A device and method for photoelectrocatalytic treatment of printing and dyeing wastewater

Abstract

The application provides a device and method for photoelectrocatalytic treatment of printing and dyeing wastewater, and relates to the field of tail water treatment of printing and dyeing wastewater. The device for photoelectrocatalytic treatment of printing and dyeing wastewater comprises a reaction tank, two groups of electrocatalytic components, an aeration component, a catalyst feeding component, a plexiglass cover and a light source. The two groups of electrocatalytic components are installed in the interior of the reaction tank in a staggered manner. The aeration component is installed at the bottom of the reaction tank. The catalyst feeding component is installed at the upper end of the interior of the reaction tank. The plexiglass cover is fixedly installed at the top of the reaction tank. The light source is fixedly installed in the plexiglass cover. The device and method for photoelectrocatalytic treatment of printing and dyeing wastewater combine TiO2 doping modification and activated carbon loading, combine TiO2 photocatalysis technology and GAC ternary electrode electrocatalysis technology, and verify the degradation effect of the method on PFCs in tail water of printing and dyeing wastewater. The aeration component can increase the combination efficiency of Fe-TiO2 / GAC and PFCs, and realize the effect of high-efficiency degradation of PFCs.

Description

Technical Field

[0001] This invention relates to the field of dyeing and printing wastewater treatment, specifically to an apparatus and method for photoelectrocatalytic treatment of dyeing and printing wastewater. Background Technology

[0002] Perfluorinated compounds (PFCs) are a class of synthetic organic compounds in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. Due to their hydrophobic, oleophobic, high-temperature resistant, and significantly reduced water surface tension properties, they are widely used in pesticides, pharmaceuticals, petrochemicals, food, electrical wires, textiles, clothing, household and automotive products. However, with the continuous release of PFCs from these products into the environment, they have caused serious pollution to the atmosphere, soil, seawater, surface water, groundwater, sediments, and food. As a novel persistent organic pollutant, PFCs possess strong chemical and physical stability, and do not undergo photolysis, hydrolysis, or biodegradation under natural conditions, exhibiting environmental persistence and biomagnification effects.

[0003] Although PFCs were previously thought to be biologically inactive, current research shows that PFCs persist in the human body for a long time and are difficult to excrete through the excretory system like other substances. In fact, different types of PFCs have shown synergistic effects in organisms, enhancing their respective toxicity. Therefore, how to control the content of PFCs in the environment has become an urgent problem to be solved.

[0004] Currently, methods for removing PFCs both domestically and internationally fall into three categories: microbial methods, adsorption methods, and oxidation methods. Microbial methods are still immature and have poor degradation effects. Adsorption is a low-cost and relatively efficient method, but it only transfers PFCs from one medium to another, failing to fundamentally break the C-F bonds and degrade them. Future research should focus on how to reuse adsorbent materials and how to safely release adsorbed PFCs to avoid secondary pollution. Although oxidation methods have a high removal rate for PFCs, the removed PFOA and PFOS only have shorter carbon chains and are not completely converted into small molecules such as F-, CO2, and H2O; that is, the defluorination rate is not high. Improving the technology to increase the defluorination rate is a future research direction. Therefore, developing new PFC treatment technologies to treat end-of-pipe wastewater from the textile dyeing and finishing industry is of great significance for mitigating environmental pollution caused by PFCs.

[0005] Photoelectrochemical synergistic technology is a composite technology that combines photochemical oxidation technology and electrochemistry to achieve synergistic effects. This technology can combine the advantages of both technologies and, to some extent, compensate for the low yield of oxidized active substances by single technologies, making it a promising research method.

