A device and method for treating 1,4-dioxane in waste spinning sewage

Abstract

The application belongs to the field of chemical industry and environmental protection technology, and discloses a device and method for treating 1,4-dioxane in waste spinning sewage. The device comprises a water inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, an efficient adsorption tank and a water outlet tank connected in sequence. The efficient adsorption tank is filled with 1,4-dioxane efficient adsorbent, and the 1,4-dioxane efficient adsorbent comprises modified activated carbon and modified zeolite. The volume ratio of the modified activated carbon to the modified zeolite is 1:(2.5-3.5). The application can effectively remove organic pollutants in waste spinning wastewater.

Description

Technical Field

[0001] This invention relates to the fields of chemical and environmental protection technology, and more specifically, to an apparatus and method for treating 1,4-dioxane in waste textile wastewater. Background Technology

[0002] Resource recovery from waste polyester textiles is an effective way to recycle waste polyester, representing an environmentally friendly and recyclable process. However, the wastewater generated during the depolymerization process of waste polyester textile recycling contains high concentrations of organic pollutants and has a complex composition. Due to the formation of byproducts in the production process, the wastewater also contains high concentrations of 1,4-dioxane. 1,4-Dioxane, an organic compound, also known as dioxane or 1,4-dioxane, is a colorless liquid with a slight odor. It is classified as slightly toxic, irritating to the skin, eyes, and respiratory system, and may cause damage to the liver, kidneys, and nervous system; acute poisoning can lead to death. The World Health Organization recommends a water pollution control standard of 50 μg / L.

[0003] CN106865733 A discloses a method for removing 1,4-dioxane from water by oxidation with persulfate. However, this invention uses persulfate as the oxidant, the reaction process requires heating, the amount of reagent consumed is large, and the cost is high.

[0004] CN104710019B discloses a method for treating chlorinated hydrocarbons / dioxanes by coupling zero-valent iron with activated sludge. Dioxane is removed under anaerobic conditions by adding zero-valent iron to activated sludge. However, this invention requires a large amount of zero-valent iron and the resulting residual activated sludge has high treatment costs.

[0005] Currently, there are few methods for treating 1,4-dioxane in wastewater treatment systems from waste textile processes. Summary of the Invention

[0006] The purpose of this invention is to provide a device and method for treating 1,4-dioxane in waste textile wastewater, which can effectively remove 1,4-dioxane from industrial wastewater.

[0007] To achieve the above objectives, one aspect of the present invention provides a treatment device for 1,4-dioxane in waste textile wastewater, the device comprising an inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank, and an effluent tank connected in sequence.

[0008] The high-efficiency adsorption tank is filled with a high-efficiency adsorbent of 1,4-dioxane, which includes modified activated carbon and modified zeolite, and the volume ratio of the modified activated carbon to the modified zeolite is 1:(2.5-3.5).

[0009] Another aspect of the present invention provides a method for treating 1,4-dioxane in waste textile wastewater, using the aforementioned device for treating 1,4-dioxane in waste textile wastewater, the method comprising:

[0010] (1) Wastewater enters the inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor for anaerobic reaction, aerobic reaction and sludge settling treatment to obtain supernatant.

[0011] (2) The supernatant enters the photo-Fenton reactor for advanced oxidation reaction to remove most of the 1,4-dioxane;

[0012] (3) The effluent from the photo-Fenton reactor enters the high-efficiency adsorption tank to further remove 1,4-dioxane from the wastewater;

[0013] (4) The effluent from the high-efficiency adsorption tank enters the effluent tank and is discharged.

[0014] The technical solution of the present invention has the following beneficial effects:

[0015] (1) This invention is designed for waste textile wastewater and can effectively remove organic pollutants from the wastewater.

[0016] (2) The photo-Fenton reactor of the present invention has high oxidation efficiency and can specifically open the ring and degrade some of the 1,4-dioxane.

[0017] (3) The high-efficiency adsorbent of the present invention is specifically designed to remove 1,4-dioxane. The modified activated carbon and modified zeolite carriers have a large adsorption capacity for 1,4-dioxane, thus achieving the removal of characteristic pollutants.

[0018] (4) The present invention has a compact structure, effectively improves the efficiency of sewage treatment, and saves on the dosage of chemicals.

[0019] (5) The process of the present invention has a short reaction flow and a simplified device structure, which can reduce the investment cost and operating cost of the reaction device.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0022] Figure 1 A schematic structural diagram of an apparatus for treating 1,4-dioxane in waste textile wastewater according to an embodiment of the present invention is shown.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Inlet tank; 2. Integrated anaerobic / aerobic reactor; 3. Photo-Fenton reactor; 4. High-efficiency adsorption tank; 5. Effluent tank; 6. H2O2 tank. Detailed Implementation

[0025] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0026] One aspect of the present invention provides a treatment device for 1,4-dioxane in waste textile wastewater, the device comprising an inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank and an effluent tank connected in sequence.

