CN115626740A - Nickel-containing electroplating wastewater treatment and recycling method - Google Patents

Abstract

The invention relates to a nickel-containing electroplating wastewater treatment and recycling method, which specifically comprises the following steps: step 1, adding a sodium hydroxide solution into the wastewater in the reaction tank to enable nickel ions to generate nickel hydroxide precipitate, and removing the nickel hydroxide precipitate from the wastewater; step 2, introducing the wastewater treated in the step 1 into a complex breaking tank, and continuously adding a sodium hydroxide solution to generate nickel sulfide precipitate to be removed from the wastewater; step 3, introducing the wastewater treated in the step 2 into a coagulating sedimentation tank, and adding a PAC solution to coagulate colloid and fine suspended particles in water to generate alum floc; step 4, introducing the wastewater treated in the step 3 into a membrane filtration tank; and 5, introducing the wastewater in the step 4 into a water outlet pool to be used as workshop reuse water. The invention adopts the integrated molding arrangement, not only solves the problem of nickel-containing wastewater treatment, but also purifies the wastewater into reuse water for the production line to use, thereby saving water and recycling water resources.

Description

A kind of nickel-containing electroplating wastewater treatment and recycling method

technical field

The invention relates to a method for treating and reusing nickel-containing electroplating wastewater, belonging to the technical field of metal surface treatment.

Background technique

Wastewater containing nickel comes from the metal surface treatment industry mainly based on electroplating. The water of nickel plating and rinsing of plated parts in the production process is the main two pieces of nickel-containing electroplating wastewater. They have a high concentration of nickel ions and the amount of waste plating solution is relatively small. During nickel electroplating or electroless nickel plating, the parts will be washed with tap water, and more than 80% of the electroplating sewage discharge in the workshop mainly comes from the rinsing water of the plated parts produced during the washing process. Different nickel plating methods have different forms in nickel-containing wastewater: nickel electroplating produces wastewater or waste liquid, and the form of nickel is mainly in the form of nickel ions (Ni2+); The formation is the combination of ionic nickel and complex solvent, and a considerable part of waste water and liquid waste is nickel that exists in the form of complexes. At the same time, there are many hypophosphate ions in the sewage.

The biochemical properties of nickel itself generate harmfulness by activating or inhibiting the activity of some enzymes in the body. The nickel contained in the metal has basically no emergency toxicity, and the toxicity of ordinary nickel salts is relatively low. It can lead to contagious skin inflammation. People with nickel poisoning show dermatitis, poor respiratory organs and respiratory tract cancer. Nickel is difficult to degrade in the natural environment. Therefore, nickel pollution is a typical heavy metal pollution. If nickel-containing wastewater is discharged arbitrarily, it will not only cause serious environmental pollution, but also cause great harm to human health.

Contents of the invention

An object of the present invention is to provide a method for treating and reusing nickel-containing electroplating wastewater in view of the defects in the prior art.

In particular, the present invention provides a method for treating and reusing nickel-containing electroplating wastewater, which specifically includes the following steps:

Step 1, adding sodium hydroxide solution to the wastewater in the reaction tank, controlling the pH value in the reaction tank, so that nickel ions can be removed from the wastewater by generating nickel hydroxide precipitates;

Step 2, introducing the treated waste water in the step 1 into the network-breaking tank and continuing to add sodium hydroxide solution to control the pH value in the network-breaking tank, then adding NaS solution and FeSO4 solution to break the complexed nickel and generate nickel sulfide precipitation from removal from wastewater;

Step 3, introducing the waste water treated in step 2 into a coagulation sedimentation tank, adding PAC solution, so that colloids and fine suspended particles in water are coagulated to generate alum flowers;

Step 4. The wastewater treated in step 3 is introduced into the membrane filter tank, and then enters the UF membrane system, pretreatment system and RO membrane system in sequence to fully remove suspended particles, bacteria and other microorganisms, small molecule organic matter and residual chlorine and other impurities in the water. Then it is pumped into a single-stage reverse osmosis circulation concentration system by a high-pressure pump to further remove smaller organic impurities, and the above-mentioned permeate is subjected to advanced treatment with exchange resin;

Step 5, introducing the wastewater in step 4 into the effluent pool for use as workshop reuse water.

Preferably, the waste water enters the regulating tank for collection before entering the reaction tank, and is used to regulate the water quantity and water quality uniformly, and the residence time is 4 hours.

Preferably, the pH range of the reaction tank in step 1 is 8-9, and the residence time is 4 hours.

Preferably, in step 2, the pH range of the network breaking tank is 10-11, and the residence time is 4 hours.

