A method and apparatus for purifying dyeing and printing wastewater based on TAPB-DMTA COF-like Fenton-like synergistic bacteria and algae.

Abstract

This invention relates to the field of wastewater treatment technology, specifically to a method and apparatus for purifying dyeing and printing wastewater based on TAPB-DMTA COF-like Fenton reactors with synergistic bacteria and algae. The specific technical solution is as follows: A method for purifying dyeing and printing wastewater includes the following steps: (1) Dyeing and printing wastewater is introduced into a photocatalytic Fenton reactor, wherein a porosity-modified photocatalyst TAPB-DMTA COF and H2O2 are added to the photocatalytic Fenton reactor, a baffle plate is provided inside the photocatalytic Fenton reactor with an angle of 30-45°, and a first illumination module is provided outside the photocatalytic Fenton reactor; (2) The wastewater treated in step (1) is introduced into a synergistic bacteria and algae SNAD reactor, wherein a photocatalyst and multi-walled carbon nanotubes are added to the synergistic bacteria and algae SNAD reactor. This invention targets recalcitrant dyes, using a porosity-modified TAPB-DMTA COF as a photocatalyst in the photocatalytic Fenton reactor to achieve complete dye degradation. For ammonia nitrogen pollutants, the SNAD reactor with bacterial and algal symbiosis eliminates the need for traditional mechanical aeration. By optimizing the extracellular electron acquisition capacity of microorganisms through bio-enhancing agents, it can achieve efficient and green removal of total nitrogen without the need to add organic carbon sources.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method and apparatus for purifying dyeing and printing wastewater based on TAPB-DMTA COF-type Fenton synergistic bacteria and algae. Background Technology

[0002] A large quantity of synthetic dyes are produced globally each year for printing and dyeing, a portion of which is discharged as wastewater. Printing and dyeing wastewater is characterized by large volume, high organic pollutant content, deep color, high alkalinity, and significant water quality fluctuations. Therefore, this type of wastewater is difficult to treat effectively using conventional wastewater treatment methods, especially for decolorization. Fenton-like reactions, as a promising advanced oxidation process, have been widely applied to the treatment of recalcitrant organic dyes. Fenton-like catalysts activate hydrogen peroxide (H₂O₂), peroxymonosulfate (PMS), or peroxydisulfide (PDS) to generate free radicals including hydroxyl radicals (·OH) and sulfate radicals (SO₄²⁻). ·- ), superoxide radicals (O2) ·- ) or singlet oxygen ( 1 Highly reactive oxygen species (ROS), including O2, oxidize or even completely mineralize organic pollutants into CO2 and H2O.

[0003] Radical-mediated heterogeneous catalytic oxidation is central to dye degradation; however, single-form or homogeneous radicals are often insufficient to satisfy the entire catalytic reaction process. Advanced oxidation mediated by hydroxyl radicals (·OH) has proven ineffective in completely removing most organic pollutants, primarily aromatic dyes, from dyeing and printing wastewater. The main reason is the accumulation of a refractory key intermediate, currently believed to be benzoquinone, in the system, leading to low overall mineralization efficiency. The original aromatic molecule can be attacked by ·OH and converted to benzoquinone, but the resulting benzoquinone intermediate is difficult to further oxidize by ·OH; therefore, the entire degradation process terminates at this stage. Once released into the environment, residual benzoquinone will have irreversible environmental impacts and, due to its high toxicity, may threaten human health. ·- It exhibits high selectivity for both electron-rich and electron-deficient substances, readily reacting with benzoquinone and further converting it into smaller molecules. Therefore, the regulation and combination of free radical types are crucial for the complete removal of ubiquitous aromatic dyes.

[0004] Furthermore, dyeing and printing wastewater contains high concentrations of ammonia nitrogen. Some reactive and direct dyes contain nitrogen-containing functional groups such as amino groups (-NH2), which enter the wastewater during the dyeing process. After the wastewater undergoes advanced oxidation processes, the oxidative degradation of these nitrogen-containing functional groups further increases the ammonia nitrogen concentration. Biological denitrification relies on the natural transformation process of microorganisms and has relatively low operating costs. However, traditional denitrification strategies require a large amount of energy, especially aeration, and the denitrification effect is limited by the carbon source in the influent. Therefore, highly efficient and energy-saving processes are needed to improve denitrification efficiency and reduce wastewater treatment costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for purifying dyeing and printing wastewater based on TAPB-DMTA COF-type Fenton synergistic bacteria and algae.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention discloses a method for purifying dyeing and printing wastewater, comprising the following steps:

[0008] (1) Dyeing and printing wastewater is fed into a photocatalytic Fenton reactor, wherein a porosity-modified photocatalyst TAPB-DMTA COF and H2O2 are added to the photocatalytic Fenton reactor, and a baffle plate is provided inside the photocatalytic Fenton reactor with an angle of 30 to 45°, and a first light module is provided outside the photocatalytic Fenton reactor.

