Photocatalytic oxidation wastewater treatment device

Abstract

The invention discloses a photocatalytic oxidation wastewater treatment device which comprises a primary treatment pond, a secondary treatment pond, a filter, a catalytic oxidation assembly and an aeration assembly, the primary treatment pond is connected with the secondary treatment pond, the filter is connected with the primary treatment pond through a pipeline, and the catalytic oxidation assembly is connected with the aeration assembly through a pipeline. The catalytic oxidation assemblies are respectively arranged in the primary treatment tank and the secondary treatment tank, and the aeration assembly is respectively connected with the primary treatment tank and the secondary treatment tank. An oxidizing agent (O2) is added into the wastewater through aeration to serve as a free radical precursor, more reactive oxygen species (ROS) are directly or indirectly generated, pollutant attack sites are expanded, pollutant degradation is accelerated, O2 is reduced into. O2 <-> through conduction band electrons, then the O2 is further protonated to generate H2O2, and finally the H2O2 is converted into. OH. CODCr can be effectively degraded through strong oxidability of hydroxyl free radicals (. OH), superoxide free radicals (. O2-) and the like generated through photocatalytic oxidation, and pathogenic bacteria, pathogens and viruses in water can be killed in cooperation with ultraviolet light.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a photocatalytic oxidation wastewater treatment device. Background Art

[0002] In wastewater treatment, the photocatalytic principle is based on the redox ability of photocatalysts under light irradiation. Usually, the photocatalytic oxidation reaction uses semiconductors as catalysts and light as energy to convert organic wastewater into non-toxic inorganic small molecule substances such as CO2, H2O, N2 or other non-toxic intermediate products. "Oxygenation cross-flow photocatalytic oxidation" is an advanced oxidation technology that combines specific reaction conditions (oxygen environment), reactor design (cross-flow type), and reaction mechanism (photocatalytic oxidation). Oxygenation cross-flow photocatalytic oxidation provides a new idea for solving complex pollutants through the synergistic optimization of dissolved oxygen in wastewater and reactor design.

[0003] The patent document with the publication number CN102001724A discloses a circulating water treatment device and process for treating organic pollutant wastewater, which is composed of a photocatalytic reactor using nanocrystalline titanium dioxide fibers and performs catalytic treatment using ultraviolet light. However, this device lacks an attachment scouring mechanism, and if the reactor is blocked, it needs to be replaced as a whole.

[0004] The patent document with the publication number CN113105038A discloses a device for enhancing photocatalytic removal of microalgae by coupling hydrodynamic cavitation and micro-nano aeration. The hydrodynamic cavitation generating device is used to form a cavitation effect in the algae-containing water body to break the cell walls of microalgae and preliminarily oxidize them; the micro-nano aeration device is used to supplement air to the water body and form micro-nano bubbles to provide active oxygen for subsequent photocatalysis; the photocatalytic draft tube is used for the collision of the broken cell walls after cavitation with micro-nano bubbles to improve the mass transfer efficiency and further deeply photocatalytically oxidize. This device is mainly used for removing microalgae and does not involve the technology of pollutant degradation. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a photocatalytic oxidation wastewater treatment device.

[0006] The present invention is achieved through the following technical solutions.

[0007] A photocatalytic oxidation wastewater treatment device provided by the present invention includes a primary treatment tank, a secondary treatment tank, a filter, a catalytic oxidation assembly, and an aeration assembly. The primary treatment tank is connected to the secondary treatment tank. The filter is connected to the primary treatment tank through a pipeline. The catalytic oxidation assemblies are respectively arranged inside the primary treatment tank and the secondary treatment tank. The aeration assemblies are respectively connected to the primary treatment tank and the secondary treatment tank.

[0008] Preferably, a partition board is arranged between the primary treatment tank and the secondary treatment tank, a connecting pipeline is arranged on the partition board, and a lifting pipe is arranged in the primary treatment tank.

[0009] Preferably, the catalytic oxidation assembly includes a bracket, a photocatalytic plate and an ultraviolet lamp tube. The bracket is connected to the inner walls of the primary treatment tank and the secondary treatment tank through a support member, and the photocatalytic plate and the ultraviolet lamp tube are respectively connected to the bracket.