Preferably, said step 3 generates inkstone peanuts and then adds polyacrylamide to aid coagulation.

Preferably, the coagulation-sedimentation tank in step 3 includes a coagulation tank, a flocculation tank and a sedimentation tank, and the waste water enters the sedimentation tank through the coagulation tank and the flocculation tank in sequence, and the residence times are 0.5H, 0.5H and 5H respectively.

Preferably, the UF membrane system in the step 4 includes a UF membrane, a fouling agent adding device, and an activated carbon filter. The water production flux of the UF membrane is 1.5-4.0 m3/h, and the membrane material is PVDF.

Preferably, the RO membrane system in step 4 includes an RO membrane, a reverse osmosis circulation concentration system and an exchange resin system, the RO membrane material is a polyamide composite membrane, the flux is 10.5m3/d branch, and the desalination rate is ≥ 99.5%.

Preferably, the exchange resin system adopts an ion exchange resin system.

Preferably, the residence time of the wastewater in the coagulation tank is 0.5h, the residence time of the wastewater in the flocculation tank is 0.5h, and the residence time of the wastewater in the sedimentation tank is 5h.

Beneficial effects: the invention not only solves the problem of nickel-containing wastewater treatment, but also purifies the wastewater into recycled water for use in the production line, so as to save water and recycle water resources;

The integrated device occupies a small space and has high processing efficiency. The public auxiliary room is integrated with the processing unit, which is convenient for assembly. The diversion unit is used to cut off the drainage inside the pool body, optimize the hydraulic head loss, increase the effective residence time, and improve the reaction processing efficiency.

Those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale.

In the attached picture:

Fig. 1 is a structural representation of an embodiment of the present invention;

Fig. 2 is a top view of an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

A method for treating and reusing nickel-containing electroplating wastewater, specifically comprising the following steps:

Step 1, adding sodium hydroxide solution to the wastewater in the reaction tank, controlling the pH range of 8 to 9 in the reaction tank, so that nickel ions can be removed from the wastewater by generating nickel hydroxide precipitates;

Step 2. Introduce the wastewater treated in step 1 into the decomplexation tank and continue to add sodium hydroxide solution to control the pH range of 10 to 11 in the decomposition tank, and then add NaS solution and FeSO4 solution to break the complexed nickel and form Nickel sulfide precipitation is removed from wastewater;

Step 3, introducing the waste water treated in step 2 into a coagulation sedimentation tank, adding PAC solution, so that colloids and fine suspended particles in water are coagulated to generate alum flowers;

Step 4. The wastewater treated in step 3 is introduced into the membrane filter tank, and then enters the UF membrane system, pretreatment system and RO membrane system in sequence to fully remove suspended particles, bacteria and other microorganisms, small molecule organic matter and residual chlorine and other impurities in the water. Then it is pumped into a single-stage reverse osmosis circulation concentration system by a high-pressure pump to further remove smaller organic impurities, and the above-mentioned permeate is subjected to advanced treatment with exchange resin;

Step 5, introducing the wastewater in step 4 into the effluent pool for use as workshop reuse water.

Preferably, the waste water enters the regulating tank for collection before entering the reaction tank.

Preferably, said step 3 generates inkstone peanuts and then adds polyacrylamide to aid coagulation.

Preferably, the coagulation-sedimentation tank in step 3 includes a coagulation tank, a flocculation tank and a sedimentation tank, and the wastewater enters the sedimentation tank through the coagulation tank and the flocculation tank in sequence.

Preferably, the UF membrane system in the step 4 includes a UF membrane, a fouling agent adding device, and an activated carbon filter. The water production flux of the UF membrane is 1.5-4.0 m3/h, and the membrane material is PVDF.

Preferably, the RO membrane system in step 4 includes an RO membrane, a reverse osmosis circulation concentration system and an exchange resin system, the RO membrane material is a polyamide composite membrane, the flux is 10.5m3/d branch, and the desalination rate is ≥ 99.5%.

Preferably, the exchange resin system adopts an ion exchange resin system.

Preferably, the residence time of the wastewater in the coagulation tank is 0.5h, the residence time of the wastewater in the flocculation tank is 0.5h, and the residence time of the wastewater in the sedimentation tank is 5h.

Please refer to Fig. 1 and Fig. 2, a nickel-containing electroplating wastewater treatment and recycling integrated device, including a body 1, the body 1 includes a parallel treatment and recovery unit 2 and a functional unit 3, the main pollution indicators of nickel-containing electroplating wastewater For: COD, ammonia nitrogen, SS and nickel, in order to meet the reuse water standard, the hardness indicators such as Ca2+ and Mg2+ also need to be softened. The nickel-containing electroplating wastewater passes through the treatment and recovery unit, and the functional unit adds drugs to the treatment and recovery unit. Workshop reuse water use.