[0009] (2) The wastewater treated in step (1) is fed into the SNAD reactor of bacteria and algae symbiosis. The SNAD reactor of bacteria and algae symbiosis is inoculated with short-cut nitrifying sludge and Chlorella vulgaris. Photocatalyst and multi-walled carbon nanotubes are added to the SNAD reactor of bacteria and algae symbiosis.

[0010] Preferably, the photocatalyst TAPB-DMTA COF is prepared using 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxy-terephthalaldehyde as raw materials and an aqueous acetic acid solution as a catalyst.

[0011] Preferably, the preparation process of the photocatalyst TAPB-DMTA COF is as follows: 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxyterephthalaldehyde are dissolved in acetonitrile in sequence, with a stirring speed of 200-300 r / min; the ultrasonic power is 100-150 W, the ultrasonic treatment lasts for 60 s with a 60 s interval, and the upper limit of the ultrasonic temperature is 35℃; the solids are ultrasonicated for 30-60 min until they are completely dissolved, and then an aqueous acetic acid solution is added to obtain the final product.

[0012] Preferably, the molar ratio of 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxyterephthalaldehyde is 1:1 to 1.5, the concentration of the acetic acid aqueous solution is 1.0 to 12.0 mol / L, and the volume ratio of the acetic acid aqueous solution to acetonitrile is 0.2 to 0.3.

[0013] Preferably, in step (1), the dosage of the photocatalyst TAPB-DMTA COF is 50–200 mg / L, the stirring speed is 500–700 r / min, and the light intensity of the first illumination module is 0.7–0.8 × 10⁻⁶. 4 The concentration of H2O2 added is 0.1–0.5 mM, and the reflux ratio is 5–10.

[0014] Preferably, the SNAD reactor for bacterial-algae symbiosis is equipped with multiple modular packing components, and a second light module is provided outside the SNAD reactor for bacterial-algae symbiosis.

[0015] Preferably, the illumination intensity of the second illumination module is 5000 to 10000 lux.

[0016] Preferably, the specific process of inoculating short-cut nitrifying sludge and Chlorella in the symbiotic SNAD reactor is as follows: add 1-2 g / L of short-cut nitrifying sludge and 1-2 g / L of anaerobic ammonia oxidation sludge, and control the dissolved oxygen to be below 1 mg / L during the reaction; after the total nitrogen removal rate reaches 85%, inoculate Chlorella at a concentration of 1-2 g / L each time, repeating 5-10 times at intervals of 2 hydraulic retention times; after inoculation with Chlorella, gradually reduce mechanical aeration by 10-20 ml / min at intervals of 2 hydraulic retention times until the oxygen production of Chlorella completely replaces mechanical aeration.

[0017] Preferably, in step (2), the dosage of the photocatalyst is 100-300 mg / L, and the dosage of the multi-walled carbon nanotube is 50-100 mg / L.

[0018] Correspondingly, a purification device based on a dyeing and printing wastewater purification method includes a photocatalytic Fenton reactor and a bacterial-algae symbiotic SNAD reactor connected to it via a pipeline. A first light module is provided outside the photocatalytic Fenton reactor, a baffle is provided inside the photocatalytic Fenton reactor, and a first stirring mechanism is provided outside the photocatalytic Fenton reactor 1.

[0019] The SNAD reactor for bacterial-algae symbiosis is equipped with multiple modular packing components, which are vertically arranged within the reactor. A second light module is installed outside the reactor, and a second stirring mechanism is installed inside the reactor.

[0020] The present invention has the following beneficial effects:

[0021] 1. This invention targets recalcitrant dyes. A photocatalytic Fenton reactor uses porosity-modified (i.e., different porosities) TAPB-DMTA COF as the photocatalyst. The modified COF can complete the reaction of ·OH and O2 in the system. ·- By adjusting and combining various methods, the degradation limitations of benzoquinone, an aromatic intermediate, are effectively overcome, achieving complete dye degradation. For ammonia nitrogen pollutants, the SNAD (Symbiotic Algae-Bacteria Dioxide) reactor eliminates traditional mechanical aeration. Through bio-enhancers, it optimizes the extracellular electron acquisition capabilities of microorganisms, achieving highly efficient and green removal of total nitrogen without the need for organic carbon sources.

