Treatment process for chlorine dioxide-ozone-ultraviolet synergistic sterilization and disinfection of industrial wastewater

Abstract

The invention provides a chlorine dioxide-ozone-ultraviolet synergistic sterilization and disinfection treatment process for industrial wastewater, and belongs to the technical field of water treatment.The chlorine dioxide-ozone-ultraviolet synergistic sterilization and disinfection treatment process comprises the following steps that 1, industrial wastewater is filtered and then subjected to preliminary precipitation; 2, conveying into a biological contact oxidation tank, treating, conveying into an inclined tube sedimentation tank, and precipitating; 3, conveying into a disinfection tank, injecting ozone, and irradiating by using an ultraviolet lamp at the same time; and 4, conveying into a purification tank, adding chlorine dioxide, and carrying out desalination treatment through a reverse osmosis composite membrane to finally obtain a purified water body. According to the chlorine dioxide-ozone-ultraviolet synergistic sterilization and disinfection treatment process for the industrial wastewater, the adverse effect of chlorine on the reverse osmosis composite membrane can be effectively reduced, and meanwhile, the reverse osmosis composite membrane is obtained by coating a hydroxyapatite doped supporting layer with a carbon nanotube modified polyarylene sulfide sulfone solution; good permeability and long-term stability are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to a treatment process for synergistic disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet light. Background Art

[0002] As a new type of efficient separation technology, reverse osmosis technology can effectively separate inorganic salt ions, and has the advantages of safety, environmental protection, easy operation, etc. In recent years, it has been more and more widely used in industrial wastewater treatment.

[0003] In the application of reverse osmosis technology, the reverse osmosis membrane is easily contaminated by bacteria and microorganisms. The contaminated reverse osmosis membrane shows a decrease in water flux and salt rejection rate. In the process of industrial wastewater treatment, chlorine is often used to disinfect the water body, which can effectively reduce the contamination of the reverse osmosis membrane by microorganisms in the water body. However, chlorine will react with the reverse osmosis membrane material, affecting the structural integrity of the membrane. At the same time, the content of acid and alkali substances in industrial wastewater is high, which will rapidly deteriorate the mechanical properties of the membrane and affect the service performance and durability of the membrane.

[0004] Therefore, in the process of industrial wastewater treatment, how to reduce the microbial contamination while improving the durability of the reverse osmosis membrane is the key research direction of scientific research workers in this field. Summary of the Invention

[0005] To solve the problems in the background art, the present invention provides a treatment process for synergistic disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet light.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A treatment process for synergistic disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet light, comprising the following steps:

[0008] Step 1: Filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3 - 5 h, and then transport it to the biological contact oxidation tank for treatment for 8 - 12 h to obtain the primary sedimented wastewater.

[0009] Step 2: Transport the primary sedimented wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 - 4 h to obtain the pretreated wastewater.

[0010] Step 3: Transport the pretreated wastewater to the disinfection tank. Adsorption resin is placed in the disinfection tank. Ozone is injected into the pretreated wastewater in the disinfection tank through a dosing device to make ozone fully mix and contact with the wastewater. At the same time, the disinfection tank is irradiated with an ultraviolet lamp.

[0011] Step 4: Transfer the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide to the purification tank for secondary disinfection, and desalinate the water after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water;

[0012] The reverse osmosis composite membrane is obtained by coating a hydroxyapatite-doped support layer with a carbon nanotube-modified polyarylene sulfide sulfone solution.

[0013] Preferably, the preparation of the reverse osmosis composite membrane in Step 4 includes the following steps:

[0014] A1. By weight, add 18-22 parts of polyarylene sulfide sulfone, 1-2 parts of polyethylene oxide, 0.5-1 part of hydroxypropyl distarch phosphate, and 76-80 parts of carbon nanotube dispersion liquid to a reactor, heat to 110-120 °C, stir and dissolve, then cool and let stand for 2-4 h to obtain a modified polyarylene sulfide sulfone solution;

[0015] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fiber membrane and PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Immerse the fiber support layer in a hydroxyapatite suspension, ultrasonically disperse for 1-2 min, and dry to obtain a hydroxyapatite-doped support layer, where the concentration of the spinning solution is 14-16 wt%, the thickness of the nylon 66 fiber membrane is 5-10 μm, and the hydroxyapatite suspension is a dispersion of 0.5-2 wt% hydroxyapatite in water;

[0016] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. Wait for 30-60 s for the solvent to evaporate, immerse it in a sodium sulfate solution at a temperature of 20-25 °C, and then place it in a pure water coagulation bath to form a membrane to obtain a nascent composite membrane;

[0017] A4. Wash the nascent composite membrane to remove the residual solvent, then soak it in an aqueous solution of 30-40 wt% glycerol for 0.5-1 h, and dry it to obtain a reverse osmosis composite membrane.

