A treatment process for separating oil emulsion wastewater in copper cable processing industry based on fiber membrane

Abstract

The application discloses a kind of processing technology based on fiber membrane separation copper cable processing industry oil emulsion wastewater, belong to water treatment technical field, comprising the following steps: copper cable processing wastewater is broken emulsion treatment, wastewater after breaking emulsion is introduced into oil-water separation unit and is filtered, PLA is set in oil-water separation unit @PP oil-water separation membrane, separated out grease is recycled, wastewater is carried out subsequent step;Wastewater after oil-water separation is introduced into advanced oxidation unit, is filtered after oxidation, flocculation and precipitation, oxidation wastewater is introduced into membrane separation unit, and is filtered by PVDF hollow fiber ultrafiltration membrane and amine oxime polyacrylonitrile hollow fiber membrane in turn, complete processing technology;The processing technology of the application combines acid precipitation demulsification, oil-water separation, multi-dimensional advanced oxidation and membrane separation and other technologies, can effectively remove heavy metal ions, emulsion, COD, BOD and other pollutants in copper cable processing wastewater, realize the deep purification treatment of wastewater, reach "zero discharge" standard.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation. Background Technology

[0002] Against the backdrop of accelerating global industrialization, the demand for copper cables is increasing daily due to their crucial role in power transmission, communications, infrastructure construction, and many other fields, and their application scope and importance are constantly expanding. However, the copper cable processing involves several stages, such as manufacturing, refining, surface treatment, testing, and quality control, all of which generate large amounts of wastewater.

[0003] The cleaning and rinsing processes remove impurities and oil from the surface of copper cables. The water used contains high concentrations of heavy metals, grease, chemical reagents, and organic pollutants, resulting in polluted wastewater. During surface treatment, pickling, passivation, and electroplating operations use large amounts of chemical agents, causing wastewater containing high concentrations of acidic and alkaline substances, heavy metal ions, and toxic and harmful components. In the cooling and lubrication stages, the high temperature and pressure during processing contaminate cooling water and lubricants, forming oily or emulsion-containing wastewater. Testing and quality control processes also generate wastewater due to the use of chemical reagents or specific operations. This type of copper cable processing wastewater not only has high levels of heavy metal ions, but also high levels of emulsions, COD, and BOD. If discharged directly without proper treatment, environmental problems such as water pollution, soil pollution, and ecological damage will follow. Therefore, it is urgent for copper cable processing companies to establish a comprehensive wastewater treatment system, employing physical, chemical, or biological methods to treat wastewater and ensure it meets discharge standards to reduce negative environmental impacts.

[0004] Currently, although there has been extensive research and some progress in copper cable processing wastewater treatment technologies both domestically and internationally, traditional copper-based wastewater treatment methods still have many drawbacks, such as poor treatment efficiency, high costs, or secondary pollution, making it difficult to meet increasingly stringent environmental protection requirements. The core problem lies in the difficulty of treating emulsion wastewater due to its complex composition, strong oil-emulsion stability, and high COD concentration. Existing copper cable processing wastewater treatment methods include acid precipitation, salting out, filtration, chemical flocculation, adsorption, low-temperature evaporation-membrane separation, and advanced oxidation, but a single process cannot achieve "zero discharge" of wastewater; a combination of processes is necessary. Demulsification, as the primary step in copper cable processing wastewater treatment, can be achieved through acid precipitation and salting out. While salting out is low-cost and simple to operate, it requires large amounts of reagents, takes a long time for sedimentation and separation, has a slow aggregation rate, and its treatment effect is affected by the surfactants in the emulsion. While acid precipitation is economical and simple, requiring only the direct addition of inorganic acids, the wastewater still exhibits high COD and BOD concentrations after demulsification, exhibiting poor biodegradability and difficulty in microbial degradation, necessitating further advanced treatment. In industry, ozone oxidation catalysis, Fenton oxidation, and flocculation sedimentation are commonly used treatment methods. Ozone catalytic oxidation boasts strong capabilities, effectively decomposing pollutants, reducing BOD and COD, decolorizing, deodorizing, sterilizing, and removing algae without secondary pollution, and offering convenient operation and management; however, its investment and operating costs are quite high. Fenton oxidation is environmentally friendly and requires minimal space, while flocculation sedimentation offers excellent treatment effects, simple operation, and convenient maintenance; however, flocculation sedimentation is unsuitable for high-concentration wastewater, and its investment and land area requirements are large, limiting the volume of wastewater that can be treated. In actual treatment, due to the complex composition of wastewater and the difficulty of treatment, technical challenges such as improving treatment efficiency, reducing treatment costs, and minimizing secondary pollution urgently need to be overcome. Summary of the Invention

[0005] The purpose of this invention is to provide a treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation, so as to solve the problem of poor treatment effect of oil emulsion wastewater from the copper cable processing industry in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation includes the following steps:

[0008] S1, acid precipitation and demulsification

[0009] The wastewater from copper cable processing is introduced into the acid precipitation demulsification unit. A demulsifier is added to the acid precipitation demulsification unit, and the mixture is stirred at 20-30℃ for 1-3 hours to obtain the demulsified wastewater.