[0006] However, the degradation effect of TiO2 modified with different elements in the treatment of dyeing and printing wastewater under photoelectric synergy is shown. The results show that the degradation efficiency of TiO2 modified with a single doping is less than 70%, while the degradation efficiency of TiO2 modified with metal-nonmetal and metal-metal oxide doping is as high as 90% or more. Moreover, how to add catalysts and combine them with photoelectric aeration is a solution that needs to be explored. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an apparatus and method for photoelectrocatalytic treatment of dyeing and printing wastewater, thus solving the problems mentioned in the background section.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: a device for photoelectrocatalytic treatment of dyeing and printing wastewater, comprising a reaction tank, and two sets of electrocatalytic components, which are alternately installed inside the reaction tank; an aeration component installed at the bottom of the reaction tank; and a catalyst feeding component installed inside the upper part of the reaction tank. An plexiglass cover is fixedly installed on the top of the reaction tank, and a light source is fixedly installed inside the plexiglass cover on the top of the reaction tank.

[0009] The bottom side of the reaction tank is equipped with an inlet and an outlet for wastewater circulation inside the reaction tank.

[0010] The electrocatalytic assembly includes an electrode assembly and a gas supply pipe A. The gas supply pipe A is fixed outside the reaction tank. Several electrode assemblies and gas supply pipes A are provided and are located inside the reaction tank. The electrode assembly and the gas supply pipe A are fixed. The sides of the electrode assemblies of two adjacent electrocatalytic assemblies that are close to each other are the anode and cathode, respectively.

[0011] Preferably, the electrode assembly includes a hollow shell and a connecting pipe A. The hollow shell has a hollow structure inside and a number of equally spaced air holes A at the bottom. The connecting pipe A has multiple connections, one end of which is fixed to the side of the hollow shell, and the other end passes through the reaction tank and is fixed to the gas supply pipe A. The connecting pipe A connects the gas supply pipe A and the hollow shell.

[0012] A cathode plate and an anode plate are fixedly installed on both sides of the hollow shell, and an anode plate and a cathode plate are installed on the side wall of the reaction tank at positions opposite to the cathode plate and the anode plate, respectively.

[0013] Preferably, the anode plate is a titanium plate and the cathode plate is graphite.

[0014] Preferably, the catalyst feeding assembly includes a catalyst pipeline and a feeding pipe. Multiple feeding pipes are provided, each located between two adjacent electrode assemblies. The upper end of each feeding pipe is fixed and connected to the catalyst pipeline. The lower outer ring of the feeding pipe is provided with multiple fan-shaped protrusions. Multiple nozzles are provided on the outer wall of the feeding pipe between two adjacent fan-shaped protrusions. The nozzles are connected to the inside of the feeding pipe.

[0015] Preferably, the aeration assembly includes a convex tube, a connecting pipe B, and an air supply pipe B. Multiple convex tubes and connecting pipes B are provided and are respectively located between two adjacent electrode assemblies. One end of the connecting pipe B passes through the reaction tank and communicates with the inside of the convex tube. The other end of the connecting pipe B is fixed and communicated with the air supply pipe B. The air supply pipe B is fixed on the side of the reaction tank.

[0016] The upper end of the convex tube is an arc surface, and the upper end of the convex tube is provided with two sets of air holes B, both of which are connected to the interior of the convex tube.

[0017] Preferably, the air holes B are inclined, with an angle of 30 degrees to the vertical direction, and the two sets of air holes B are symmetrically arranged around the longitudinal center line of the convex tube, with each set of air holes B consisting of multiple air holes distributed at equal intervals.

[0018] Preferably, one end of the gas supply pipe A is sealed, and the other end is fixed to and connected to the gas supply pipe B.

[0019] Preferably, the hollow shell is suspended inside the reaction tank, and both the cathode plate and the anode plate are fixed to the side of the hollow shell with bolts.

[0020] A method for photoelectrocatalytic treatment of dyeing and printing wastewater includes the following steps:

[0021] S1: Turn on the light source and circulate the water inlet and outlet.