[0018] Preferably, the carbon nanotube dispersion liquid in Step A1 is a DMF dispersion liquid of 0.1-0.3 wt% carboxylated carbon nanotubes.

[0019] Preferably, the concentration of the spinning solution in Step A2 is 14-16 wt%, and the thickness of the nylon 66 fiber membrane is 5-10 μm.

[0020] Preferably, the air permeability of the PP non-woven fabric in Step A2 is 2 cm 3 / cm 2 / s.

[0021] Preferably, in step A2, the hydroxyapatite suspension is a dispersion of 0.5-2 wt% hydroxyapatite in water.

[0022] Preferably, the ozone input amount in step 3 is 10 mg / L.

[0023] Preferably, the addition amount of chlorine dioxide in step 4 is 5 mg / L.

[0024] The present application has the following beneficial effects:

[0025] 1. The present invention provides a treatment process for synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide-ozone-ultraviolet light, which uses chlorine dioxide-ozone-ultraviolet light to synergistically sterilize and disinfect water bodies, can effectively reduce the adverse effects of chlorine on the reverse osmosis composite membrane. In addition, the reverse osmosis composite membrane prepared by a specific method has good antibacterial effects and chemical resistance, can achieve high water flux and desalination rate, shows good durability and long-term stability, and finally realizes a long service life.

[0026] 2. In the preparation of the reverse osmosis composite membrane, polyarylene sulfide sulfone is used as the main material, and polyarylene sulfide sulfone is modified by carboxylated carbon nanotubes. Since carbon nanotubes have a high specific surface area, carboxylation treatment endows them with a certain negative charge, which can regulate the surface activity and surface charge of the membrane material, improve the roughness of the membrane material, and enhance the hydrophilic and chemical resistance of polyarylene sulfide sulfone, making the reverse osmosis composite membrane exhibit high permeation performance and a long service life; hydroxyapatite is doped in the functional material nylon 66 fiber membrane. Since hydroxyapatite is a high-strength adsorption material and has active hydroxyl groups at the same time, it can effectively combine the functional material with the main material, improve the anti-pollution and chemical resistance of the membrane, and make the reverse osmosis composite membrane have high permeation performance and service life.

[0027] 3. Utilizing the synergistic effect of hydroxyapatite and carboxylated carbon nanotubes can improve the interfacial bonding performance of the reverse osmosis composite membrane, regulate the uniformity of the micropore size in the cross-section, enhance the chemical resistance and anti-pollution ability of the membrane during the filtration process, thereby improving the durability of the reverse osmosis composite membrane and extending its service life. Specific Embodiments

[0028] The following further elaborates on the present application with reference to examples.

[0029] The raw materials of the examples and comparative examples of the present application are all commercially available, unless otherwise specified.

[0030] Example 1

[0031] A treatment process for synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide-ozone-ultraviolet light, comprising the following steps:

[0032] Step 1: Filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 4 hours, and then transport it to the biological contact oxidation tank for treatment for 10 hours to obtain the primary sedimented wastewater.

[0033] Step 2: Transport the primary sedimented wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 3 hours to obtain the pretreated wastewater.

[0034] Step 3: Transport the pretreated wastewater to the disinfection tank. Adsorption resin is placed in the disinfection tank. Inject ozone into the disinfection tank through the dosing equipment to make ozone fully mix and contact with the pretreated wastewater in the disinfection tank. At the same time, irradiate the disinfection tank with an ultraviolet lamp. The ozone dosage is 10 mg / L.

[0035] Step 4: Transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide to the purification tank for secondary disinfection of the water body. The dosage of chlorine dioxide is 5 mg / L. Desalt the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain the purified water body.

[0036] The preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0037] A1. By weight, add 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 part of hydroxypropyl distarch phosphate, and 78 parts of carbon nanotube dispersion to the reactor, heat to 115 °C, stir and dissolve, then cool and stand for 3 hours to obtain the modified polyarylene sulfide sulfone solution. The carbon nanotube dispersion is a DMF dispersion of 0.2 wt% carboxylated multi-walled carbon nanotubes.