[0010] S2, Oil-water separation

[0011] The wastewater after demulsification is introduced into the oil-water separation unit for filtration. The oil-water separation unit is equipped with a PLA@PP oil-water separation membrane. After filtration, the separated oil is recycled, and the wastewater is used for subsequent steps.

[0012] S3, Advanced Oxidation

[0013] After oil-water separation, the wastewater is introduced into an advanced oxidation unit. First, the pH value of the wastewater is adjusted to 3-4. Then, ferrous sulfate heptahydrate is added and stirred for 15 minutes. Hydrogen peroxide solution is then added and stirred for 2 hours. After that, flocculant is added, and after flocculation and sedimentation, the mixture is filtered to obtain oxidized wastewater.

[0014] S4, Membrane Separation

[0015] The oxidized wastewater is introduced into the membrane separation unit and filtered successively through a PVDF hollow fiber ultrafiltration membrane and an ammonium oxime-modified polyacrylonitrile hollow fiber membrane to complete the treatment process.

[0016] This invention provides a copper cable processing wastewater treatment process as follows: a coupled process of acid precipitation demulsification—oil-water separation—advanced oxidation—membrane separation. First, concentrated sulfuric acid or concentrated nitric acid is used as a demulsifier to break the stable charge balance, reducing the repulsive force between droplets, causing small droplets to collide and aggregate, ultimately achieving separation of the oil and water phases. Then, a PLA@PP oil-water separation membrane is used to dynamically separate the water and oil phases. Next, an advanced oxidation process removes most organic pollutants and residual oil. Finally, a PVDF hollow porous fiber ultrafiltration membrane removes organic pollutants, microorganisms, and oil, while an ammonium-oxime polyacrylonitrile adsorption membrane deeply removes copper, aluminum, and iron ions, achieving compliant wastewater discharge. This integrated process is convenient, efficient, and low-cost, enabling "zero discharge" of industrial wastewater, reducing energy consumption in copper cable processing wastewater treatment, improving purification efficiency, saving costs for copper cable processing enterprises, promoting technological advancements in industrial wastewater treatment, supporting sustainable development for enterprises, and protecting the ecological environment.

[0017] Furthermore, the volume ratio of demulsifier to copper cable processing wastewater in S1 is 0.15-0.35:100, and the demulsifier is concentrated sulfuric acid or concentrated nitric acid.

[0018] Furthermore, the filtration pressure in S2 is 0.02-0.1 MPa, the filtration flow rate is 200 L / h-1500 L / h, and the filtration temperature is room temperature.

[0019] Furthermore, the preparation method of the PLA@PP oil-water separation membrane in S2 includes the following steps:

[0020] Step a: Add zinc oxide and polypropylene resin to a twin-screw extruder for melt blending and granulation to obtain masterbatch. Add the masterbatch and polypropylene resin to a meltblown machine and obtain polypropylene (PP) meltblown fabric through meltblown spinning.

[0021] Step b: Wash the polypropylene (PP) meltblown fabric with deionized water, take it out and dry it, then place it in the treatment chamber of the plasma treatment machine, draw a vacuum, and carry out plasma treatment to obtain pretreated meltblown fabric.

[0022] Step c: Add polylactic acid (PLA) to a mixed solvent composed of dichloromethane and N,N-dimethylformamide, controlling the mass fraction of PLA to be 6-10%. Arrange the pretreated meltblown on the receiving roller of the needleless spinning machine, and obtain PLA@PP oil-water separation membrane through spinning treatment.

[0023] Furthermore, in step a, the mass ratio of zinc oxide to polypropylene resin in the masterbatch preparation process is 20-30:100, and the mass ratio of masterbatch to polypropylene resin is 1:4-19.

[0024] Furthermore, in step a, the meltblown extruder is a single-screw extruder, with the temperature settings for each zone as follows: Zone 1 130℃±5℃, Zone 2 150℃±5℃, and Zone 3 160℃±5℃. The melt sprayed from the meltblown extruder enters the spinneret, where high-pressure hot air stretches and pulls the sprayed fibers. The fibers are then collected by a roller screen to obtain polypropylene (PP) meltblown fabric.