[0027] The high-efficiency adsorption tank is filled with a high-efficiency adsorbent of 1,4-dioxane, which includes modified activated carbon and modified zeolite, and the volume ratio of the modified activated carbon to the modified zeolite is 1:(2.5-3.5).

[0028] According to the present invention, preferably, the modified activated carbon is modified coconut shell activated carbon; the modified activated carbon is prepared by a method comprising the following steps:

[0029] Coconut shell activated carbon was thoroughly mixed with an aqueous solution of Mn(NO3)2, then filtered, washed, and dried to obtain the first solid mixture.

[0030] The first solid mixture was thoroughly mixed with an aqueous solution of Na2CO3, then filtered, washed, and dried to obtain the second solid mixture.

[0031] The second solid mixture was calcined in the presence of a protective gas to obtain the modified coconut shell activated carbon.

[0032] According to the present invention, preferably, the concentration of the Mn(NO3)2 aqueous solution is 0.1-0.8 mol / L, and the concentration of the Na2CO3 aqueous solution is 0.3-0.6 mol / L;

[0033] The calcination temperature is 300-380℃, and the time is 2-4 hours.

[0034] In this invention, the coconut shell activated carbon and Mn(NO3)2 aqueous solution are thoroughly mixed as follows: the coconut shell activated carbon is immersed in the Mn(NO3)2 aqueous solution, and then shaken in a constant temperature shaker at 250-350 r / min at 20-30℃ for 1-2 hours. The first solid mixture is thoroughly mixed with Na2CO3 aqueous solution as follows: the first solid mixture is immersed in the Na2CO3 aqueous solution, and then shaken in a constant temperature shaker at 250-350 r / min at 20-30℃ for 1-2 hours.

[0035] According to the present invention, preferably, the modified zeolite is prepared by a method comprising the following steps:

[0036] (1) Sodium aluminate, sodium hydroxide and water are stirred and mixed until clear, then silica sol is added and stirred, then seed crystals and zinc nitrate hexahydrate are added, and aged until gel state is obtained to obtain gel material;

[0037] (2) The gel-state material is statically crystallized, and then centrifuged, washed and dried to obtain the modified zeolite;

[0038] The seed crystal is prepared by a method comprising the following steps: mixing, aging, and crystallizing tetrapropylammonium hydroxide and an aqueous ethanol solution to obtain the seed crystal.

[0039] In this invention, tetraethyl orthosilicate (TEOS) is used as the silicon source, tetrapropylammonium hydroxide (TPAOH) is used as the template agent, and an aqueous ethanol solution is used as the solvent.

[0040] According to the present invention, preferably, in the preparation of the modified zeolite: in step (1), before aging, the molar ratio of each active component and water in the material to be aged is: Na2O:SiO2:Al2O3:H2O:Zn=9~12:100:2.5~3.5:800~2200:0.05~0.32; the molar ratio of sodium aluminate and sodium hydroxide is 1:2~3; the mass ratio of silica sol and seed crystals is 25-40:1;

[0041] In this invention, Na2O is derived from the sodium aluminate and sodium hydroxide, and SiO2 is derived from the silica sol and seed crystals;

[0042] In step (2), the static crystallization temperature is 150-200℃ and the time is 10-15h;

[0043] In the preparation of the seed crystals: the mass concentration of the ethanol aqueous solution is 15-25 wt%;

[0044] The molar ratio of the tetrapropylammonium hydroxide to the tetraethyl orthosilicate (calculated as SiO2) is 0.03-0.1:1;

[0045] The crystallization temperature is 75-85℃, and the time is 2-4 days;

[0046] The seed crystals have a particle size of 60-90 nm.

[0047] According to the present invention, preferably, the volume filling ratio of the high-efficiency adsorbent is 60-80%.

[0048] According to the present invention, preferably, the integrated anaerobic / aerobic reactor includes an anaerobic zone, an aerobic zone, and a sedimentation zone arranged sequentially; a multi-stage baffle is provided between the anaerobic zone and the aerobic zone; an aeration pipe is provided at the bottom of the aerobic zone, and the spacing between the aeration pipes is 10-15 cm; a biological carrier is provided in the aerobic zone; and the sedimentation zone adopts an internal hanging structure.

[0049] The biological carrier is preferably polyurethane foam.