[0022] S2: Prepare and apply catalysts, and construct a TiO2 composite material system with synergistic modification by Fe doping and GAC loading through a sol-gel method combined with impregnation and calcination process;

[0023] Preparation of Fe-TiO2 precursor: The sol-gel method was adopted, with tetrabutyl titanate (TBT) as the titanium source and ferric nitrate as the Fe source. Fe doping concentration gradients were set (0.1, 0.5, 1.0, 2.0, 5.0 wt%). By controlling the hydrolysis pH (3.0-4.5) and sol aging time (24 h), homogeneous Fe-TiO2 gel was obtained.

[0024] GAC loading process: Pretreated GAC (particle size 1-2 mm) is impregnated in Fe-TiO2 sol, and the loading amount is controlled (5-30 wt%) by ultrasonic assistance (40 kHz) and calcination process (N2 protection, 400-600℃).

[0025] Fe-TiO2 / GAC is introduced into the reaction tank through catalyst pipelines and dosing pipes. The fan-shaped protrusions disperse the Fe-TiO2 / GAC catalyst into the dyeing and printing wastewater, and work in conjunction with the cathode plate and anode plate.

[0026] S3: Energize the cathode plate and anode plate and connect the gas supply pipe B to the aerator. When the cathode plate and anode plate are electrolyzing, the bottom of the hollow shell is aerated.

[0027] S4: During electrolysis, air is also introduced through the bottom convex tube, which aerates the space between the two adjacent cathode plates and anode plates.

[0028] S5: Catalyst replacement. The Fe-TiO2 / GAC whose catalytic performance has decreased to 40% of its initial value is removed and replaced. The sol-gel method is used again, and the process and conditions are completely consistent with those used in the preparation of Fe-TiO2 / GAC.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This device and method for photoelectrocatalytic treatment of dyeing and printing wastewater utilizes an electrocatalytic component and a catalyst feeding component. After energization, an upflow fluidized bed reactor is used to treat the wastewater effluent. By combining the voltage and current density between the cathode and anode plates, electrolytic treatment of the wastewater can be achieved. Furthermore, because the hollow shell is connected to a gas path, bubbles are ejected from its bottom during electrolysis, achieving aeration at the bottom of the electrodes. This creates a longitudinal turbulence in the wastewater near the electrodes. Fe-TiO2 / GAC is fed into the reaction tank through catalyst pipelines and feeding pipes. The fan-shaped protrusions disperse the Fe-TiO2 / GAC catalyst into the wastewater, improving the efficiency of the Fe-TiO2 / GAC photoelectrocatalytic synergistic system in degrading PFCs. This application combines TiO2 doping modification with activated carbon loading, integrating TiO2 photocatalysis technology with ternary electrode electrocatalysis technology, demonstrating the effectiveness of this method in degrading PFCs in dyeing and printing wastewater effluent.

[0031] The device and method for photoelectrocatalytic treatment of dyeing and printing wastewater, by setting up an aeration component, also introduces air through the bottom convex tube, so that the two adjacent cathode plates and anode plates will be aerated. During electrolysis, the aeration between the plates and the aeration at the bottom of the plates achieve a perfect mixing of the electrolyzed wastewater and the catalyst, which can increase the binding efficiency of Fe-TiO2 / GAC with PFCs and achieve the effect of high-efficiency degradation of PFCs.

[0032] The device and method for photoelectrocatalytic treatment of dyeing and printing wastewater utilizes an plexiglass cover and a light source. The plexiglass cover can achieve photocatalysis using sunlight during the day, while the light source can assist in photocatalysis when there is no sunlight. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention;

[0034] Figure 2This is a cross-sectional view of the structure of the present invention;

[0035] Figure 3 For the present invention Figure 2 Enlarged view of the structure at point A in the middle;

[0036] Figure 4 This is a partial structural breakdown diagram of the present invention;

[0037] Figure 5 This is a structural diagram of the catalyst feeding component of the present invention;

[0038] Figure 6 For the present invention Figure 5 Enlarged view of the structure at point B;

[0039] Figure 7 This is a structural diagram of the electrocatalytic component and reaction cell of the present invention;

[0040] Figure 8 This is a distribution diagram of the two sets of electrocatalytic components of the present invention;

[0041] Figure 9 This is a structural diagram of the electrode assembly of the present invention;

[0042] Figure 10 This is a structural diagram of the aeration component of the present invention;

[0043] Figure 11 For the present invention Figure 10 Enlarged view of the structure at point C.