[0022] 2. The photocatalytic Fenton reactor disclosed in this invention uses porosity-modified TAPB-DMTA COF as the photocatalyst, adjusting and combining ·OH and O2 in the photocatalytic Fenton reaction. ·- This achieves effective and complete removal of dyes, with a COD removal efficiency of 90-95%. The integrated algae-bacterial SNAD reactor further removes organic matter from the water, achieving a COD removal efficiency of 50-60%. Simultaneously, it removes total nitrogen from the water, with a total nitrogen removal efficiency of 95%.

[0023] 3. The photocatalytic Fenton reactor disclosed in this invention achieves deep and complete removal of recalcitrant substances (such as aromatic dyes) from biologically treated dyeing and printing wastewater. After porosity modification, O2 in the COF-mediated reaction system... ·- Generation. Types of COF free radicals (·OH and O2) after porosity modification. ·- By adjusting and matching the ingredients, the highly toxic and recalcitrant key intermediate benzoquinone can be eliminated, thus achieving effective and complete removal of aromatic dyes.

[0024] 4. Low-porosity TAPB-DMTA COF exhibits excellent photocatalytic activity under low-power light sources. Previous studies have generally used high-power lamp sources to simulate sunlight (6–10 × 10⁻⁶). 4 To obtain a high-energy light source, photocatalysis requires high-energy ultraviolet light or high-pressure mercury lamp irradiation to remove organic matter. Low-porosity TAPB-DMTA COF, under ultra-low power LED lamps (4900 lux), can catalyze a Fenton-like reaction to achieve efficient removal of organic dyes. It boasts advantages such as low cost, environmental friendliness, and ease of industrialization, and holds promise for achieving all-weather catalytic green pollution control driven by ultra-low energy consumption visible light.

[0025] 5. The SNAD (Symbiotic Algae-Algae) wastewater treatment technology boasts advantages of low energy consumption and high efficiency. The oxygen required by ammonia-oxidizing bacteria is entirely provided by the photosynthesis of algae, eliminating the need for additional aeration supply to the entire system. Compared to traditional denitrification processes, the SNAD reactor can reduce aeration energy consumption and carbon source supply by 100%, achieving low-energy, high-efficiency carbon and nitrogen removal.

[0026] 6. Adding TAPB-DMTA COF and multi-walled carbon nanotubes can enhance the denitrification performance of bacteria and algae. Photogenerated electrons from photoexcited TAPB-DMTA COF can improve the light utilization rate of algae, enhance their oxygen production efficiency, and ensure continuous oxygen supply for subsequent denitrification. Multi-walled carbon nanotubes, acting as nanowires, can enhance the transfer of photogenerated electrons and interspecific electrons between bacteria and algae, improve their ability to acquire extracellular electrons, and provide functional microorganisms with more reducing power for energy metabolism, thus contributing to enhanced denitrification performance in SNAD reactors. Attached Figure Description

[0027] Figure 1 A schematic diagram of a device for purifying dyeing and printing wastewater based on TAPB-DMTA COF-type Fenton synergistic bacteria and algae.

[0028] Figure 2 The original TAPB-DMTA COF SEM image;

[0029] Figure 3 SEM image of low-porosity TAPB-DMTA COF;

[0030] Figure 4 Powder X-ray diffraction pattern;

[0031] Figure 5 The nitrogen adsorption isotherm at 77K;

[0032] Figure 6 (A) UV-Vis DRS spectrum and estimated band gap (inset) and (B) XPS spectrum;

[0033] Figure 7 This is a diagram of a free radical trapping experiment;

[0034] Figure 8 Figure 1 shows the degradation experiment of low-porosity TAPB-DMTA COF after 5 cycles.

[0035] Figure 9 The image shows the liquid chromatography-mass spectrum of benzoquinone (m / z 108.3) in the reaction system.

