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

Abstract

The invention belongs to the technical field of chemical engineering and environmental protection, and discloses a device and a 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 which are sequentially connected, wherein the efficient adsorption tank is filled with an efficient adsorbent of 1, 4-dioxane, the efficient adsorbent of 1, 4-dioxane comprises 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 method aims at the waste spinning wastewater, and organic pollutants in the wastewater can be effectively removed.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering and environmental protection technology, and more specifically, to a device and method for treating 1,4-dioxane in waste textile sewage. Background Art

[0002] The resource recovery of waste polyester textiles can effectively realize the recycling of waste polyester, which is an environmentally friendly, renewable and cyclic process. The process wastewater generated during the regeneration and depolymerization of waste polyester textiles contains high concentrations of organic pollutants and complex components. Due to the formation of by-products in the production process, the wastewater also contains high concentrations of 1,4-dioxane. 1,4-Dioxane, an organic compound, is also known as dioxane and 1,4-dioxane. It is a colorless liquid with a slight fragrance. It is slightly toxic and irritating to the skin, eyes and respiratory system, and may cause damage to the liver, kidneys and nervous system. Acute poisoning may lead to death. The World Health Organization recommends a water control standard of 50μg / L.

[0003] CN106865733 A discloses a method for removing 1,4-dioxane from water, wherein 1,4-dioxane is removed from water by persulfate oxidation. However, the invention uses persulfate as an oxidant, and the reaction process requires heating, resulting in large amounts of reagent consumption and high costs.

[0004] CN104710019B discloses a method for treating chlorinated hydrocarbons / dioxanes by coupling zero-valent iron and activated sludge, wherein dioxanes are removed under anaerobic conditions by adding zero-valent iron to the activated sludge. However, the amount of zero-valent iron added in the invention is large, and the cost of treating the remaining activated sludge is high.

[0005] Currently, there are few methods for treating 1,4-dioxane in wastewater treatment systems of wastewater treatment plants. Summary of the invention

[0006] The purpose of the present invention is to provide a device and method for treating 1,4-dioxane in waste textile wastewater, so as to effectively remove 1,4-dioxane in industrial wastewater.

[0007] In order to achieve the above-mentioned object, one aspect of the present invention provides a device for treating 1,4-dioxane in waste textile wastewater, the device comprising a water inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank and a water outlet tank connected in sequence;

[0008] The high-efficiency adsorption pool is filled with a high-efficiency adsorbent for 1,4-dioxane, and the high-efficiency adsorbent for 1,4-dioxane 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 above-mentioned device for treating 1,4-dioxane in waste textile wastewater, and the method comprises:

[0010] (1) The wastewater enters the water inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor to undergo anaerobic reaction, aerobic reaction and sludge sedimentation treatment to obtain a supernatant;

[0011] (2) the supernatant enters the photo-Fenton reactor to undergo an 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) The present invention is directed to waste textile wastewater and can effectively remove organic pollutants in the wastewater.

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

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

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

[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. BRIEF DESCRIPTION OF THE DRAWINGS

[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 a device for treating 1,4-dioxane in waste textile wastewater according to an embodiment of the present invention is shown.

[0023] Description of reference numerals:

[0024] 1. Water inlet tank, 2. Integrated anaerobic / aerobic reactor, 3. Photo-Fenton reactor, 4. High-efficiency adsorption tank, 5. Water outlet tank, 6. H2O2 tank DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present 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 device for treating 1,4-dioxane in waste textile wastewater, the device comprising a water inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank and a water outlet tank connected in sequence;

[0027] The high-efficiency adsorption pool is filled with a high-efficiency adsorbent for 1,4-dioxane, and the high-efficiency adsorbent for 1,4-dioxane 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 preparation method comprising the following steps:

[0029] The coconut shell activated carbon and the Mn(NO3)2 aqueous solution are fully mixed, and then filtered, washed, and dried to obtain a first solid mixture;

[0030] The first solid mixture is fully mixed with a Na2CO3 aqueous solution, and then filtered, washed, and dried to obtain a second solid mixture;

[0031] The second solid mixture is 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°C and the calcination time is 2-4h.

[0034] In the present invention, the coconut shell activated carbon and the Mn(NO3)2 aqueous solution are fully mixed by immersing the coconut shell activated carbon in the Mn(NO3)2 aqueous solution and then shaking it in a constant temperature oscillator at a speed of 250-350r / min at 20-30°C for 1-2h. The first solid mixture is fully mixed with the Na2CO3 aqueous solution by immersing the first solid mixture in the Na2CO3 aqueous solution and then shaking it in a constant temperature oscillator at a speed of 250-350r / min at 20-30°C for 1-2h.

