A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater

Abstract

The present invention provides a treatment process for the synergistic sterilization and disinfection of industrial wastewater using chlorine dioxide, ozone and ultraviolet rays, which belongs to the field of water treatment technology and comprises the following steps: 1. filtering the industrial wastewater and performing preliminary precipitation; 2. transporting it to a biological contact oxidation tank, and transporting it to an inclined tube sedimentation tank after treatment for precipitation; 3. transporting it to a disinfection tank, injecting ozone, and irradiating it with an ultraviolet lamp at the same time; 4. transporting it to a purification tank, adding chlorine dioxide, and performing desalination treatment by a reverse osmosis composite membrane to finally obtain purified water. The present invention provides a treatment process for the synergistic sterilization and disinfection of industrial wastewater using chlorine dioxide, ozone and ultraviolet rays, which can effectively reduce the adverse effects of chlorine on the reverse osmosis composite membrane, and the reverse osmosis composite membrane is obtained by coating a hydroxyapatite-doped support layer with a carbon nanotube-modified polyaryl sulfide sulfone solution, and has good permeability and long-term stability.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a treatment process for industrial wastewater through chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection. Background Art

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

[0003] In the application of reverse osmosis technology, reverse osmosis membranes are susceptible to bacterial contamination. Contaminated reverse osmosis membranes manifest as decreased water flux and desalination rates. Chlorine is often used to sterilize and disinfect water in industrial wastewater, effectively reducing microbial contamination of reverse osmosis membranes. However, chlorine reacts with the reverse osmosis membrane material, affecting its structural integrity. Furthermore, the high content of acidic and alkaline substances in industrial wastewater can significantly deteriorate the mechanical properties of the membrane, affecting its performance and durability.

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

[0005] In order to solve the problems existing in the background technology, the present invention provides a treatment process for industrial wastewater by chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

[0008] Step 1: filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3-5 hours, then transfer it to the biological contact oxidation tank for treatment for 8-12 hours to obtain primary sedimentation wastewater;

[0009] 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;

[0010] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the pretreated wastewater in the disinfection tank through a dosing device, allow the ozone and wastewater to fully mix and contact, and irradiate the disinfection tank with an ultraviolet lamp at the same time;

[0011] 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 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 comprises the following steps:

[0014] 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 a 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;

[0015] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1-2 minutes, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 14-16wt%, the thickness of the nylon 66 fiber membrane is 5-10μm, and the hydroxyapatite suspension is a dispersion of 0.5-2wt% hydroxyapatite in water;

[0016] A3. The modified polyarylene sulfide sulfone solution was evenly coated on the hydroxyapatite-doped support layer using a flat-plate scraper. After the solvent evaporated for 30-60 seconds, the layer was immersed in a sodium sulfate solution at a temperature of 20-25°C and then placed in a pure water coagulation bath to form a membrane, obtaining a nascent composite membrane.

[0017] A4. The nascent composite membrane was 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.

[0018] Preferably, the carbon nanotube dispersion in step A1 is a DMF dispersion containing 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 nonwoven fabric in step A2 is 2 cm 3 / cm 2 / s.

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

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

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

[0024] This application has the following beneficial effects:

[0025] 1. The present invention provides a treatment process for industrial wastewater using chlorine dioxide, ozone, and ultraviolet rays for synergistic sterilization and disinfection. The synergistic sterilization and disinfection of water bodies using chlorine dioxide, ozone, and ultraviolet rays can effectively reduce the adverse effects of chlorine on reverse osmosis composite membranes. In addition, the reverse osmosis composite membrane prepared by a specific method has good antibacterial effect and chemical resistance, can achieve a high water flux and desalination rate, exhibits good durability and long-term stability, and ultimately achieves a long service life.

[0026] 2. In the preparation of reverse osmosis composite membranes, polyarylene sulfide sulfone is used as the main material and is modified by carboxylating carbon nanotubes. Since carbon nanotubes have a high specific surface area, the carboxylation treatment makes them have a certain negative charge, which can adjust the surface activity and surface charge of the membrane material, improve the roughness of the membrane material, and enhance the hydrophilicity and chemical resistance of polyarylene sulfide sulfone, so that the reverse osmosis composite membrane exhibits higher permeability and longer service life; hydroxyapatite is doped into the functional material nylon 66 fiber membrane. Since hydroxyapatite is a high-strength adsorption material and has active hydroxyl groups, 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 higher permeability and service life.