Preferably, the treatment and recycling unit 2 and the functional unit 3 are integrated.

In the actual implementation of the present application, the processing and recovery unit and the functional unit are integrated, occupying a small space, and have high processing efficiency. The utility room and the processing unit are integrated, and the assembly is convenient. The invention has better environmental protection management ability, more innovative technical level and stronger economic benefits.

The treatment and recovery unit 2 includes a regulating pool 21, a reaction pool 22, a network breaking pool 23, a coagulation sedimentation pool, an intermediate pool 27, a membrane filtration pool 28, and an outlet pool 29 for sequentially treating wastewater. The dosing room 31, the glue room 32, the power distribution room 33 and the automatic control room 34, the regulating pool 21, the reaction pool 22, the network breaking pool 23, the coagulation sedimentation pool, the intermediate pool 27, the membrane filtration pool 28 and the outlet pool 29 are provided with communicating waterways, and a plurality of diversion units 210 are respectively arranged in the regulating pool 21 , the reaction pool 22 and the collateral breaking pool 23 .

During the specific implementation of this application, the regulating pool is used to collect nickel-containing wastewater. The purpose of setting the regulating pool is to adjust the water volume and water quality evenly, to ensure the homogenization of the water volume and water quality of subsequent wastewater, and to improve the treatment efficiency of the system;

Design size: L*B*H＝6*4*2.5(m)

Residence time: 4h.

During the specific implementation of the present application, the design size of the reaction pool is: L*B*H=6*4*2.5 (m).

Preferably, the coagulation-sedimentation tank includes a coagulation tank 24, a flocculation tank 25 and a sedimentation tank 26 for sequentially treating wastewater, and a Connected waterways.

Preferably, the reaction tank 22 , the decollation tank 23 , the coagulation tank 24 and the flocculation tank 25 are all equipped with agitators.

Preferably, the settling tank adopts a back-to-back sinking type.

During the specific implementation of this application, continue to add sodium hydroxide solution in the network breaking tank, control the pH range of the tank to 10-11, then add NaS solution and FeSO4 solution, so that the complexed nickel is broken, and nickel sulfide precipitates are generated and removed from the waste water .

Design size: L*B*H＝6*4*2.5(m)

Residence time: 4h.

When the present application is implemented specifically, the coagulation sedimentation tank: PAC solution is added under partial acidic-neutral conditions to coagulate the colloids and fine suspended particles in the water to generate alum flowers, add polyacrylamide to aid coagulation, improve the structure of alum flowers, and improve the structure of the alum flowers. Settling performance;

Preferably, a UF membrane system, a pretreatment system and an RO system for sequentially treating wastewater are arranged in the membrane filtration tank.

Preferably, the pretreatment system includes a scale agent adding device, an activated carbon filter and a security filter arranged in sequence to remove suspended particles, microorganisms such as bacteria, small molecular organic matter and residual chlorine impurities in the water.

Preferably, the RO membrane system includes a circulation concentration device and an advanced treatment device, which is pumped into the circulation concentration device by a high-pressure pump, and enters the advanced treatment device after removing tiny organic impurities.

Preferably, the water production flux of the UF membrane system is 1.5-4.0 m3/h, and the UF membrane in the UF membrane system is made of polyvinylidene fluoride.

Preferably, the flux of the RO membrane system: 10.5m3/d branch, the salt rejection rate: ≥99.5%, and the RO membrane in the RO membrane system is a polyamide composite membrane.

Preferably, the circulation concentration device adopts a single-stage reverse osmosis circulation concentration device, and the advanced treatment device adopts ion exchange resin for advanced treatment.

Preferably, the processing and recovery unit and the functional unit are integrated.

When the application was specifically implemented, the specific working method of the membrane filter tank was as follows:

Enter the pretreatment system composed of UF membrane system, antiscalant adding device, activated carbon filter and security filter in order to fully remove suspended particles, bacteria and other microorganisms, small molecular organic matter and residual chlorine and other impurities in the water, so that the pretreated water can meet the Reverse osmosis feed water requirements to prevent membrane fouling and concentrated water scaling on one side of the RO membrane, and then pumped into a single-stage reverse osmosis circulation concentration system by a high-pressure pump to further remove smaller organic impurities. The permeate is further treated by the subsequent ion exchange resin and used as workshop reuse water.

