A high-concentration organic wastewater degradation device and degradation method

Abstract

The present invention discloses a high-concentration organic wastewater degradation device and a degradation method, belonging to the technical field of organic wastewater treatment. The high-concentration organic wastewater degradation device includes a photocatalytic oxidation device and an electrochemical catalytic oxidation device connected to the photocatalytic oxidation device; the photocatalytic oxidation device further includes a liquid-to-gas feed component, a gas-to-gas feed component, and a gas-to-gas transfer component arranged between the liquid-to-gas feed component and the gas-to-gas feed component. The present invention is applied to the degradation of high-concentration organic wastewater, and solves the problem that the existing treatment system that couples photocatalytic oxidation and electrocatalytic oxidation cannot ensure sufficient and uniform contact and mixing between gas and liquid, between catalyst and gas and liquid, and between catalyst and light source due to the structural design, resulting in low degradation efficiency and poor degradation effect. The present invention has the characteristics of being able to achieve instantaneous uniform mixing of materials and efficient heat transfer, increase the contact area between gas and liquid, high degradation efficiency, and good degradation effect.

Description

Technical Field

[0001] The invention belongs to the technical field of organic wastewater treatment, and in particular relates to a high-concentration organic wastewater degradation device and a degradation method. Background Art

[0002] High-concentration organic wastewater has the following main characteristics: 1) High organic matter concentration, COD is generally above 2000 mg / L, and some are even as high as tens of thousands or even hundreds of thousands of mg / L. Relatively speaking, BOD is low, and the ratio of BOD to COD of many wastewaters is less than 0.3; 2) Complex composition, containing toxic substances. The organic matter in the wastewater is mostly aromatic compounds and heterocyclic compounds, and also contains sulfides, nitrides, heavy metals and toxic organic matter; 3) High chroma and odor. Some wastewater emits a pungent odor, which has adverse effects on the surrounding environment; 4) It has strong acidity and alkalinity. Due to the above characteristics of high-concentration organic wastewater, high-concentration organic wastewater has the following hazards: 1) Due to biodegradation, high-concentration organic wastewater will cause the receiving water body to be hypoxic or even anaerobic, and most aquatic organisms will die, thereby producing stench and deteriorating water quality and the environment; 2) Sensory pollution, high-concentration organic wastewater not only makes the water body lose its use value, but also seriously affects the normal life of people near the water body; 3) Toxicity hazards, ultra-high-concentration organic wastewater contains a large amount of toxic organic matter, which will continue to accumulate and store in natural environments such as water bodies and soil, and finally enter the human body, endangering human health. With the continuous improvement of environmental protection requirements, the treatment of high-concentration organic wastewater has become a major problem in the current production and development of enterprises.

[0003] Chinese patent CN217677149U discloses a photoelectric synergistic catalytic oxidation treatment system for high-concentration organic wastewater, including a pretreatment tank, a mixing start-up zone, a photocatalytic reaction zone, an electrochemical promotion zone, a precipitation separation zone, and a catalyst interception zone. The system uses photoelectric synergistic catalytic oxidation to treat high-concentration organic wastewater.

[0004] Although the above patent couples the use of photocatalytic oxidation and electrocatalytic oxidation to improve the degradation efficiency of high-concentration organic wastewater to a certain extent, the structural design of its treatment system cannot ensure that all catalysts have catalytic effects and that the catalysts and light sources are fully and evenly contacted and mixed, resulting in low degradation efficiency and poor degradation effect. In addition, the catalyst is mixed with the organic wastewater during the treatment, and the catalyst needs to be retained in the catalyst retention zone later, which poses a problem of catalyst recovery. Summary of the invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to overcome the problem that the existing treatment system that couples photocatalytic oxidation and electrocatalytic oxidation cannot ensure sufficient and uniform contact and mixing between gas and liquid, between catalyst and gas and liquid, and between catalyst and light source due to structural design, resulting in low degradation efficiency and poor degradation effect. A high-concentration organic wastewater degradation equipment and degradation method are proposed, which can achieve instantaneous uniform mixing of materials and efficient heat transfer, increase the contact area between gas and liquid, have high degradation efficiency and good degradation effect.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] On one hand, the present invention provides a high-concentration organic wastewater degradation device, including a photocatalytic oxidation device, and an electrochemical catalytic oxidation device connected to the photocatalytic oxidation device; the photocatalytic oxidation device further includes a liquid-mass feed component, a gas-gas feed component, and a gas-gas transfer component arranged between the liquid-mass feed component and the gas-gas feed component. The liquid-mass feed component includes a connected water inlet, a liquid-mass microchannel reaction zone, and a water outlet; the water inlet is used for inputting high-concentration organic wastewater into the liquid-mass microchannel reaction zone; the liquid-mass microchannel reaction zone includes a plurality of liquid-mass microchannel pipes arranged in parallel, a plurality of first pores are uniformly opened on a side wall of the liquid-mass microchannel pipe close to the gas-gas feed component, a light source is arranged on the inner wall of the liquid-mass microchannel pipe and a catalyst is uniformly coated; the water outlet is connected to the electrochemical catalytic oxidation device. The gas-gas feed assembly includes a connected gas inlet and a gas-gas microchannel dispersion area; the gas inlet is connected to an air source or an oxygen source; the gas-gas microchannel dispersion area includes a plurality of gas-gas microchannel pipes arranged in parallel, and a plurality of second air holes are evenly opened on a side wall of the gas-gas microchannel pipe close to the liquid-mass microchannel reaction area. The gas-gas transmission component is provided with a plurality of third air holes, the gas inlet end of the third air hole is connected to the second air hole, and the gas outlet end of the third air hole is connected to the first air hole.