[0027] 3. The synergistic effect of hydroxyapatite and carboxylated carbon nanotubes can improve the interfacial bonding performance of the reverse osmosis composite membrane, adjust the uniformity of the micropore size in the cross section, and improve 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. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

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

[0030] Example 1

[0031] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

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

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

[0034] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the disinfection tank through a dosing device, allow the ozone to fully mix and contact with the pretreated wastewater in the disinfection tank, and irradiate the disinfection tank with an ultraviolet lamp at the same time, wherein the ozone input amount is 10 mg / L;

[0035] Step 4: transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide into the purification tank to perform secondary disinfection on the water body, wherein the amount of chlorine dioxide added is 5 mg / L, and desalinate the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water body.

[0036] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0037] A1. In parts by weight, 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 parts of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion were added to a reactor, heated to 115°C, stirred to dissolve, cooled, and allowed to stand for 3 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion is a 0.2 wt% dispersion of carboxylated multi-walled carbon nanotubes in DMF;

[0038] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 minute, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 15wt%, the thickness of the nylon 66 fiber membrane is 10μm, and the hydroxyapatite suspension is a dispersion of 1.0wt% hydroxyapatite in water;

[0039] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0040] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 35 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0041] Example 2

[0042] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

[0043] Step 1: filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 4 hours, then transfer it to the biological contact oxidation tank for treatment for 10 hours to obtain primary sedimentation wastewater;

[0044] Step 2: transporting the primary wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 hours to obtain pretreated wastewater;

[0045] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the disinfection tank through a dosing device, allow the ozone to fully mix and contact with the pretreated wastewater in the disinfection tank, and irradiate the disinfection tank with an ultraviolet lamp at the same time, wherein the ozone input amount is 10 mg / L;

[0046] Step 4: transport the pretreated wastewater in the disinfection tank to the purification tank, add chlorine dioxide into the purification tank to perform secondary disinfection on the water body, wherein the amount of chlorine dioxide added is 5 mg / L, and desalinate the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water body.

[0047] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0048] A1. In parts by weight, 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion were added to a reactor, heated to 120°C, stirred to dissolve, cooled, and allowed to stand for 4 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion was a 0.2 wt% dispersion of carboxylated carbon nanotubes in DMF;

[0049] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 minute, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 15wt%, the thickness of the nylon 66 fiber membrane is 10μm, and the hydroxyapatite suspension is a dispersion of 0.5wt% hydroxyapatite in water;

[0050] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0051] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 35 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0052] Example 3

[0053] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

[0054] Step 1: filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 5 hours, then transfer it to the biological contact oxidation tank for treatment for 8 hours to obtain primary sedimentation wastewater;

[0055] Step 2: transporting the primary wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 hours to obtain pretreated wastewater;

[0056] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the disinfection tank through a dosing device, allow the ozone to fully mix and contact with the pretreated wastewater in the disinfection tank, and irradiate the disinfection tank with an ultraviolet lamp at the same time, wherein 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 into the purification tank to perform secondary disinfection on the water body, wherein the amount of chlorine dioxide added is 5 mg / L, and desalinate the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water body.

[0058] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0059] A1. In parts by weight, 22 parts of polyarylene sulfide sulfone, 1 part of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 76 parts of a carbon nanotube dispersion were added to a reactor, heated to 110°C, stirred to dissolve, cooled, and allowed to stand for 2 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion was a 0.3 wt% carboxylated carbon nanotube dispersion in DMF;

[0060] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 2 minutes, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 14wt%, the thickness of the nylon 66 fiber membrane is 5μm, and the hydroxyapatite suspension is a dispersion of 2wt% hydroxyapatite in water;

[0061] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 60 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0062] A4. The nascent composite membrane was washed with water to remove residual solvent, then immersed in a 40 wt % glycerol aqueous solution for 1 h and dried to obtain a reverse osmosis composite membrane.

[0063] Example 4

[0064] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

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

[0066] Step 2: transporting the primary wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 4 hours to obtain pretreated wastewater;

[0067] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the disinfection tank through a dosing device, allow the ozone to fully mix and contact with the pretreated wastewater in the disinfection tank, and irradiate the disinfection tank with an ultraviolet lamp at the same time, wherein 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 into the purification tank to perform secondary disinfection on the water body, wherein the amount of chlorine dioxide added is 5 mg / L, and desalinate the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water body.

[0069] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0070] A1. In parts by weight, 18 parts of polyarylene sulfide sulfone, 2 parts of polyethylene oxide, 1 part of hydroxypropyl distarch phosphate, and 79 parts of a carbon nanotube dispersion were added to a reactor, heated to 110°C, stirred to dissolve, cooled, and allowed to stand for 4 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion was a 0.1 wt% dispersion of carboxylated carbon nanotubes in DMF.