[0010] Preferably, the photocatalytic plate is arranged horizontally, and several layers are sequentially arranged on the photocatalytic plate from bottom to top in the vertical direction. Several ultraviolet lamp tubes are arranged vertically, and the ultraviolet lamp tubes penetrate through the photocatalytic plate.

[0011] Preferably, the substrate of the photocatalytic plate is aluminum, and the coating material on the surface is TiO2.

[0012] Preferably, the photocatalytic plate is provided with honeycomb-shaped mesh holes with a specific surface area of not less than 400 m 2 / g, and the honeycomb-shaped mesh holes are arranged as inclined holes.

[0013] Preferably, the filter includes a shell, a partition board and a filter element. The partition board and the filter element are arranged in the shell, and the filter element is connected to the shell through the partition board.

[0014] Preferably, the aeration assembly includes an aeration blower, a main pipeline and an aeration pipe. The aeration blower is connected to the air inlet end of the main pipeline. The main pipeline is connected to the aeration pipe through a branch pipeline. An air supply pipe is arranged on the main pipeline. The aeration pipe and the air supply pipe are arranged at the bottom of the primary treatment tank and the secondary treatment tank.

[0015] Preferably, a one-way valve is arranged on the main pipeline, valves are arranged on the branch pipeline and the air supply pipe, and several air nozzles are arranged on the aeration pipe.

[0016] Preferably, a baffle plate is arranged in the secondary treatment tank. One end of the baffle plate is connected to the inner wall of the secondary treatment tank, and the water inlet end of the filter is connected to a water inlet pump through a pipeline.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The turbidity of the water entering the primary treatment tank and the secondary treatment tank is ensured by the precision filter, and the photocatalytic efficiency is guaranteed.

[0019] 2. The aeration pipe is arranged, and through the way of pneumatic lifting circulation, it is beneficial to the full contact between the wastewater in the treatment tank and the photocatalytic plate. At the same time, oxygen is filled into the water body, significantly improving the rate and efficiency of the photocatalytic oxidation reaction, inhibiting the electron-hole recombination, and enhancing the charge separation.

[0020] 3. The pneumatic lifting pipes on both sides not only make the water cycle through the catalytic oxidation assembly, but also increase the oxygenation and aeration to ensure the photocatalytic efficiency.

[0021] 4. The wastewater flows by gravity from the first-stage treatment tank to the second-stage treatment tank through the lift pipe. The dissolved oxygen in the first-stage treatment tank is transferred to the second-stage treatment tank along with the wastewater. The second-stage treatment tank uses a folded-flow method to treat the wastewater, which is more conducive to photocatalytic oxidation and further improves the deep treatment capacity of the wastewater.

[0022] 5. Adding an oxidant (O2) to the wastewater through aeration can be used as a free radical precursor to directly or indirectly generate more reactive oxygen species (ROS), expand the pollutant attack sites, accelerate pollutant degradation, and the conduction band electrons reduce O2 to ·O2 - After that, it is further protonated to generate H2O2, which is finally converted to ·OH.

[0023] 6. The strong oxidizing properties of the hydroxyl radicals (·OH) and superoxide radicals (·O2 - ) generated by the photocatalytic oxidation of the device effectively degrade the COD Cr In addition, it can cooperate with ultraviolet light to kill pathogenic bacteria, pathogens, and viruses in water, and the disinfection rate reaches 99.9%. Description of the Drawings

[0024] Figure 1 is the structural schematic diagram of the present invention;

[0025] Figure 2 is the schematic diagram of the present invention;

[0026] Figure 3 is the top view structural schematic diagram of the present invention;

[0027] Figure 4 is the schematic diagram of the water flow direction of the present invention;

[0028] Figure 5 is the structural schematic diagram of the catalytic oxidation component of the present invention;

[0029] Figure 6 is the structural schematic diagram of the honeycomb mesh holes of the photocatalytic plate of the present invention;

[0030] Figure 7 is the water flow schematic diagram of the lift pipe of the present invention;

[0031] Figure 8 is the structural schematic diagram of the aeration pipe of the present invention;

[0032] Figure 9 is the structural schematic diagram of the filter of the present invention;

[0033] In the figure: 1 - primary treatment tank, 11 - partition board, 12 - connecting pipe, 13 - lifting pipe, 2 - secondary treatment tank, 21 - baffle plate, 3 - filter, 31 - housing, 32 - partition board, 33 - filter element, 4 - catalytic oxidation component, 41 - bracket, 42 - ultraviolet lamp tube, 43 - support, 44 - bolt, 5 - aeration component, 51 - aeration blower, 52 - main pipe, 53 - aeration pipe, 54 - branch pipe, 55 - air supply pipe, 56 - check valve, 57 - valve, 58 - air nozzle, 6 - photocatalytic plate, 7 - feed water pump. Detailed implementation manners

[0034] The technical solutions of the present invention will be further described below, but the scope of protection claimed is not limited thereto.

