Device and method for treating printing and dyeing wastewater through photoelectrocatalysis

Abstract

The invention provides a device and a method for treating printing and dyeing wastewater through photoelectrocatalysis, and relates to the field of tail water treatment of printing and dyeing wastewater. The device for treating printing and dyeing wastewater through photoelectrocatalysis comprises a reaction tank and further comprises two groups of electro-catalysis components which are mounted in the reaction tank in a staggered manner; comprising an aeration assembly which is mounted at the bottom of a reaction tank; comprising a catalyst feeding assembly mounted in the upper end of a reaction tank, an organic glass cover is fixedly mounted at the top of the reaction tank, and a light source is fixedly mounted at the top of the reaction tank in the organic glass cover. According to the device and the method for treating the printing and dyeing wastewater through photoelectrocatalysis, by arranging the electrocatalysis assembly and the catalyst feeding assembly, TiO2 doping modification and activated carbon loading are combined, and a TiO2 photocatalysis technology and a GAC ternary electrode electrocatalysis technology are combined, so that the degradation effect of the method on PFCs in tail water of the printing and dyeing wastewater is verified; the combination efficiency of Fe-TiO2 / GAC and PFCs can be improved, and the effect of efficiently degrading PFCs is achieved.

Description

Technical Field

[0001] The present invention relates to the field of printing and dyeing wastewater tail treatment, and specifically to a device and method for photocatalytic and electrocatalytic treatment of printing and dyeing wastewater. Background Art

[0002] Perfluorinated compounds (PFCs) are a class of synthetic organic compounds in which all hydrogen atoms connected to carbon atoms are replaced by fluorine atoms. Because of their hydrophobic, oil-repellent, high-temperature resistant, and significant water surface tension reduction properties, they are widely used in fields such as pesticides, pharmaceuticals, petrochemicals, food, wires, textiles, clothing, household and automotive products. As PFCs in products are continuously released into the environment, they have currently caused serious pollution to the atmosphere, soil, seawater, surface water, groundwater, sediments, and food. As a new type of persistent organic pollutant, PFCs have strong chemical and physical stability, do not undergo photolysis, hydrolysis, or biodegradation under natural conditions, and have environmental persistence and biological magnification effects.

[0003] Although PFCs were previously considered to be biologically inactive, existing research has shown that PFCs persist in the human body for a long time and are difficult to excrete through the excretory system like other substances. Moreover, different types of PFCs have shown a synergistic effect in organisms, enhancing their respective toxicities. 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 at home and abroad include three categories: microbial methods, adsorption methods, and oxidation methods. Among them, microbial methods are not yet mature and have poor degradation effects; the adsorption method is a method with relatively low cost and high efficiency, but its treatment of PFCs only transfers them from one medium to another, and does not fundamentally break the C—F bond for degradation. The future research focus should be on how to recycle the adsorption materials and how to safely release the adsorbed PFCs to avoid secondary pollution; although the oxidation method has a relatively high removal rate of PFCs, the removed PFOA and PFOS only have their carbon chain lengths shortened, and do not all become small molecule substances such as F−, CO2, and H2O, that is, the defluorination rate is not high. How to improve the technology to increase the defluorination rate is a future research direction. Therefore, developing new PFC treatment technologies to treat the end tail water of textile dyeing and finishing industrial wastewater is of great significance for alleviating the environmental pollution caused by PFCs.

[0005] The photo-electro synergistic technology is a composite technology that combines photochemical oxidation technology and electrochemistry to play a synergistic role. This technology can not only combine the advantages of the two technologies but also make up for the disadvantage of the low yield of oxidizing active substances of a single technology to a certain extent, and is a very promising research method.