[0008] Preferably, the first pores, the second pores and the third pores are all circular, and the diameters of the first pores, the second pores and the third pores gradually decrease from top to bottom.

[0009] Preferably, the electrochemical catalytic oxidation device further comprises an anode, a cathode, and a three-dimensional electrode; the anode and the cathode are arranged apart, and the photocatalytic oxidation device is located between the anode and the cathode; the three-dimensional electrode adopts an iron-carbon mixture.

[0010] Preferably, the photocatalytic oxidation device also includes a first shell, which is mounted on the outside of the liquid-mass microchannel reaction zone, the gas-gas microchannel dispersion zone and the gas-gas transfer component, and the water inlet, the water outlet and the air inlet pass through the first shell; the electrochemical catalytic oxidation device also includes a second shell, which is mounted on the outside of the anode, the cathode, and the three-dimensional electrode; the water outlet passes through the first shell and is connected to the inner cavity of the second shell.

[0011] Preferably, the three-dimensional electrodes are continuously distributed along the side walls and bottom of the second shell.

[0012] Preferably, the photocatalytic oxidation device also includes a plate-frame coating arranged between the liquid-mass microchannel reaction zone and the gas-gas transfer component, and between the gas-gas microchannel dispersion zone and the gas-gas transfer component, and a cover plate fastening the liquid-mass microchannel reaction zone, the gas-gas transfer component, the gas-gas microchannel dispersion zone and the plate-frame coating.

[0013] Preferably, the photocatalytic oxidation device further comprises a filter assembly connected to the water inlet, a water inlet pump connected to the water inlet, and a blower connected to the air inlet; the electrochemical catalytic oxidation device further comprises a power supply.

[0014] Another aspect of the present invention provides a method for degrading high-concentration organic wastewater using the high-concentration organic wastewater degradation equipment described in any of the above technical solutions, which comprises a mass transfer step, a photocatalytic oxidation step, and an electrocatalytic oxidation step in sequence.

[0015] Preferably, the mass transfer step further includes: high-concentration organic wastewater enters a plurality of the liquid-mass microchannel pipes through the water inlet; oxygen or air enters a plurality of the gas-gas microchannel pipes through the air inlet, and is dispersed into microbubbles with smaller diameters under the action of a plurality of the second pores, and the microbubbles are further dispersed through the gas-gas transfer component under the action of the pressure difference and enter the liquid-mass microchannel pipes through the first pores to be uniformly mixed with the high-concentration organic wastewater; the photocatalytic oxidation step further includes: the high-concentration organic wastewater and microbubbles uniformly mixed in the liquid-mass microchannel pipes are subjected to photocatalytic oxidation reaction degradation under the action of a light source and a catalyst arranged on the inner wall of the liquid-mass microchannel pipe to obtain organic wastewater degraded into small molecular pollutants; the electrocatalytic oxidation step further includes: the organic wastewater degraded into small molecular pollutants enters the electrochemical catalytic oxidation device through the water outlet for electrocatalytic oxidation degradation.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides a high-concentration organic wastewater degradation device, which achieves sufficient and uniform contact and mixing between gas and liquid, between catalyst and gas and liquid, and between catalyst and light source by optimizing the structure of the photocatalytic oxidation device, and at the same time increases the residence time of gas and high-concentration organic wastewater in the liquid-mass microchannel reaction zone, effectively improves the degradation efficiency, and ensures the degradation effect;

[0018] The present invention also provides a degradation method, which effectively increases the contact area between the gas and liquid phases and improves the degradation efficiency by setting a mass transfer step. At the same time, by limiting the degradation order to a photocatalytic oxidation step first and an electrocatalytic oxidation step later, on the one hand, the type of catalyst and the coating thickness can be determined based on the concentration and type of the pollutants. On the other hand, high-concentration organic wastewater is first broken into small molecules by photocatalytic oxidation and then enters electrocatalytic oxidation for degradation, which can reduce the electrocatalytic oxidation reaction time and thus save energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a high-concentration organic wastewater degradation device provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of the structure of a photocatalytic oxidation device provided in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the structure of a liquid feed assembly provided in an embodiment of the present invention;

