Baffling type photocatalytic sewage purification method

Abstract

The invention discloses a baffling type photocatalytic sewage purification method, and belongs to the technical field of sewage treatment. According to the photocatalytic sewage purification method, baffle plates are transversely and fixedly connected in a baffle box in a staggered mode, a light guide body is fixedly connected to the upper portions of the baffle plates, a photocatalytic filler layer is laid on the surfaces of the baffle plates, and the photocatalytic filler layer is prepared by bonding a single material or a mixed material of granular TiO2, ZnO and Al2O3; in specific use, sewage is guided by the baffle plate in the baffling box body, is purified under the synergistic photocatalysis effect of the light guide body and the photocatalysis filler, and is discharged out of the baffling box body after being purified, so that the photocatalysis process is promoted, and the photocatalysis efficiency is enhanced. The problem of low photocatalytic reaction efficiency caused by insufficient reaction in existing photocatalytic sewage treatment is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and more particularly to a baffled photocatalytic sewage purification method. Background Art

[0002] Sewage and wastewater have a significant impact on the human ecological environment. my country's sewage discharge has increased year by year, and water treatment capacity has also increased. Good water treatment technology is crucial for effective sewage treatment. Photocatalysis has gained attention for its high oxidation efficiency, zero secondary pollution, environmental sustainability, wide applicability, and low cost. Photocatalysts are a general term for chemical substances that can catalyze when stimulated by photons. They are typically powdered solids or liquid sols. However, the use of devices to implement photocatalysis technology generally has limitations. This can lead to inadequate sewage contact with the photocatalyst, resulting in an incomplete reaction and thus affecting the efficiency of the photocatalytic reaction. Summary of the Invention

[0003] 1. Technical problem to be solved by the invention: In response to the problem of low photocatalytic reaction efficiency caused by insufficient reaction in existing photocatalytic sewage treatment, the present invention provides a baffled photocatalytic sewage purification method. The sewage is purified in the baffle box through the baffle plate guidance, light guide and photocatalytic filler synergistic photocatalytic action, thereby improving the photocatalytic reaction efficiency.

[0004] 2. Technical solution: In order to achieve the above object, the technical solution provided by the present invention is: A baffled photocatalytic sewage purification method is disclosed, wherein a baffle is fixedly connected in a staggered transverse direction in a baffle box, a light guide is fixedly connected above the baffle, a photocatalytic filler layer is laid on the surface of the baffle, and the photocatalytic filler layer is made of a single material or a mixed material of granular TiO2, ZnO and Al2O3 bonded together; in specific use, sewage is purified in the baffle box through the guidance of the baffle, the synergistic photocatalytic action of the light guide and the photocatalytic filler, and is discharged from the baffle box after purification, thereby promoting the photocatalytic process and enhancing the photocatalytic efficiency.

[0005] A further technical solution is that the distance between the light guide and the photocatalytic filler layer is 4cm-10cm, that is, the height of the light guide. Within this height range, the light guide can effectively transmit the light emitted by the light source to the photocatalyst filler area. Light will attenuate to a certain extent during the propagation process. The minimum height of 4cm can ensure that there is enough light energy to reach the filler surface to excite the photocatalyst. The maximum height of 10cm is to avoid excessive attenuation of light during the propagation process and ensure the utilization rate of light energy; if the height of the light guide is less than 4cm, it may not be able to fully transmit light to the entire filler area; if it is greater than 10cm, the excessive attenuation of light intensity will reduce the photocatalytic efficiency; the radius of the light guide is 1cm-5cm; ensure that light can be evenly distributed on the surface of the photocatalyst filler. A suitable radius can ensure that the luminous area of the light guide is moderate, so that the light energy can evenly cover the filler area and avoid uneven light distribution; if the radius is less than 1 cm, the luminous area of the light guide is too small, which may cause uneven light distribution on the filler surface, with too strong light intensity in some areas and too weak light intensity in some areas, affecting the uniformity of the photocatalytic reaction; if the radius is greater than 5 cm, the luminous area of the light guide is too large, which may cause increased energy loss during the propagation of light, and also increase the manufacturing cost of the equipment; the surface of the photocatalytic filler layer is distributed in an arc shape with a height of 0.5-3 cm, ensuring that the sewage can fully contact the photocatalyst filler on the baffle; when the filler height is too low, less than 0.5 cm, the photocatalytic reaction surface area provided by the filler is insufficient, making it difficult to effectively adsorb and degrade pollutants in the sewage, while the filler height is too high, greater than 3 cm, which will increase the flow resistance of sewage in the packing layer, and may prevent the water from flowing evenly through the packing layer, resulting in short-flow or dead zone phenomena, and reducing the efficiency of the photocatalytic reaction; the height of the sewage water layer is controlled at 0.5-4cm to form an appropriate liquid film thickness on the surface of the photocatalyst; if the water layer is too thin, less than 0.5cm, the sewage will stay on the packing surface for too short a time, the contact time between the pollutants and the photocatalyst will be insufficient, and the photocatalytic reaction will be difficult to proceed fully; if the water layer is too thick, greater than 4cm, it will increase the attenuation of light in the water, making it impossible for the light emitted by the ultraviolet lamp to effectively penetrate deep into the packing, reducing the utilization rate of the photocatalyst, and at the same time increasing the resistance of the water flow, affecting the flow state of sewage in the reactor; the arc surface distribution can be a convex arc surface or a concave arc surface, so as to expand the contact surface between the photocatalytic packing layer and the submersible, and further enhance the photocatalytic efficiency.