[0071] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 minute, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 16wt%, the thickness of the nylon 66 fiber membrane is 10μm, and the hydroxyapatite suspension is a dispersion of 0.5wt% hydroxyapatite in water;

[0072] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 20°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0073] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 30 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0074] Example 5

[0075] A chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater comprises the following steps:

[0076] Step 1: filter the industrial wastewater and discharge it into the primary sedimentation tank for preliminary sedimentation for 3 hours, then transfer it to the biological contact oxidation tank for treatment for 8 hours to obtain primary sedimentation wastewater;

[0077] Step 2: transporting the primary wastewater from the biological contact oxidation tank to the inclined tube sedimentation tank for sedimentation for 2 hours to obtain pretreated wastewater;

[0078] Step 3: transport the pretreated wastewater to a disinfection tank, place an adsorption resin in the disinfection tank, inject ozone into the disinfection tank through a dosing device, allow the ozone to fully mix and contact with the pretreated wastewater in the disinfection tank, and irradiate the disinfection tank with an ultraviolet lamp at the same time, wherein 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 into the purification tank to perform secondary disinfection on the water body, wherein the amount of chlorine dioxide added is 5 mg / L, and desalinate the water body after secondary disinfection through a reverse osmosis composite membrane to finally obtain purified water body.

[0080] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0081] A1. In parts by weight, 18 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 parts of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion were added to a reactor, heated to 120°C, stirred to dissolve, cooled, and allowed to stand for 2 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion is a 0.1 wt% dispersion of carboxylated carbon nanotubes in DMF;

[0082] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 min, and drying to obtain a hydroxyapatite-doped support layer, wherein 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 dispersion of 1.5 wt% hydroxyapatite in water;

[0083] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 60 seconds, the layer was immersed in a sodium sulfate solution at 22°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0084] A4. The nascent composite membrane was washed with water to remove residual solvent, then immersed in a 30 wt % glycerol aqueous solution for 1 h and dried to obtain a reverse osmosis composite membrane.

[0085] Comparative Example 1

[0086] The only difference between this comparative example and Example 1 is that in step 4, the pretreated wastewater in the disinfection tank is not subjected to secondary disinfection, which specifically includes the following contents:

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

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that, in step 4 of preparing the reverse osmosis composite membrane, no carboxylated multi-walled carbon nanotubes are added, that is, the carbon nanotube dispersion is replaced with DMF. Specifically, the following steps are included:

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

[0091] A1. In parts by weight, 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 parts of hydroxypropyl distarch phosphate and 78 parts of DMF were added to a reactor, heated to 115 ° C, stirred to dissolve, cooled, and allowed to stand for 3 hours to obtain a modified polyarylene sulfide sulfone solution;

[0092] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 minute, and drying to obtain a hydroxyapatite-doped support layer, wherein 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;

[0093] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0094] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 35 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0095] Comparative Example 3

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

[0097] The preparation of the reverse osmosis composite membrane in step 4 comprises the following steps:

[0098] A1. In parts by weight, 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 parts of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion were added to a reactor, heated to 115°C, stirred to dissolve, cooled, and allowed to stand for 3 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion was a 0.2 wt% dispersion of multi-walled carbon nanotubes in DMF;

[0099] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in a hydroxyapatite suspension, ultrasonically dispersing for 1 minute, and drying to obtain a hydroxyapatite-doped support layer, wherein 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. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0101] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 35 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0102] Comparative Example 4

[0103] The only difference between this comparative example and Example 1 is that no hydroxyapatite is added in the preparation of the reverse osmosis composite membrane in step 4. Specifically, the following steps are included:

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

[0105] A1. In parts by weight, 20 parts of polyarylene sulfide sulfone, 1.5 parts of polyethylene oxide, 0.5 parts of hydroxypropyl distarch phosphate, and 78 parts of a carbon nanotube dispersion were added to a reactor, heated to 115°C, stirred to dissolve, cooled, and allowed to stand for 3 hours to obtain a modified polyarylene sulfide sulfone solution, wherein the carbon nanotube dispersion was a 0.2 wt% dispersion of multi-walled carbon nanotubes in DMF;

[0106] A2. Dissolve nylon 66 in formic acid to obtain a spinning solution, which is then electrospun on a PP non-woven fabric to obtain a fiber support layer composed of a nylon 66 fiber membrane and a PP non-woven fabric. The air permeability of the PP non-woven fabric is 2 cm. 3 / cm 2 / s, placing the fiber support layer in water, soaking for 1 min, and drying to obtain a hydroxyapatite-doped support layer, wherein the concentration of the spinning solution is 15%, and the thickness of the nylon 66 fiber membrane is 10 μm;

[0107] A3. The modified polyarylene sulfide sulfone solution was evenly coated onto the hydroxyapatite-doped support layer using a flat-bed scraper. After the solvent evaporated for 30 seconds, the layer was immersed in a sodium sulfate solution at 25°C and then placed in a pure water coagulation bath to form a membrane, yielding a nascent composite membrane.