[0036] In the diagram: 1. Photocatalytic Fenton reactor, 2. Algal-bacterial symbiotic SNAD reactor, 3. First inlet pump, 4. Photocatalyst TAPB-DMTA COF, 5. First illumination module, 6. Inlet pump, 7. First stirring mechanism, 8. Backflow pump, 9. Baffle plate, 10. Second inlet pump, 11. Second stirring mechanism, 12. Packing assembly, 13. Second illumination module, 14. Bio-enhancing agent. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0039] This invention discloses a method for purifying dyeing and printing wastewater, characterized by comprising the following steps:

[0040] (1) Dyeing and printing wastewater is fed into a photocatalytic Fenton reactor 1 to remove recalcitrant organic matter from the wastewater. The photocatalytic Fenton reactor 1 is equipped with a porosity-modified photocatalyst TAPB-DMTA COF and H2O2. The added photocatalyst TAPB-DMTA COF possesses dye-specific and highly efficient removal characteristics, effectively overcoming the degradation limitations of the aromatic intermediate benzoquinone and achieving complete dye degradation. The photocatalytic Fenton reactor is equipped with baffles to increase the reaction path, ensuring sufficient contact between the photocatalyst TAPB-DMTA COF and the wastewater, and achieving effective catalyst retention through gravity settling. The baffle angle is 30–45°. A first illumination module 5 is installed outside the photocatalytic Fenton reactor, with a light intensity of 0.7–0.8 × 10⁻⁶. 4 The concentration of lux is increased to improve the light source required for photocatalysis; the dosage of photocatalyst TAPB-DMTA COF is 50-200 mg / L, the stirring speed is 500-700 r / min, the H2O2 concentration is 0.1-0.5 mM, and the reflux ratio is 5-10.

[0041] (2) The wastewater treated in step (1) is fed into the SNAD reactor 2 (i.e., the simultaneous short-cut nitrification, anaerobic ammonia oxidation, and denitrification (SNAD) reactor). The SNAD reactor is inoculated with short-cut nitrifying sludge and Chlorella. The sludge includes Chlorella, ammonia-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria, and denitrifying bacteria. Nitrogen in the dyeing wastewater is removed without aeration or carbon source addition. During operation, the SNAD reactor is supplemented with bio-enhancing agent 14, which adheres to the biofilm. Bio-enhancing agent 14 includes a photocatalyst and multi-walled carbon nanotubes, which enhances the transfer of photogenerated electrons and interspecific electrons by bacteria and algae, improves their ability to acquire extracellular electrons, and enhances the nitrogen removal performance of the SNAD reactor. The photocatalyst is a common TAPB-DMTA COF. The algae-bacterial symbiotic SNAD reactor is equipped with multiple modular packing components 12, and a second light module 13 is installed outside the reactor. The light intensity of the second light module 13 is 5000–10000 lux. The dosage of the photocatalyst is 100–300 mg / L, and the dosage of the multi-walled carbon nanotubes is 50–100 mg / L.

[0042] Furthermore, the photocatalyst TAPB-DMTA COF is prepared using 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxy-terephthalaldehyde as raw materials and an aqueous acetic acid solution as a catalyst.

[0043] Specifically, the preparation process of the photocatalyst TAPB-DMTA COF is as follows: 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxyterephthalaldehyde are dissolved in acetonitrile in sequence, with a stirring speed of 200-300 r / min; the ultrasonic power is 100-150 W, ultrasonication is performed for 60 s with a 60 s interval, and the upper limit of the ultrasonic temperature is 35℃; ultrasonication is performed for 30-60 min until the solid is completely dissolved, and then an aqueous acetic acid solution is added to obtain the final product.

[0044] The molar ratio of 1,3,5-tris(4-aminophenyl)benzene to 2,5-dimethoxytetraphenylbenzene is 1:1 to 1.5, the concentration of the acetic acid aqueous solution is 1.0 to 12.0 mol / L, and the volume ratio of the acetic acid aqueous solution to acetonitrile is 0.2 to 0.3.

[0045] Furthermore, photocatalytic TAPB-DMTA COF materials with different porosities can be prepared by changing the concentration of the acetic acid aqueous solution. As a preferred option, the porosity-modified photocatalyst TAPB-DMTA COF exhibits the best Fenton dye removal performance when the acetic acid aqueous solution is 12M.

[0046] Furthermore, the specific process of inoculating short-cut nitrifying sludge and Chlorella in the aforementioned symbiotic SNAD reactor is as follows: 1-2 g / L of short-cut nitrifying sludge and 1-2 g / L of anaerobic ammonia oxidation sludge are added, and the dissolved oxygen is controlled below 1 mg / L during the reaction; after the total nitrogen removal rate reaches 85%, Chlorella is inoculated, with each inoculation concentration of 1-2 g / L, and inoculation is repeated every 2 hydraulic retention times (HRT), for 5-10 times; after inoculation with Chlorella, mechanical aeration is gradually reduced, decreasing by 10-20 ml / min every 2 hydraulic retention times (HRT), until the oxygen production of Chlorella completely replaces mechanical aeration.