[0025] Furthermore, the diameter of the spinneret is 0.35mm, the hot air temperature is 110℃±5℃, and the receiving distance is 40cm±5cm.

[0026] Furthermore, the basis weight of the polypropylene (PP) meltblown fabric is 35 g / m². 2 .

[0027] Furthermore, in step b, the plasma treatment power is 25-75W, and the treatment time is 2-5 minutes.

[0028] Furthermore, in step c, the volume ratio of dichloromethane to N,N-dimethylformamide is 4-6:6-4.

[0029] Furthermore, in step c, the spinning voltage is 40-60kV, the roller speed is 0.5m / min, and the spinning time is 2h.

[0030] Furthermore, the pH adjuster in S3 is calcium hydroxide or potassium hydroxide.

[0031] Furthermore, the amount of ferrous sulfate heptahydrate in S3 is 1.2-1.3% of the mass of the wastewater after oil-water separation, the amount of hydrogen peroxide solution is 1.3-1.4% of the volume of the wastewater after oil-water separation, and the amount of flocculant is 0.01-0.03% of the mass of the wastewater after oil-water separation.

[0032] Furthermore, the hydrogen peroxide solution has a mass fraction of 30%.

[0033] Furthermore, the flocculant is at least one of polyacrylamide (PAM), polyaluminum chloride (PAC), and polyferric sulfate (PFS).

[0034] Furthermore, the filtration pressure in S4 is 0.06-0.1 MPa.

[0035] Furthermore, the method for preparing amine-oxime-modified polyacrylonitrile hollow fiber membrane includes the following steps:

[0036] Prepare a 0.1-0.3 mol / L hydroxylamine hydrochloride solution and adjust the pH of the hydroxylamine hydrochloride solution to 7 with sodium carbonate. Then add the polyacrylonitrile hollow fiber membrane to the solution and heat it in a water bath at 55-75℃ for 2-4 hours. After that, take it out, wash it three times with distilled water, and dry it to obtain the amine-oxime-modified polyacrylonitrile hollow fiber membrane.

[0037] The beneficial effects of this invention are:

[0038] 1. The treatment process of this invention combines multiple technologies such as acid precipitation demulsification, oil-water separation, multidimensional advanced oxidation and membrane separation, which can effectively remove pollutants such as heavy metal ions, emulsions, COD, and BOD from copper cable processing wastewater, achieving deep purification treatment of wastewater and reaching the "zero discharge" standard.

[0039] 2. This invention employs a novel, highly efficient oil-water separation process that can deeply remove residual grease, reduce subsequent membrane fouling and catalytic process stress, and ensure stable overall process operation. The PLA@PP oil-water separation membrane organically combines zinc oxide-doped PP meltblown fabric and polylactic acid fiber membrane, with both working synergistically to form a separation membrane with a multi-level porous structure. The PP meltblown fabric has a pore size between 100-500 nanometers, while the polylactic acid fiber membrane has a pore size below 100 nanometers, allowing for the retention of oil emulsion molecules of different sizes. This achieves the retention of small molecule oil emulsions while also... The nanofiber membrane will not be clogged by large-sized oil emulsions. In addition, zinc oxide is added to the meltblown fabric during the preparation process. The surface of zinc oxide can be positively charged under different pH conditions (such as neutral or weakly acidic environments). It adsorbs negatively charged oil droplets (such as crude oil containing carboxylic acid groups) through electrostatic interaction, promotes oil droplet aggregation, and accelerates the separation process. At the same time, zinc oxide has a rough surface, which can be combined with low surface energy materials to construct a superhydrophobic-superoleophilic surface. This structure increases the contact area between the material and the oil phase, selectively adsorbs oil droplets and repels water, and achieves efficient separation.

[0040] 3. The advanced oxidation process in this invention improves the mineralization efficiency of organic matter, with a COD removal rate of 70-85%, while also increasing the utilization rate of H2O2 and accelerating the reaction rate.

[0041] 4. The application of PLA@PP oil-water separation membrane in this invention enables lower operating pressure, lower energy consumption, higher water recovery rate, reduced concentrate volume, less membrane fouling, and more stable operation compared to traditional reverse osmosis, while ensuring stable compliance with emission standards or reuse.

[0042] 5. The overall combined process of this invention is convenient and low-cost, which can reduce energy consumption in the treatment of copper cable processing wastewater, improve purification efficiency, save enterprise costs, and has good economic and environmental benefits. Attached Figure Description

[0043] The invention will now be further described with reference to the accompanying drawings.

