Photocatalytic reactor and application thereof

Abstract

The invention relates to the field of risk management and control of organic pollution sites, and discloses a photocatalytic reaction device and application thereof. The photocatalytic reaction device comprises a columnar light guide frame and a light source groove, the light source groove is arranged along the central axis of the columnar light guide frame, the light source groove is used for placing a photocatalytic light source, and the light source groove is connected with the columnar light guide frame through a plurality of light guide plates. An inner cavity of the columnar light guide frame is divided into a plurality of chambers through the light guide plates, and the chambers are filled with photocatalytic reaction materials; a plurality of flow guide grooves are formed in the outer wall of the columnar light guide frame, and the flow guide grooves are used for guiding underground water to circulate; a shell sleeve is arranged on the periphery of the columnar light guide frame and is made of a photocatalytic reaction material. According to the photocatalytic reaction device, the light utilization efficiency is improved, the enrichment effect of pollutants in a reaction medium is enhanced, and the removal efficiency of the pollutants is improved.

Description

Technical Field

[0001] This invention relates to the field of risk management technology for organic contaminated sites, specifically to a photocatalytic reaction device and its application. Background Technology

[0002] With the rapid development of society, economy, and industrialization, the problem of industrial site pollution is becoming increasingly serious. Benzene compounds, represented by benzene, xylene, styrene, and benzo[a]pyrene, are potent carcinogens and are widely present in contaminated sites. Due to their high toxicity and volatility, they can not only diffuse through water bodies but also be adsorbed into groundwater, increasing environmental risks and remediation costs. Furthermore, remediation may result in backflow and continued pollution, further increasing the risk of site contamination. If left uncontrolled, this will cause profound harm to surrounding sensitive receptors. Therefore, adopting targeted technologies and materials to achieve long-term and effective risk management of contaminated sites is of great significance.

[0003] Photocatalysis, as a green and efficient advanced oxidation technology, is a method of material conversion using light energy. It has wide applications in water splitting, CO2 reduction, water pollution control, and organic synthesis. In water pollution control, photocatalysis can effectively treat Cr... 6+ Pt 4+ Au 3+ Heavy metals and organic pollutants such as benzene compounds, halides, and cyanides are characterized by being safe, controllable, and causing no secondary pollution. Therefore, photocatalysis technology has broad application value in the remediation of contaminated sites.

[0004] In the field of site pollution control and remediation, research on photocatalysis technology mainly revolves around the preparation of photocatalysts and the development of photocatalytic reaction devices. Regarding photocatalyst preparation, patent application CN113509813B discloses a method for synthesizing Ag@Fe3O4@C / TiO2 nanomaterials and their applications. This invention solves the bandgap problem of titanium dioxide photocatalysis by synthesizing photocatalytic nanomaterials through doping, and utilizes visible light to remove formaldehyde and benzene compounds. Regarding the development of photocatalytic reaction devices, patent application CN215102562U discloses a device for remediating organically polluted groundwater. This device is directly deployed in the contaminated site, intercepting and filtering the contaminated groundwater through a flow guide wall and filter layer. After treatment by the built-in photocatalytic unit, the organic pollutants in the groundwater are degraded and removed. However, this device still suffers from low light utilization efficiency and easy clogging of the photocatalytic reaction material.

[0005] Therefore, there is an urgent need to develop a photocatalytic reaction device to improve light utilization efficiency, enhance the enrichment of pollutants in the reaction medium, and solve the problem of easy clogging of photocatalytic reaction materials in the process of soil and groundwater management. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low light utilization efficiency and poor pollutant enrichment in the existing technology of soil and groundwater treatment and management. It provides a photocatalytic reaction device and its application. This photocatalytic reaction device improves light utilization efficiency by optimizing the distribution of the catalytic reaction light field. Moreover, by loading photocatalytic materials and adsorbent materials, it enhances the enrichment of pollutants in the reaction medium, solves the problem of easy clogging of photocatalytic reaction materials, and utilizes the excitation of free radicals by ultraviolet light, thereby improving the removal efficiency of pollutants.