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

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

[0037] (2) subjecting the gel-state material to static crystallization, and then subjecting it to centrifugation, washing, and drying to obtain the modified zeolite;

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

[0039] In the present invention, tetraethyl orthosilicate (TEOS) is used as a silicon source, tetrapropylammonium hydroxide (TPAOH) is used as a template, and an ethanol aqueous solution is used as a 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 to sodium hydroxide is 1:2-3; the mass ratio of silica sol to seed crystal is 25-40:1;

[0041] In the present 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° C. and the time is 10-15 h;

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

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

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

[0046] The particle size of the seed crystal is 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 comprises an anaerobic zone, an aerobic zone and a sedimentation zone arranged in sequence; a multi-stage baffle is arranged between the anaerobic zone and the aerobic zone; an aeration pipe is arranged at the bottom of the aerobic zone, and the spacing between the aeration pipes is 10-15 cm; a biological carrier is arranged in the aerobic zone; the sedimentation zone adopts an internal hanging structure;

[0049] The biological carrier is preferably foamed polyurethane.

[0050] In the present invention, preferably, a multi-stage baffle is arranged between the anaerobic zone and the aerobic zone; an aeration silicone tube is arranged at the bottom of the aerobic zone, the bubble rising speed is 0.4-0.8m / s, and the aeration dissolved oxygen concentration is 0.4-0.7mg / L; internal circulation is realized by air and hydraulic flow, and the internal circulation ratio is 100-300%, which effectively resists the impact of water inlet fluctuation; the sedimentation zone adopts an internal hanging structure, which saves space and is conducive to sludge return; a biological carrier is arranged in the aerobic zone; through anaerobic and aerobic reactions, the anaerobic chain breaking decomposition of macromolecular organic matter and the effect of aerobic biochemical degradation are effectively achieved.

[0051] According to the present invention, preferably, a UV lamp and a titanium catalyst plate are provided in the photo-Fenton reactor, and an inlet at the bottom is connected to the H2O2 tank;

[0052] The photo-Fenton reactor is a cylindrical reactor, the ultraviolet lamp is arranged in a ring shape in 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 catalyst plate is arranged close to the inner wall surface of the photo-Fenton reactor;

[0054] A soft-bristled rotating brush is also arranged in the photo-Fenton reactor.

[0055] In the present invention, the rotation speed of the soft-bristle rotating brush is 1 revolution / h, and the soft-bristle rotating brush is used to keep the active centers of the catalyst in effective contact with the pollutants.

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

[0057] (1) The wastewater enters the water inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor to undergo anaerobic reaction, aerobic reaction and sludge sedimentation treatment to obtain a supernatant;

[0058] (2) the supernatant enters the photo-Fenton reactor to undergo an 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 the present invention, waste textile wastewater enters the integrated anaerobic / aerobic reactor through a lifting pump, most of the organic matter is removed by efficient anaerobic biochemical reaction in the anaerobic zone, and some large molecular organic matter is decomposed into small molecular organic matter; the effluent from the anaerobic zone flows into the aerobic zone by gravity, and the organic pollutants in the wastewater are removed through aerobic biochemical reaction; 1,4-dioxane is difficult to biodegrade, and enters the photo-Fenton oxidation reactor with the effluent from the biochemical reactor to remove 1,4-dioxane in a targeted manner; the remaining 1,4-dioxane is adsorbed by a high-efficiency adsorption tank and then discharged in compliance with the 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°C, the hydraulic retention time is 4-10h, and the feed load is 1-10kg / m 3 ·d;

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

[0065] The present invention is further described below by examples:

[0066] Detection method: COD analysis in water samples was performed according to GB / T 11914-1989 (potassium dichromate method). 1,4-dioxane in water samples was determined by liquid-liquid extraction-gas chromatography-mass spectrometry, the extraction sample volume was 50mL-5L, and the detection limit of 1,4-dioxane was 0.05mg / L (50μg / L).

[0067] Example 1

[0068] like Figure 1As shown, this embodiment provides a treatment device for 1,4-dioxane in waste textile wastewater, which includes an inlet tank 1, an integrated anaerobic / aerobic reactor 2, a photo-Fenton reactor 3, a high-efficiency adsorption tank 4 and an outlet tank 5 which are 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 outlet of the integrated anaerobic / aerobic reactor 2 is connected to the inlet of the photo-Fenton reactor 3 through a pipeline; the outlet of 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 outlet tank 5 through a pipeline; the effluent of the high-efficiency adsorption tank 4 meets the discharge standards.