[0050] In this invention, preferably, a multi-stage baffle is provided between the anaerobic zone and the aerobic zone; an aeration silica gel tube is provided at the bottom of the aerobic zone, with a bubble rising speed of 0.4-0.8 m / s and an aeration dissolved oxygen concentration of 0.4-0.7 mg / L; internal circulation is achieved through air and hydraulic propulsion, with an internal circulation ratio of 100-300%, effectively resisting the impact of influent fluctuations; the sedimentation zone adopts an internal hanging structure, saving space and facilitating sludge return; a biological carrier is provided in the aerobic zone; through anaerobic and aerobic reactions, the anaerobic chain-breaking decomposition of macromolecular organic matter and the aerobic biochemical degradation effect are effectively achieved.

[0051] According to the present invention, preferably, the photo-Fenton reactor is equipped with an ultraviolet lamp and a titanium-based catalyst plate, and a bottom inlet is connected to an H2O2 tank;

[0052] The photo-Fenton reactor is a cylindrical reactor, and the ultraviolet lamp is arranged in a ring inside the photo-Fenton reactor. The ultraviolet lamp is 20-30 cm away from the side wall of the photo-Fenton reactor, and the ultraviolet lamp is cylindrical.

[0053] The titanium-based catalyst plate is set in close contact with the inner wall of the photo-Fenton reactor.

[0054] The photo-Fenton reactor is also equipped with a soft-bristled rotating brush.

[0055] In this invention, the rotating speed of the soft-bristled brush is 1 revolution / h. The soft-bristled brush is used to ensure that the active center of the catalyst can be effectively contacted with the contaminants.

[0056] Another aspect of the present invention provides a method for treating 1,4-dioxane in waste textile wastewater, using the aforementioned device for treating 1,4-dioxane in waste textile wastewater, the method comprising:

[0057] (1) Wastewater enters the inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor for anaerobic reaction, aerobic reaction and sludge settling treatment to obtain supernatant.

[0058] (2) The supernatant enters the photo-Fenton reactor for advanced oxidation reaction to remove most of the 1,4-dioxane;

[0059] (3) The effluent from the photo-Fenton reactor enters the high-efficiency adsorption tank to further remove 1,4-dioxane from the wastewater;

[0060] (4) The effluent from the high-efficiency adsorption tank enters the effluent tank and is discharged.

[0061] In this invention, waste textile wastewater enters an integrated anaerobic / aerobic reactor via a lift pump. In the anaerobic zone, most of the organic matter is removed through a highly efficient anaerobic biochemical reaction, and some large organic molecules are decomposed into smaller organic molecules. The effluent from the anaerobic zone flows by gravity into the aerobic zone, where organic pollutants are removed through an aerobic biochemical reaction. 1,4-Dioxane is difficult to biodegrade and enters a photo-Fenton oxidation reactor with the effluent from the biochemical reactor for targeted removal of 1,4-dioxane. The remaining 1,4-dioxane is adsorbed by a highly efficient adsorption tank and then discharged in compliance with standards.

[0062] According to the present invention, preferably, in step (1), the pH is adjusted to 7.0-8.5;

[0063] In the integrated anaerobic / aerobic reactor, the biochemical temperature is 25-38℃, the hydraulic retention time is 4-10h, and the feed loading is 1-10kg / m³. 3 ·d;

[0064] In step (2), the wavelength of the light source in the photo-Fenton reactor is 210-260 nm, and the light intensity is 30-120 μw / cm². 2 The hydraulic residence time is 1-3 hours.

[0065] The present invention is further illustrated by the following examples:

[0066] Detection method: COD in water samples was analyzed according to GB / T 11914-1989 (potassium dichromate method). 1,4-Dioxane was determined using liquid-liquid extraction-gas chromatography-mass spectrometry (LC-GC-MS), with an extraction sample volume of 50 mL to 5 L. The detection limit for 1,4-dioxane was 0.05 mg / L (50 μg / L).

[0067] Example 1

[0068] like Figure 1As shown, this embodiment provides a treatment device for 1,4-dioxane in waste textile wastewater. The device includes an inlet tank 1, an integrated anaerobic / aerobic reactor 2, a photo-Fenton reactor 3, a high-efficiency adsorption tank 4, and an effluent tank 5 connected in sequence. Specifically, wastewater enters the integrated anaerobic / aerobic reactor 2 from the bottom through a feed pump from the inlet tank 1. The effluent from the integrated anaerobic / aerobic reactor 2 is connected to the inlet of the photo-Fenton reactor 3 through a pipeline. The effluent from the photo-Fenton reactor 3 is pumped to the high-efficiency adsorption tank 4. The outlet of the high-efficiency adsorption tank 4 is connected to the inlet of the effluent tank 5 through a pipeline. The effluent from the high-efficiency adsorption tank 4 is discharged after meeting the standards.

