction reactor (7) is arranged between the acidic dissolution tank (6) and the Fenton reaction tank (3) via a pipeline; The acid-resistant nanofiltration system (8) is used for separating nickel ions and is connected to the anti-high turbidity ultrafiltration system (5) through a pipeline. The acid-resistant nanofiltration system (8) is also connected to the nickel plating pool (1) and the rinsing pool (2) through two pipelines.

2. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that, In the Fenton reaction tank (3), ferrous salt and 30% by mass hydrogen peroxide are added to the rinse liquid, and then the pH is adjusted to 3.5-4.5 using acid solution, and the mass ratio of hydrogen peroxide to the COD of the rinse liquid is 0.1-0.2:

100.

3. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that, The anti-high turbidity ultrafiltration system (5) is provided with an anti-high turbidity ultrafiltration membrane, the anti-high turbidity ultrafiltration membrane is a polyethersulfone ultrafiltration membrane, and the pore size of the anti-high turbidity ultrafiltration membrane is 10nm~20nm.

4. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that, An acid-resistant nanofiltration membrane is provided in the acid-resistant nanofiltration system (8), and the nickel ion retention rate of the acid-resistant nanofiltration membrane is ≥98%.

5. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that, Acidic solution is used to adjust the pH in the acidic dissolution tank (6) to 1-2.

6. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that: The pipeline between the anti-high turbidity ultrafiltration system (5) and the acid-resistant nanofiltration system (8) is connected to the PP precision filter (4) and is provided with a backwash tank (11).

7. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that: A concentrated liquid pool (9) is provided on the pipeline between the acid-resistant nanofiltration system (8) and the nickel plating pool (1).

8. The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is characterized in that: A recycled water production pool (10) is provided on the pipeline between the acid-resistant nanofiltration system (8) and the rinsing pool (2).

9. A process for treating acidic electroplating wastewater, characterized in that: The acidic electroplating wastewater treatment equipment based on Fenton oxidation-acid-resistant nanofiltration membrane separation according to claim 1 is used for treatment, comprising the following steps: Electroplating is performed in a nickel plating tank (1) to obtain nickel-plated parts, the nickel-plated parts are transported to a rinsing tank (2), and the nickel-plated parts are rinsed with water to remove the electrolyte on the surface of the nickel-plated parts to obtain a rinsing solution; In the Fenton reaction tank (3), the rinse liquid, hydrogen peroxide and ferrous salt are mixed, and the pH is adjusted to 3.5-4.5 with acid. After 6-10 hours of Fenton reaction, the COD value of the rinse liquid is reduced to less than 200 mg / L; After the Fenton reaction is completed, hydrogen peroxide is continuously added to the Fenton reaction tank (3) and stirred for 2 h to 4 h to ensure that all ferrous ions in the rinse solution are oxidized to ferric ions, and the online redox potential (ORP) value reaches 700 mV, with a variation range of less than ±5 mV, to obtain iron precipitate; The iron precipitate is coarsely filtered using a PP precision filter (4) and then filtered using an anti-high turbidity ultrafiltration system (5) to separate the concentrate and the filtrate; the iron precipitate is transported to an acidic dissolution tank (6) to recover the iron ions; The filtrate enters the acid-resistant nanofiltration system (8), and the acid-resistant nanofiltration system (8) is used to separate nickel ions in the filtrate, and the nickel ions are recycled to the nickel plating pool (1).

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