[0006] However, the degradation effect of TiO2 doped with different elements in treating printing and dyeing wastewater under the synergistic effect of photoelectricity showed that the degradation efficiency of single doped modified TiO2 was less than 70%, while the degradation efficiency of metal-non-metal and metal-metal oxide doped modified TiO2 was as high as over 90%. In addition, how to add catalysts and then cooperate with photoelectric aeration is a solution that needs to be explored. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a device and method for photoelectrocatalytic treatment of printing and dyeing wastewater, which solves the problems raised in the above background technology.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: a device for photoelectrocatalytic treatment of printing and dyeing wastewater, comprising a reaction tank, and also comprising two groups of electrocatalytic components, the two groups of electrocatalytic components are staggeredly installed inside the reaction tank; comprising an aeration component, the aeration component is installed at the bottom of the reaction tank; comprising a catalyst input component, which is installed inside the upper end of the reaction tank, the top of the reaction tank is fixedly installed with an organic glass cover, and the top of the reaction tank is fixedly installed with a light source in the organic glass cover; A water inlet and a water outlet are installed on one side of the bottom of the reaction tank, respectively, to realize the sewage circulation inside the reaction tank; The electrocatalytic assembly includes a plate assembly and a gas pipe A, which is fixed to the outside of the reaction tank. There are several plate assemblies and gas pipes A, both of which are arranged inside the reaction tank. The plate assemblies are fixed to the gas pipe A, and the sides of the plate assemblies contained in two adjacent electrocatalytic assemblies that are close to each other are the anode and cathode respectively.

[0009] Preferably, the electrode plate assembly includes a hollow shell and a connecting tube A. The interior of the hollow shell is a hollow structure, and a plurality of pores A are provided at the bottom and are evenly distributed. The connecting tube A is provided with a plurality of pores, 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 delivery pipe A. The connecting tube A connects the gas delivery pipe A and the hollow shell. The two side surfaces of the hollow shell are respectively fixedly mounted with a cathode plate and an anode plate, and the side wall of the reaction pool is respectively mounted with an anode plate and a cathode plate at positions opposite to the cathode plate and the anode plate.

[0010] Preferably, the anode plate is a titanium plate, and the cathode plate is graphite.

[0011] Preferably, the catalyst delivery assembly includes a catalyst pipeline and a delivery pipe. There are multiple delivery pipes, which are respectively located between two adjacent plate assemblies. The upper ends of the delivery pipes are fixed to and connected with the catalyst pipelines. The outer circle of the lower end of the delivery pipe is provided with multiple fan-shaped protrusions. The outer wall of the delivery pipe is provided with multiple nozzles between two adjacent fan-shaped protrusions, and the nozzles are connected with the inside of the delivery pipe.

[0012] Preferably, the aeration assembly includes a convex tube, a connecting pipe B, and an air delivery pipe B. There are multiple convex tubes and connecting pipes B, which are respectively located between two adjacent electrode plate assemblies. One end of the connecting pipe B penetrates the reaction tank and is communicated with the inside of the convex tube, and the other ends of the connecting pipe B are fixedly connected and communicated with the air delivery pipe B. The air delivery pipe B is fixed on the side of the reaction tank; The upper end of the convex tube is an arc surface, and there are two groups of air holes B on the upper end of the convex tube. The air holes B are all communicated with the inside of the convex tube.

[0013] Preferably, the air holes B are inclined, and the included angle with the vertical direction is 30 degrees. The two groups of air holes B are symmetrically arranged with respect to the longitudinal center line of the convex tube, and each group of air holes B is a plurality of equally spaced distributions.

[0014] Preferably, one end of the air delivery pipe A is sealed, and the other ends are fixedly connected and communicated with the air delivery pipe B.

[0015] Preferably, the hollow shell is suspended inside the reaction tank, and the cathode plate and the anode plate are both fixed to the side of the hollow shell by bolts.