[0047] This invention discloses a purification device based on a method for purifying dyeing and printing wastewater, comprising a photocatalytic Fenton reactor 1 and a bacterial-algae symbiotic SNAD reactor 2 connected to it via a pipeline. A second inlet pump 10 is installed on the pipeline. A first illumination module 5 is installed outside the photocatalytic Fenton reactor 1 to increase the light source required for photocatalysis. A baffle plate 4 with an angle of 30-45° is installed inside the photocatalytic Fenton reactor 1 to ensure sufficient contact between the photocatalyst TAPB-DMTA COF and the wastewater, and to achieve effective catalyst retention through gravity settling. A first stirring mechanism 7, such as magnetic stirring, is installed outside the photocatalytic Fenton reactor 1. The photocatalytic Fenton reactor 1 is fed with water by a first inlet pump 3.

[0048] Furthermore, a feed pump 6 is installed outside the photocatalytic Fenton reactor 1 to complete the addition of H2O2. The photocatalytic Fenton reactor 1 is also equipped with a reflux pump 8, the inlet and outlet of which are connected to the photocatalytic Fenton reactor 1 and located near its top and bottom, respectively. Combined with the first stirring mechanism 7, this ensures sufficient contact between the photocatalyst TAPB-DMTACOF and the wastewater, and baffles are installed to increase the reaction range.

[0049] Furthermore, the algae-bacterial symbiotic SNAD reactor 2 is equipped with multiple modular packing components 12, which are vertically arranged within the reactor. A second lighting module 13 is installed outside the reactor, and a second stirring mechanism 11 is installed inside to ensure sufficient contact between the wastewater and the packing components (such as sponge packing). It should be noted that the packing material in the packing components can be sponge. As one embodiment, the sponge packing is a cube with a side length of 2-3 cm, and the volumetric filling ratio is 30-50%. The sponge packing is vertically fixed at equal intervals within the algae-bacterial symbiotic SNAD reactor 2.

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] Example 1

[0052] Synthesis of photocatalyst TAPB-DMTA COF:

[0053] 1,3,5-Tris(4-aminophenyl)benzene (TAPB, 353 mg, 1 mmol) and 2,5-dimethoxyterephthalaldehyde (DMTA, 293 mg, 1.5 mmol) were added to a flask containing 240 mL of acetonitrile and sonicated at room temperature for 60 min to completely dissolve the monomers. Then, 48 mL of 6 M acetic acid solution was added to obtain a mixture. After standing at 25 °C for 12 h, the mixture was centrifuged to collect the resulting yellow precipitate, which was washed three times with ACN and ultrapure water, respectively. The precipitate was then dried under vacuum at 80 °C for 24 h to obtain the original TAPB-DMTA COF. The product prepared above was characterized by SEM. Figure 2 It is known that the prepared material has a rough surface and an urchin-like morphology, forming a hierarchical porous structure that can provide abundant channels for organic pollutants.

[0054] Example 2

[0055] Synthesis of low-porosity photocatalyst TAPB-DMTA COF:

[0056] 1,3,5-Tris(4-aminophenyl)benzene (TAPB, 353 mg, 1 mmol) and 2,5-dimethoxyterephthalaldehyde (DMTA, 293 mg, 1.5 mmol) were added to a flask containing 240 mL of acetonitrile and sonicated at room temperature for 60 min to completely dissolve the monomers. Then, 48 mL of 12 M acetic acid solution was added to obtain a mixture. After standing at 25 °C for 12 h, the yellow precipitate was collected by centrifugation and washed three times with ACN and ultrapure water, respectively. The precipitate was then dried under vacuum at 80 °C for 24 h to obtain a low-porosity TAPB-DMTA COF. The product prepared above was characterized by SEM. Figure 3 It can be seen that the prepared material has a similar morphology to the original TAPB-DMTA COF, but is more spherical.