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

[0070] Among them, 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, shaken in a constant temperature oscillator at a speed of 300 r / min at 25°C for 1 hour, filtered, washed with deionized water, and dried at 105°C to obtain a first solid mixture; the first solid mixture is immersed in a 0.3 mol / L Na2CO3 aqueous solution, shaken in a constant temperature oscillator at a speed of 300 r / min at 25°C for 1 hour, filtered, washed with deionized water, and dried to obtain a second solid mixture; under the protection of inert gas, the second solid mixture is calcined in a muffle furnace at a calcination temperature of 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: Ethyl orthosilicate, tetrapropylammonium hydroxide and an ethanol aqueous solution with a mass concentration of 20wt% are mixed evenly, aged at room temperature for 24h, then placed in a polytetrafluoroethylene kettle, and crystallized 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 tetrapropylammonium hydroxide to the ethyl orthosilicate calculated as SiO2 is 0.03:1.

[0072] Preparation of modified zeolite: Add NaAlO2 and NaOH to deionized water, stir mechanically at room temperature for 30 minutes until clear; add silica sol with a mass concentration of 30wt%, stir at room temperature for 30 minutes, then add the above-mentioned seeds and zinc nitrate hexahydrate, and age for 1 hour until gel state; put into polytetrafluoroethylene lined kettle and statically crystallize at 170℃ for 12 hours; cool to room temperature, centrifuge and wash until neutral; then dry in an oven at 100℃ for 12 hours, and the average particle size is 1-2mm. Among them, before aging, the molar ratio of each active component and water in the material to be aged is: Na2O:SiO2:Al2O3:H2O:Zn=10:100:3:1500:0.20; Na2O comes from the sodium aluminate and sodium hydroxide, and the molar ratio of the sodium aluminate and sodium hydroxide is 1:2.3; SiO2 comes from the silica sol and seeds, and the mass ratio of the silica sol and seeds is 32:1;

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

[0074] Among them, the photo-Fenton reactor 3 is provided with an ultraviolet lamp and a titanium catalyst plate, and an inlet at the bottom is connected to the H2O2 tank 6; the photo-Fenton reactor 3 is a cylindrical reactor, the ultraviolet lamp is arranged in a ring shape in the photo-Fenton reactor 3, the ultraviolet lamp is 25 cm away from the side wall of the photo-Fenton reactor 3, and the ultraviolet lamp is cylindrical; the titanium catalyst plate is arranged close to the inner wall of the photo-Fenton reactor 3; the photo-Fenton reactor 3 is also provided with a soft-bristle rotating brush, and the rotation speed of the soft-bristle rotating brush is 1 cycle / h.

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

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

[0077] (1) Wastewater enters the water inlet tank 1, is homogenized, and the pH is adjusted to 8.0. It enters the integrated anaerobic / aerobic reactor 2 through a feed pump to undergo anaerobic and aerobic reactions to remove most of the organic matter in the wastewater. After the aerobic reaction mud-water mixture settles in the sedimentation zone, the sludge is returned to obtain a supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 30°C, the hydraulic retention time is 4h, and the feed load is 2.4kg / m 3 ·d; the aeration dissolved oxygen concentration is about 0.5mg / L, the bubble rising speed is about 0.5m / s; the internal circulation ratio is 150%;

[0078] (2) The supernatant flows into the photo-Fenton reactor 3 by gravity to undergo an advanced oxidation reaction to remove most of the 1,4-dioxane; wherein the wavelength of the light source in the photo-Fenton reactor 3 is 254 nm and the light intensity is 56 μw / cm 2 , the hydraulic retention time is 1h, and the mass concentration of 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 pool 4 flows by gravity into the effluent pool 5 and is discharged in compliance with the standards. The effluent COD concentration after treatment is 31 mg / L, and the 1,4-dioxane concentration is 51.2 μg / L.