[0016] A method for photocatalytic treatment of printing and dyeing wastewater includes the following steps: S1: Turn on the light source and circulate the water inlet end and the water outlet end; S2: Prepare and put in the catalyst, and construct a Fe-doped and GAC-loaded synergistically modified TiO2 composite material system through the sol-gel method combined with the impregnation and calcination process; Preparation of Fe-TiO2 precursor: Using the sol-gel method, tetrabutyl titanate (TBT) as the titanium source and ferric nitrate as the Fe source, set the Fe doping concentration gradient (0.1, 0.5, 1.0, 2.0, 5.0 wt%), and obtain a homogeneous Fe-TiO2 gel by controlling the hydrolysis pH (3.0 - 4.5) and the sol aging time (24 h); GAC loading process: Immerse the pretreated GAC (particle size 1 - 2 mm) in the Fe-TiO2 sol, and realize the loading amount regulation (5 - 30 wt%) through ultrasonic assistance (40kHz) and the calcination process (N2 protection, 400 - 600 °C); Fe-TiO2 / GAC is put into the reaction tank through the catalyst pipeline and the feeding pipe. The fan-shaped protrusions disperse the Fe-TiO2 / GAC catalyst into the printing and dyeing wastewater and cooperate with the work of the cathode plate and the anode plate; S3: Electrify the cathode plate and the anode plate, and turn on the air delivery pipe B and the aerator. When the cathode plate and the anode plate are electrolyzing, aeration work is carried out at the bottom of the hollow shell; S4: During electrolysis, air is also introduced into the bottom convex tube, so that aeration will occur between two adjacent cathode plates and anode plates; S5: Catalyst replacement. The Fe-TiO2 / GAC with its catalytic performance reduced to 40% of the initial value is taken out and replaced. The sol-gel method is used again, and the process and conditions are exactly the same as those when preparing Fe-TiO2 / GAC.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The device and method for photocatalytic treatment of printing and dyeing wastewater, by setting up an electrocatalytic component and a catalyst input component, after power-on, the upflow fluidized bed reactor is used to treat the tail water of printing and dyeing wastewater. Combining the voltage and current density between the cathode plate and the anode plate, the electrolytic treatment of printing and dyeing wastewater can be realized. And because the hollow shell is connected to the gas path, bubbles will be ejected at the bottom during electrolysis, realizing aeration at the bottom of the electrode plate. Therefore, a longitudinal turbulence can be carried out on the sewage near the electrode plate. Fe-TiO2 / GAC is put into the reaction pool through the catalyst pipeline and the feeding pipe, and the fan-shaped protrusions disperse the Fe-TiO2 / GAC catalyst into the printing and dyeing wastewater, improving the efficiency of the Fe-TiO2 / GAC photocatalytic and electrocatalytic synergistic system for degrading PFCs. This application combines the doping modification of TiO2 and the loading of activated carbon, and combines the TiO2 photocatalytic technology and the ternary electrode electrocatalytic technology, verifying the degradation effect of this method on PFCs in the tail water of printing and dyeing wastewater.

[0018] The device and method for photocatalytic treatment of printing and dyeing wastewater, by setting up an aeration component, the convex pipe at the bottom also introduces air, so aeration will occur between two adjacent cathode plates and anode plates. During electrolysis, the aeration between the electrode plates and the aeration at the bottom of the electrode plates achieve a perfect mixing flow of the electrolytic sewage and the catalyst, which can increase the binding efficiency of Fe-TiO2 / GAC and PFCs, and achieve the effect of high-efficiency degradation of PFCs.

[0019] The device and method for photocatalytic treatment of printing and dyeing wastewater, by setting up an organic glass cover and a light source, the organic glass cover can utilize sunlight for photocatalysis during the day, and when there is no sunlight, the light source can assist in realizing photocatalysis. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a structural sectional view of the present invention; Figure 3 is the present invention Figure 2 The enlarged structural view of part A in; Figure 4 is a partial structural split view of the present invention; Figure 5 is the structural diagram of the catalyst input component of the present invention; Figure 6 is the present inventionFigure 5 Enlarged view of the structure at position B in the [specific context not provided]; Figure 7 Structural diagram of the electrocatalytic component and the reaction tank of the present invention; Figure 8 Distribution diagram of two groups of electrocatalytic components of the present invention; Figure 9 Structural diagram of the electrode plate assembly of the present invention; Figure 10 Structural diagram of the aeration component of the present invention; Figure 11 For the present invention Figure 10 Enlarged view of the structure at position C in the [specific context not provided].