[0038] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, and then perform electrospinning on the PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fiber membrane and PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Place the fiber support layer in a hydroxyapatite suspension, ultrasonically disperse for 1 minute, and dry to obtain the hydroxyapatite-doped support layer. The concentration of the spinning solution is 15 wt%, the thickness of the nylon 66 fiber membrane is 10 μm, and the hydroxyapatite suspension is a 1.0 wt% dispersion of hydroxyapatite in water.

[0039] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. Wait for 30 s for the solvent to evaporate, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a membrane to obtain the as-prepared composite membrane.

[0040] A4. Wash the as-prepared composite membrane with water to remove the residual solvent, then soak it in an aqueous solution of 35 wt% glycerol for 0.5 h, and air-dry it to obtain a reverse osmosis composite membrane.

[0041] Example 2

[0042] A treatment process for the synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet includes the following steps:

[0043] Step 1: Filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 4 h, then transport it into the biological contact oxidation tank for treatment for 10 h to obtain the primary sedimented wastewater.

[0044] Step 2: Transport the primary sedimented wastewater from the biological contact oxidation tank into the inclined tube sedimentation tank for sedimentation for 2 h to obtain the pretreated wastewater.

[0045] Step 3: Transport the pretreated wastewater into the disinfection tank. Adsorption resin is placed in the disinfection tank. Inject ozone into the disinfection tank through a dosing device to make ozone fully mix and contact with the pretreated wastewater in the disinfection tank. At the same time, irradiate the disinfection tank with an ultraviolet lamp, where the ozone dosage is 10 mg / L.

[0046] Step 4: Transport the pretreated wastewater in the disinfection tank into the purification tank, add chlorine dioxide to the purification tank for secondary disinfection of the water body, where the addition amount of chlorine dioxide is 5 mg / L. Desalt the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain the purified water body.

[0047] Among them, the preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0048] A1. By weight, add 20 parts of polyarylethersulfone, 1.5 parts of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 78 parts of carbon nanotube dispersion into a reactor, heat to 120 °C, stir and dissolve, then cool and let stand for 4 h to obtain a modified polyarylethersulfone solution, where the carbon nanotube dispersion is a DMF dispersion of 0.2 wt% carboxylated carbon nanotubes;

[0049] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fiber membrane and PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Place the fiber support layer in a hydroxyapatite suspension, ultrasonically disperse for 1 min, and dry to obtain a hydroxyapatite-doped support layer, where the concentration of the spinning solution is 15 wt%, the thickness of the nylon 66 fiber membrane is 10 μm, and the hydroxyapatite suspension is a 0.5 wt% dispersion of hydroxyapatite in water;

[0050] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. After the solvent evaporates for 30 s, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a film, obtaining a primary composite membrane;

[0051] A4. Wash the primary composite membrane to remove the residual solvent, then soak it in an aqueous solution of 35 wt% glycerol for 0.5 h, and air dry to obtain a reverse osmosis composite membrane.

[0052] Example 3

[0053] A treatment process for industrial wastewater by synergistic disinfection of chlorine dioxide - ozone - ultraviolet light includes the following steps:

[0054] Step 1, Filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 5 h, and then transport it to the biological contact oxidation tank for treatment for 8 h to obtain primary sedimented wastewater;

[0055] Step 2, Transport the primary sedimented wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 h to obtain pretreated wastewater;

[0056] Step 3, Transport the pretreated wastewater to the disinfection tank. Adsorption resin is placed in the disinfection tank. Inject ozone into the disinfection tank through a dosing device to make ozone fully mix and contact with the pretreated wastewater in the disinfection tank. At the same time, irradiate the disinfection tank with an ultraviolet lamp, where the ozone input amount is 10 mg / L;

[0057] Step 4, Transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide to the purification tank for secondary disinfection of the water body, where the addition amount of chlorine dioxide is 5 mg / L. Desalt the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water.