[0035] Embodiment:

[0036] As Figures 1 to 9 shown, a photocatalytic oxidation wastewater treatment device includes a primary treatment tank 1, a secondary treatment tank 2, a filter 3, a catalytic oxidation component 4 and an aeration component 5. The primary treatment tank 1 is connected to the secondary treatment tank 2. The filter 3 is connected to the primary treatment tank 1 through a pipeline. The catalytic oxidation component 4 is respectively arranged inside the primary treatment tank 1 and the secondary treatment tank 2. The aeration component 5 is respectively connected to the primary treatment tank 1 and the secondary treatment tank 2. The catalytic oxidation component 4 catalyzes and oxidizes the wastewater through the ultraviolet lamp tube 42 and the photocatalytic plate 6.

[0037] The primary treatment tank 1 converts organic wastewater into non-toxic inorganic small molecule substances such as CO2, H2O, N2 or other non-toxic intermediate products.

[0038] The secondary treatment tank 2 further converts organic wastewater into non-toxic inorganic small molecule substances such as CO2, H2O, N2 or other non-toxic intermediate products to ensure the quality of the effluent water.

[0039] A partition board 11 is arranged between the primary treatment tank 1 and the secondary treatment tank 2. A connecting pipe 12 is arranged on the partition board 11. The water in the primary treatment tank 1 flows into the secondary treatment tank 2 through the connecting pipe 12. A lifting pipe 13 is arranged inside the primary treatment tank 1.

[0040] The riser 13 is vertically arranged on both sides of the primary treatment tank 1. One end of the air supply pipe 55 extends into the bottom of the riser 13. When the air supply pipe 55 exhausts air, the gas rises along the riser 13 to drive the water flow upward, thereby lifting the wastewater on both sides to the upper part of the primary treatment tank 1. The wastewater can then flow back to the bottom of the primary treatment tank 1 through the catalytic oxidation component 4, achieving the effect of the wastewater circulating through the photocatalytic oxidation component 4 multiple times. The riser 13 can achieve rapid oxygenation and pneumatic lifting circulation, and at the same time ensure that the catalytic oxidation component 4 area in the primary treatment tank 1 is not affected by the aeration bubbles, effectively solving the scattering and blocking of ultraviolet rays by the bubbles during the aeration process and ensuring the photocatalytic efficiency.

[0041] The catalytic oxidation component 4 includes a bracket 41, a photocatalytic plate 6, and an ultraviolet lamp tube 42. The bracket 41 is connected to the inner walls of the primary treatment tank 1 and the secondary treatment tank 2 through a support 43. The photocatalytic plate 6 and the ultraviolet lamp tube 42 are respectively connected to the bracket 41.

[0042] The photocatalytic plate 6 is horizontally arranged, and several layers are sequentially arranged from bottom to top in the vertical direction. The photocatalytic plate 6 is firmly connected to the bracket 41 through bolts 44. This setting facilitates the replacement of the photocatalytic plate 6. Several ultraviolet lamp tubes 42 are vertically arranged, and the ultraviolet lamp tubes 42 penetrate through the photocatalytic plate 6.

[0043] The base material of the photocatalytic plate 6 is aluminum, and the surface coating material is TiO2 as a catalyst.

[0044] The photocatalytic plate 6 is provided with honeycomb mesh holes with a specific surface area of not less than 400 m 2 / g to ensure the contact area between the pollutants in the wastewater and the catalyst. The honeycomb mesh holes are obliquely arranged to ensure that after the pneumatically lifted circulating water passes through the cross-flow mesh holes, it can be better homogenized, and at the same time, the pollutants and the photocatalytic plate can quickly come into contact.