[0021] In the figure: 1, reaction tank; 2, electrocatalytic component; 201, electrode plate assembly; 2011, hollow shell; 2012, connecting pipe A; 2013, air hole A; 2014, cathode plate; 2015, anode plate; 202, gas delivery pipe A; 3, aeration component; 301, convex pipe; 302, connecting pipe B; 303, gas delivery pipe B; 304, air hole B; 4, catalyst input component; 401, catalyst pipeline; 402, dosing pipe; 403, fan-shaped protrusion; 404, nozzle; 5, plexiglass cover; 6, light source; 7, water inlet end; 8, water outlet end. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0023] It should be noted that all the directional indications in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If this specific posture changes, the directional indications will also change accordingly.

[0024] In the present application, unless otherwise clearly defined and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0025] In addition, in this application, descriptions such as "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0026] As Figure 1-10 shown, a device for photocatalytic treatment of printing and dyeing wastewater includes a reaction tank 1, and also includes two groups of electrocatalytic components 2, which are installed in the reaction tank 1 in a staggered manner; an aeration component 3 is included, and the aeration component 3 is installed at the bottom of the reaction tank 1; a catalyst input component 4 is included, which is installed inside the upper end of the reaction tank 1. An organic glass cover 5 is fixedly installed at the top of the reaction tank 1, and a light source 6 is fixedly installed inside the organic glass cover 5 at the top of the reaction tank 1.

[0027] One side of the bottom of the reaction tank 1 is respectively provided with a water inlet end 7 and a water outlet end 8 for realizing the internal sewage circulation of the reaction tank 1.

[0028] The electrocatalytic component 2 includes a plate component 201 and an air delivery pipe A202. The air delivery pipe A202 is fixed outside the reaction tank 1. There are several plate components 201 and air delivery pipes A202, all of which are arranged inside the reaction tank 1. The plate component 201 is fixed to the air delivery pipe A202. The sides of the plate components 201 included in two adjacent electrocatalytic components 2 that are close to each other are respectively the anode and the cathode.

[0029] The wastewater enters the reaction tank 1 from the water inlet end 7 through a peristaltic pump. The water outlet end 8 is used for draining water. The water inlet end 7 and the water outlet end 8 cooperate to determine the hydraulic retention time. A light source 6, a xenon lamp or an LED lamp, 500W, is arranged above the reaction device. The light source 6 is fixed on the organic glass cover. The cover body is square and can completely cover the reaction device and can be conveniently removed. The light source 6 is about 10 cm away from the reaction device. When the reaction is taking place inside the reaction tank 1, the light source 6 is in an on state.

[0030] The air delivery pipe A202 is connected to an aerator, and the plate component 201 is connected to a storage battery.

[0031] The electrode plate assembly 201 includes a hollow shell 2011 and a connecting pipe A2012. The interior of the hollow shell 2011 is a hollow structure, and a number of equally spaced air holes A2013 are provided at the bottom. There are multiple connecting pipes A2012, one end of which is fixed to the side surface of the hollow shell 2011, and the other end penetrates through the reaction tank 1 and then is fixed to the air delivery pipe A202. The connecting pipe A2012 connects the air delivery pipe A202 and the hollow shell 2011.

[0032] Cathode plates 2014 and anode plates 2015 are respectively and fixedly installed on both side surfaces of the hollow shell 2011. At positions on the side wall of the reaction tank 1 opposite to the cathode plates 2014 and anode plates 2015, anode plates 2015 and cathode plates 2014 are respectively installed.

[0033] The anode plates 2015 and the cathode plates 2014 are respectively connected to the anode and cathode of a DC power supply. There is one DC power supply on each side, and each DC power supply controls two compartments. The air delivery pipe A202 can press the air from the aerator into the hollow shell 2011 and discharge it from the bottom of the air holes A2013, realizing aeration at the bottom of the cathode plates 2014 or the anode plates 2015.

[0034] The anode plates 2015 are titanium plates, and the cathode plates 2014 can be made of graphite or stainless steel plates.