[0058] Among them, the preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0059] A1. By weight, add 22 parts of polyarylene sulfide sulfone, 1 part of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 76 parts of carbon nanotube dispersion to a reactor, heat to 110 °C, stir and dissolve, then cool and let stand for 2 h to obtain a modified polyarylene sulfide sulfone solution, where the carbon nanotube dispersion is a DMF dispersion of 0.3 wt% carboxylated carbon nanotubes;

[0060] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, and then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fiber membrane and PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s, place the fiber support layer in the hydroxyapatite suspension, disperse it by ultrasonic for 2 min, dry it to obtain the hydroxyapatite-doped support layer. The concentration of the spinning solution is 14 wt%, the thickness of the nylon 66 fiber membrane is 5 μm, and the hydroxyapatite suspension is a 2 wt% dispersion of hydroxyapatite in water;

[0061] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. Wait for 60 s for the solvent to evaporate, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a film to obtain a primary composite membrane;

[0062] A4. Wash the primary composite membrane to remove the residual solvent, then soak it in an aqueous solution of 40 wt% glycerol for 1 h, and air dry it to obtain a reverse osmosis composite membrane.

[0063] Example 4

[0064] A treatment process for synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet includes the following steps:

[0065] Step 1, filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3 h, then transport it to the biological contact oxidation tank for treatment for 12 h to obtain the primary sedimented wastewater;

[0066] Step 2, transport the primary sedimented wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 4 h to obtain the pretreated wastewater;

[0067] Step 3, transport the pretreated wastewater to the disinfection tank. Adsorption resin is placed in the disinfection tank. Inject ozone into the disinfection tank through a dosing device to make ozone fully mix and contact with the pretreated wastewater in the disinfection tank. At the same time, irradiate the disinfection tank with an ultraviolet lamp. The ozone input amount is 10 mg / L;

[0068] Step 4, transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide to the purification tank for secondary disinfection of the water body. The addition amount of chlorine dioxide is 5 mg / L. Desalt the water body after secondary disinfection through the reverse osmosis composite membrane to finally obtain the purified water body.

[0069] Among them, the preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0070] A1. By weight, add 18 parts of polyarylene sulfide sulfone, 2 parts of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 79 parts of carbon nanotube dispersion to the reactor, heat to 110 °C, stir and dissolve, then cool and stand for 4 h to obtain the modified polyarylene sulfide sulfone solution. The carbon nanotube dispersion is a 0.1 wt% DMF dispersion of carboxylated carbon nanotubes;

[0071] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, and then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of a nylon 66 fiber membrane and a PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Place the fiber support layer in a hydroxyapatite suspension, disperse it by ultrasonic for 1 min, and then dry it to obtain a hydroxyapatite-doped support layer. The concentration of the spinning solution is 16 wt%, the thickness of the nylon 66 fiber membrane is 10 μm, and the hydroxyapatite suspension is a dispersion of 0.5 wt% hydroxyapatite in water;

[0072] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfone solution on the hydroxyapatite-doped support layer. Wait for 30 s for the solvent to evaporate, immerse it in a sodium sulfate solution at 20 °C, and then place it in a pure water coagulation bath to form a film, obtaining a primary composite membrane;

[0073] A4. Wash the primary composite membrane to remove the residual solvent, then soak it in an aqueous solution of 30 wt% glycerol for 0.5 h, and dry it to obtain a reverse osmosis composite membrane.

[0074] Example 5

[0075] A treatment process for the synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide - ozone - ultraviolet light includes the following steps:

[0076] Step 1, Filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3 h, and then transport it to the biological contact oxidation tank for treatment for 8 h to obtain primary sedimented wastewater;

[0077] Step 2, Transport the primary sedimented wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 h to obtain pretreated wastewater;

[0078] Step 3, Transport the pretreated wastewater to the disinfection tank. Adsorption resin is placed in the disinfection tank. Inject ozone into the disinfection tank through a dosing device to make ozone fully mix and contact with the pretreated wastewater in the disinfection tank. At the same time, irradiate the disinfection tank with an ultraviolet lamp, where the ozone input amount is 10 mg / L;

[0079] Step 4, Transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide to the purification tank for secondary disinfection of the water body, where the addition amount of chlorine dioxide is 5 mg / L. Desalt the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water.