[0007] To achieve the above objectives, a first aspect of the present invention provides a photocatalytic reaction device. The photocatalytic reaction device includes a cylindrical light guide frame and a light source slot. The light source slot is arranged along the central axis of the cylindrical light guide frame and is used to hold a photocatalytic light source. The light source slot is connected to the cylindrical light guide frame through a plurality of light guide plates, and the plurality of light guide plates divide the inner cavity of the cylindrical light guide frame into a plurality of chambers, each chamber being filled with a photocatalytic reaction material. A plurality of flow channels are formed on the outer wall of the cylindrical light guide frame for guiding the flow of groundwater. A shell is provided on the outer periphery of the cylindrical light guide frame, and the shell is formed of a photocatalytic reaction material.

[0008] Preferably, the light guide frame and the light guide plate are made of at least one of acrylic resin, polycarbonate and epoxy resin.

[0009] Preferably, the number of light guide plates is 4-8.

[0010] Preferably, the outer surfaces of the light guide frame and the light guide plate are respectively coated with TPU film layers.

[0011] Preferably, the photocatalytic reaction material includes optical fiber fabric and a photocatalyst and adsorbent loaded on the optical fiber fabric.

[0012] Preferably, the photocatalyst is TiO2.

[0013] Preferably, the adsorbent is activated carbon and / or molecular sieve.

[0014] Preferably, the optical fiber fabric is made of polystyrene and / or polycarbonate.

[0015] Preferably, the photocatalytic reaction material is prepared through the following steps:

[0016] The surface of the optical fiber fabric is etched to form several light leakage points, then photocatalysts and adsorbents are loaded sequentially, and then folded and shaped.

[0017] Preferably, the housing is wrapped around the bottom and sides of the light guide frame.

[0018] Preferably, the photocatalytic reaction material used to form the shell is the same as the photocatalytic reaction material filled in the cavity.

[0019] The second aspect of this invention provides the application of the above-mentioned photocatalytic reaction device in the management and control of soil and groundwater.

[0020] Preferably, the photocatalytic reaction device is installed on a permeable reaction wall and / or a bioreactor core.

[0021] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0022] (1) Based on the high efficiency and controllability of photocatalysis technology, it can treat specific pollutants in a targeted manner. At the same time, it can also treat different target pollutants by adjusting the material formula and light source wavelength, making it suitable for site pollution control and remediation under complex pollution conditions.

[0023] (2) By introducing light-conducting materials and adjusting the device structure and combination method, it can be applied in different scenarios and can be adapted to various site pollution in-situ treatment technologies such as permeable reactive walls, bio-reactive cores, and extraction treatment. It can effectively improve light utilization efficiency and pollutant treatment efficiency while ensuring the long-term effectiveness of the treatment process, and achieve effective treatment and long-term management of polluted sites in multiple scenarios.

[0024] (3) By combining the use of benzene series adsorption materials, photocatalytic materials and adsorption materials are coupled. By adjusting the ratio and carrier structure, the two processes of pollutant adsorption and photocatalytic reaction are carried out efficiently, thereby further improving the intensity of photocatalytic reaction.

[0025] (4) In the treatment and management of soil and groundwater, by controlling the wavelength of the light source, the number of microbial populations within the treatment area can be reduced while treating pollutants, the generation of bacterial flocs can be reduced, the problem of easy clogging of reaction media can be solved, and the long-term effectiveness of treatment and remediation can be guaranteed.

[0026] (5) No reagents need to be added during the treatment of pollutants, making it green, efficient, and avoiding secondary pollution. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the photocatalytic reaction device described in this invention;

[0028] Figure 2 This is a schematic diagram of the structure of the photocatalytic reaction device and the permeable reactive wall technology described in this invention.