[0057] The physicochemical properties of the pristine TAPB-DMTA COF prepared in Example 1 and the low-porosity TAPB-DMTA COF prepared in Example 2 were characterized. Powder X-ray diffraction (PXRD) results showed that TAPB-DMTA COF exhibited a characteristic peak at 2θ (2.6), and the low-porosity TAPB-DMTA COF possessed higher crystallinity. Figure 4 Nitrogen adsorption analysis was performed at 77 K to determine the porosity of 6M COF and low-porosity TAPB-DMTA COF. Figure 5According to nonlocal density functional theory (NLDFT), the pore sizes of the original TAPB-DMTA COF and the low-porosity TAPB-DMTA COF were calculated to be 3.1 nm and 2.7 nm, respectively.

[0058] The optical and electrical properties of the pristine TAPB-DMTA COF prepared in Example 1 and the low-porosity TAPB-DMTA COF prepared in Example 2 were tested, such as... Figure 6 As shown. Due to the conjugated structure of TAPB-DMTA COF, both the original TAPB-DMTA COF and the low-porosity TAPB-DMTA COF have a wide visible light absorption range (around 680 nm), corresponding to narrow band gaps of 1.51 eV and 1.47 eV, respectively. Figure 6 A) A decrease in the band gap is beneficial for increasing the absorption range. The valence band electron positions (VB) of pristine TAPB-DMTA COF and low-porosity TAPB-DMTA COF, determined by valence band X-ray photoelectron spectroscopy (VBXPS), are 1.37 eV and 1.09 eV, respectively. Figure 6 B); their conduction bands (CB) are -0.14 eV and -0.38 eV, respectively. Compared to the original TAPB-DMTACOF, the CB positions of the low-porosity TAPB-DMTA COF are more frequent than those of O2 reduced to O2. ·- The electrode potential is much more negative than -0.33 eV, indicating that photoexcited electrons are captured by dissolved O2 and thus generate O2. ·- It directly oxidizes organic molecules in aqueous solution. The very short lifespan of ·OH in the aqueous phase (~10 μs) limits its transfer from the formation site to the target organic compound, while O2... ·- These substances can remain in the system for hundreds of seconds, meaning that porosity modification can increase the contact between ROS and pollutants in the reaction system, thereby enhancing the degradation efficiency of organic matter. Furthermore, research shows that O2... ·- Free radicals are the main active substances in the photodegradation of aromatic dyes in the liquid phase. Meanwhile, the reduction of the CB position thermodynamically favors the single-electron reduction of O2. Conversely, the CB level of the original TAPB-DMTACOF is only -0.14 eV, which cannot excite O2. ·- and 1 O2 formation. Therefore, the variation of ROS in the low-porosity TAPB-DMTA COF photocatalytic mediated Fenton-like reaction system is beneficial to improving dye removal efficiency.

[0059] Example 3

[0060] Catalytic degradation experiments were conducted on the original TAPB-DMTA COF prepared in Example 1 and the low-porosity TAPB-DMTA COF prepared in Example 2.

[0061] 1. The photocatalyst TAPB-DMTA COF is used to degrade malachite green in a liquid environment.

[0062] A 20 mg / L malachite solution was prepared and placed in a photocatalytic Fenton reactor. 200 mg / L LAPB-DMTACOF was added, and pre-adsorption was performed for 60 min in the dark. A low-power LED lamp was used as the light source, and H₂O₂ was added. The ·OH and HO₂· / O₂ in the reaction system were removed using tert-butanol (TBA) and hydroquinone (pBQ) scavengers, respectively. ·- Free radicals were captured in a trapping experiment, and the degradation effect was as follows: Figure 7 As shown, in the original TAPB-DMTA COF-mediated oxidation system, ·OH plays a dominant role in the degradation of malachite green, while in the low-porosity TAPB-DMTA COF reaction system, HO2· / O2 ·- Its contribution to the removal of organic matter is higher than that of ·OH. Therefore, the TAPB-DMTA COF-mediated reaction system with improved porosity tends to generate HO2 with a longer lifetime. · / O2 ·- , and HO2 · / O2 ·- It can be further directed to 1 O2 conversion. (Compared to HO2) · / O2 ·- and ·OH, 1 O2 can also play a role in the chain initiation and chain propagation reactions of aromatic organic dyes. Therefore, porosity modification enables the conversion of ·OH in the reaction system into long-lived HO2. · / O2 ·- and 1 The conversion of O2 is beneficial to achieving efficient removal of malachite green by the low-porosity TAPB-DMTA COF photocatalytic Fenton-like system.

[0063] 2. Cyclic degradation effect of photocatalyst TAPB-DMTA COF

[0064] The photocatalyst TAPB-DMTA COF is used to degrade malachite green in a liquid environment.