[0069] The high-efficiency adsorption tank 4 is filled with a high-efficiency adsorbent of 1,4-dioxane, which includes modified activated carbon and modified zeolite, with a volume ratio of 1:3; the volume filling ratio of the high-efficiency adsorbent is 80%.

[0070] The modified activated carbon is modified coconut shell activated carbon. The coconut shell activated carbon is immersed in a 0.5 mol / L Mn(NO3)2 aqueous solution and shaken for 1 hour at 300 r / min in a constant-temperature shaker at 25°C. After filtration, washing with deionized water, and drying at 105°C, a first solid mixture is obtained. The first solid mixture is then immersed in a 0.3 mol / L Na2CO3 aqueous solution and shaken for 1 hour at 300 r / min in a constant-temperature shaker at 25°C. After filtration, washing with deionized water, and drying, a second solid mixture is obtained. Under inert gas protection, the second solid mixture is calcined in a muffle furnace at 350°C for 2 hours to obtain modified coconut shell activated carbon with an average particle size of 1-2 mm.

[0071] Preparation of seed crystals: Tetrapropyl ammonium hydroxide and 20 wt% ethanol aqueous solution were mixed evenly and aged at room temperature for 24 h. The mixture was then placed in a polytetrafluoroethylene autoclave and crystallized at 80 °C for 3 days to obtain microcrystalline liquid (seed crystals) with a particle size of 80 nm. The molar ratio of the tetrapropyl ammonium hydroxide to the tetrapropyl ammonium hydroxide (calculated as SiO2) was 0.03:1.

[0072] Preparation of modified zeolite: NaAlO2 and NaOH were added to deionized water and mechanically stirred at room temperature for 30 min until clear. 30 wt% silica sol was added, and the mixture was stirred at room temperature for 30 min. Then, the above-mentioned seed crystals and zinc nitrate hexahydrate were added, and the mixture was aged for 1 h until gelled. The mixture was then placed in a polytetrafluoroethylene-lined autoclave and statically crystallized at 170℃ for 12 h. After cooling to room temperature, the mixture was centrifuged and washed until neutral. Finally, it was dried in a 100℃ oven for 12 h, with an average particle size of 1-2 mm. Before aging, the molar ratio of each active component and water in the material to be aged was: Na2O:SiO2:Al2O3:H2O:Zn=10:100:3:1500:0.20; Na2O originated from the sodium aluminate and sodium hydroxide, with a molar ratio of sodium aluminate to sodium hydroxide of 1:2.3; SiO2 originated from the silica sol and seed crystals, with a mass ratio of silica sol to seed crystals of 32:1.

[0073] The integrated anaerobic / aerobic reactor 2 includes an anaerobic zone, an aerobic zone, and a sedimentation zone arranged sequentially; a multi-stage baffle is set between the anaerobic zone and the aerobic zone; an aeration silica gel tube is set at the bottom of the aerobic zone, and the spacing between the aeration silica gel tubes is 10cm; a biological carrier is set in the aerobic zone; the sedimentation zone adopts an internal hanging structure; and the biological carrier is polyurethane foam.

[0074] The photo-Fenton reactor 3 is equipped with an ultraviolet lamp and a titanium-based catalyst plate, and has an inlet at the bottom connected to an H2O2 tank 6. The photo-Fenton reactor 3 is a cylindrical reactor, with the ultraviolet lamp arranged in a ring inside the reactor 3, 25 cm away from the side wall of the reactor 3, and the ultraviolet lamp is cylindrical. The titanium-based catalyst plate is arranged in close contact with the inner wall of the photo-Fenton reactor 3. The photo-Fenton reactor 3 is also equipped with a soft-bristled rotating brush, which rotates at a speed of 1 revolution / h.

[0075] In this embodiment, the COD of the waste textile wastewater to be treated is 1458 mg / L, and the 1,4-dioxane concentration is 12.8 mg / L.

[0076] Using the above-mentioned device, the specific processing method is as follows:

[0077] (1) Wastewater enters the influent tank 1, is homogenized, and the pH is adjusted to 8.0. It is then pumped into the integrated anaerobic / aerobic reactor 2 for anaerobic and aerobic reactions to remove most of the organic matter. After the aerobic sludge-water mixture settles in the settling zone, the sludge is returned to the supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 30℃, the hydraulic retention time is 4h, and the feed load is 2.4kg / m³. 3 •d; the dissolved oxygen concentration during aeration is approximately 0.5 mg / L, and the bubble rising speed is approximately 0.5 m / s; the internal circulation ratio is 150%;

[0078] (2) The supernatant flows by gravity into the photo-Fenton reactor 3 for advanced oxidation to remove most of the 1,4-dioxane; wherein, in the photo-Fenton reactor 3, the wavelength of the light source is 254 nm and the light intensity is 56 μw / cm². 2 The hydraulic retention time is 1 hour, and the mass concentration of the hydrogen peroxide used is 30%.