[0045] The filter 3 includes a housing 31, a partition 32, and a filter element 33. The partition 32 and the filter element 33 are arranged in the housing 31. The filter element 33 is connected to the housing 31 through the partition 32. The partition 32 divides the housing 31 into upper and lower chambers. The filter element 33 is arranged in the upper chamber. The wastewater can enter the lower chamber through the filter element 33. The wastewater enters the filter 3 through the water inlet at the upper part of the housing 31 and flows out from the water outlet at the lower part of the housing 31 after being filtered by the filter element 33. The inlet end of the filter 3 is connected to the inlet pump 7 through a pipeline.

[0046] The filter 3 is used to remove the suspended solids and turbidity in the wastewater, ensure the penetrability of ultraviolet light in the primary treatment tank 1 and the secondary treatment tank 2, and at the same time avoid the attachment of solid substances on the photocatalytic plate 6 and the ultraviolet lamp tube 42.

[0047] The aeration component 5 includes an aeration fan 51, a main pipeline 52, and an aeration pipe 53. The aeration fan 51 is connected to the air inlet end of the main pipeline 52. The main pipeline 52 is connected to the aeration pipe 53 through a branch pipeline 54. An air supply pipe 55 is arranged on the main pipeline 52. The aeration pipe 53 and the air supply pipe 55 are arranged at the bottom inside the primary treatment tank 1 and the secondary treatment tank 2. The aeration pipe 53 can be arranged in a rectangular shape around. The aeration pipe 53 is arranged at the bottom of the catalytic oxidation component 4 to increase the dissolved oxygen. The aeration pipe 53 adopts a working mode of periodic short-time intermittent aeration to clean the attachments on the photocatalytic plate 6 and the ultraviolet lamp tube 42 and ensure the photocatalytic oxidation efficiency.

[0048] A check valve 56 is arranged on the main pipeline 52 to prevent the air flow from flowing back to the aeration fan 51. Valves 57 are arranged on the branch pipeline 54 and the air supply pipe 55 to facilitate the opening and closing of different branch pipelines 54 and air supply pipes 55. A number of air nozzles 58 are arranged on the aeration pipe 53, and air is ejected through the air nozzles 58 to achieve aeration.

[0049] A baffle plate 21 is arranged inside the secondary treatment tank 2. One end of the baffle plate 21 is connected to the inner wall of the secondary treatment tank 2. The height of the baffle plate 21 is less than the height of the secondary treatment tank 2, so that the water flow can flow through one end above and below the baffle plate 21. A number of baffle plates 21 are arranged alternately up and down, making the water flow flow in a meandering line.

[0050] The wastewater treatment method of this photocatalytic wastewater treatment device includes: the wastewater is pumped into the precision filter 3 through the water pump 7 for filtration. The filtered wastewater passes through the primary treatment tank 1 and the secondary treatment tank 2 in sequence, and the treated wastewater is discharged. The specific steps are as follows:

[0051] After the pre-treatment of the wastewater, through the filtration of the precision filter 7, the turbidity of the wastewater ≤ 3 NTU; the filtered wastewater enters the primary treatment tank 1 for photocatalytic oxidation. In the primary treatment tank 1, pneumatic lift pipes 13 are used on both sides to circulate and oxygenate the wastewater, maintaining the DO ≥ 6 mg / L in the wastewater, and the pneumatic lift circulation water volume is more than 5 times the water inflow of the primary treatment tank 1; 2 groups of catalytic oxidation components 4 are arranged in the primary treatment tank 1. The catalytic oxidation component 4 is composed of several ultraviolet lamp tubes 42 and several layers of honeycomb mesh photocatalytic plates 6. Among them, the photocatalytic plates 6 are placed horizontally, and several ultraviolet lamp tubes 42 vertically pass through several layers of photocatalytic plates 6 evenly. After the wastewater is circulated and treated in the primary treatment tank 1 for multiple times, it flows to the secondary treatment tank 2 through the communication pipeline 12 arranged in the upper area of the partition plate 11. 3 groups of catalytic oxidation components 4 are arranged in the secondary treatment tank 2, and the water flow is in a meandering and one-way circulation. The wastewater is discharged after being treated in the secondary treatment tank 2.