[0081] Example 2

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

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

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

[0085] (1) Wastewater enters the water inlet tank 1, is homogenized, and the pH is adjusted to 7.9. It enters the integrated anaerobic / aerobic reactor 2 through a feed pump to undergo anaerobic and aerobic reactions to remove most of the organic matter in the wastewater. After the aerobic reaction mud-water mixture settles in the sedimentation zone, the sludge is returned to obtain a supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 32°C, the hydraulic retention time is 5h, and the feed load is 4.4kg / m 3 d; the aeration dissolved oxygen concentration is about 0.5mg / L, the bubble rising speed is about 0.6m / s; the internal circulation ratio is 200%;

[0086] (2) The supernatant flows into the photo-Fenton reactor 3 by gravity to undergo advanced oxidation reaction to remove most of the 1,4-dioxane; wherein the wavelength of the light source in the photo-Fenton reactor 3 is 230 nm and the light intensity is 84 μw / cm 2The hydraulic retention time is 1.5h and the mass concentration of 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 pool 4 flows by gravity into the effluent pool 5 and is discharged in compliance with the standards. The effluent COD concentration after treatment is 51 mg / L, and the 1,4-dioxane concentration is 54.4 μg / L.

[0089] Example 3

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

[0091] The device for treating 1,4-dioxane in waste textile wastewater of Example 2 is used, and the specific treatment method is as follows:

[0092] (1) Wastewater enters the water inlet tank 1, is homogenized, and the pH is adjusted to 7.9. It enters the integrated anaerobic / aerobic reactor 2 through a feed pump to undergo anaerobic and aerobic reactions to remove most of the organic matter in the wastewater. After the aerobic reaction mud-water mixture settles in the sedimentation zone, the sludge is returned to obtain a supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 28°C, the hydraulic retention time is 6h, and the feed load is 5.2kg / m 3 d; the aeration dissolved oxygen concentration is about 0.7mg / L, the bubble rising speed is about 0.7m / s; the internal circulation ratio is 250%;

[0093] (2) The supernatant flows into the photo-Fenton reactor 3 by gravity to undergo advanced oxidation reaction to remove most of the 1,4-dioxane; wherein the wavelength of the light source in the photo-Fenton reactor 3 is 238 nm and the light intensity is 84 μw / cm 2 The hydraulic retention time is 2h and the mass concentration of 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 pool 4 flows by gravity into the effluent pool 5 and is discharged in compliance with the standards. The effluent COD concentration after treatment is 46 mg / L, and the 1,4-dioxane concentration is 55.7 μg / L.

[0096] Example 4

[0097] The only difference between the treatment device for 1,4-dioxane in waste textile wastewater of this embodiment and that of Example 1 is that the seed crystals used in the preparation of modified zeolite are different. The seed crystals of this embodiment are prepared by uniformly mixing tetraethyl orthosilicate, tetrapropylammonium hydroxide and a 20 wt % ethanol aqueous solution, aging at room temperature for 24 h, and then charging into a polytetrafluoroethylene kettle and crystallizing at 80° C. for 3 days to obtain a microcrystalline liquid (seed crystal) with a particle size of 80 nm; wherein the molar ratio of tetraethyl orthosilicate calculated on 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 is 91.3 mg / L.

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

[0100] (1) Wastewater enters the water inlet tank 1, is homogenized, and the pH is adjusted to 8.1. It enters the integrated anaerobic / aerobic reactor 2 through a feed pump to undergo anaerobic and aerobic reactions to remove most of the organic matter in the wastewater. After the aerobic reaction mud-water mixture settles in the sedimentation zone, the sludge is returned to obtain a supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 35°C, the hydraulic retention time is 7h, and the feed load is 7.2kg / m 3 d; the aeration dissolved oxygen concentration is about 0.4mg / L, the bubble rising speed is about 0.4m / s; the internal circulation ratio is 100%;

[0101] (2) The supernatant flows into the photo-Fenton reactor 3 by gravity to undergo advanced oxidation reaction to remove most of the 1,4-dioxane; wherein the wavelength of the light source in the photo-Fenton reactor 3 is 230 nm and the light intensity is 112 μw / cm 2 The hydraulic retention time is 2.5h and the mass concentration of 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 pool 4 flows by gravity into the effluent pool 5 and is discharged in compliance with the standards. The effluent COD concentration after treatment 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 is 111.5 mg / L.