[0108] A4. The nascent composite membrane was washed with water to remove residual solvent, and then immersed in a 35 wt % glycerol aqueous solution for 0.5 h and dried to obtain a reverse osmosis composite membrane.

[0109] Comparative Example 5

[0110] The only difference between this comparative example and Example 1 is that, in step 4, in the preparation of the reverse osmosis composite membrane, the carboxylated carbon nanotubes are replaced by carbon nanotubes, and no hydroxyapatite is added.

[0111] Proven effectiveness

[0112] The permeability and service life of each set of reverse osmosis composite membranes were tested for the chlorine dioxide-ozone-ultraviolet synergistic disinfection process for industrial wastewater treatment described in Examples 1-5 and Comparative Examples 1-5. The specific testing procedure was as follows: The reverse osmosis composite membranes were exposed to a 2000 ppm NaCl solution at a pH of 7-8, a temperature of 25°C, and a test pressure of 225 psi to test their performance. The test results are shown in Table 1.

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

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

[0115] Water flux (J) refers to the volume (V) of water that passes through a unit membrane area (S) per unit time (t) under certain operating conditions. The unit of water flux (J) is L·m -2 ·h -1 ; V is the volume of permeate (unit is L), S is the effective surface area of ​​RO composite membrane (unit is m 2 ), t is the water penetration time (unit: h).

[0116] The formula for calculating the desalination rate is: R = (1-C p / C f )*100%;

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

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

[0119]

[0120]

[0121] Result Analysis

[0122] Analysis of Examples 1-5 and Comparative Examples 1-5, combined with Table 1, reveals that the chlorine dioxide-ozone-ultraviolet ray synergistic sterilization and disinfection process for industrial wastewater provided by the present invention is capable of efficiently treating and purifying industrial wastewater. The provided reverse osmosis composite membrane exhibits excellent permeability, with an initial water flux exceeding 74.9% and an initial salt removal rate exceeding 99.1%. Furthermore, the membrane exhibits high permeability retention and durability, demonstrating a long service life. Detailed analysis is as follows:

[0123] Comparative Example 1 Compared with Example 1, in the treatment process, no secondary disinfection of the water body was performed, that is, no chlorine dioxide was added, and the service life of the reverse osmosis composite membrane was greatly reduced. Chlorine dioxide has a great impact on the durability of the reverse osmosis composite membrane;

[0124] Comparative Example 2 Compared with Example 1, in the preparation of the reverse osmosis composite membrane, no carboxylated multi-walled carbon nanotubes were added, and the permeability and service life were greatly reduced, indicating that the modification of polyarylene sulfide sulfone with carboxylated multi-walled carbon nanotubes can significantly improve the permeability and durability of the reverse osmosis composite membrane;

[0125] Comparative Example 3 Compared with Example 1, in the preparation of the reverse osmosis composite membrane, the carboxylated multi-walled carbon nanotubes were replaced with multi-walled carbon nanotubes. The permeability and service life were reduced, indicating that the carboxylation treatment of multi-walled carbon nanotubes can improve the permeability and durability of the reverse osmosis composite membrane;

[0126] Comparative Example 4 Compared with Example 1, in the preparation of the reverse osmosis composite membrane, no hydroxyapatite was added, and the permeability and service life were reduced, indicating that the addition of hydroxyapatite can improve the permeability and durability of the reverse osmosis composite membrane;

[0127] In Comparative Example 5, compared with Example 1, in the preparation of the reverse osmosis composite membrane, the carboxylated multi-walled carbon nanotubes were replaced with multi-walled carbon nanotubes, and hydroxyapatite was not added. The permeability was reduced and the service life was greatly reduced. This shows 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, thereby significantly improving the long-term stability and durability of the reverse osmosis composite membrane.

[0128] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0129] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents 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 treatment process 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 transfer 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 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 process for industrial wastewater according to claim 1, 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 a 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. Nylon 66 was dissolved in formic acid to obtain a spinning solution, which was then electrospun onto a PP non-woven fabric to obtain a nylon 66 fiber membrane and PP non-woven fabric composite fiber support layer. The fiber support layer was placed in a hydroxyapatite suspension, ultrasonically dispersed for 1-2 minutes, and dried to obtain a hydroxyapatite-doped support layer. A3. The modified polyarylene sulfide sulfone solution was evenly coated on the hydroxyapatite-doped support layer using a flat-plate scraper. After the solvent evaporated for 30-60 seconds, the layer was immersed in a sodium sulfate solution at a temperature of 20-25°C and then placed in a pure water coagulation bath to form a membrane, obtaining a nascent composite membrane. A4. The nascent composite membrane was 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 process for industrial wastewater according to claim 2, 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 process for industrial wastewater according to claim 2, 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 process for industrial wastewater according to claim 2, characterized in that: The air permeability of the PP nonwoven fabric in step A2 is 2cm 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 amount 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.

Images