[0006] A further technical solution is that the baffle is a stepped baffle, and the photocatalytic filler layer is also laid in a corresponding stepped manner. The sewage flows down in a stepped manner, which can better contact the filler; the hydraulic retention time of the sewage in the baffle box is 1min-20min. The photocatalytic reaction requires a certain amount of time for the photocatalyst to fully adsorb the pollutants in the sewage, and undergo oxidation-reduction reactions under the action of light to degrade the pollutants; a shorter hydraulic retention time means that the reactor has a stronger processing capacity and can process a large amount of sewage in a shorter time, but may reduce the purification effect; a longer hydraulic retention time can improve the purification effect, but will increase the volume and cost of the reactor and reduce the operating efficiency of the equipment; the range of 1-20min ensures a certain purification effect while also taking into account the processing capacity and economy of the equipment. For some pollutants with faster reaction rates, a shorter hydraulic retention time, such as 1-5 minutes, may be sufficient to achieve a better purification effect; while for pollutants with slower reaction rates, a longer hydraulic retention time, such as 10-20 minutes, is required to ensure the full progress of the reaction; the light intensity of the light guide is 130lux-160lux, and the wavelength is 190nm-400nm; catalysts generally have the ability to absorb and utilize light within a specific wavelength range. The wavelength range is set to 190-400nm in order to cover the effective spectral response range of the photocatalyst, so that the photocatalyst can fully utilize the light emitted by the light source for photocatalytic reactions and improve the utilization rate of light energy. Different pollutants in sewage may have different absorption and reaction characteristics to light of different wavelengths; the wavelength range of 190-400nm covers the ultraviolet light region, 10-400nm and part of the visible light region, 400-760nm, and the upper limit of 400nm is mainly the ultraviolet light region. Light within this range can undergo photochemical reactions with a variety of pollutants, or degrade pollutants through photocatalytic effects.

[0007] A further technical solution is a stepped baffle with a slope structure, with a slope of 1%-0.3%. This ensures that the water has the potential energy to flow downward while delaying the hydraulic retention time of the sewage in the device. Gravity is used to give the water the potential energy to flow downward, ensuring that the sewage can flow smoothly within the reactor. This small slope allows the sewage to flow through each section of the baffle in sequence without consuming too much additional energy, achieving a stepped downward flow. If the slope is too small, less than 0.1%, gravity may not be sufficient to overcome the friction and other resistance of the water on the baffle, causing the water to flow slowly or even stagnate, affecting the sewage treatment efficiency. If the slope is too large, greater than 0.3%, the water flow rate will be too fast, reducing the contact time between the sewage and the photocatalyst filler and reducing the effect of the photocatalytic reaction. A smaller slope range can ensure the structural stability and installation accuracy of the baffle. Excessively large slopes may complicate the structure of the baffles, increasing the difficulty of manufacturing and installation, and may cause the baffles to vibrate or displace under the impact of water flow, affecting the normal operation of the equipment; the upper and lower spacing of the baffles is 2.5-5 cm, which helps to enhance the mass transfer process between pollutants in the water and the photocatalyst filler. In a photocatalytic water purification reactor, appropriate baffle spacing is conducive to the water flow passing through the photocatalyst filler area at an appropriate speed and path, thereby fully contacting the light emitted by the ultraviolet lamp. If the baffle spacing is set in the range of 2.5-5 cm, it can ensure that the water flow in the tube body has sufficient time to contact the photocatalyst and ultraviolet light, allowing the photocatalytic reaction to proceed effectively; when the spacing is too large, greater than 5 cm, the water flow rate may be too fast, resulting in insufficient contact time between the water and the photocatalyst and ultraviolet light, affecting the full progress of the photocatalytic reaction and reducing the water purification efficiency; and when the spacing is too small, less than 2.5 cm, the water flow may be too slow, and even water flow short-circuiting or dead corners may occur, which is also not conducive to the uniform development of the photocatalytic reaction throughout the tube body.