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

[0107] (1) Wastewater enters the water inlet tank 1, is homogenized, and the pH is adjusted to 8.1. It enters the integrated anaerobic / aerobic reactor 2 through a feed pump to undergo anaerobic and aerobic reactions to remove most of the organic matter in the wastewater. After the aerobic reaction mud-water mixture settles in the sedimentation zone, the sludge is returned to obtain a supernatant. In the integrated anaerobic / aerobic reactor 2, the biochemical temperature is 36°C, the hydraulic retention time is 8h, and the feed load is 5.8kg / m 3 ·d; the aeration dissolved oxygen concentration is about 0.7mg / L, the bubble rising speed is about 0.8m / s; the internal circulation ratio is 300%;

[0108] (2) The supernatant flows into the photo-Fenton reactor 3 by gravity to undergo advanced oxidation reaction to remove most of the 1,4-dioxane; wherein the wavelength of the light source in the photo-Fenton reactor 3 is 220 nm and the light intensity is 120 μw / cm 2 The hydraulic retention time is 3h and the mass concentration of 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 pool 4 flows by gravity into the effluent pool 5 and is discharged in compliance with the standards. The effluent COD concentration after treatment is 42 mg / L, and the 1,4-dioxane concentration is 59.5 μg / L.

[0111] Comparative Example 1

[0112] The difference between the treatment device of 1,4-dioxane in waste textile wastewater of this comparative example and Example 5 is only that the modified zeolite used in the 1,4-dioxane high-efficiency adsorbent is replaced by 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 is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device of this comparative example is used for treatment, and the specific treatment method and process parameters are the same as those in Example 5;

[0114] The comparative example has low treatment efficiency for COD and 1,4-dioxane. The COD concentration of the effluent after treatment is 160 mg / L, and the 1,4-dioxane concentration is 283 μg / L.

[0115] Comparative Example 2

[0116] The difference between the treatment device of 1,4-dioxane in waste textile wastewater of this comparative example and Example 5 is only that the modified activated carbon used as the efficient adsorbent for 1,4-dioxane is replaced by modified peanut shell activated carbon, and 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, oscillated in a constant temperature oscillator at 25°C and a speed of 300 r / min for 1 hour, filtered, washed with deionized water, and dried at 105°C to obtain a first solid mixture; the first solid mixture is immersed in a 0.3 mol / L Na2CO3 aqueous solution, oscillated in a constant temperature oscillator at 25°C and a speed of 300 r / min for 1 hour, filtered, washed with deionized water, and dried in sequence to obtain a second solid mixture; under the protection of inert gas, the second solid mixture is calcined in a muffle furnace at a calcination temperature of 350°C for 2 hours 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 is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device of this comparative example is used for treatment, and the specific treatment method and process parameters are the same as those in Example 5;

[0118] The comparative example has low treatment efficiency for COD and 1,4-dioxane. The COD concentration of the effluent after treatment is 192 mg / L, and the 1,4-dioxane concentration is 489 μg / L.

[0119] Comparative Example 3

[0120] The difference between the treatment device for 1,4-dioxane in waste textile wastewater of this comparative example and Example 5 is that the modified activated carbon and modified zeolite used in the 1,4-dioxane high-efficiency adsorbent are replaced by ordinary zeolite with a particle size of 2-3 mm 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 is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device of this comparative example is used for treatment, and the specific treatment method and process parameters are the same as those in Example 5;

[0122] The comparative example has low treatment efficiency for COD and 1,4-dioxane. The COD concentration of the effluent after treatment is 142 mg / L, and the 1,4-dioxane concentration is 1896 μg / L.

[0123] Comparative Example 4

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

[0125] The COD of the waste textile wastewater to be treated in this comparative example is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device of this comparative example is used for treatment, and the specific treatment method and process parameters are the same as those in Example 5;

[0126] The comparative example has low treatment efficiency for COD and 1,4-dioxane. The COD concentration of the effluent after treatment is 101 mg / L, and the 1,4-dioxane concentration is 126 μg / L.

[0127] Comparative Example 5

[0128] The difference between the treatment device and treatment method of 1,4-dioxane in waste textile wastewater in this comparative example and Example 5 is that the photo-Fenton reactor 3 is replaced by an ozone oxidation reactor;

[0129] The COD of the wastewater to be treated in this comparative example is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device and treatment method of this comparative example are used for treatment, and the COD concentration of the effluent after treatment is 359 mg / L, and the 1,4-dioxane concentration is 1547 μg / L.

[0130] Comparative Example 6

[0131] The difference between the treatment device and treatment method of 1,4-dioxane in waste textile wastewater of this comparative example and Example 5 is that the photo-Fenton reactor 3 is replaced by a photocatalytic reactor;

[0132] The COD of the wastewater to be treated in this comparative example is 2548 mg / L, and the 1,4-dioxane is 111.5 mg / L. The device and treatment method of this comparative example are used for treatment, and the COD concentration of the effluent after treatment is 296 mg / L, and the 1,4-dioxane concentration is 1038 μg / L.