[0035] The catalyst input assembly 4 includes a catalyst pipeline 401 and a dosing pipe 402. There are multiple dosing pipes 402, which are respectively located between two adjacent electrode plate assemblies 201. The upper ends of the dosing pipes 402 are all fixed and communicated with the catalyst pipeline 401. Multiple sector-shaped protrusions 403 are provided on the outer periphery of the lower end of the dosing pipe 402. Multiple spray nozzles 404 are provided on the outer wall of the dosing pipe 402 between two adjacent sector-shaped protrusions 403. The spray nozzles 404 are communicated with the inside of the dosing pipe 402.

[0036] The catalyst is sent into the catalyst pipeline 401 through a pump and a flow meter, and then discharged from the dosing pipe 402 during the electrolysis reaction. Due to the setting of the sector-shaped protrusions 403, it can be defined that the catalyst diffuses outwards, can diffuse to a wider position in the wastewater, and can also approach two adjacent electrode plates.

[0037] The aeration assembly 3 includes convex pipes 301, connecting pipes B302 and air delivery pipes B303. There are multiple convex pipes 301 and connecting pipes B302, and they are respectively located between two adjacent electrode plate assemblies 201. One end of the connecting pipe B302 penetrates through the reaction tank 1 and then is communicated with the inside of the convex pipe 301. The other ends of the connecting pipes B302 are all fixed and communicated with the air delivery pipe B303. The air delivery pipe B303 is fixed on the side surface of the reaction tank 1; The upper end of the convex pipe 301 is an arc surface, and two groups of air holes B304 are provided at the upper end of the convex pipe 301. The air holes B304 are all communicated with the inside of the convex pipe 301.

[0038] The air delivery pipe B303 is connected to the aerator, which can supply air into the convex pipe 301, and the gas can flow from the air holes B304 into the wastewater during aeration.

[0039] The air holes B304 are inclined, and the angle with the vertical direction is thirty degrees. Two groups of air holes B304 are symmetrically arranged with respect to the longitudinal center line of the convex pipe 301, and each group of air holes B304 is a plurality of equally spaced distributions.

[0040] The air holes B304 can make the aeration act on the cathode plate 2014 or the anode plate 2015, and cooperate with the catalyst delivery pipe 402 and the aeration at the bottom of the plate, so that the degradation of PFCs is more efficient.

[0041] One end of the air delivery pipe A202 is sealed, and the other ends are all fixed and communicated with the air delivery pipe B303.

[0042] The hollow shell 2011 is suspended inside the reaction tank 1, and the cathode plate 2014 and the anode plate 2015 are both fixed to the side surface of the hollow shell 2011 by bolts.

[0043] Both the anode plate 2015 and the cathode plate 2014 can be removed from the hollow shell 2011 for replacement, and the circuits of the plates can be concentrated inside the hollow shell 2011, and then connected to an external storage battery through the connecting pipe A2012.

[0044] A method for photocatalytic treatment of printing and dyeing wastewater includes the following steps: S1: Turn on the light source 6, and circulate the water inlet end 7 and the water outlet end 8; S2: Prepare and put in the catalyst. Using tetrabutyl titanate as the titanium source, ethanol as the dispersant, and acetic acid as the hydrolysis inhibitor, Fe-TiO2 / GAC is prepared by the sol-gel method. Fe-TiO2 / GAC is put into the reaction tank 1 through the catalyst pipeline 401 and the delivery pipe 402. The fan-shaped protrusion 403 disperses the Fe-TiO2 / GAC catalyst into the printing and dyeing wastewater, and cooperates with the work of the cathode plate 2014 and the anode plate 2015; S3: Electrify the cathode plate 2014 and the anode plate 2015, and turn on the air delivery pipe B303 and the aerator. When the cathode plate 2014 and the anode plate 2015 are electrolyzing, aeration work is carried out at the bottom of the hollow shell 2011; S4: During electrolysis, air is also introduced into the bottom convex pipe 301, so that aeration occurs between two adjacent cathode plates 2014 and anode plates 2015; S5: Catalyst replacement. Take out and replace the Fe-TiO2 / GAC whose catalytic performance has decreased to 40% of the initial value, and use the sol-gel method again. The process and conditions are exactly the same as those when preparing Fe-TiO2 / GAC.