[0065] A 20 mg / L malachite solution was prepared and placed in a photocatalytic Fenton reactor. 200 mg / L low-porosity TAPB-DMTA COF was added. Pre-adsorption was performed for 60 min in the dark. A low-power LED lamp was used as the light source, and H2O2 was added. The degradation effect after 5 cycles was as follows: Figure 8As shown in the figure, after five consecutive cycles of testing, the low-porosity TAPB-DMTA COF-mediated photocatalytic Fenton-like system maintained a removal rate of approximately 95% for malachite green, indicating that the low-porosity TAPB-DMTA COF possesses stability and applicability for repeated use.

[0066] 3. After the photocatalyst TAPB-DMTA COF degraded malachite green in a liquid environment, the degradation intermediates of malachite green in the Fenton-like system were analyzed by liquid chromatography-mass spectrometry (LC-MS). LC-MS results showed that no significant enrichment of benzoquinone intermediates was found in the 12M COF photocatalytically mediated Fenton-like system. Figure 9 Therefore, in the 12M COF photocatalytically mediated Fenton-like system, ·OH and O2 ·- The coexistence of these substances enables the effective and complete removal of aromatic dyes, ensuring the safety of wastewater quality during reuse or discharge.

[0067] Example 4

[0068] The algae-bacterial symbiotic SNAD reactor is equipped with numerous modular packing components. A second lighting module with a light intensity of 5000–10000 lux is located on the outside of the reactor. The sponge packing is a cube with a side length of 2–3 cm and a volume filling ratio of 30–50%. The sponge packing is vertically fixed at equal intervals within the algae-bacterial symbiotic SNAD reactor.

[0069] The SNAD reactor with bacterial-algae symbiosis was inoculated with 1-2 g / L of short-cut nitrification sludge and 1-2 g / L of anaerobic ammonia oxidation sludge, with dissolved oxygen controlled below 1 mg / L during the process. After the total nitrogen removal rate reached 85%, Chlorella was inoculated at a concentration of 1-2 g / L each time, with inoculation occurring every two hydraulic retention times (HRT), repeated 5-10 times. After inoculation with Chlorella, mechanical aeration was gradually reduced by 10-20 ml / min every two HRTs until oxygen production from Chlorella completely replaced mechanical aeration.

[0070] During operation, a bio-enhancing agent is added to the biofilm of the algae-bacterial symbiotic SNAD reactor. This bio-enhancing agent consists of a photocatalyst (TAPB-DMTA COF) and carbon nanowires (multi-walled carbon nanotubes). The TAPB-DMTA COF dosage is 200 mg / L, and the multi-walled carbon nanotube dosage is 50 mg / L. The denitrification performance of the algae-bacterial symbiotic SNAD reactor during mechanical aeration and during Chlorella oxygen production is shown in Tables 1 and 2 below.

[0071] Table 1. Denitrification performance of the SNAD reactor with algal-bacterial symbiosis during mechanical aeration operation.

[0072]

[0073]

[0074] Table 2. Denitrification performance of the Chlorella oxygen production stage in the SNAD reactor with bacterial-algal symbiosis.

[0075]

[0076] Example 5

[0077] This embodiment provides a method for treating dyeing and printing wastewater from a certain enterprise by combining a photocatalytic Fenton reactor with a symbiotic algae-bacteria SNAD reactor. The treatment parameters of the symbiotic algae-bacteria SNAD reactor are the same as in Example 4, and the treatment parameters of the photocatalytic Fenton reactor are the same as those disclosed in the purification method of this invention. The photocatalyst used is the low-porosity TAPB-DMTA COF prepared in Example 2. The dosage of low-porosity TAPB-DMTA COF in the photocatalytic Fenton reactor is 150 mg / L, the hydrogen peroxide concentration is 0.5 mM, and the reflux ratio is 5. The influent and effluent water quality of the dyeing and printing wastewater from the enterprise is shown in Table 3. The wastewater volume is 3500 m³. 3 / d.

[0078] Table 3. Water quality of influent and effluent from a certain enterprise's dyeing and printing wastewater.