[0079] (3) The effluent from the photo-Fenton reactor 3 enters the high-efficiency adsorption tank 4 to further remove 1,4-dioxane from the wastewater;

[0080] (4) The effluent from the high-efficiency adsorption tank 4 flows by gravity into the effluent tank 5 and is discharged in compliance with standards. The COD concentration of the treated effluent is 31 mg / L and the 1,4-dioxane concentration is 51.2 μg / L.

[0081] Example 2

[0082] The only difference between this embodiment and the treatment device for 1,4-dioxane in waste textile wastewater in Example 1 is the seed crystal used in the preparation of the modified zeolite. The seed crystal in this embodiment is prepared by mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and a 20wt% aqueous ethanol solution evenly, aging at room temperature for 24 hours, and then loading it into a polytetrafluoroethylene reactor and crystallizing at 80°C for 3 days to obtain a microcrystalline liquid (seed crystal) with a particle size of 80nm; wherein, the molar ratio of the tetraethyl orthosilicate, calculated as TPAOH and SiO2, is 0.05.

[0083] In this embodiment, the COD of the waste textile wastewater to be treated is 3367 mg / L, and the 1,4-dioxane concentration is 35.6 mg / L.

[0084] Using the above-mentioned device, the specific processing method is as follows:

[0085] (1) Wastewater enters the influent tank 1, is homogenized, and the pH is adjusted to 7.9. It is then pumped into the integrated anaerobic / aerobic reactor 2 for anaerobic and aerobic reactions to remove most of the organic matter. After the aerobic sludge-water mixture settles in the settling zone, the sludge is recycled to obtain the supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 32℃, the hydraulic retention time is 5h, and the feed load is 4.4kg / m³. 3 •d; the dissolved oxygen concentration during aeration is approximately 0.5 mg / L, and the bubble rising speed is approximately 0.6 m / s; the internal circulation ratio is 200%;

[0086] (2) The supernatant flows by gravity into the photo-Fenton reactor 3 for advanced oxidation to remove most of the 1,4-dioxane; wherein, in the photo-Fenton reactor 3, the wavelength of the light source is 230 nm and the light intensity is 84 μw / cm². 2The hydraulic retention time is 1.5 hours, and the mass concentration of the hydrogen peroxide used is 30%.

[0087] (3) The effluent from the photo-Fenton reactor 3 enters the high-efficiency adsorption tank 4 to further remove 1,4-dioxane from the wastewater;

[0088] (4) The effluent from the high-efficiency adsorption tank 4 flows by gravity into the effluent tank 5 and is discharged in compliance with standards. The COD concentration of the treated effluent is 51 mg / L and the 1,4-dioxane concentration is 54.4 μg / L.

[0089] Example 3

[0090] In this embodiment, the COD of the waste textile wastewater to be treated is 2742 mg / L, and the 1,4-dioxane concentration is 68.9 mg / L.

[0091] The treatment device for 1,4-dioxane in waste textile wastewater, as described in Example 2, is as follows:

[0092] (1) Wastewater enters the influent tank 1, is homogenized, and the pH is adjusted to 7.9. It then enters the integrated anaerobic / aerobic reactor 2 via a feed pump for anaerobic and aerobic reactions to remove most of the organic matter. After the aerobic sludge-water mixture settles in the settling zone, the sludge is returned to the supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 28℃, the hydraulic retention time is 6h, and the feed load is 5.2kg / m³. 3 •d; The dissolved oxygen concentration during aeration is approximately 0.7 mg / L, and the bubble rising speed is approximately 0.7 m / s; The internal circulation ratio is 250%;

[0093] (2) The supernatant flows by gravity into the photo-Fenton reactor 3 for advanced oxidation to remove most of the 1,4-dioxane; wherein, in the photo-Fenton reactor 3, the wavelength of the light source is 238 nm and the light intensity is 84 μw / cm². 2 The hydraulic retention time is 2 hours, and the mass concentration of the hydrogen peroxide used is 30%.

[0094] (3) The effluent from the photo-Fenton reactor 3 enters the high-efficiency adsorption tank 4 to further remove 1,4-dioxane from the wastewater;

[0095] (4) The effluent from the high-efficiency adsorption tank 4 flows by gravity into the effluent tank 5 and is discharged in compliance with standards. The COD concentration of the treated effluent is 46 mg / L and the 1,4-dioxane concentration is 55.7 μg / L.