[0044] In the diagram: 1. Reaction tank; 2. Electrocatalytic assembly; 201. Electrode assembly; 2011. Hollow shell; 2012. Connecting pipe A; 2013. Vent A; 2014. Cathode plate; 2015. Anode plate; 202. Gas supply pipe A; 3. Aeration assembly; 301. Protruding pipe; 302. Connecting pipe B; 303. Gas supply pipe B; 304. Vent B; 4. Catalyst feeding assembly; 401. Catalyst pipeline; 402. Feeding pipe; 403. Fan-shaped protrusion; 404. Nozzle; 5. Acrylic glass cover; 6. Light source; 7. Water inlet; 8. Water outlet. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0046] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0047] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0049] like Figure 1-10 As shown, an apparatus for photoelectrocatalytic treatment of dyeing and printing wastewater includes a reaction tank 1, two sets of electrocatalytic components 2, which are alternately installed inside the reaction tank 1; an aeration component 3 installed at the bottom of the reaction tank 1; a catalyst feeding component 4 installed inside the upper part of the reaction tank 1; an plexiglass cover 5 fixedly installed on the top of the reaction tank 1; and a light source 6 fixedly installed inside the plexiglass cover 5 on the top of the reaction tank 1.

[0050] The bottom side of the reaction tank 1 is equipped with an inlet 7 and an outlet 8, which are used to realize the circulation of sewage inside the reaction tank 1.

[0051] The electrocatalytic assembly 2 includes an electrode assembly 201 and a gas supply pipe A202. The gas supply pipe A202 is fixed outside the reaction tank 1. There are several electrode assemblies 201 and gas supply pipes A202, all located inside the reaction tank 1. The electrode assembly 201 and the gas supply pipe A202 are fixed. The sides of the electrode assemblies 201 of two adjacent electrocatalytic assemblies 2 that are close to each other are the anode and cathode, respectively.

[0052] Wastewater enters the reaction tank 1 from the inlet 7 via a peristaltic pump, and the outlet 8 is used for drainage. The inlet 7 and outlet 8 work together to determine the hydraulic residence time. A light source 6, a xenon lamp or LED lamp, 500W, is installed above the reaction device. The light source 6 is fixed on an plexiglass cover. The cover is square and can completely cover the reaction device and can be easily removed. The light source 6 is about 10cm away from the reaction device. When the reaction is inside the reaction tank 1, the light source 6 is in the on state.

[0053] The gas supply pipe A202 is connected to the aerator, and the electrode assembly 201 is connected to the battery.

[0054] The electrode assembly 201 includes a hollow shell 2011 and a connecting pipe A2012. The hollow shell 2011 has a hollow structure inside and a number of equally spaced air holes A2013 at the bottom. The connecting pipe A2012 has multiple connections, one end of which is fixed to the side of the hollow shell 2011, and the other end passes through the reaction tank 1 and is fixed to the gas supply pipe A202. The connecting pipe A2012 connects the gas supply pipe A202 and the hollow shell 2011.

[0055] A cathode plate 2014 and an anode plate 2015 are fixedly installed on both sides of the hollow shell 2011, and an anode plate 2015 and a cathode plate 2014 are installed on the side wall of the reaction tank 1 at positions opposite to the cathode plate 2014 and the anode plate 2015, respectively.

[0056] The anode plate 2015 and the cathode plate 2014 are connected to the anode and cathode of the DC power supply, respectively. There is a DC power supply on the left and right sides, and each DC power supply controls two compartments. The air supply pipe A202 can compress the air from the aerator into the hollow shell 2011 and discharge it from the bottom of the air hole A2013, thereby realizing aeration of the bottom of the cathode plate 2014 or the anode plate 2015.