[0022] Figure 4 Another schematic diagram of the structure of the liquid feed assembly provided by an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of the structure of a gas-gas feed assembly provided in an embodiment of the present invention;

[0024] Figure 6 Another schematic diagram of the structure of the gas-gas feeding assembly provided in an embodiment of the present invention;

[0025] Figure 7 A schematic diagram of the assembly of a photocatalytic oxidation device provided in an embodiment of the present invention;

[0026] Figure 8 A schematic diagram of the structure of the plate-frame coating provided by an embodiment of the present invention;

[0027] In the above figures: 1. liquid-mass microchannel reaction zone; 101. liquid-mass microchannel pipeline; 102. first air hole; 2. water inlet; 3. water outlet; 4. air inlet; 5. gas-gas microchannel dispersion zone; 501. gas-gas microchannel pipeline; 502. second air hole; 6. gas-gas transfer component; 7. anode; 8. cathode; 9. three-dimensional electrode; 10. first shell; 11. second shell; 12. plate and frame coating; 13. cover plate; 14. filter assembly; 15. water inlet pump; 16. blower; 17. power supply. DETAILED DESCRIPTION

[0028] The technical scheme in the specific embodiment of the present invention will be described in detail and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only some specific implementation methods of the overall technical scheme of the present invention, rather than all implementation methods. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0029] On the one hand, the present invention provides a high-concentration organic wastewater degradation device, such as Figure 1 As shown, it includes a photocatalytic oxidation device and an electrochemical catalytic oxidation device connected to the photocatalytic oxidation device; Figure 2 As shown, the photocatalytic oxidation device further includes a liquid feed component, a gas feed component, and a gas transfer component 6 disposed between the liquid feed component and the gas feed component. Figure 3 As shown, the liquid-mass feed assembly includes a connected water inlet 2, a liquid-mass microchannel reaction zone 1 and a water outlet 3; the water inlet 2 is used to input high-concentration organic wastewater into the liquid-mass microchannel reaction zone 1; the liquid-mass microchannel reaction zone 1 includes a plurality of liquid-mass microchannel pipes 101 arranged in parallel, such as Figure 4 As shown, a plurality of first air holes 102 are evenly opened on one side wall of the liquid-mass microchannel pipeline 101 close to the gas-gas feed assembly, a light source is provided on the inner wall of the liquid-mass microchannel pipeline 101 and a catalyst is evenly coated; the water outlet 3 is connected to the electrochemical catalytic oxidation device. Figure 5 As shown, the gas-gas feed assembly includes a connected gas inlet 4 and a gas-gas microchannel dispersion area 5; the gas inlet 4 is connected to an air source or an oxygen source; the gas-gas microchannel dispersion area 5 includes a plurality of gas-gas microchannel pipes 501 arranged in parallel, such as Figure 6 As shown, a plurality of second pores 502 are evenly formed on a side wall of the gas-gas microchannel pipe 501 close to the liquid-gas microchannel reaction zone 1. A plurality of third pores are formed on the gas-gas transmission member 6, the gas inlet end of the third pore is connected to the second pore 502, and the gas outlet end of the third pore is connected to the first pore 102. The present invention adopts two advanced oxidation technologies to increase the amount of ·OH generated, as well as other active free radicals, such as superoxide free radicals (·O 2- ), hydrogen peroxide (H2O2), singlet oxygen ( 1O2) and other oxygen active free radicals to improve the degradation efficiency of organic pollutants. The liquid-mass microchannel reaction zone 1 is composed of a plurality of liquid-mass microchannel pipes 101 arranged in parallel, and the gas-gas microchannel dispersion zone 5 is composed of a plurality of gas-gas microchannel pipes 501 arranged in parallel, each of which constitutes a microchannel. In addition, the first pore 102 on the liquid-mass microchannel pipe 101 and the second pore 502 on the gas-gas microchannel pipe 501 have the same small hole distribution law, and the microchannels and small holes on both sides are connected. To ensure that the gas can enter the microchannel of the liquid-mass feed assembly through the gas-gas transfer member 6 and strengthen the mass transfer capacity between gas and liquid, the microchannel pressure of the gas-gas feed assembly is slightly higher than the pressure of the microchannel of the liquid-mass feed assembly. In addition, the inner wall of the microchannel of the liquid-mass feed assembly is coated with a porous catalyst and a lamp tube that generates a light source. The porous catalyst can be quickly activated under the condition of light, and the organic matter in the catalytic wastewater is rapidly oxidized. Regarding the photocatalytic oxidation device, according to the pressure difference principle, the gas can enter the microchannel of the liquid-mass feed component (i.e., the liquid-mass microchannel pipeline 101) through the gas-gas transfer component 6. The inner wall of the microchannel of the liquid-mass feed component is coated with a porous catalyst and a lamp tube that generates a light source. Optionally, in order to combine the catalyst and the inner wall of the microchannel, an adhesive needs to be added to strengthen the bonding between the two. The catalyst and the adhesive ratio must ensure the catalytic activity of the catalyst and also ensure that the catalyst and the inner wall of the microchannel have strong bonding. Among them, the small piece adopts the dipping method, and the large component uses the coating installation machine for operation. Under the condition of light, the catalyst generates photogenerated electrons (e - ) and holes (h + ), e - and h + Migrate to the catalyst surface and degrade organic pollutants through redox reactions, or - and h + Under the action of the liquid feed component, strong oxidizing and reducing substances are formed, which degrade organic pollutants into CO2 and H2O. The wastewater flows into the electrocatalytic oxidation device after the reaction in the liquid feed component.