[0079]

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for purifying printing and dyeing wastewater, characterized by: The method comprises the following steps: (1) the printing and dyeing wastewater is introduced into a photocatalytic Fenton reactor (1), a porosity modified photocatalyst TAPB-DMTA COF and H2O2 are added in the photocatalytic Fenton reactor, a baffle (9) is arranged in the photocatalytic Fenton reactor, the angle of the baffle (9) is 30-45°, a first light module (5) is arranged outside the photocatalytic Fenton reactor; the adding amount of the photocatalyst TAPB-DMTA COF is 50-200 mg / L, the stirring speed is 500-700 r / min, the light intensity of the first light module (5) is 0.7-0.8 x 10 4 lux, the adding concentration of H2O2 is 0.1-0.5 mM, and the reflux ratio is 5-10; (2) the wastewater treated in step (1) is introduced into a bacteria-algae symbiotic SNAD reactor (2) inoculated with short-cut nitrification sludge and chlorella, and a photocatalyst and multi-walled carbon nanotubes are added into the bacteria-algae symbiotic SNAD reactor (2); The specific process of inoculating short-cut nitrification sludge and chlorella in the bacteria-algae symbiotic SNAD reactor (2) is as follows: 1-2 g / L of short-cut nitrification sludge and 1-2 g / L of anaerobic ammonia oxidation sludge are added, and the dissolved oxygen is controlled to be lower than 1 mg / L during the reaction; after the total nitrogen removal rate reaches 85%, chlorella is inoculated at a concentration of 1-2 g / L, and the inoculation is repeated 5-10 times at an interval of 2 hydraulic retention times; after the chlorella is inoculated, the mechanical aeration is gradually reduced at an interval of 2 hydraulic retention times by 10-20 ml / min until the oxygen production of the chlorella completely replaces the mechanical aeration.

2. A method for purifying printing and dyeing wastewater according to claim 1, characterized in that: The photocatalyst TAPB-DMTA COF is prepared from 1, 3, 5-tris (4-aminophenyl) benzene and 2, 5-dimethoxy benzene formaldehyde, and acetic acid aqueous solution is used as a catalyst.

3. A method of purifying printing and dyeing wastewater according to claim 2, characterized in that: The preparation process of the photocatalyst TAPB-DMTA COF is as follows: 1, 3, 5-tris (4-aminophenyl) benzene and 2, 5-dimethoxy benzene formaldehyde are sequentially dissolved in acetonitrile, the stirring speed is 200-300 r / min, the ultrasonic power is 100-150 W, the ultrasonic time is 60 s, the interval is 60 s, and the upper limit of the ultrasonic temperature is 35℃; 1, 3, 5-tris (4-aminophenyl) benzene and 2, 5-dimethoxy benzene formaldehyde are respectively ultrasonically treated for 30-60 min until the solids are completely dissolved, and then acetic acid aqueous solution is added.

4. A method of purifying printing and dyeing wastewater according to claim 3, characterized in that: The molar ratio of 1, 3, 5-tris (4-aminophenyl) benzene to 2, 5-dimethoxy benzene formaldehyde is 1:1-1.5, the concentration of the acetic acid aqueous solution is 1.0-12.0 mol / L, and the volume ratio of the acetic acid aqueous solution to acetonitrile is 0.2-0.

3.

5. The method for purifying printing and dyeing wastewater according to claim 1, characterized in that: The bacteria-algae symbiotic SNAD reactor (2) is provided with a plurality of modular filler assemblies (12), and the bacteria-algae symbiotic SNAD reactor is provided with a second light module (13) outside.

6. A method of purifying printing and dyeing wastewater according to claim 5, characterized in that: The light intensity of the second light module (13) is 5000-10000 lux.

7. The method for purifying printing and dyeing wastewater according to claim 1, characterized in that: In step (2), the addition amount of the photocatalyst is 100-300 mg / L, and the addition amount of the multi-walled carbon nanotubes is 50-100 mg / L.

8. A purification apparatus based on the purification method of printing and dyeing wastewater according to any one of claims 1 to 7, characterized by: The method comprises a photocatalytic Fenton reactor (1) and a bacteria-algae symbiotic SNAD reactor (2) in communication with the photocatalytic Fenton reactor (1) through a pipeline, a light module is arranged outside the photocatalytic Fenton reactor (1) and the bacteria-algae symbiotic SNAD reactor (2) respectively, a baffle (9) is arranged in the photocatalytic Fenton reactor (1), and a first stirring mechanism (7) is arranged outside the photocatalytic Fenton reactor (1); The bacteria-algae symbiotic SNAD reactor (2) is provided with a plurality of modular filler assemblies (12), and the filler assemblies (12) are vertically arranged in the bacteria-algae symbiotic SNAD reactor (2); the bacteria-algae symbiotic SNAD reactor (2) is provided with a second stirring mechanism (11).

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