In the specific implementation of this application, the process flow of an integrated device for the treatment and reuse of nickel-containing electroplating wastewater is as follows: water inlet→adjustment tank→reaction tank→broken network→coagulation, flocculation→sedimentation tank→intermediate tank→membrane Filter pool (UF→security filter→RO)→outlet pool, the water out of the pool is used as workshop reuse water. It not only solves the problem of nickel-containing wastewater treatment, but also purifies the wastewater into recycled water for use in the production line, so as to save water and recycle water resources. The functional unit and the recovery treatment unit are integrally formed, which is easy to assemble. The interior of the pool body is separated and drained by the diversion wall, which optimizes the hydraulic head loss, increases the effective residence time, and improves the reaction treatment efficiency.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principle. Those skilled in the art should understand that the scope of disclosure involved in this application is not limited to the technical solutions formed by the specific combination of the above technical features, but also covers the technical solutions made by the above technical features or Other technical solutions formed by any combination of equivalent features. For example, a technical solution formed by replacing the above-mentioned features with technical features with similar functions disclosed in this application (but not limited to).

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

1. A nickel-containing electroplating wastewater treatment and recycling method is characterized by comprising the following steps:

step 1, adding a sodium hydroxide solution into the wastewater in the reaction tank, and controlling the pH value in the reaction tank to remove nickel ions, which are generated into nickel hydroxide precipitates, from the wastewater;

step 2, introducing the wastewater treated in the step 1 into a complex breaking tank, continuously adding a sodium hydroxide solution, controlling the pH value in the complex breaking tank, adding a NaS solution and a FeSO4 solution, breaking the complex nickel, generating a nickel sulfide precipitate, and removing the nickel sulfide precipitate from the wastewater;

step 3, introducing the wastewater treated in the step 2 into a coagulating sedimentation tank, and adding a PAC solution to coagulate colloid and fine suspended particles in water to generate alum floc;

step 4, introducing the wastewater treated in the step 3 into a membrane filter tank, sequentially entering a UF membrane system, a pretreatment system and an RO membrane system, fully removing microorganisms such as suspended particles and bacteria, micromolecular organic matters, residual chlorine and other impurities in the water, pumping the wastewater into a single-stage reverse osmosis circulating concentration system by a high-pressure pump, further removing more tiny organic matter impurities, and performing exchange resin advanced treatment on the penetrating fluid;

and 5, introducing the wastewater in the step 4 into a water outlet pool to be used as workshop reuse water.

2. The method for treating and recycling nickel-containing electroplating wastewater according to claim 1, wherein the wastewater enters the regulating tank for collection before entering the reaction tank, and is used for uniformly regulating the water quantity and the water quality, and the retention time is 4h.

3. The method for treating and recycling nickel-containing electroplating wastewater according to claim 1, wherein the pH value in the reaction tank of the step 1 is in a range of 8-9, and the retention time is 4h.

4. The method for treating and recycling nickel-containing electroplating wastewater according to claim 1, wherein the pH value in the complexation breaking tank in the step 2 is within a range of 10-11, and the retention time is 4h.

5. The method for treating and recycling nickel-containing electroplating wastewater according to claim 1, wherein step 3 comprises adding polyacrylamide to the inkstone.

6. The nickel-containing electroplating wastewater treatment and reuse method according to claim 1, wherein the coagulation sedimentation tank of step 3 comprises a coagulation tank, a flocculation tank and a sedimentation tank, and wastewater sequentially passes through the coagulation tank and the flocculation tank and enters the sedimentation tank, and the retention time is 0.5H, 0.5H and 5H respectively.

7. The method according to claim 1, wherein the UF membrane system of step 4 comprises a UF membrane, a scale adding device, and an activated carbon filter, wherein the UF membrane has a water flux of 1.5-4.0 m3/h and is made of PVDF.

8. The method for treating and recycling nickel-containing electroplating wastewater according to claim 1, wherein the RO membrane system of the step 4 comprises an RO membrane, a reverse osmosis circulating concentration system and an exchange resin system, the RO membrane is a polyamide composite membrane, the flux is 10.5m 3/d-branched, and the desalination rate is not less than 99.5%.

9. The method for treating and recycling nickel-containing electroplating wastewater according to claim 8, wherein the exchange resin system is an ion exchange resin system.

10. The method for treating and recycling nickel-containing electroplating wastewater according to claim 6, wherein the retention time of the wastewater in the coagulation tank is 0.5h, the retention time of the wastewater in the flocculation tank is 0.5h, and the retention time of the wastewater in the sedimentation tank is 5h.

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