[0029] Figure 3This is a schematic diagram of the structure of the photocatalytic reaction device and the bioreactor core technology described in this invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Light guide frame; 2. Chamber; 3. Light source slot; 4. Flow guide slot; 5. Shell; 6. Light guide plate. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] like Figure 1 As shown, the photocatalytic reaction device of the present invention includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place a photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through several light guide plates 6, and the several light guide plates 6 divide the inner cavity of the cylindrical light guide frame 1 into several chambers 2, which are filled with photocatalytic reaction material. Several flow channels 4 are formed on the outer wall of the cylindrical light guide frame 1, which are used to guide the flow of groundwater. A shell 5 is provided on the outer periphery of the cylindrical light guide frame 1, and the shell 5 is formed of photocatalytic reaction material. According to the photocatalytic reaction device of the present invention, the main line and branch line light paths are designed in the partitioned core by using light guide plates and light guide fiber materials to optimize the distribution of the catalytic reaction light field, improve light utilization efficiency, and achieve long-term treatment of pollution within the effective range.

[0035] In the photocatalytic reaction device of the present invention, the light guide frame 1 and the light guide plate 6 are respectively made of at least one of acrylic resin, polycarbonate, and epoxy resin. To ensure the stable conduct of the photocatalytic reaction, the light guide frame 1 and the light guide plate 6 are preferably made of at least one of optical-grade acrylic resin, optical-grade polycarbonate, and optical-grade epoxy resin, more preferably optical-grade acrylic resin. In the present invention, to ensure uniform light distribution and thus stable photocatalytic reaction, the light guide frame 1 is preferably columnar. The diameter of the light guide frame 1 can be 250-350 mm, preferably 260-325 mm; the height of the light guide frame 1 can be 700-1200 mm, preferably 800-1000 mm.

[0036] In the photocatalytic reaction device of the present invention, the number of light guide plates 6 can be 4-8, preferably 5-7. The height of the light guide plate 6 can be 700-1200mm, preferably 800-1000mm. In a preferred embodiment, the height of the light guide plate 6 is the same as the height of the light guide frame 1. The main and branch light paths are adjusted by the light guide frame 1 and the light guide plate 6 to ensure uniform light distribution. The number of chambers 2 is the same as the number of light guide plates 6.

[0037] In the photocatalytic reaction device of the present invention, the outer surfaces of the light guide frame 1 and the light guide plate 6 may be coated with TPU film layers, preferably high-transparency TPU films. The TPU film layer is a polyurethane film layer, the light transmittance of the high-transparency TPU film is 85-92%, the thickness of the high-transparency TPU film is 0.05-0.1 mm, and the high-transparency TPU film can have wear-resistant and low-temperature resistant properties. In the present invention, the high-transparency TPU film can be commercially available or prepared according to conventional methods in the art. Specific preparation methods can be found in patent application CN115260450B.

[0038] In the photocatalytic reaction device of the present invention, to ensure uniform light distribution, the photocatalytic light source is preferably located in the center of the photocatalytic reaction device and extends throughout the entire device. The photocatalytic light source can be an ultraviolet light source. The wavelength of the photocatalytic light source can be 300-400 nm, preferably 340-380 nm; the light intensity of the photocatalytic light source can be 0.3-0.6 mW / cm². 2 The preferred value is 0.4-0.6 mW / cm. 2 When the target pollutant is xylene, the wavelength of the photocatalytic light source is determined to be 365 nm, and the light intensity of the photocatalytic light source is 0.5 mW / cm². 2When the target pollutant is styrene, the wavelength of the photocatalytic light source is determined to be 275 nm, and the light intensity of the photocatalytic light source is 0.7 mW / cm². 2 The diameter of the light source slot 3 can be 25-40mm, preferably 30-34mm. In practical applications, by controlling the wavelength of the light source, the number of microbial populations within the treatment area can be reduced while treating pollutants, the generation of bacterial flocs can be reduced, the problem of easy clogging of photocatalytic reaction materials can be solved, and the long-term effectiveness of treatment and remediation can be guaranteed.