[0052] In the present invention, electrons (e - ) - hole (h + ) pairs are generated by exciting the catalyst with ultraviolet light. e -Generate superoxide radical (·O2 - ) with O2, and h + oxidize water or OH - to generate hydroxyl radical (·OH). During the photocatalysis process, the rapid recombination of photo-generated electrons (e - ) and holes (h + ) is the key factor limiting the efficiency. This invention patent uses an air-lift pipe and an aeration pipe to add an external oxidant O2 to the wastewater to improve the rate and efficiency of the photocatalytic oxidation reaction, inhibit electron-hole recombination, and enhance charge separation. Its mechanism of action is as follows: Using O2 as an electron acceptor, it quickly captures the electrons in the conduction band (CB) to generate superoxide radical (·O2 - ). The consumption of conduction band electrons reduces the probability of recombination with valence band holes (h + ), thereby prolonging the carrier lifetime. The addition of O2 significantly improves the photocatalytic efficiency, inhibits charge recombination, provides additional free radicals and multi-path synergistic oxidation.

Claims

1. A photocatalytic oxidation wastewater treatment device, characterized in that: The invention comprises a primary treatment tank (1), a secondary treatment tank (2), a filter (3), a catalytic oxidation component (4) and an aeration component (5), wherein the primary treatment tank (1) is connected to the secondary treatment tank (2), the filter (3) is connected to the primary treatment tank (1) through a pipeline, the catalytic oxidation component (4) is respectively arranged inside the primary treatment tank (1) and the secondary treatment tank (2), and the aeration component (5) is respectively connected to the primary treatment tank (1) and the secondary treatment tank (2).

2. A photocatalytic oxidation wastewater treatment device as claimed in claim 1, characterized in that: A partition (11) is arranged between the primary treatment tank (1) and the secondary treatment tank (2), a connecting pipe (12) is arranged on the partition (11), and a lifting pipe (13) is arranged in the primary treatment tank (1).

3. A photocatalytic oxidation wastewater treatment device as claimed in claim 1, characterized in that: The catalytic oxidation assembly (4) comprises a bracket (41), a photocatalytic plate (6) and an ultraviolet lamp (42); the bracket (41) is connected to the inner walls of a primary treatment tank (1) and a secondary treatment tank (2) via a support member (43); and the photocatalytic plate (6) and the ultraviolet lamp (42) are respectively connected to the bracket (41).

4. A photocatalytic oxidation wastewater treatment device as claimed in claim 3, characterized in that: The photocatalytic plates (6) are arranged horizontally, and a plurality of layers of the photocatalytic plates (6) are arranged in sequence from bottom to top in the vertical direction. A plurality of ultraviolet lamp tubes (42) are arranged vertically, and the ultraviolet lamp tubes (42) are arranged to penetrate the photocatalytic plates (6).

5. A photocatalytic oxidation wastewater treatment device as claimed in claim 3, characterized in that: The base material of the photocatalytic plate (6) is aluminum, and the surface coating material is TiO2.

6. A photocatalytic oxidation wastewater treatment device as claimed in claim 3, characterized in that: The photocatalytic plate (6) is provided with a specific surface area of ​​not less than 400m 2 / g honeycomb mesh, the honeycomb mesh is arranged in an oblique hole.

7. A photocatalytic oxidation wastewater treatment device as claimed in claim 1, characterized in that: The filter (3) comprises a housing (31), a partition (32) and a filter element (33); the partition (32) and the filter element (33) are arranged in the housing (31); and the filter element (33) is connected to the housing (31) via the partition (32).

8. The photocatalytic oxidation wastewater treatment device according to claim 1, characterized in that: The aeration assembly (5) comprises an aeration fan (51), a main pipeline (52) and an aeration pipe (53); the aeration fan (51) is connected to the air inlet end of the main pipeline (52); the main pipeline (52) is connected to the aeration pipe (53) via a branch pipeline (54); an air supply pipe (55) is arranged on the main pipeline (52); the aeration pipe (53) and the air supply pipe (55) are arranged at the bottom of the primary treatment tank (1) and the secondary treatment tank (2).

9. A photocatalytic oxidation wastewater treatment device as claimed in claim 8, characterized in that: A one-way valve (56) is provided on the main pipeline (52), valves (57) are provided on the branch pipeline (54) and the air supply pipe (55), and a plurality of air nozzles (58) are provided on the aeration pipe (53).

10. The photocatalytic oxidation wastewater treatment device according to claim 1, characterized in that: A baffle (21) is arranged in the secondary treatment tank (2), one end of the baffle (21) is connected to the inner wall of the secondary treatment tank (2), and the water inlet end of the filter (3) is connected to the water inlet pump (7) through a pipeline.

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