[0030] At present, the treatment methods of high-concentration organic wastewater mainly include biological method and physical and chemical method. Among them, the biological method is mature in technology and has stable treatment effect. It mainly uses aerobic treatment of aerobic microorganisms and anaerobic treatment of anaerobic microorganisms. The biological method combines aerobic treatment of aerobic microorganisms and anaerobic treatment of anaerobic microorganisms to remove pollutants. It has good removal effect on various pollutants. However, it also has the disadvantages of large reaction pool area, high construction investment, large sludge production, and troublesome operation and maintenance. With the increasingly stringent national environmental protection standards, the shortcomings of traditional biological treatment methods limit their promotion and application; physical and chemical methods mainly include coagulation, adsorption, advanced oxidation, electrochemistry and ion exchange. Among them, advanced oxidation technology mainly produces hydroxyl radicals (·OH) through light, sound, electricity and other pathways, with ·OH as the core oxidant, non-selectively and rapidly oxidizing organic matter in sewage. In actual application, the commonly used advanced oxidation technologies are mainly electrocatalytic oxidation technology and Fenton technology. Among them, electrocatalytic oxidation is to put a solution or suspension of organic matter into the electrolytic cell, and degrade organic pollutants through direct oxidation and indirect oxidation. Direct oxidation is that the pollutants directly lose electrons at the anode and undergo oxidation. Indirect oxidation is to use anions with lower electrode potential in the solution to lose electrons at the anode to generate newer and stronger active substances, which are used to oxidize and decompose COD, BOD5, NH3-N, etc. in the water. However, electrocatalytic oxidation technology also has the problems of soluble electrode oxidation method, excessive electrode consumption, low current efficiency, and low reactor efficiency. Therefore, the energy consumption of using electrocatalytic oxidation method to completely decompose organic matter in water is high, and the equipment cost is also high; Fenton technology uses H2O2 as an oxidant and in Fe 2+ Under catalytic action, ·OH is decomposed to produce ·OH, and organic matter is oxidized and decomposed into small molecules through electron transfer and other pathways. At the same time, Fe 2+ Oxidized to Fe 3+It produces coagulation precipitation and removes a large amount of organic matter. It can be seen that Fenton reagent has two functions in water treatment: oxidation and coagulation. However, on the one hand, the pH of its reaction is 3-4, and it needs to add acid and alkali, and other types of inorganic salts will be introduced. On the other hand, the utilization rate of H2O2 is not high, and it cannot fully mineralize organic matter. In addition, Fenton technology mainly converts difficult-to-degrade organic matter into relatively easy-to-biodegrade organic matter, and generally cannot completely degrade organic matter. Therefore, COD can only be partially removed. In summary, the existing high-concentration organic wastewater technology has the following defects and shortcomings: ① Using H2O2 as an oxidant, the treatment cost is high; ② The cost of electrocatalytic oxidation equipment is high, and the energy consumption of oxidizing organic matter is high; ③ The recombination rate of photogenerated electrons and holes in photocatalytic oxidation technology is fast, and the efficiency of catalytic oxidation is low; ④ The use of a single process produces a relatively low OH content, and the oxidation of organic matter is not thorough; ⑤ The single process mainly has a more obvious effect on a certain industry and a certain water quality. There is a lot of high-concentration organic wastewater produced by Chinese enterprises. Although the existing technologies can degrade organic matter, the treatment effect is limited when used alone. Therefore, it is of great significance to couple multiple technologies and utilize gas-liquid two-phase contact to improve mass transfer efficiency.