[0057] The anode plate 2015 is made of titanium, while the cathode plate 2014 can be made of graphite or stainless steel.

[0058] The catalyst feeding assembly 4 includes a catalyst pipeline 401 and a feeding pipe 402. Multiple feeding pipes 402 are provided, which are respectively located between two adjacent electrode assemblies 201. The upper end of each feeding pipe 402 is fixed and connected to the catalyst pipeline 401. Multiple fan-shaped protrusions 403 are provided on the outer ring of the lower end of the feeding pipe 402. Multiple nozzles 404 are provided on the outer wall of the feeding pipe 402 between two adjacent fan-shaped protrusions 403. The nozzles 404 are connected to the inside of the feeding pipe 402.

[0059] The catalyst is fed into the catalyst pipeline 401 by a pump and a flow meter, and then discharged from the feed pipe 402 during the electrolysis reaction. Due to the fan-shaped protrusion 403, the catalyst can be defined to diffuse outwards, allowing it to spread more widely in the wastewater and also to approach two adjacent plates.

[0060] The aeration assembly 3 includes a convex tube 301, a connecting tube B302, and an air supply tube B303. Multiple convex tubes 301 and multiple connecting tubes B302 are provided and are respectively located between two adjacent electrode assemblies 201. One end of the connecting tube B302 passes through the reaction tank 1 and communicates with the inside of the convex tube 301. The other end of the connecting tube B302 is fixed and communicated with the air supply tube B303. The air supply tube B303 is fixed on the side of the reaction tank 1.

[0061] The upper end of the convex tube 301 is an arc surface. The upper end of the convex tube 301 is provided with two sets of air holes B304, and the air holes B304 are connected to the interior of the convex tube 301.

[0062] The air supply pipe B303 is connected to the aerator and can supply air into the convex pipe 301. During aeration, the gas can flow from the air hole B304 into the wastewater.

[0063] The vents B304 are inclined at an angle of 30 degrees to the vertical direction. The two sets of vents B304 are symmetrically arranged around the longitudinal centerline of the convex tube 301, and each set of vents B304 consists of multiple vents distributed at equal intervals.

[0064] The pores B304 allow aeration to be applied to the cathode plate 2014 or anode plate 2015, and in conjunction with the catalyst delivery pipe 402 and the aeration at the bottom of the plates, the degradation of PFCs can be made more efficient.

[0065] One end of the gas supply pipe A202 is sealed, and the other end is fixed and connected to the gas supply pipe B303.

[0066] The hollow shell 2011 is suspended inside the reaction tank 1, and the cathode plate 2014 and the anode plate 2015 are fixed to the side of the hollow shell 2011 with bolts.

[0067] Both the anode plate 2015 and the cathode plate 2014 can be removed and replaced from the hollow shell 2011, and the wiring of the plates can be concentrated inside the hollow shell 2011 and then connected to an external battery through the connecting pipe A2012.

[0068] A method for photoelectrocatalytic treatment of dyeing and printing wastewater includes the following steps:

[0069] S1: Turn on the light source 6 and circulate the water inlet 7 and outlet 8;

[0070] S2: Prepare and add catalyst. Use tetrabutyl titanate as titanium source, ethanol as dispersant and acetic acid as hydrolysis inhibitor. Prepare Fe-TiO2 / GAC by sol-gel method. Fe-TiO2 / GAC is added to reaction tank 1 through catalyst pipeline 401 and addition pipe 402. Fan-shaped protrusion 403 disperses Fe-TiO2 / GAC catalyst into dyeing and printing wastewater and works in conjunction with cathode plate 2014 and anode plate 2015.

[0071] S3: Energize the cathode plate 2014 and anode plate 2015, and connect the gas supply pipe B303 to the aerator. When the cathode plate 2014 and anode plate 2015 are electrolyzing, the bottom of the hollow shell 2011 is aerated.

[0072] S4: During electrolysis, air is also introduced into the bottom convex tube 301, so that air will be aerated between the two adjacent cathode plates 2014 and anode plates 2015.