[0008] A further technical solution is that a vertical baffle is fixedly connected to the step-connected parts of the stepped baffles, and the height of the baffle is slightly higher than the photocatalytic filler layer to prevent the water flow from carrying the filler down or forming accumulations at the broken bottom.

[0009] A further technical solution is that a protective cover is installed around the light guide, and the light guide is arranged inside the protective cover to prevent the light source from being covered by sewage, resulting in insufficient light intensity in the device, affecting the sewage purification effect. At the same time, it can also slow down the wear of the light guide caused by long-term contact with sewage and extend the service life of the light guide.

[0010] A further technical solution is to set reflective mirrors on the inner wall of the deflector box and the bottom surface of the deflector, so that the bottom surface and four sides of the deflector that contact the filler have a reflective function, thereby improving the utilization rate of the light emitted by the light-emitting element in the cavity of the light guide, thereby improving the photocatalytic effect of the filler placed on the surface of the deflector.

[0011] A further technical solution is that the photocatalytic filler layer is granular TiO2 doped with rare earth element Tb, with a doping rate of 0.1-0.2% or RGO / TiO2 composite material, which can further improve the photocatalytic efficiency when combined with appropriate process conditions.

[0012] A further technical solution is to connect the water inlet to an external water pump, which controls the uniform water inflow, and install an interception filter at the water outlet to prevent the water from carrying away the filler and flowing out.

[0013] A further technical solution is that the baffle is made of metal or silicate, the reflective mirror surface is metal polished, and a mirror structure or an electroplated reflective coating structure is set inside the silicate plate, so that the bottom surface and four sides of the baffle contacting the filler have a reflective function.

[0014] 3. Beneficial effects: Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: In the baffled photocatalytic sewage purification method of the present invention, sewage flows into the box through the water inlet, the light guide is located on the water surface, the photocatalyst filler is located underwater, and the sewage flows down in a stepped manner to fully contact the filler. Under the action of the photocatalyst, the sewage can be purified. At the same time, the photocatalytic process is promoted under the action of the ultraviolet lamp, thereby improving the photocatalytic reaction degradation rate of the sewage and the removal rate of pollutants, and enhancing the photocatalytic efficiency by more than 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a baffled photocatalytic sewage purification device according to a specific embodiment.

[0016] In the figure: 1. Water inlet pump; 2. Baffle box; 3. Protective cover; 4. Light guide; 5. Reflective mirror; 6. Baffle; 7. Baffle; 8. Intercepting filter; 9. Photocatalytic filler layer; 21. Water inlet; 22. Water outlet. DETAILED DESCRIPTION

[0017] In order to further understand the content of the present invention, the invention is described in detail with reference to the accompanying drawings.

[0018] Example 1 The baffled photocatalytic sewage purification device and purification method of this embodiment are as follows: Figure 1As shown, the purification device includes a baffle box 2, a light guide 4, a baffle 6 and a photocatalytic filler layer 9; the baffle box 2 is a sealed box made of a non-transparent material, with a water inlet 21 provided on the upper portion of one side wall and a water outlet 22 provided on the lower portion of the other side wall; there are multiple light guides 4, which are fixedly connected transversely to the top surface of the baffle box 2 and the lower plate surface of the baffle 6; the baffle 6 is fixedly connected transversely to the inner wall of the baffle box 2, with alternate water flow spacing reserved between its free end and the side wall where the water inlet 21 and the water outlet 22 are located, forming an S-shaped return water flow direction; the photocatalytic filler layer 9 is laid on the upper plate surface of the baffle 6. That is, the baffle is fixedly connected transversely in the baffle box, the light guide is fixedly connected above the baffle, and the photocatalytic filler layer is laid on the surface of the baffle, and the photocatalytic filler layer is made of a single material or a mixed material of granular TiO2, ZnO and Al2O3.

[0019] In the deflection-type photocatalytic sewage purification method of this embodiment, during specific use, sewage flows into the deflection box 2 through the water inlet 21, the light guide 4 is located above the water surface, and the photocatalytic filler layer 9 is located below the water surface. The sewage flows in an S-shaped return flow direction. The sewage is purified in the deflection box through the deflection plate guidance, the light guide and the photocatalytic filler under the synergistic photocatalytic action, and can fully contact the filler, thereby enhancing the photocatalytic efficiency.