[0044] Figure 1 These are actual water quality images of the copper cable processing wastewater before and after treatment by the processing technology described in Embodiment 1 of the present invention.

[0045] Figure 2 This is a graph showing the test results of COD content in the demulsified wastewater obtained from the treatment process S1 of the copper cable processing industry oil emulsion wastewater based on fiber membrane separation provided in Examples 1-5 of this invention;

[0046] Figure 3 This is a graph showing the COD content test results in the effluent before the addition of flocculant obtained from the S3 process of the copper cable processing industry oil emulsion wastewater treatment based on fiber membrane separation provided in Examples 1-6 of this invention.

[0047] Figure 4 This is a graph showing the test results of COD content in the oxidized wastewater obtained from the S3 treatment process of oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation, as provided in Embodiments 1 and 7-8 of this invention.

[0048] Figure 5 This is a graph showing the test results of COD content in the effluent from the treatment process of oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation provided in Embodiment 1 and Comparative Examples 1-4 of the present invention. Detailed Implementation

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] The oil emulsion wastewater from a copper cable processing enterprise in Anhui Province was used as the sample. The pH of the oil emulsion wastewater was 8-9.5 and the COD concentration was 800-1500 mg / L.

[0051] Preparation Example 1

[0052] The preparation of PLA@PP oil-water separation membrane includes the following steps:

[0053] Step a: Add zinc oxide and polypropylene resin to a twin-screw extruder at a mass ratio of 20:100 for melt blending and granulation to obtain masterbatch. Add the masterbatch and polypropylene resin to a meltblown machine and meltblown spinneret. The mass ratio of masterbatch to polypropylene resin is 1:19, resulting in a basis weight of 35 g / m³. 2 Polypropylene meltblown fabric;

[0054] Step b: Wash the polypropylene meltblown fabric with deionized water, take it out and dry it, then place it in the treatment chamber of the SCE-100 plasma treatment machine, vacuum it, and perform plasma treatment at 25W for 2 minutes to obtain the pretreated meltblown fabric.

[0055] Step c: Add polylactic acid to a mixed solvent composed of dichloromethane and N,N-dimethylformamide, controlling the mass fraction of polylactic acid to be 6% and the volume ratio of dichloromethane to N,N-dimethylformamide to be 4:6. Arrange the pretreated meltblown on the receiving roller of the needleless spinning machine, and perform spinning treatment with a spinning voltage of 40kV, a roller speed of 0.5m / min, and a spinning time of 2h to obtain a PLA@PP oil-water separation membrane.

[0056] In step a, the meltblown extruder uses a single-screw extruder with the following temperature settings for each zone: Zone 1 130℃±5℃, Zone 2 150℃±5℃, and Zone 3 160℃±5℃. The melt extruded from the meltblown extruder enters the spinneret, where high-pressure hot air stretches and pulls the sprayed fibers. The fibers are then collected by a roller screen to obtain polypropylene (PP) meltblown fabric.

[0057] The spinneret diameter is 0.35mm, the hot air temperature is 110℃±5℃, and the receiving distance is 40cm±5cm.

[0058] Preparation Example 2

[0059] The preparation of PLA@PP oil-water separation membrane includes the following steps:

[0060] Step a: Add zinc oxide and polypropylene resin to a twin-screw extruder at a mass ratio of 25:100 for melt blending and granulation to obtain masterbatch. Add the masterbatch and polypropylene resin to a meltblown machine and meltblown spinneret. The mass ratio of masterbatch to polypropylene resin is 1:11, resulting in a product with a basis weight of 35 g / m³. 2 Polypropylene meltblown fabric;

[0061] Step b: Wash the polypropylene meltblown fabric with deionized water, take it out and dry it, then place it in the treatment chamber of the SCE-100 plasma treatment machine, vacuum it, and perform plasma treatment at 50W for 3 minutes to obtain the pretreated meltblown fabric.

[0062] Step c: Add polylactic acid to a mixed solvent composed of dichloromethane and N,N-dimethylformamide, controlling the mass fraction of polylactic acid to be 8% and the volume ratio of dichloromethane to N,N-dimethylformamide to be 6:4. Arrange the pretreated meltblown on the receiving roller of the needleless spinning machine and perform spinning treatment. The spinning voltage is 50kV, the roller speed is 0.5m / min, and the spinning time is 2h to obtain PLA@PP oil-water separation membrane.

[0063] In step a, the meltblown extruder uses a single-screw extruder with the following temperature settings for each zone: Zone 1 130℃±5℃, Zone 2 150℃±5℃, and Zone 3 160℃±5℃. The melt extruded from the meltblown extruder enters the spinneret, where high-pressure hot air stretches and pulls the sprayed fibers. The fibers are then collected by a roller screen to obtain polypropylene (PP) meltblown fabric.