[0073] S5: Catalyst replacement. The Fe-TiO2 / GAC whose catalytic performance has decreased to 40% of its initial value is removed and replaced. The sol-gel method is used again, and the process and conditions are completely consistent with those used in the preparation of Fe-TiO2 / GAC.

[0074] In use, the catalyst is first prepared, and a TiO2 composite material system with Fe doping and GAC loading is constructed by combining the sol-gel method with impregnation and calcination process.

[0075] ①Preparation of Fe-TiO2 precursor: The sol-gel method was adopted, with tetrabutyl titanate (TBT) as the titanium source and ferric nitrate as the Fe source. Fe doping concentration gradients were set (0.1, 0.5, 1.0, 2.0, 5.0 wt%). By controlling the hydrolysis pH (3.0-4.5) and sol aging time (24 h), homogeneous Fe-TiO2 gel was obtained.

[0076] ②GAC loading process: Pretreated GAC (particle size 1-2 mm) is impregnated in Fe-TiO2 sol, and the loading amount is controlled (5-30 wt%) by ultrasonic assistance (40 kHz) and calcination process (N2 protection, 400-600℃).

[0077] The effects of dispersant and hydrolysis inhibitor additions on TiO2 gelation time were investigated; the effects of metal ion type and doping amount on photocatalytic and photoelectrocatalytic degradation efficiency of PFCs were studied. The Fe-TiO2 / GAC with the highest degradation efficiency was characterized by SEM and XRD to analyze its surface morphology and the crystal form of the modified TiO2.

[0078] The inlet 7 is connected to a peristaltic pump to realize the wastewater circulation inside the reaction tank 1. The electrode assembly 201 is energized, and the catalyst is put into the wastewater from the catalyst pipeline 401 and the dosing pipe 402. The fan-shaped protrusion 403 can better disperse the Fe-TiO2 / GAC catalyst into the dyeing and printing wastewater.

[0079] After the gas is introduced, aeration will be carried out at the bottom of the electrode plate, and aeration will also be carried out between the cathode plate 2014 and the anode plate 2015. The aeration of both and the catalyst delivery pipe 402 can achieve better mixing, which can increase the binding efficiency of Fe-TiO2 / GAC with PFCs and achieve the effect of high-efficiency degradation of PFCs.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0081] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for photoelectrocatalytic treatment of dyeing and printing wastewater, comprising a reaction tank (1), characterized in that: It also includes two sets of electrocatalytic components (2), which are installed alternately inside the reaction tank (1); it includes an aeration component (3), which is installed at the bottom of the reaction tank (1); it includes a catalyst feeding component (4), which is installed inside the upper end of the reaction tank (1); an organic glass cover (5) is fixedly installed on the top of the reaction tank (1); and a light source (6) is fixedly installed inside the organic glass cover (5) on the top of the reaction tank (1). The bottom side of the reaction tank (1) is equipped with an inlet (7) and an outlet (8) to realize the internal sewage circulation of the reaction tank (1); The electrocatalytic assembly (2) includes an electrode assembly (201) and a gas supply pipe A (202). The gas supply pipe A (202) is fixed outside the reaction tank (1). There are several electrode assemblies (201) and gas supply pipes A (202) inside the reaction tank (1). The electrode assembly (201) and the gas supply pipe A (202) are fixed. The sides of the electrode assemblies (201) of two adjacent electrocatalytic assemblies (2) that are close to each other are the anode and cathode, respectively. The electrode assembly (201) includes a hollow shell (2011) and a connecting pipe A (2012). The hollow shell (2011) has a hollow structure inside and several equidistantly distributed air holes A (2013) at the bottom. The connecting pipe A (2012) has multiple holes, one end of which is fixed to the side of the hollow shell (2011), and the other end passes through the reaction tank (1) and is fixed to the gas supply pipe A (202). The connecting pipe A (2012) connects the gas supply pipe A (202) and the hollow shell (2011). A cathode plate (2014) and an anode plate (2015) are fixedly installed on both sides of the hollow shell (2011). An anode plate (2015) and a cathode plate (2014) are installed on the side wall of the reaction tank (1) at positions opposite to the cathode plate (2014) and the anode plate (2015). The catalyst feeding assembly (4) includes a catalyst pipeline (401) and a feeding pipe (402). Multiple feeding pipes (402) are provided, which are located between two adjacent electrode assemblies (201). The upper end of each feeding pipe (402) is fixed and connected to the catalyst pipeline (401). Multiple fan-shaped protrusions (403) are provided on the outer ring of the lower end of the feeding pipe (402). Multiple nozzles (404) are provided on the outer wall of the feeding pipe (402) between two adjacent fan-shaped protrusions (403). The nozzles (404) are connected to the inside of the feeding pipe (402). The aeration assembly (3) includes a convex tube (301), a connecting tube B (302) and an air supply tube B (303). Multiple convex tubes (301) and connecting tubes B (302) are provided and are respectively located between two adjacent electrode assemblies (201). One end of the connecting tube B (302) passes through the reaction tank (1) and communicates with the inside of the convex tube (301). The other end of the connecting tube B (302) is fixed and communicated with the air supply tube B (303). The air supply tube B (303) is fixed on the side of the reaction tank (1). The upper end of the convex tube (301) is an arc surface, and the upper end of the convex tube (301) is provided with two sets of air holes B (304), and the air holes B (304) are all connected to the interior of the convex tube (301). The air holes B (304) are inclined and the angle with the vertical direction is thirty degrees. The two sets of air holes B (304) are symmetrically arranged with the longitudinal center line of the convex tube (301). Each set of air holes B (304) consists of multiple air holes distributed at equal distances.