[0080] Among them, the preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0081] A1. By weight, 18 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 part of hydroxypropyl distarch phosphate, and 78 parts of carbon nanotube dispersion are added to a reactor, heated to 120 °C, stirred until dissolved, cooled, and allowed to stand for 2 h to obtain a modified polyarylene sulfide sulfone solution, where the carbon nanotube dispersion is a DMF dispersion of 0.1 wt% carboxylated carbon nanotubes;

[0082] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, and then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fibers and the PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Place the fiber support layer in a hydroxyapatite suspension, ultrasonically disperse for 1 min, and dry to obtain a hydroxyapatite-doped support layer, where the concentration of the spinning solution is 16 wt%, the thickness of the nylon 66 fiber membrane is 8 μm, and the hydroxyapatite suspension is a 1.5 wt% dispersion of hydroxyapatite in water;

[0083] A3. Use a flat film scraping machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. After the solvent evaporates for 60 s, immerse it in a sodium sulfate solution at a temperature of 22 °C, and then place it in a pure water coagulation bath to form a film to obtain a primary composite membrane;

[0084] A4. Wash the primary composite membrane to remove residual solvents, then soak it in an aqueous solution of 30 wt% glycerol for 1 h, and air dry to obtain a reverse osmosis composite membrane.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is only that in step 4, the pretreated wastewater in the disinfection tank is not disinfected for the second time, which specifically includes the following content:

[0087] Step 4: Transport the pretreated wastewater in the disinfection tank to the purification tank, and desalt the water body through the reverse osmosis composite membrane to finally obtain purified water.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is only that in the preparation of the reverse osmosis composite membrane in step 4, carboxylated multi-walled carbon nanotubes are not added, that is, the carbon nanotube dispersion is replaced with DMF, which specifically includes the following content:

[0090] The preparation of the reverse osmosis composite membrane described in step 4 includes the following steps:

[0091] A1. By weight, add 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 part of hydroxypropyl distarch phosphate, and 78 parts of DMF into a reactor, heat to 115 °C, stir to dissolve, then cool and let stand for 3 h to obtain a modified polyarylene sulfide sulfone solution;

[0092] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fibers and the PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s. Place the fiber support layer in a hydroxyapatite suspension, ultrasonically disperse for 1 min, and dry to obtain a hydroxyapatite-doped support layer, where the concentration of the spinning solution is 15%, the thickness of the nylon 66 fiber membrane is 10 μm, and the hydroxyapatite suspension is a 1.0 wt% dispersion of hydroxyapatite in water;

[0093] A3. Use a flat film casting machine to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. After the solvent evaporates for 30 s, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a film, obtaining a nascent composite membrane;

[0094] A4. Wash the nascent composite membrane to remove residual solvents, then soak it in an aqueous solution of 35 wt% glycerol for 0.5 h, and dry it to obtain a reverse osmosis composite membrane.

[0095] Comparative Example 3

[0096] The difference between this comparative example and Example 1 is only that in the preparation of the reverse osmosis composite membrane in Step 4, carboxylated carbon nanotubes are replaced by carbon nanotubes, which specifically includes the following:

[0097] The preparation of the reverse osmosis composite membrane described in Step 4 includes the following steps:

[0098] A1. By weight, add 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 part of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion into a reactor, heat to 115 °C, stir to dissolve, then cool and let stand for 3 h to obtain a modified polyarylene sulfide sulfone solution, where the carbon nanotube dispersion is a DMF dispersion of 0.2 wt% multi-walled carbon nanotubes;

[0099] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of nylon 66 fibers and the PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s, place the fiber support layer in the hydroxyapatite suspension, ultrasonically disperse for 1 min, dry to obtain the hydroxyapatite-doped support layer, where the concentration of the spinning solution is 15%, the thickness of the nylon 66 fiber membrane is 10 μm, and the hydroxyapatite suspension is a dispersion of 1.0 wt% hydroxyapatite in water;

[0100] A3. Use a flat film coater to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. After the solvent evaporates for 30 s, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a film to obtain a primary composite membrane;

[0101] A4. Wash the primary composite membrane to remove the residual solvent, then soak it in an aqueous solution of 35 wt% glycerol for 0.5 h, and air dry to obtain a reverse osmosis composite membrane.

[0102] Comparative Example 4

[0103] The difference between this comparative example and Example 1 is only that in the preparation of the reverse osmosis composite membrane in step 4, hydroxyapatite is not added, and the specific content is as follows:

[0104] The preparation of the reverse osmosis composite membrane described in step 4 includes the following steps:

[0105] A1. By weight, add 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 part of hydroxypropyl distarch phosphate, and 78 parts of carbon nanotube dispersion to a reactor, heat to 115 °C, stir to dissolve, then cool and stand for 3 h to obtain a modified polyarylene sulfide sulfone solution, where the carbon nanotube dispersion is a DMF dispersion of 0.2 wt% multi-walled carbon nanotubes;