[0064] The spinneret diameter is 0.35mm, the hot air temperature is 110℃±5℃, and the receiving distance is 40cm±5cm.

[0065] Preparation Example 3

[0066] The preparation of PLA@PP oil-water separation membrane includes the following steps:

[0067] Step a: Add zinc oxide and polypropylene resin to a twin-screw extruder at a mass ratio of 30:100 for melt blending and granulation to obtain masterbatch. Add the masterbatch and polypropylene resin to a meltblown machine and meltblown spinneret. The mass ratio of masterbatch to polypropylene resin is 1:4, resulting in a product with a basis weight of 35 g / m³. 2 Polypropylene meltblown fabric;

[0068] Step b: Wash the polypropylene meltblown fabric with deionized water, take it out and dry it, then place it in the treatment chamber of the SCE-100 plasma treatment machine, vacuum it, and perform plasma treatment at 75W for 5 minutes to obtain the pretreated meltblown fabric.

[0069] Step c: Add polylactic acid to a mixed solvent composed of dichloromethane and N,N-dimethylformamide, controlling the mass fraction of polylactic acid to be 10% and the volume ratio of dichloromethane to N,N-dimethylformamide to be 6:4. Arrange the pretreated meltblown on the receiving roller of the needleless spinning machine, and perform spinning treatment with a spinning voltage of 60kV, a roller speed of 0.5m / min, and a spinning time of 2h to obtain a PLA@PP oil-water separation membrane.

[0070] In step a, the meltblown extruder uses a single-screw extruder with the following temperature settings for each zone: Zone 1 130℃±5℃, Zone 2 150℃±5℃, and Zone 3 160℃±5℃. The melt extruded from the meltblown extruder enters the spinneret, where high-pressure hot air stretches and pulls the sprayed fibers. The fibers are then collected by a roller screen to obtain polypropylene (PP) meltblown fabric.

[0071] The spinneret diameter is 0.35mm, the hot air temperature is 110℃±5℃, and the receiving distance is 40cm±5cm.

[0072] Compare with Example 1

[0073] The preparation of the PP separation membrane includes the following steps:

[0074] Zinc oxide and polypropylene resin were melt-blended and granulated in a twin-screw extruder at a mass ratio of 30:100 to obtain a masterbatch. The masterbatch and polypropylene resin were then added to a meltblown machine and melt-blown spun into a 1:4 mass ratio, yielding a product with a basis weight of 35 g / m³. 2 Polypropylene meltblown fabric;

[0075] The meltblown extruder uses a single-screw extruder, with the following temperature settings for each zone: Zone 1 130℃±5℃, Zone 2 150℃±5℃, and Zone 3 160℃±5℃. The melt extruded from the meltblown extruder enters the spinneret, where high-pressure hot air stretches and pulls the atomized fibers. The fibers are then collected by a roller screen to obtain polypropylene (PP) meltblown fabric.

[0076] The spinneret diameter is 0.35mm, the hot air temperature is 110℃±5℃, and the receiving distance is 40cm±5cm.

[0077] Compare with Example 2

[0078] This comparative example is a polylactic acid (PLA) separation membrane. The preparation of the PLA separation membrane includes the following steps:

[0079] Polylactic acid (PLA) was added to a mixed solvent consisting of dichloromethane and N,N-dimethylformamide, with the mass fraction of PLA controlled at 10% and the volume ratio of dichloromethane to N,N-dimethylformamide at 6:4. The pretreated meltblown membrane was placed on the receiving roller of a needleless spinning machine and spun at a voltage of 60 kV, a roller speed of 0.5 m / min, and a spinning time of 2 h to obtain a PLA@PP oil-water separation membrane.

[0080] Compare with Example 3

[0081] The preparation of the PLA@PP oil-water separation membrane differs from that of Preparation Example 1 in that zinc oxide is removed from Preparation Example 1.

[0082] Compare with Example 4

[0083] The preparation of PLA@PP oil-water separation membrane includes the following steps:

[0084] Polylactic acid was added to a mixed solvent consisting of dichloromethane and N,N-dimethylformamide, with the mass fraction of polylactic acid controlled at 10% and the volume ratio of dichloromethane to N,N-dimethylformamide at 6:4. Polypropylene meltblown fabric was placed on the receiving roller of a needleless spinning machine and spun at a spinning voltage of 60kV, a roller speed of 0.5m / min, and a spinning time of 2h to obtain a PLA@PP oil-water separation membrane. The preparation process of polypropylene meltblown fabric was the same as in Preparation Example 1.