[0031] The above-mentioned high-concentration organic wastewater degradation equipment provided by the present invention achieves sufficient and uniform contact and mixing between gas and liquid, between catalyst and gas and liquid, and between catalyst and light source by optimizing the structure of the photocatalytic oxidation device, while increasing the residence time of gas and high-concentration organic wastewater in the liquid-mass microchannel reaction zone 1, increasing the reaction time, effectively improving the degradation efficiency, and ensuring the degradation effect. Specifically, the technical solution adds oxygen as an oxidant, which is relatively cheap and easy to obtain compared to ozone, and has a low processing cost. In addition, the use of oxygen (or air) as an oxidant makes the gas highly dispersed in the liquid, thereby greatly enhancing the mass transfer capacity between the gas and the liquid, and can achieve instantaneous uniform mixing of the materials and efficient heat transfer; the present invention limits the use of a gas-gas transfer member 6 and a gas-gas feed assembly to transfer the gas. Through the gas-gas feed assembly, the gas can first be dispersed into microbubbles with smaller diameters, and the pressure of the gas-gas feed assembly is slightly higher than the pressure of the liquid feed assembly. The film and the gas-gas transfer member 6 can ensure that the gas and the liquid can be evenly mixed, and the contact area between the gas and liquid is increased, ensuring that the wastewater reacts smoothly in the liquid feed assembly, thereby improving the degradation efficiency; the microchannel of the liquid feed assembly (i.e., the liquid microchannel pipeline 101) is coated with a catalyst and a lamp tube that generates a light source to catalyze the rapid oxidation reaction of organic matter in the wastewater. The catalyst can be selected according to the water quality of the wastewater, and has multiple selectivity. It should be noted that the reasons for coating the catalyst on the inner wall of the microchannel are: 1) The catalyst coating on the inner wall of the microchannel is fixed. Compared with the sewage mixed with the flowing catalyst and then entering the photocatalyst area for reaction, it can avoid the catalyst from being lost with the sewage, reduce the subsequent catalyst recovery device, and reduce investment and floor space; 2) The catalyst is coated on the inner wall of the microchannel to ensure that all catalysts can receive light, generate electron holes, and promote the degradation of organic matter. In addition, the microchannel is a pipeline structure, and the continuous entry of sewage can react evenly with the catalyst in the microchannel to avoid unstable water quality in the later stage. The present invention preferably uses a lamp tube close to the sunlight source as the light source. When activating the catalyst, the sunlight has a wide wavelength and can activate catalysts within the ultraviolet and visible light ranges. Optionally, it can also choose to use sunlight or photovoltaic power generation to reduce energy utilization.

[0032] In a preferred embodiment, the first pore 102, the second pore 502 and the third pore are all circular, and the diameters of the first pore 102, the second pore 502 and the third pore gradually decrease from top to bottom. It should be noted that from top to bottom here means that the diameter of the pores closer to the air inlet and the water inlet is larger, and the diameter of the pores closer to the water outlet is smaller, in order to ensure that the gas-liquid contact is uniform and sufficient. The overall microchannel structure will improve the efficiency of photocatalytic degradation. The distribution of small holes on the liquid-mass microchannel reaction zone 1 and the gas-gas microchannel dispersion zone 5 will vary according to the water inlet and outlet positions. The pore shape is circular, and the pores gradually decrease from top to bottom. Specifically, the pore size is set according to the gas flow rate and the distance from the outlet 3 to ensure that the sewage and exhaust gas can be evenly mixed. The internal space of the microchannel is small, and the catalyst is coated on it. Under the condition of light, it can fully contact with the sewage. In the device that treats the same amount of water, the microchannel structure can divide the entire device into multiple pipeline structures, increase the contact area between pollutants and catalysts, avoid the rapid combination of photogenerated electrons and holes, and improve the degradation efficiency.

[0033] In a preferred embodiment, the electrochemical catalytic oxidation device further comprises an anode 7, a cathode 8, and a three-dimensional electrode 9; the anode 7 and the cathode 8 are arranged separately, and the photocatalytic oxidation device is located between the anode 7 and the cathode 8; the three-dimensional electrode 9 is made of an iron-carbon mixture. Figure 1 As shown in the assembly, the anode 7 and the cathode 8 are fixed at a certain distance in the electrochemical catalytic oxidation device, the three-dimensional iron-carbon mixture electrode 9 is located between the anode 7 and the cathode 8, and the line of the power supply 17 is connected. Compared with the two-dimensional electrode, the three-dimensional electrode 9 adds a particle electrode. The photocatalytic oxidation device needs to be placed on the particle electrode (i.e., the three-dimensional iron-carbon mixture electrode 9). It is necessary to ensure the tolerance of the particle electrode, the requirements for the particle electrode are high, and the internal space is relatively small. It is difficult to put the photocatalytic oxidation device inside. A tetrafluoro rod (or other non-conductive material) bracket is set at the bottom of the photocatalytic oxidation device to ensure that both the electrochemical catalytic oxidation device and the photocatalytic oxidation device can degrade organic pollutants. Optionally, the electrochemical catalytic oxidation device uses iron as the anode 7 and graphite C as the cathode 8, and adds an iron-carbon mixture as a three-dimensional electrode 9 to form a three-dimensional electrocatalytic oxidation device, which utilizes direct oxidation and indirect oxidation to degrade organic pollutants in the solution, improves the B / C ratio, and completely decomposes macromolecular organic matter that is difficult to biodegrade into simple inorganic molecules such as CO2 and H2O, degrades COD, and finally the effluent from the equipment is discharged through the overflow weir after standing. Optionally, the degradation rate of the Fenton-like system can also be promoted by adding H2O2.