[0106] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, and then perform electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by the composite of a nylon 66 fiber membrane and a PP non-woven fabric, where the air permeability of the PP non-woven fabric is 2 cm 3 / cm 2 / s, place the fiber support layer in water, soak for 1 min, dry to obtain the hydroxyapatite-doped support layer, where the concentration of the spinning solution is 15%, and the thickness of the nylon 66 fiber membrane is 10 μm;

[0107] A3. Use a flat film coater to evenly coat the modified polyarylene sulfide sulfone solution on the hydroxyapatite-doped support layer. After the solvent evaporates for 30 s, immerse it in a sodium sulfate solution at 25 °C, and then place it in a pure water coagulation bath to form a film to obtain a primary composite membrane;

[0108] A4. Wash the primary composite membrane to remove the residual solvent, then soak it in an aqueous solution of 35 wt% glycerol for 0.5 h, and air dry to obtain a reverse osmosis composite membrane.

[0109] Comparative Example 5

[0110] The difference between this comparative example and Example 1 is only that in the preparation of the reverse osmosis composite membrane in Step 4, the carboxylated carbon nanotubes are replaced with carbon nanotubes, and hydroxyapatite is not added at the same time.

[0111] Effect verification

[0112] For the treatment process of synergistic sterilization and disinfection of chlorine dioxide - ozone - ultraviolet rays for a certain industrial wastewater in Examples 1 - 5 and Comparative Examples 1 - 5, the permeation performance and service life of the reverse osmosis composite membranes in each group were tested. The specific test process is as follows: The reverse osmosis composite membrane was placed under the conditions of a 2000 ppm NaCl solution, a pH of 7 - 8, a temperature of 25 °C, and a test pressure of 225 psi to test the performance of the reverse osmosis composite membrane, and the test results are shown in Table 1.

[0113] The permeation performance was used to calculate the water flux (J) and salt rejection rate (R) of the reverse osmosis composite membrane according to the formula respectively.

[0114] Water flux calculation formula: J = V / (S * t) * 100%;

[0115] Among them, the water flux (J) refers to the volume (V) of water permeating through the unit membrane area (S) per unit time (t) under certain operating conditions. The unit of the water flux (J) is L·m -2 ·h -1 ; V is the volume of the permeate (unit: L), S is the effective surface area of the reverse osmosis composite membrane (unit: m 2 ), and t is the water permeation time (unit: h).

[0116] Salt rejection rate calculation formula: R = (1 - C p / C f ) * 100%;

[0117] Among them, R represents the rejection rate of the reverse osmosis composite membrane to the solute, that is, the salt rejection rate. C p , C f respectively represent the concentration of the permeate after the raw water passes through the reverse osmosis composite membrane and the concentration of the raw water.

[0118] The service life is based on the initial water flux and initial salt rejection rate of the reverse osmosis composite membrane. During the continuous operation of the treatment process described in the examples and comparative examples, the time when the water flux retention rate of the reverse osmosis composite membrane drops to 85% or the salt rejection rate retention rate drops to 95%.

[0119]

[0120]

[0121] Result analysis

[0122] By analyzing Examples 1-5 and Comparative Examples 1-5 and combining with Table 1, it can be seen that a treatment process for synergistic sterilization and disinfection of industrial wastewater by chlorine dioxide-ozone-ultraviolet rays provided by the present invention can efficiently treat and purify industrial wastewater. The provided reverse osmosis composite membrane has good permeation effect, with an initial water flux of more than 74.9% and an initial salt rejection rate of more than 99.1%. At the same time, it has a relatively high permeation performance retention rate and durability, showing a long service life. The specific analysis is as follows:

[0123] Compared with Example 1, in the treatment process of Comparative Example 1, the water body was not disinfected twice, that is, chlorine dioxide was not added, and the service life of the reverse osmosis composite membrane was significantly reduced, indicating that chlorine dioxide has a great influence on the durability of the reverse osmosis composite membrane;

[0124] Compared with Example 1, in the preparation of the reverse osmosis composite membrane of Comparative Example 2, carboxylated multi-walled carbon nanotubes were not added, and both the permeation performance and the service life were significantly reduced, indicating that the modification of polyarylene sulfide sulfone with carboxylated multi-walled carbon nanotubes can significantly improve the permeation effect and durability of the reverse osmosis composite membrane;