[0085] Example 1

[0086] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation includes the following steps:

[0087] S1, acid precipitation and demulsification

[0088] The copper cable processing wastewater was introduced into the acid precipitation demulsification unit. 98wt% concentrated sulfuric acid was added to the acid precipitation demulsification unit. The amount of concentrated sulfuric acid was 0.15% of the volume of the copper cable processing wastewater. The mixture was stirred at 20℃ for 2 hours to obtain the demulsified wastewater.

[0089] S2, Oil-water separation

[0090] The demulsified wastewater was introduced into an oil-water separation unit for filtration. The oil-water separation unit was equipped with the PLA@PP oil-water separation membrane of Preparation Example 1. After filtration, the filtration pressure was 0.05 MPa and the filtration flow rate was 300 L / h. The separated oil was recycled and the wastewater was used in subsequent steps.

[0091] S3, Advanced Oxidation

[0092] The wastewater after oil-water separation was introduced into an advanced oxidation unit. First, the pH value of the wastewater was adjusted to 3 using calcium hydroxide as the adjuster. Then, ferrous sulfate heptahydrate was added at a concentration of 1.2% of the wastewater mass. After stirring for 15 minutes, 30 wt% hydrogen peroxide solution was added at a concentration of 1.3% of the wastewater volume. The mixture was stirred for 2 hours. Then, polyacrylamide was added at a concentration of 0.01% of the wastewater mass. After stirring for 30 minutes, the mixture was allowed to stand for 2 hours and then filtered to obtain oxidized wastewater.

[0093] S4, Membrane Separation

[0094] The oxidized wastewater is introduced into the membrane separation unit and filtered successively through a PVDF hollow fiber ultrafiltration membrane and an ammonium oxime-modified polyacrylonitrile hollow fiber membrane at a filtration pressure of 0.06 MPa to complete the treatment process.

[0095] Water quality was observed in the copper cable processing wastewater before treatment and the treated effluent from Example 1. The results are as follows: Figure 1 As shown, by Figure 1As can be seen, the treated wastewater became clear.

[0096] A method for preparing amine-oxime-modified polyacrylonitrile hollow fiber membranes includes the following steps:

[0097] Prepare a 0.2 mol / L hydroxylamine hydrochloride solution and adjust the pH of the hydroxylamine hydrochloride solution to 7 with sodium carbonate. Then add the polyacrylonitrile hollow fiber membrane to the solution and heat it in a water bath at 60°C for 3 hours. After that, take it out, wash it three times with distilled water, and dry it to obtain the AOPAN hollow fiber membrane.

[0098] Example 2

[0099] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation includes the following steps:

[0100] S1, acid precipitation and demulsification

[0101] The copper cable processing wastewater was introduced into the acid precipitation demulsification unit. 98wt% concentrated sulfuric acid was added to the acid precipitation demulsification unit. The amount of concentrated sulfuric acid was 0.2% of the volume of the copper cable processing wastewater. The mixture was stirred at 20℃ for 2 hours to obtain the demulsified wastewater.

[0102] S2, Oil-water separation

[0103] The demulsified wastewater was introduced into an oil-water separation unit for filtration. The oil-water separation unit was equipped with the PLA@PP oil-water separation membrane of Preparation Example 1. After filtration, the filtration pressure was 0.06 MPa and the filtration flow rate was 200 L / h. The separated oil was recycled and the wastewater was used in subsequent steps.

[0104] S3, Advanced Oxidation

[0105] The wastewater after oil-water separation was introduced into an advanced oxidation unit. First, the pH value of the wastewater was adjusted to 3.5. Then, ferrous sulfate heptahydrate was added at a concentration of 1.3% of the wastewater mass. After stirring for 15 minutes, 30 wt% hydrogen peroxide solution was added at a concentration of 1.3% of the wastewater volume. The mixture was stirred for 2 hours. Then, polyacrylamide was added at a concentration of 0.02% of the wastewater mass. After stirring for 30 minutes, the mixture was allowed to stand for 2 hours and then filtered to obtain oxidized wastewater.

[0106] S4, Membrane Separation

[0107] The oxidized wastewater is introduced into the membrane separation unit and filtered successively through a PVDF hollow fiber ultrafiltration membrane and an ammonium oxime-modified polyacrylonitrile hollow fiber membrane at a filtration pressure of 0.07 MPa to complete the treatment process and obtain the discharged water.