[0096] Example 4

[0097] The only difference between this embodiment and the treatment device for 1,4-dioxane in waste textile wastewater in Example 1 is the seed crystal used in the preparation of the modified zeolite. The seed crystal in this embodiment is prepared by mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and a 20wt% aqueous ethanol solution evenly, aging at room temperature for 24 hours, and then loading it into a polytetrafluoroethylene reactor and crystallizing it at 80°C for 3 days to obtain a microcrystalline liquid (seed crystal) with a particle size of 80nm; wherein, the molar ratio of the tetraethyl orthosilicate, calculated as TPAOH and SiO2, is 0.07.

[0098] In this embodiment, the COD of the waste textile wastewater to be treated is 1925 mg / L, and the 1,4-dioxane concentration is 91.3 mg / L.

[0099] Using the above-mentioned device, the specific processing method is as follows:

[0100] (1) Wastewater enters the influent tank 1, is homogenized, and the pH is adjusted to 8.1. It is then pumped into the integrated anaerobic / aerobic reactor 2 for anaerobic and aerobic reactions to remove most of the organic matter. After the aerobic sludge-water mixture settles in the settling zone, the sludge is recycled to obtain the supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 35℃, the hydraulic retention time is 7h, and the feed load is 7.2kg / m³. 3 •d; The dissolved oxygen concentration during aeration is approximately 0.4 mg / L, and the bubble rising speed is approximately 0.4 m / s; The internal circulation ratio is 100%;

[0101] (2) The supernatant flows by gravity into the photo-Fenton reactor 3 for advanced oxidation to remove most of the 1,4-dioxane; wherein, in the photo-Fenton reactor 3, the wavelength of the light source is 230 nm and the light intensity is 112 μw / cm². 2 The hydraulic retention time is 2.5 hours, and the mass concentration of the hydrogen peroxide used is 30%.

[0102] (3) The effluent from the photo-Fenton reactor 3 enters the high-efficiency adsorption tank 4 to further remove 1,4-dioxane from the wastewater;

[0103] (4) The effluent from the high-efficiency adsorption tank 4 flows by gravity into the effluent tank 5 and is discharged in compliance with standards. The COD concentration of the treated effluent is 37 mg / L and the 1,4-dioxane concentration is 57.9 μg / L.

[0104] Example 5

[0105] In this embodiment, the COD of the waste textile wastewater to be treated is 2548 mg / L, and the 1,4-dioxane concentration is 111.5 mg / L.

[0106] The treatment device for 1,4-dioxane in waste textile wastewater from Example 1 is used, and the specific treatment method is as follows:

[0107] (1) Wastewater enters the influent tank 1, is homogenized, and the pH is adjusted to 8.1. It then enters the integrated anaerobic / aerobic reactor 2 via a feed pump for anaerobic and aerobic reactions to remove most of the organic matter. After the aerobic sludge-water mixture settles in the settling zone, the sludge is returned to the supernatant. The integrated anaerobic / aerobic reactor 2 has a biochemical temperature of 36℃, a hydraulic retention time of 8 hours, and a feed load of 5.8 kg / m³. 3 •d; the dissolved oxygen concentration during aeration is approximately 0.7 mg / L, the bubble rising speed is approximately 0.8 m / s; the internal circulation ratio is 300%;

[0108] (2) The supernatant flows by gravity into the photo-Fenton reactor 3 for advanced oxidation to remove most of the 1,4-dioxane; wherein, in the photo-Fenton reactor 3, the wavelength of the light source is 220 nm and the light intensity is 120 μw / cm². 2 The hydraulic retention time is 3 hours, and the mass concentration of the hydrogen peroxide used is 30%.

[0109] (3) The effluent from the photo-Fenton reactor 3 enters the high-efficiency adsorption tank 4 to further remove 1,4-dioxane from the wastewater;

[0110] (4) The effluent from the high-efficiency adsorption tank 4 flows by gravity into the effluent tank 5 and is discharged in compliance with standards. The COD concentration of the treated effluent is 42 mg / L and the 1,4-dioxane concentration is 59.5 μg / L.

[0111] Comparative Example 1

[0112] The only difference between this comparative example and the treatment device for 1,4-dioxane in waste textile wastewater in Example 5 is that the modified zeolite used as the high-efficiency adsorbent for 1,4-dioxane is replaced with ordinary zeolite with a particle size of 2-3 mm.

[0113] The COD of the waste textile wastewater to be treated in this comparative example was 2548 mg / L, and the 1,4-dioxane concentration was 111.5 mg / L. The apparatus used in this comparative example was employed for treatment, and the specific treatment methods and process parameters were the same as in Example 5.