[0020] Example 2 The baffled photocatalytic sewage purification device and method of this embodiment has the same basic structure as that of embodiment 1, except that: Figure 1 As shown, the surface of the photocatalytic filler layer 9 is distributed in an arc surface, which can be a convex arc surface or a concave arc surface, so as to expand the contact surface between the photocatalytic filler layer 9 and the submersible, and further enhance the photocatalytic efficiency. The baffle 6 is a stepped baffle, and the photocatalytic filler layer 9 is also laid in a corresponding stepped manner. The sewage flows down in a stepped manner, which can more fully contact the filler. The stepped baffle has a sinking slope structure. The stepped baffles are fixedly connected to the step connection points of the step baffles. The height of the baffle 7 is slightly higher than the photocatalytic filler layer 9 to prevent the water flow from carrying the filler down or forming accumulations at the bottom. A protective cover 3 is installed on the periphery of the light guide 4, and the light guide 4 is arranged inside the protective cover 3 to prevent the light source from being covered by sewage, resulting in insufficient light intensity in the device, affecting the sewage purification effect, and at the same time slowing down the wear of the light guide 4 caused by long-term contact with sewage, thereby extending the service life of the light guide 4. A reflective mirror 5 is provided on the inner wall of the deflection box 2 and the bottom surface of the deflection plate 6, so that the bottom surface and four sides of the deflection plate 6 contacting the filler have a reflective function, thereby improving the utilization rate of the light emitted by the light-emitting element in the cavity of the light guide 4, thereby improving the photocatalytic effect of the filler placed on the surface of the deflection plate 6.

[0021] Example 3 The baffled photocatalytic sewage purification device and method of this embodiment has the same basic structure as that of embodiment 2, except that: Figure 1 As shown, the water inlet 21 is externally connected to the water inlet pump 1, which controls the uniform water inlet. An interception filter 8 is installed at the water outlet 22 to prevent the water flow from carrying the filler out. The baffle 6 is a three-step stepped baffle, and the photocatalytic filler layer 9 is also laid in a corresponding three-step stepped manner. The stepped baffle has a settling slope structure, which delays the hydraulic retention time of sewage in the device while ensuring that the water flow has the potential energy to flow downward. There are at least three baffles 6. The light guide 4 is an ultraviolet lamp. The baffle 7 can be made of inorganic metal or silicate materials such as stainless steel, copper or glass. The reflective mirror surface is metal polished, and a mirror structure or an electroplated reflective coating structure is set inside the silicate plate, so that the bottom surface and four sides of the baffle contacting the filler have a reflective function, thereby improving the utilization rate of the light emitted by the light-emitting element in the cavity of the light guide 4, thereby improving the photocatalytic effect of the filler placed on the surface of the baffle 6.

[0022] In the baffled photocatalytic sewage purification method of this embodiment, sewage is pumped into the water inlet through the water inlet pump 1 and flows into the box body. The focusing component composed of the ultraviolet lamp tube and the reflective mirror 5 is located above the water surface, and the photocatalyst filler is located below the water surface. The sewage flows down in three steps in a stepped manner to fully contact the filler. Under the action of the photocatalyst, the sewage can be purified. At the same time, the photocatalytic process is promoted under the action of the ultraviolet lamp tube, further enhancing the photocatalytic efficiency.

[0023] Example 4 The baffled photocatalytic sewage purification device and method of this embodiment have the same basic structure and purification method as in Example 3. In the purification method, the various factors affecting the photocatalytic efficiency and the post-treatment efficiency of the sewage treatment are tested and compared as shown in Table 1: Table 1: Comparison of sewage treatment efficiency testing

[0024] The following conclusions can be drawn from the above comparison table: The packing layer is made of a single material, TiO2. The system is suitable for domestic wastewater containing organic matter, depending on factors such as packing height, baffle spacing, wastewater type, treatment time, light guide height / radius, and light intensity. COD removal rates can reach 75%-80%. TiO2 can effectively degrade organic matter in wastewater at a light intensity of 130 lux.

[0025] The ZnO packing layer, a single material, is suitable for wastewater containing heavy metal ions, and its removal rate can reach 65%-70%, depending on factors such as the packing material, packing height, baffle spacing, wastewater type, treatment time, light guide height / radius, and light intensity. This demonstrates that ZnO can photocatalytically reduce heavy metal ions under a light intensity of 130 lux.