[0108] A method for preparing amine-oxime-modified polyacrylonitrile hollow fiber membranes includes the following steps:

[0109] Prepare a 0.1 mol / L hydroxylamine hydrochloride solution and adjust the pH of the hydroxylamine hydrochloride solution to 7 with sodium carbonate. Then add the polyacrylonitrile hollow fiber membrane to the solution and heat it in a water bath at 55°C for 2 hours. After that, take it out, wash it three times with distilled water, and dry it to obtain the AOPAN hollow fiber membrane.

[0110] Example 3

[0111] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation includes the following steps:

[0112] S1, acid precipitation and demulsification

[0113] The copper cable processing wastewater was introduced into the acid precipitation demulsification unit. 98wt% concentrated sulfuric acid was added to the acid precipitation demulsification unit. The amount of concentrated sulfuric acid was 0.25% of the volume of the copper cable processing wastewater. The mixture was stirred at 20℃ for 2 hours to obtain the demulsified wastewater.

[0114] S2, Oil-water separation

[0115] The demulsified wastewater was introduced into an oil-water separation unit for filtration. The oil-water separation unit was equipped with the PLA@PP oil-water separation membrane of Preparation Example 1. After filtration, the filtration pressure was 0.05 MPa and the filtration flow rate was 500 L / h. The separated oil was recycled and the wastewater was used for subsequent steps.

[0116] S3, Advanced Oxidation

[0117] The wastewater after oil-water separation was introduced into an advanced oxidation unit. First, the pH value of the wastewater was adjusted to 3.5. Then, ferrous sulfate heptahydrate was added at a rate of 1.2% of the wastewater mass. After stirring for 15 minutes, 30 wt% hydrogen peroxide solution was added at a rate of 1.35% of the wastewater volume. The mixture was stirred for 2 hours. Then, polyacrylamide was added at a rate of 0.03% of the wastewater mass. After stirring for 30 minutes, the mixture was allowed to stand for 2 hours and then filtered to obtain oxidized wastewater.

[0118] S4, Membrane Separation

[0119] The oxidized wastewater is introduced into the membrane separation unit and filtered successively through a PVDF hollow fiber ultrafiltration membrane and an ammonium oxime-modified polyacrylonitrile hollow fiber membrane at a filtration pressure of 0.08 MPa to complete the treatment process.

[0120] A method for preparing amine-oxime-modified polyacrylonitrile hollow fiber membranes includes the following steps:

[0121] Prepare a 0.3 mol / L hydroxylamine hydrochloride solution and adjust the pH of the hydroxylamine hydrochloride solution to 7 with sodium carbonate. Then add the polyacrylonitrile hollow fiber membrane to the solution and heat it in a water bath at 75°C for 4 hours. After that, take it out, wash it three times with distilled water, and dry it to obtain the AOPAN hollow fiber membrane.

[0122] Example 4

[0123] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the amount of concentrated sulfuric acid used in S1 is 0.3% of the volume of the copper cable processing wastewater.

[0124] Example 5

[0125] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the amount of concentrated sulfuric acid used in S1 is 0.35% of the volume of copper cable processing wastewater.

[0126] Example 6

[0127] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 2 in that the amount of hydrogen peroxide solution used in S4 is 1.4% of the volume of wastewater after oil-water separation.

[0128] Example 7

[0129] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Preparation Example 2.

[0130] Example 8

[0131] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Preparation Example 3.

[0132] Comparative Example 1

[0133] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Comparative Example 1.

[0134] Comparative Example 2

[0135] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Comparative Example 2.

[0136] Comparative Example 3

[0137] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Comparative Example 3.

[0138] Comparative Example 4

[0139] A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation is different from Example 1 in that the PLA@PP oil-water separation membrane in S2 of Example 1 is replaced with the product of Comparative Example 4.

[0140] The COD content of the demulsified wastewater obtained from the treatment process S1 of the copper cable processing industry oil emulsion wastewater based on fiber membrane separation provided in Examples 1-5 was detected, and the detection results are as follows: Figure 2 As shown, by Figure 2 It can be seen that after adding different volumes of concentrated sulfuric acid, the COD value of the wastewater initially decreases and then remains constant. This is because the addition of concentrated sulfuric acid alters the pH of the emulsion system. Many emulsions rely on emulsifiers for stability. Emulsifier molecules generally have hydrophilic and hydrophobic portions. When concentrated sulfuric acid is added, the pH of the emulsion system decreases, altering the properties of the emulsifier. On one hand, some emulsifiers lose their emulsifying ability under acidic conditions, forming non-emulsifying salts upon contact with acid. On the other hand, acid can neutralize the alkaline components in the emulsion, disrupting the previously stable charge balance, reducing the repulsive force between droplets, causing small droplets to collide and aggregate, ultimately achieving the separation of the oil and aqueous phases, thus demulsifying the emulsion. Once the system reaches equilibrium, adding more concentrated sulfuric acid will no longer decrease its COD value.