[0034] In a preferred embodiment, the photocatalytic oxidation device also includes a first shell 10, which is mounted on the outside of the liquid-mass microchannel reaction zone 1, the gas-gas microchannel dispersion zone 5 and the gas-gas transfer component 6, and the water inlet 2, the water outlet 3 and the air inlet 4 pass through the first shell 10; the electrochemical catalytic oxidation device also includes a second shell 11, which is mounted on the outside of the anode 7, the cathode 8, and the three-dimensional electrode 9; the water outlet 3 passes through the first shell 10 and is connected to the inner cavity of the second shell 11.

[0035] In a preferred embodiment, the three-dimensional electrodes 9 are continuously distributed along the sidewalls and the bottom of the second housing 11. The position of the three-dimensional electrodes 9 is specifically limited in this embodiment because the three-dimensional electrodes at the bottom can react quickly when the organic wastewater enters the electrocatalytic oxidation device, and compared with the three-dimensional electrodes placed at the top, the contact reaction time can be increased, thereby accelerating degradation and improving removal efficiency.

[0036] In a preferred embodiment, the photocatalytic oxidation device further comprises a plate-frame coating 12 disposed between the liquid-mass microchannel reaction zone 1 and the gas-gas transfer member 6, and between the gas-gas microchannel dispersion zone 5 and the gas-gas transfer member 6, and a cover plate 13 fastening the liquid-mass microchannel reaction zone 1, the gas-gas transfer member 6, the gas-gas microchannel dispersion zone 5 and the plate-frame coating 12. Figure 7 As shown, the interior of the photocatalytic oxidation device is assembled in the order of liquid-mass microchannel reaction zone 1, plate-frame coating 12, gas-gas transmission component 6, plate-frame coating 12, and gas-gas microchannel dispersion zone 5. The cover plate 13 is placed outside the assembly to fasten all the components. The two sides of the liquid-mass microchannel reaction zone 1 are respectively provided with a water inlet 2 and a water outlet 3, and one side of the gas-gas microchannel dispersion zone 5 is provided with an air inlet 4. Among them, the structure of the plate-frame coating 12 is as shown in FIG. Figure 8 shown.

[0037] In a preferred embodiment, the photocatalytic oxidation device further includes a filter assembly 14 connected to the water inlet 2, a water inlet pump 15 connected to the water inlet 2, and a blower 16 connected to the air inlet 4; the electrochemical catalytic oxidation device further includes a power supply 17. Among them, the filter assembly 14 is arranged above the liquid-mass microchannel reaction zone 1. By setting the filter assembly 14, the wastewater first enters the filter assembly 14 to remove the suspended solids (SS) in the wastewater to avoid clogging the microchannel. The wastewater flowing out of the water outlet 3 is adjusted to a certain pH range, and a certain amount of supporting electrolyte can also be added externally. The blower 16 is started to introduce air into the equipment, and the air flow rate is adjusted. The power supply 17 is turned on, and the voltage and current of the DC regulated power supply 17 are changed to make the electrochemical reaction proceed at a certain current density and fully react with the organic matter.

[0038] On the other hand, the present invention provides a method for degrading high-concentration organic wastewater using a high-concentration organic wastewater degradation device of any of the above technical solutions, which includes a mass transfer step, a photocatalytic oxidation step, and an electrocatalytic oxidation step in sequence. This patent is a photoelectrocatalytic coupling, and specifically defines photocatalytic oxidation followed by electrocatalytic oxidation for the following reasons: the sewage is first photocatalytically oxidized to break the pollutant concentration into small molecules, and the type of catalyst and coating thickness can be determined based on the concentration and type of pollutants. After photocatalytic oxidation, most of the pollutants entering the electrocatalytic oxidation are small molecule pollutants, which can reduce the electrocatalytic oxidation reaction time and save energy.