[0114] This comparative example showed low efficiency in treating COD and 1,4-dioxane, with the treated effluent COD concentration at 160 mg / L and the 1,4-dioxane concentration at 283 μg / L.

[0115] Comparative Example 2

[0116] The only difference between this comparative example and the treatment device for 1,4-dioxane in waste textile wastewater in Example 5 is that the modified activated carbon used as the high-efficiency adsorbent for 1,4-dioxane is replaced with modified peanut shell activated carbon. The modified peanut shell activated carbon is prepared by the following method: the peanut shell activated carbon is immersed in a 0.5 mol / L Mn(NO3)2 aqueous solution and shaken in a constant temperature shaker at 300 r / min at 25°C for 1 h. After filtration, washing with deionized water, and drying at 105°C, a first solid mixture is obtained. The first solid mixture is immersed in a 0.3 mol / L Na2CO3 aqueous solution and shaken in a constant temperature shaker at 300 r / min at 25°C for 1 h. After filtration, washing with deionized water, and drying, a second solid mixture is obtained. Under inert gas protection, the second solid mixture is calcined in a muffle furnace at 350°C for 2 h to obtain modified peanut shell activated carbon with an average particle size of 1-2 mm.

[0117] The COD of the waste textile wastewater to be treated in this comparative example was 2548 mg / L, and the 1,4-dioxane concentration was 111.5 mg / L. The apparatus used in this comparative example was employed for treatment, and the specific treatment methods and process parameters were the same as in Example 5.

[0118] This comparative example showed low efficiency in treating COD and 1,4-dioxane, with the treated effluent COD concentration at 192 mg / L and the 1,4-dioxane concentration at 489 μg / L.

[0119] Comparative Example 3

[0120] The only difference between this comparative example and the waste textile wastewater treatment device in Example 5 is that the modified activated carbon and modified zeolite used in the high-efficiency adsorbent of 1,4-dioxane are replaced with ordinary zeolite and ordinary activated carbon with a particle size of 2-3 mm.

[0121] The COD of the waste textile wastewater to be treated in this comparative example was 2548 mg / L, and the 1,4-dioxane concentration was 111.5 mg / L. The apparatus used in this comparative example was employed for treatment, and the specific treatment methods and process parameters were the same as in Example 5.

[0122] This comparative example showed low efficiency in treating COD and 1,4-dioxane, with the treated effluent COD concentration at 142 mg / L and the 1,4-dioxane concentration at 1896 μg / L.

[0123] Comparative Example 4

[0124] The only difference between this comparative example and the treatment device for 1,4-dioxane in waste textile wastewater in Example 5 is that the volume ratio of modified activated carbon and modified zeolite used as the 1,4-dioxane high-efficiency adsorbent is different. In this comparative example, the volume ratio of modified activated carbon to modified zeolite is 2:1.

[0125] The COD of the waste textile wastewater to be treated in this comparative example was 2548 mg / L, and the 1,4-dioxane concentration was 111.5 mg / L. The apparatus used in this comparative example was employed for treatment, and the specific treatment methods and process parameters were the same as in Example 5.

[0126] This comparative example showed low efficiency in treating COD and 1,4-dioxane, with the effluent COD concentration after treatment being 101 mg / L and the 1,4-dioxane concentration being 126 μg / L.

[0127] Comparative Example 5

[0128] The only difference between the treatment apparatus and method for 1,4-dioxane in waste textile wastewater in this comparative example and Example 5 is that the photo-Fenton reactor 3 is replaced with an ozone oxidation reactor.

[0129] The wastewater to be treated in this comparative example had a COD of 2548 mg / L and a 1,4-dioxane concentration of 111.5 mg / L. Using the apparatus and treatment method of this comparative example, the effluent COD concentration after treatment was 359 mg / L and the 1,4-dioxane concentration was 1547 μg / L.

[0130] Comparative Example 6

[0131] The only difference between the treatment apparatus and method for 1,4-dioxane in waste textile wastewater in this comparative example and Example 5 is that the photo-Fenton reactor 3 is replaced with a photocatalytic reactor.

[0132] The wastewater to be treated in this comparative example had a COD of 2548 mg / L and a 1,4-dioxane concentration of 111.5 mg / L. Using the apparatus and treatment method of this comparative example, the effluent COD concentration after treatment was 296 mg / L and the 1,4-dioxane concentration was 1038 μg / L.