[0045] In use, first prepare the catalyst. By combining the sol-gel method with the impregnation and calcination process, a TiO2 composite material system with synergistic modification of Fe doping and GAC loading is constructed.

[0046] ① Preparation of Fe-TiO2 precursor: Using the sol-gel method, tetrabutyl titanate (TBT) as the titanium source and ferric nitrate as the Fe source, set the Fe doping concentration gradient (0.1, 0.5, 1.0, 2.0, 5.0 wt%), and obtain a homogeneous Fe-TiO2 gel by controlling the hydrolysis pH (3.0 - 4.5) and the sol aging time (24 h).

[0047] ② GAC loading process: Immerse the pretreated GAC (particle size 1 - 2 mm) in the Fe-TiO2 sol, and realize the regulation of the loading amount (5 - 30 wt%) through ultrasonic assistance (40 kHz) and the calcination process (N2 protection, 400 - 600 °C).

[0048] Investigate the effects of the addition amounts of the dispersant and the hydrolysis inhibitor on the gel time of TiO2; study the effects of the types and doping amounts of metal ions on the photocatalytic and photoelectrocatalytic degradation efficiency of PFCs. Perform SEM and XRD characterizations on the Fe-TiO2 / GAC with the highest degradation efficiency, and analyze its surface morphology and the crystal form of the modified TiO2.

[0049] Connect the peristaltic pump to the water inlet end 7 to realize the wastewater circulation inside the reaction tank 1. Electrify the plate assembly 201, and at the same time input the catalyst into the wastewater from the catalyst pipeline 401 and the dosing pipe 402. The fan-shaped protrusion 403 can make the Fe-TiO2 / GAC catalyst better disperse into the printing and dyeing wastewater.

[0050] After introducing the gas, aeration will be carried out at the bottom of the plate, and there will also be aeration between the cathode plate 2014 and the anode plate 2015. The aeration of both combined with the catalyst dosing pipe 402 can achieve better mixed flow, increase the binding efficiency of Fe-TiO2 / GAC and PFCs, and achieve the effect of high-efficiency degradation of PFCs.

[0051] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0052] In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0053] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for photoelectrocatalytic treatment of printing and dyeing wastewater, comprising a reaction tank (1), characterized in that: It also includes two groups of electrocatalytic components (2), which are staggeredly installed inside the reaction tank (1); an aeration component (3), which is installed at the bottom of the reaction tank (1); and a catalyst injection component (4), which is installed inside the upper end of the reaction tank (1); a plexiglass cover (5) is fixedly installed on the top of the reaction tank (1); and a light source (6) is fixedly installed on the top of the reaction tank (1) inside the plexiglass cover (5); A water inlet (7) and a water outlet (8) are respectively installed on one side of the bottom of the reaction tank (1) for realizing sewage circulation inside the reaction tank (1); The electrocatalytic assembly (2) comprises a plate assembly (201) and a gas pipe A (202), wherein the gas pipe A (202) is fixed to the outside of the reaction tank (1), and a plurality of plate assemblies (201) and gas pipe A (202) are provided, both of which are arranged inside the reaction tank (1). The plate assembly (201) and the gas pipe A (202) are fixed, and the sides of the plate assemblies (201) included in two adjacent electrocatalytic assemblies (2) that are close to each other are the anode and cathode, respectively.

2. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 1, characterized in that: The electrode assembly (201) comprises a hollow shell (2011) and a connecting tube A (2012); the interior of the hollow shell (2011) is a hollow structure, and a plurality of pores A (2013) are provided at the bottom thereof and are distributed at equal distances; a plurality of connecting tubes A (2012) are provided, one end of which is fixed to the side of the hollow shell (2011), and the other end of which penetrates the reaction pool (1) and is then fixed to the gas transmission pipe A (202); the connecting tube A (2012) connects the gas transmission pipe A (202) and the hollow shell (2011); A cathode plate (2014) and an anode plate (2015) are fixedly mounted on the two side surfaces of the hollow shell (2011), and an anode plate (2015) and a cathode plate (2014) are mounted on the side walls of the reaction pool (1) at positions opposite to the cathode plate (2014) and the anode plate (2015).