[0133] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes 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 comprises a water inlet tank, an integrated anaerobic / aerobic reactor, a photo-Fenton reactor, a high-efficiency adsorption tank and a water outlet tank which are connected in sequence; The high-efficiency adsorption pool is filled with a high-efficiency adsorbent for 1,4-dioxane, and the high-efficiency adsorbent for 1,4-dioxane 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).

2. The device according to claim 1, wherein: The modified activated carbon is modified coconut shell activated carbon; the modified activated carbon is prepared by a preparation method comprising the following steps: The coconut shell activated carbon and the Mn(NO3)2 aqueous solution are fully mixed, and then filtered, washed, and dried to obtain a first solid mixture; The first solid mixture is fully mixed with a Na2CO3 aqueous solution, and then filtered, washed, and dried to obtain a second solid mixture; The second solid mixture is calcined in the presence of a protective gas to obtain the modified coconut shell activated carbon.

3. The device according to claim 2, 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°C and the calcination time is 2-4h.

4. The device according to claim 1, wherein: The modified zeolite is prepared by a preparation method comprising the following steps: (1) Sodium aluminate, sodium hydroxide and water are stirred and mixed until they are clear, then silica sol is added and stirred, seed crystals and zinc nitrate hexahydrate are added, and the mixture is aged until it is in a gel state to obtain a gel material; (2) subjecting the gel-state material to static crystallization, and then subjecting it to centrifugation, washing, and drying to obtain the modified zeolite; The seed crystal is prepared by a method comprising the following steps: mixing, aging and crystallizing tetraethyl orthosilicate, tetrapropylammonium hydroxide and an ethanol aqueous solution to obtain the seed crystal. In the present invention, tetraethyl orthosilicate is used as a silicon source, tetrapropylammonium hydroxide is used as a template agent, and an ethanol aqueous solution is used as a solvent.

5. The device according to claim 4, 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 to sodium hydroxide is 1:2-3; the mass ratio of silica sol to seed crystal is 25-40:1; In step (2), the static crystallization temperature is 150-200° C. and the time is 10-15 h; In the preparation of the seed crystals: the mass concentration of the ethanol aqueous solution is 15-25wt%; The molar ratio of the tetrapropylammonium hydroxide to the ethyl orthosilicate calculated as SiO2 is 0.03-0.1:1; The crystallization temperature is 75-85°C and the time is 2-4 days; The particle size of the seed crystal is 60-90 nm.

6. The device according to claim 1, wherein: The volume filling ratio of the high-efficiency adsorbent is 60-80%.

7. The device according to claim 1, wherein: The integrated anaerobic / aerobic reactor includes an anaerobic zone, an aerobic zone and a sedimentation zone arranged in sequence; a multi-stage baffle is arranged between the anaerobic zone and the aerobic zone; an aeration pipe is arranged at the bottom of the aerobic zone, and the spacing between the aeration pipes is 10-15 cm; a biological carrier is arranged in the aerobic zone; and the sedimentation zone adopts an internal hanging structure; The biological carrier is preferably foamed polyurethane.

8. The device according to claim 1, wherein: The photo-Fenton reactor is provided with an ultraviolet lamp and a titanium catalyst plate, and an inlet at the bottom is connected to the H2O2 tank; The photo-Fenton reactor is a cylindrical reactor, the ultraviolet lamp is arranged in a ring shape in 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; The titanium catalyst plate is arranged close to the inner wall surface of the photo-Fenton reactor; A soft-bristled rotating brush is also arranged in the photo-Fenton reactor.

9. A method for treating 1,4-dioxane in waste textile wastewater, using the device for treating 1,4-dioxane in waste textile wastewater according to any one of claims 1 to 8, characterized in that: The treatment method includes: (1) The wastewater enters the water inlet tank, is homogenized and pH adjusted, and then enters the integrated anaerobic / aerobic reactor to undergo anaerobic reaction, aerobic reaction and sludge sedimentation treatment to obtain a supernatant; (2) the supernatant enters the photo-Fenton reactor to undergo an advanced oxidation reaction 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.

10. The processing method according to claim 1, 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°C, the hydraulic retention time is 4-10h, and the feed load is 1-10kg / m 3 ·d; In step (2), in the photo-Fenton reactor, the wavelength of the light source is 210-260nm, and the light intensity is 30-120μw / cm 2 , the hydraulic retention time is 1-3h.

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