2. The apparatus for photoelectrocatalytic treatment of dyeing and printing wastewater according to claim 1, characterized in that: The anode plate (2015) is a titanium plate, and the cathode plate (2014) is graphite.

3. The apparatus for photoelectrocatalytic treatment of dyeing and printing wastewater according to claim 2, characterized in that: One end of the gas supply pipe A (202) is sealed, and the other end is fixed and connected to the gas supply pipe B (303).

4. The apparatus for photoelectrocatalytic treatment of dyeing and printing wastewater according to claim 3, characterized in that: The hollow shell (2011) is suspended inside the reaction tank (1), and the cathode plate (2014) and the anode plate (2015) are fixed to the side of the hollow shell (2011) with bolts.

5. A method for photoelectrocatalytic treatment of dyeing and printing wastewater, applied to the photoelectrocatalytic treatment apparatus for dyeing and printing wastewater as described in claim 4, characterized in that: Includes the following steps: S1: Turn on the light source (6) and circulate the water inlet (7) and outlet (8). S2: Prepare and add catalyst. Use tetrabutyl titanate as titanium source, ethanol as dispersant and acetic acid as hydrolysis inhibitor. Prepare Fe-TiO2 / GAC by sol-gel method. Fe-TiO2 / GAC is added to reaction tank (1) through catalyst pipeline (401) and addition pipe (402). Fan-shaped protrusion (403) disperses Fe-TiO2 / GAC catalyst into dyeing wastewater and works in conjunction with cathode plate (2014) and anode plate (2015). S3: Energize the cathode plate (2014) and anode plate (2015) and connect the gas pipe B (303) to the aerator. When the cathode plate (2014) and anode plate (2015) are electrolyzing, the bottom of the hollow shell (2011) is aerated. S4: During electrolysis, air is also introduced into the bottom convex tube (301), so that air will be aerated between the two adjacent cathode plates (2014) and anode plates (2015); S5: Catalyst replacement. The Fe-TiO2 / GAC whose catalytic performance has decreased to 40% of its initial value is removed and replaced. The sol-gel method is used again, and the process and conditions are completely consistent with those used in the preparation of Fe-TiO2 / GAC.

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