[0026] The packing layer, made of a single material, Al2O3, is suitable for oily wastewater, and its oil removal rate can reach 60%-65%, depending on factors such as packing height, baffle spacing, wastewater type, treatment time, light guide height / radius, and light intensity. This demonstrates that Al2O3 removes oil through a combination of adsorption and photocatalysis.

[0027] The packing layer is The combined materials, combined with the corresponding filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity and other factors, are suitable for printing and dyeing wastewater. The COD removal rate can reach 85%-90%. The combined materials can synergistically degrade organic dyes in printing and dyeing wastewater under a light intensity of 140 lux.

[0028] The packing layer is The combined materials, combined with the appropriate filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity, and other factors, are suitable for hospital sewage, achieving a bacterial removal rate of 90%-95%. It has strong oxidizing properties under 140 lux light intensity and can kill bacteria. Impurities are further removed by adsorption.

[0029] The packing layer is The combined materials, in synergy with the corresponding filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity and other factors, are suitable for domestic sewage containing organic matter; the COD removal rate can reach 80%-85%. The combined material can effectively degrade organic matter and remove suspended solids under a light intensity of 140 lux.

[0030] The packing layer is The combined materials, combined with the corresponding filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity and other factors, are suitable for domestic sewage containing heavy metal ions, and the COD removal rate can reach 85%-90%. The heavy metal ion removal rate can reach 80%-85%.

[0031] The filler layer is TiO2 doped with the rare earth element Tb (terbium). When the Tb doping rate is 0.15%, under the synergistic effect of factors such as the corresponding filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity, the COD removal rate can reach 90.9%, which is more than 20% higher than before doping, achieving technical effects unexpected by technicians in this field.

[0032] The filler layer is an RGO / TiO2 composite material. Under the synergistic effect of factors such as the corresponding filler height, baffle spacing, sewage type, treatment time, light guide height / radius / light intensity, the photocatalytic degradation rate of bisphenol A is 2.93 times that of pure TiO2, achieving technical effects that were unexpected by technicians in this field.

[0033] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure and manufacturing steps are not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without creatively designing them, they shall fall within the scope of protection of the present invention.

Claims

1. A baffled photocatalytic wastewater purification method, characterized in that: A baffle is fixedly connected to the baffle box in a displaced and transverse manner, a light guide is fixedly connected above the baffle, and a photocatalytic filler layer is laid on the surface of the baffle. The photocatalytic filler layer is made of a single material or a mixed material of granular TiO2, ZnO and Al2O3. The sewage is purified in the baffle box through the baffle guide, the light guide and the photocatalytic filler under the coordinated photocatalytic action, and is discharged from the baffle box after purification.

2. The baffled photocatalytic wastewater purification method according to claim 1, characterized in that: The distance between the light guide and the photocatalytic filler layer is 4cm-10cm, and the radius is 1cm-5cm; the surface of the photocatalytic filler layer is distributed in an arc shape, and the height is 0.5-3cm.

3. The baffled photocatalytic wastewater purification method according to claim 1, characterized in that: The baffle is a stepped baffle, and the photocatalytic filler layer is also laid in a corresponding stepped manner; the hydraulic retention time of sewage in the baffle box is 1min-20min; the light intensity of the light guide is 130lux-160lux.

4. The baffled photocatalytic wastewater purification method according to claim 3, characterized in that: The stepped baffle plate sinking slope structure has a slope of 1%-0.3%; the upper and lower spacing of the baffle plates is 2.5-5 cm.

5. The baffled photocatalytic wastewater purification method according to claim 4, characterized in that: The step-type baffles are fixedly connected to the step-connected positions of the step-type baffles, and the height of the baffles is higher than the photocatalytic filler layer.

6. The baffled photocatalytic wastewater purification method according to claim 4, characterized in that: A protective cover is installed on the periphery of the light guide; and a reflective mirror is provided on the inner wall of the deflection box and the bottom plate of the deflection plate.

7. The baffled photocatalytic wastewater purification method according to claim 5, characterized in that: The photocatalytic filler layer is granular TiO2 doped with rare earth element Tb, with a doping rate of 0.1-0.2% or RGO / TiO2 composite material.

8. The baffled photocatalytic wastewater purification method according to claim 5 or 7, characterized in that: The baffle is made of metal or silicate, the reflective mirror surface is metal polishing, and a mirror structure or an electroplated reflective coating structure is arranged inside the silicate plate.

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