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

4. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 1, characterized in that: The catalyst delivery assembly (4) comprises a catalyst pipeline (401) and a delivery pipe (402). A plurality of delivery pipes (402) are provided and are respectively located between two adjacent electrode plate assemblies (201). The upper ends of the delivery pipes (402) are fixed to and communicate with the catalyst pipeline (401). The outer ring of the lower end of the delivery pipe (402) is provided with a plurality of fan-shaped protrusions (403). The outer wall of the delivery pipe (402) is provided with a plurality of nozzles (404) between two adjacent fan-shaped protrusions (403). The nozzles (404) are communicated with the inside of the delivery pipe (402).

5. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 1, characterized in that: The aeration assembly (3) comprises a convex pipe (301), a connecting pipe B (302) and a gas supply pipe B (303). The convex pipe (301) and the connecting pipe B (302) are provided in plurality and are respectively located between two adjacent electrode assemblies (201). One end of the connecting pipe B (302) passes through the reaction tank (1) and is connected to the interior of the convex pipe (301). The other end of the connecting pipe B (302) is fixed to and connected to the gas supply pipe B (303). The gas supply pipe B (303) is fixed to the side of the reaction tank (1). The upper end of the convex tube (301) is an arc surface. Two groups of air holes B (304) are provided at the upper end of the convex tube (301). The air holes B (304) are both connected to the interior of the convex tube (301).

6. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 5, characterized in that: The air holes B (304) are arranged obliquely, with an angle of thirty degrees with the vertical direction. The two groups of air holes B (304) are arranged symmetrically about the longitudinal center line of the convex tube (301), and each group of air holes B (304) has a plurality of air holes distributed at equal distances.

7. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 5, characterized in that: One end of the gas delivery pipe A (202) is sealed, and the other end is fixed to and connected with the gas delivery pipe B (303).

8. The device for photoelectrocatalytic treatment of printing and dyeing wastewater according to claim 1, characterized in that: The hollow shell (211) 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) by bolts.

9. A method for photoelectrocatalytic treatment of printing and dyeing wastewater, applied to the device for photoelectrocatalytic treatment of printing and dyeing wastewater according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Turn on the light source (6) and circulate the water inlet (7) and the water outlet (8); S2: Prepare and add catalysts, and construct a TiO2 composite material system with Fe doping and GAC loading synergistic modification through sol-gel method combined with impregnation and calcination process; Preparation of Fe-TiO2 precursor: The sol-gel method was used, with tetrabutyl titanate (TBT) as the titanium source and ferric nitrate as the Fe source. The Fe doping concentration gradient (0.1, 0.5, 1.0, 2.0, 5.0 wt%) was set, and the homogeneous Fe-TiO2 gel was obtained by controlling the hydrolysis pH (3.0-4.5) and the sol aging time (24 h). GAC loading process: pretreated GAC (particle size 1-2 mm) was impregnated into Fe-TiO2 sol, and the loading amount was controlled (5-30 wt%) by ultrasound assistance (40 kHz) and calcination process (N2 protection, 400-600℃); Fe-TiO2 / GAC is introduced into the reaction tank (1) through the catalyst pipeline (401) and the introduction pipe (402), and the fan-shaped protrusion (403) disperses the Fe-TiO2 / GAC catalyst into the printing and dyeing wastewater and cooperates with the cathode plate (2014) and the anode plate (2015); S3: The cathode plate (2014) and the anode plate (2015) are energized, and the gas transmission pipe B (303) and the aerator are connected. When the cathode plate (2014) and the anode plate (2015) are electrolyzed, the bottom of the hollow shell (2011) is aerated; S4: During electrolysis, air is also introduced through the convex tube (301) at the bottom, so that aeration occurs between the two adjacent cathode plates (2014) and the anode plate (2015); S5: Catalyst replacement. The Fe-TiO2 / GAC whose catalytic performance has dropped to 40% of the initial value is taken out and replaced, and the sol-gel method is used again. The process and conditions are exactly the same as those for the preparation of Fe-TiO2 / GAC.

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