[0125] Compared with Example 1, in the preparation of the reverse osmosis composite membrane of Comparative Example 3, carboxylated multi-walled carbon nanotubes were replaced by multi-walled carbon nanotubes, and both the permeation performance and the service life were reduced to some extent, indicating that the carboxylation treatment of multi-walled carbon nanotubes can improve the permeation effect and durability of the reverse osmosis composite membrane;

[0126] Compared with Example 1, in the preparation of the reverse osmosis composite membrane of Comparative Example 4, hydroxyapatite was not added, and both the permeation performance and the service life were reduced to some extent, indicating that the addition of hydroxyapatite can improve the permeation effect and durability of the reverse osmosis composite membrane;

[0127] Compared with Example 1, in the preparation of the reverse osmosis composite membrane of Comparative Example 5, carboxylated multi-walled carbon nanotubes were replaced by multi-walled carbon nanotubes, and at the same time, hydroxyapatite was not added. The permeation performance was reduced to some extent, and the service life was significantly reduced, indicating that the carboxylation treatment of multi-walled carbon nanotubes and hydroxyapatite can produce synergistic effects while improving the permeation effect of the reverse osmosis composite membrane, significantly improving the long-term stability and durability of the reverse osmosis composite membrane.

[0128] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0129] In addition, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater, characterized in that: The processing technology comprises the following steps: Step 1, filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3-5 hours, then transport it to the biological contact oxidation tank for treatment for 8-12 hours to obtain primary sedimentation wastewater; Step 2, transporting the primary wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2-4 hours to obtain pretreated wastewater; Step 3, transporting the pretreated wastewater to a disinfection tank, placing an adsorption resin in the disinfection tank, injecting ozone into the pretreated wastewater in the disinfection tank through a dosing device, and irradiating the disinfection tank with an ultraviolet lamp; Step 4, transporting the pretreated wastewater in the disinfection tank to the purification tank, adding chlorine dioxide to the purification tank for secondary disinfection, and desalting the water after the secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water; The reverse osmosis composite membrane is obtained by coating a hydroxyapatite-doped support layer with a carbon nanotube-modified polyarylene sulfide sulfone solution.

2. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection treatment process for industrial wastewater according to claim 1 is characterized in that: The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps: A1. In parts by weight, 18-22 parts of polyarylene sulfide sulfone, 1-2 parts of polyethylene oxide, 0.5-1 parts of hydroxypropyl distarch phosphate and 76-80 parts of carbon nanotube dispersion are added to a reactor, heated to 110-120 ° C, stirred to dissolve, cooled, and allowed to stand for 2-4h to obtain a modified polyarylene sulfide sulfone solution; A2. dissolving nylon 66 in formic acid to obtain a spinning solution, and then electrospinning on a PP non-woven fabric to obtain a fiber support layer formed by a composite of nylon 66 fiber membrane and PP non-woven fabric, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1-2 minutes, and drying to obtain a hydroxyapatite-doped support layer; A3. The modified polyarylene sulfide sulfone solution is uniformly coated on the hydroxyapatite doped support layer using a flat film scraper, and the solvent is evaporated for 30-60 seconds, immersed in a sodium sulfate solution at a temperature of 20-25°C, and then placed in a pure water coagulation bath to convert into a membrane to obtain a primary composite membrane; A4. The nascent composite membrane is washed with water to remove residual solvent, and then immersed in a 30-40 wt % glycerol aqueous solution for 0.5-1 h and dried to obtain a reverse osmosis composite membrane.

3. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection treatment process for industrial wastewater according to claim 2 is characterized in that: The carbon nanotube dispersion in step A1 is a DMF dispersion of carboxylated carbon nanotubes with a concentration of 0.1-0.3 wt %.

4. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection treatment process for industrial wastewater according to claim 2 is characterized in that: The concentration of the spinning solution in step A2 is 14-16 wt %, and the thickness of the nylon 66 fiber membrane is 5-10 μm.

5. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection treatment process for industrial wastewater according to claim 2 is characterized in that: The air permeability of the PP nonwoven fabric in step A2 is 2 cm 3 / cm 2 / s.

6. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater according to claim 2, characterized in that: The hydroxyapatite suspension in step A2 is a dispersion of hydroxyapatite in water with a concentration of 0.5-2 wt%.

7. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater according to claim 1, characterized in that: The ozone input in step 3 is 10 mg / L.

8. The chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater according to claim 1, characterized in that: The amount of chlorine dioxide added in step 4 is 5 mg / L.

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