[0039] In a preferred embodiment, the mass transfer step further includes: high-concentration organic wastewater enters a plurality of liquid-mass microchannel pipes 101 through the water inlet 2; oxygen or air enters a plurality of gas-gas microchannel pipes 501 through the gas inlet 4, and is dispersed into microbubbles with smaller diameters under the action of a plurality of second air holes 502, and the microbubbles are further dispersed through the gas-gas transfer element 6 under the action of the pressure difference and enter the liquid-mass microchannel pipe 101 through the first air hole 102 to be uniformly mixed with the high-concentration organic wastewater; the photocatalytic oxidation step further includes: the high-concentration organic wastewater and microbubbles uniformly mixed in the liquid-mass microchannel pipe 101 are subjected to photocatalytic oxidation reaction degradation under the action of the light source and catalyst arranged on the inner wall of the liquid-mass microchannel pipe 101 to obtain organic wastewater degraded into small molecular pollutants; the electrocatalytic oxidation step further includes: the organic wastewater degraded into small molecular pollutants enters the electrochemical catalytic oxidation device through the water outlet 3 for electrocatalytic oxidation degradation. Specifically, a certain amount of high-concentration organic wastewater is introduced into the liquid-mass microchannel reaction zone 1 through the water inlet pump 15, and the suspended matter is removed through the filter component 14. Then the high-concentration organic wastewater enters through the water inlet 2 and enters the microchannel reactor whose inner wall is coated with a porous catalyst coating and a lamp tube for generating a light source. The catalyst is activated by the light source and reacts with the incoming oxygen (or air) for a residence time of 30-60 minutes. Then, the wastewater flows into the electrochemical catalytic oxidation device through the water outlet 3, and the pH of the solution is adjusted to a certain range. Under the action of the DC regulated power supply 17, the anode 7, the cathode 8 and the iron-carbon mixture three-dimensional electrode 9 are oxidized and reduced to degrade organic matter for a residence time of 60-120 minutes.

[0040] Performance Testing

[0041] In order to more clearly and in detail introduce the degradation effect of the high-concentration organic wastewater degradation equipment and degradation method provided in the embodiment of the present invention, the high-concentration organic wastewater degradation equipment and degradation method (first photocatalytic oxidation and then electrocatalytic oxidation) provided in the embodiment of the present invention, and the existing photocatalytic method, photocatalytic oxidation method, electrocatalytic oxidation method, and electrocatalytic oxidation first followed by photocatalytic oxidation method are used to treat organic wastewater, and the treatment effect is shown in Table 1.

[0042] Table 1 Degradation efficiency of different degradation methods

[0043]

[0044] Among them, Rhodamine B (RhB) is a common pollutant for detecting photocatalysis and electrocatalysis, and chlortetracycline (CTC) and sulfamethoxazole (SMX) are pollutants in the pharmaceutical industry. From the above experimental data, it can be seen that the degradation efficiency of the present invention is better than that of electrocatalytic oxidation followed by photocatalytic oxidation.

[0045] From the actual application cases, we can know that when using Fenton oxidation technology, it is usually combined with micro-electrolysis catalytic oxidation technology. Micro-electrolysis catalytic oxidation technology uses the micro-electrolysis material filled in the wastewater to generate a 1.2V potential difference to electrolyze the wastewater without electricity, so as to achieve the purpose of degrading organic pollutants. By combining the primary battery system, it is believed that micro-electrolysis catalytic oxidation technology can be combined with electrocatalytic oxidation technology to form an electric field in its action space. OH, Fe 2+ etc. can undergo redox reactions with many components in wastewater, destroying the chromophores or auxochromes of colored substances in colored wastewater, and even breaking the chains, thus achieving the effect of degradation and decolorization. The generated Fe 2+ Further oxidized to Fe 3+ , has strong adsorption-flocculation activity, especially under alkaline conditions, it generates ferrous hydroxide and ferric hydroxide colloidal flocculants, which adsorb dispersed microparticles and organic macromolecules in water. The combination of micro-electrolysis catalytic oxidation technology and electrocatalytic oxidation technology can be considered to constitute a three-dimensional electrocatalytic oxidation device, which can increase the surface-to-volume ratio of the electrolytic cell, improve the current efficiency and treatment effect, greatly improve the electrode specific surface area and mass transfer rate, the potential distribution of the solution is relatively uniform, and the main body of the solution has a uniform temperature field. The specific treatment methods and degradation efficiencies are shown in Table 2 below.

[0046] Table 2 Degradation efficiency of different electrocatalytic oxidation methods

[0047]

[0048] Among them, electrocatalytic oxidation 1 uses a titanium electrode as a cathode and titanium plated with ruthenium and iridium as an anode plate; electrocatalytic oxidation 2 uses iron as an anode and graphite C as a cathode; and three-dimensional electrocatalytic oxidation is the electrocatalytic oxidation method provided by the present invention.