[0141] The COD content in the effluent before the addition of flocculant obtained from process S3 of the copper cable processing industry oil emulsion wastewater treatment process based on fiber membrane separation provided in Examples 1-6 was detected. The detection results are as follows: Figure 3 As shown, by Figure 3 It can be seen that the COD values ​​of Examples 3, 4, 5 and 6 are similar, indicating that the treatment effect is good.

[0142] The COD content of the oxidation wastewater obtained from process S3 of the fiber membrane separation treatment process for oil emulsion wastewater from the copper cable processing industry provided in Examples 1 and 7-8 was detected. The detection results are as follows: Figure 4 As shown in the figure, the COD content of the oxidized effluent is less than 140 mg / L.

[0143] The COD content in the effluent from the treatment processes of oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation provided in Example 1 and Comparative Examples 1, 2, 3, and 4 was detected. The results are as follows: Figure 5 As shown, by Figure 5 It can be seen that the COD content in the effluent obtained in Example 1 was the lowest, indicating the best treatment effect.

[0144] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0145] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation, characterized in that, Includes the following steps: S1. Demulsify the copper cable processing wastewater to obtain demulsified wastewater; S2. The demulsified wastewater is introduced into the oil-water separation unit for filtration. The oil-water separation unit is equipped with a PLA@PP oil-water separation membrane. The separated oil is recovered, and the wastewater is used for subsequent steps. S3. The wastewater after oil-water separation is introduced into the advanced oxidation unit. The pH value of the wastewater after oil-water separation is adjusted to 3-4. Then, ferrous sulfate heptahydrate is added and stirred for 15 minutes. Hydrogen peroxide solution is added and stirred for 2 hours. Then, flocculant is added. After flocculation and sedimentation, the mixture is filtered to obtain oxidized wastewater. S4. The oxidation wastewater is introduced into the membrane separation unit and filtered through a PVDF hollow fiber ultrafiltration membrane and an ammonium oxime-modified polyacrylonitrile hollow fiber membrane to complete the treatment process. The preparation method of PLA@PP oil-water separation membrane in S2 includes the following steps: Step a: Melt-blend zinc oxide and polypropylene resin to obtain masterbatch, add masterbatch and polypropylene resin into meltblown machine, meltblown spinning to obtain polypropylene meltblown fabric; Step b: Clean the polypropylene meltblown fabric with deionized water, take it out and dry it, and then perform plasma treatment to obtain pretreated meltblown fabric. Step c: Add polylactic acid to a mixed solvent composed of dichloromethane and N,N-dimethylformamide, and control the mass fraction of polylactic acid to 6-10%. Arrange the pretreated meltblown on the receiving roller of the needleless spinning machine, and obtain PLA@PP oil-water separation membrane through spinning treatment.

2. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, The specific operation of S1 is as follows: introduce the copper cable processing wastewater into the acid precipitation demulsification unit, add demulsifier to the acid precipitation demulsification unit, stir at 20-30℃ for 1-3 hours to obtain demulsified wastewater.

3. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 2, characterized in that, The volume ratio of demulsifier to copper cable processing wastewater in S1 is 0.15-0.35:100, and the demulsifier is concentrated sulfuric acid or concentrated nitric acid.

4. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, In step a, the mass ratio of zinc oxide to polypropylene resin in the preparation of masterbatch is 20-30:100, and the mass ratio of masterbatch to polypropylene resin is 1:4-19.

5. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, In step a, the meltblown machine uses a single-screw extruder, and the temperature configuration of each zone is as follows: Zone 1 130℃±5℃, Zone 2 150℃±5℃, Zone 3 160℃±5℃.

6. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, The basis weight of polypropylene meltblown fabric is 35 g / m². 2 .

7. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, In step b, the plasma treatment power is 25-75W, and the treatment time is 2-5 minutes.

8. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, In step c, the spinning voltage is 40-60kV, the roller speed is 0.5m / min, and the spinning time is 2h.

9. The treatment process for oil emulsion wastewater from the copper cable processing industry based on fiber membrane separation according to claim 1, characterized in that, The dosage of ferrous sulfate heptahydrate in S3 is 1.2-1.3% of the mass of the wastewater after oil-water separation, the dosage of hydrogen peroxide solution is 1.3-1.4% of the volume of the wastewater after oil-water separation, and the dosage of flocculant is 0.01-0.03% of the mass of the wastewater after oil-water separation.

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