[0133] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A device for treating 1,4-dioxane in waste textile wastewater, characterized in that, The device includes an inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank, and an outlet tank connected in sequence. The high-efficiency adsorption tank is filled with a high-efficiency adsorbent of 1,4-dioxane, which includes modified activated carbon and modified zeolite, and the volume ratio of the modified activated carbon to the modified zeolite is 1:(2.5-3.5). The modified activated carbon is modified coconut shell activated carbon; the modified activated carbon is prepared by a method including the following steps: Coconut shell activated carbon was thoroughly mixed with an aqueous solution of Mn(NO3)2, then filtered, washed, and dried to obtain the first solid mixture. The first solid mixture was thoroughly mixed with an aqueous solution of Na2CO3, then filtered, washed, and dried to obtain the second solid mixture. The second solid mixture was calcined in the presence of a protective gas to obtain the modified coconut shell activated carbon. The modified zeolite is prepared by a method comprising the following steps: (1) Sodium aluminate, sodium hydroxide and water are stirred and mixed until clear, then silica sol is added and stirred, then seed crystals and zinc nitrate hexahydrate are added, and aged until gel state is obtained to obtain gel material; (2) The gel-state material is statically crystallized, and then centrifuged, washed and dried to obtain the modified zeolite; The seed crystal is prepared by a method comprising the following steps: mixing, aging, and crystallizing tetrapropylammonium hydroxide and an aqueous ethanol solution to obtain the seed crystal.

2. The apparatus according to claim 1, wherein, The concentration of the Mn(NO3)2 aqueous solution is 0.1-0.8 mol / L, and the concentration of the Na2CO3 aqueous solution is 0.3-0.6 mol / L; The calcination temperature is 300-380℃, and the time is 2-4 hours.

3. The apparatus according to claim 1, wherein, In the preparation of the modified zeolite: in step (1), before aging, the molar ratio of each active component and water in the material to be aged is: Na2O: SiO2: Al2O3: H2O: Zn = 9~12:100:2.5~3.5:800~2200:0.05~0.32; the molar ratio of sodium aluminate and sodium hydroxide is 1:2~3; the mass ratio of silica sol and seed crystal is 25-40:

1. In step (2), the static crystallization temperature is 150-200℃ and the time is 10-15h; In the preparation of the seed crystals: the mass concentration of the ethanol aqueous solution is 15-25 wt%; The molar ratio of the tetrapropylammonium hydroxide to the tetraethyl orthosilicate (calculated as SiO2) is 0.03-0.1:1; The crystallization temperature is 75-85℃, and the time is 2-4 days; The seed crystals have a particle size of 60-90 nm.

4. The apparatus according to claim 1, wherein, The volumetric filling ratio of the high-efficiency adsorbent is 60-80%.

5. The apparatus according to claim 1, wherein, The integrated anaerobic / aerobic reactor includes an anaerobic zone, an aerobic zone, and a settling zone arranged sequentially; a multi-stage baffle is set between the anaerobic zone and the aerobic zone; an aeration pipe is set at the bottom of the aerobic zone, and the spacing between the aeration pipes is 10-15cm; a biological carrier is set in the aerobic zone; and the settling zone adopts an internal hanging structure.

6. The apparatus according to claim 5, wherein, The biological carrier is polyurethane foam.

7. The apparatus according to claim 1, wherein, The photo-Fenton reactor is equipped with an ultraviolet lamp and a titanium-based catalyst plate, and has an inlet at the bottom connected to an H2O2 tank. The photo-Fenton reactor is a cylindrical reactor, and the ultraviolet lamp is arranged in a ring inside the photo-Fenton reactor. The ultraviolet lamp is 20-30cm away from the side wall of the photo-Fenton reactor, and the ultraviolet lamp is cylindrical. The titanium-based catalyst plate is set in close contact with the inner wall of the photo-Fenton reactor. The photo-Fenton reactor is also equipped with a soft-bristled rotating brush.

8. A method for treating 1,4-dioxane in waste textile wastewater, comprising using the treatment apparatus for 1,4-dioxane in waste textile wastewater as described in any one of claims 1-7, characterized in that, The processing method includes: (1) Wastewater enters the inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor for anaerobic reaction, aerobic reaction and sludge settling treatment to obtain supernatant; (2) The supernatant enters the photo-Fenton reactor for advanced oxidation to remove most of the 1,4-dioxane; (3) The effluent from the photo-Fenton reactor enters the high-efficiency adsorption tank to further remove 1,4-dioxane from the wastewater; (4) The effluent from the high-efficiency adsorption tank enters the effluent tank and is discharged.

9. The processing method according to claim 8, wherein, In step (1), the pH is adjusted to 7.0-8.5; In the integrated anaerobic / aerobic reactor, the biochemical temperature is 25-38℃, the hydraulic retention time is 4-10h, and the feed load is 1-10kg / m³. 3 •d; In step (2), the wavelength of the light source in the photo-Fenton reactor is 210-260 nm, and the light intensity is 30-120 μw / cm². 2 The hydraulic residence time is 1-3 hours.

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