Claims

1. A high-concentration organic wastewater degradation device, characterized in that: It comprises a photocatalytic oxidation device and an electrochemical catalytic oxidation device connected to the photocatalytic oxidation device; the photocatalytic oxidation device further comprises: A liquid-mass feed assembly, comprising a connected water inlet, a liquid-mass microchannel reaction zone and a water outlet; the water inlet is used to input high-concentration organic wastewater into the liquid-mass microchannel reaction zone; the liquid-mass microchannel reaction zone comprises a plurality of liquid-mass microchannel pipes arranged in parallel, a plurality of first air holes are evenly opened on a side wall of the liquid-mass microchannel pipe close to the gas-gas feed assembly, a light source is provided on the inner wall of the liquid-mass microchannel pipe and a catalyst is evenly coated; the water outlet is connected to the electrochemical catalytic oxidation device; A gas-gas feed assembly comprises a connected gas inlet and a gas-gas microchannel dispersion area; the gas inlet is connected to an air source or an oxygen source; the gas-gas microchannel dispersion area comprises a plurality of gas-gas microchannel pipes arranged in parallel, and a plurality of second air holes are evenly opened on a side wall of the gas-gas microchannel pipe close to the liquid-mass microchannel reaction area; The gas-gas transfer component is arranged between the liquid-mass feed component and the gas-gas feed component. The gas-gas transfer component is provided with a plurality of third gas holes. The gas inlet ends of the third gas holes are connected to the second gas holes, and the gas outlet ends of the third gas holes are connected to the first gas holes.

2. The high-concentration organic wastewater degradation equipment according to claim 1, characterized in that: The first pore, the second pore and the third pore are all circular, and the diameters of the first pore, the second pore and the third pore gradually decrease from top to bottom.

3. The high-concentration organic wastewater degradation equipment according to claim 1, characterized in that: The electrochemical catalytic oxidation device further comprises an anode, a cathode, and a three-dimensional electrode; the anode and the cathode are arranged apart, and the photocatalytic oxidation device is located between the anode and the cathode; the three-dimensional electrode adopts an iron-carbon mixture.

4. The high-concentration organic wastewater degradation equipment according to claim 3, characterized in that: The photocatalytic oxidation device also includes a first shell, which is mounted on the outside of the liquid-mass microchannel reaction area, the gas-gas microchannel dispersion area and the gas-gas transfer component, and the water inlet, the water outlet and the air inlet pass through the first shell; the electrochemical catalytic oxidation device also includes a second shell, which is mounted on the outside of the anode, the cathode and the three-dimensional electrode; the water outlet passes through the first shell and is connected to the inner cavity of the second shell.

5. The high-concentration organic wastewater degradation equipment according to claim 4, characterized in that: The three-dimensional electrodes are continuously distributed along the side walls and the bottom of the second shell.

6. The high-concentration organic wastewater degradation equipment according to claim 1, characterized in that: The photocatalytic oxidation device also includes a plate-frame coating arranged between the liquid-mass microchannel reaction zone and the gas-gas transfer component, and between the gas-gas microchannel dispersion zone and the gas-gas transfer component, and a cover plate fastening the liquid-mass microchannel reaction zone, the gas-gas transfer component, the gas-gas microchannel dispersion zone and the plate-frame coating.

7. The high-concentration organic wastewater degradation equipment according to claim 1, characterized in that: The photocatalytic oxidation device further comprises a filter assembly connected to the water inlet, a water inlet pump connected to the water inlet, and a blower connected to the air inlet; the electrochemical catalytic oxidation device further comprises a power source.

8. A method for degrading high-concentration organic wastewater using the high-concentration organic wastewater degradation equipment according to any one of claims 1 to 7, characterized in that: The method includes a mass transfer step, a photocatalytic oxidation step, and an electrocatalytic oxidation step in sequence.

9. The degradation method according to claim 8, characterized in that: The mass transfer step further comprises: high-concentration organic wastewater enters the plurality of liquid-mass microchannel pipes through the water inlet; oxygen or air enters the plurality of gas-gas microchannel pipes through the gas inlet, and is dispersed into microbubbles with smaller diameters under the action of the plurality of second air holes; the microbubbles are further dispersed through the gas-gas transfer element under the action of the pressure difference and enter the liquid-mass microchannel pipes through the first air holes to be uniformly mixed with the high-concentration organic wastewater; The photocatalytic oxidation step further comprises: the high-concentration organic wastewater and microbubbles uniformly mixed in the liquid-mass microchannel pipeline are subjected to photocatalytic oxidation reaction degradation under the action of a light source and a catalyst arranged on the inner wall of the liquid-mass microchannel pipeline to obtain organic wastewater containing small molecular pollutants; The electrocatalytic oxidation step further comprises: the organic wastewater degraded into small molecular pollutants enters the electrochemical catalytic oxidation device through the water outlet for electrocatalytic oxidation degradation.

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