[0039] In the photocatalytic reaction device of the present invention, the photocatalytic reaction material may include optical fiber fabric and a photocatalyst and adsorbent supported on the optical fiber fabric. By adjusting the pore size distribution and functional group distribution of the adsorbent material, the selective adsorption of target pollutants is enhanced. The adsorption can also enrich the target pollutants and provide a driving force for the migration of target pollutants within the treatment range. Moreover, by coupling the photocatalytic material and the adsorbent material, the photocatalytic reaction efficiently removes the target pollutants, releases the adsorption sites of the material, and restores the adsorption capacity of the material. Thus, by adjusting the ratio and the carrier structure, the two processes of pollutant adsorption and photocatalytic reaction can be carried out efficiently, achieving long-term treatment of pollution within the treatment range. In a specific embodiment, the mass ratio of the photocatalyst, the adsorbent, and the optical fiber fabric is 1:(300-600):(50-100).

[0040] In the photocatalytic reaction device of the present invention, the photocatalyst can be TiO2. To ensure the intensity of the photocatalytic reaction, the TiO2 is preferably nano-TiO2. In some specific embodiments, the diameter of the nano-TiO2 is 2-20 nm. In the present invention, the nano-TiO2 can be commercially available or prepared according to conventional methods in the art. Specific preparation methods can be found in patent application CN117088407B.

[0041] In the photocatalytic reaction device of the present invention, the adsorbent can be activated carbon and / or molecular sieve. The adsorption capacity for benzene compounds is enhanced by adjusting the pore size and functional groups of the activated carbon or molecular sieve. To enhance the adsorption capacity for pollutants, the activated carbon is preferably mesoporous activated carbon. The median pore size of the mesoporous activated carbon is preferably 3-30 nm, more preferably 3.5-5.5 nm; the activated carbon contains at least one of hydroxyl, carboxyl, and ketone groups. The median pore size of the molecular sieve is preferably 2-20 nm, more preferably 2-3 nm.

[0042] In the photocatalytic reaction device of the present invention, the optical fiber fabric can be made of polystyrene and / or polycarbonate. The diameter of the optical fiber material in the optical fiber fabric can be 0.1-0.7 mm, preferably 0.3-0.5 mm. The optical fiber fabric can adjust the main and branch optical paths, thereby optimizing the light field distribution of the catalytic reaction and improving light utilization efficiency.

[0043] In the photocatalytic reaction device of the present invention, the photocatalytic reaction material can be prepared by the following steps: the surface of the optical fiber fabric is etched to form a number of light leakage points, then the photocatalyst and adsorbent are loaded sequentially, and then the fabric is folded and shaped.

[0044] The surface engraving operation can be carried out by extrusion imprinting to arrange a number of light leakage points on the surface of the optical fiber.

[0045] The process of loading the photocatalyst may include: loading the photocatalyst onto the surface of the optical fiber fabric after surface marking by a dip-coating method. The specific method of the dip-coating method can be found in patent application CN110064439B. Specifically, nano-TiO2 is prepared into an ethanol solution with a concentration of 0.1-0.3 wt%, and ultrasonically stirred to uniformly disperse the nano-TiO2 to form a seed solution. The optical fiber fabric is then immersed in the seed solution for 6-18 hours, and then removed and dried at 50-100°C for later use.

[0046] The process of loading the adsorbent may include: immersing the adsorbent in acid, followed by low-temperature drying, and then sequentially dispersing it in ethanol, padding, and drying. The acid may be hydrochloric acid and / or nitric acid, preferably hydrochloric acid. The concentration of the acid may be 0.1-1 mol / L, preferably 0.3-0.8 mol / L. The low-temperature drying conditions include: a temperature of 40-60℃, preferably 55-60℃; and a time of 8-12 h, preferably 10-12 h. The concentration of the ethanol may be 30-75%. The padding conditions include: a temperature of 50-80℃, preferably 65-80℃; and a time of 0.5-1 h, preferably 0.5-0.6 h. The drying conditions include: a temperature of 105-200℃, preferably 130-180℃; and a time of 2-8 h, preferably 2-4 h.

[0047] In the photocatalytic reaction device described in this invention, the flow channel 4 guides the flow of groundwater, enhancing the material cycle in the reaction process and reducing the impact on the groundwater flow field and water level during soil and groundwater remediation and management. The width of the flow channel 4 can be 15-35 mm, preferably 20-30 mm. The flow channel 4 can be arranged in an array. To ensure the pollution control effect, the flow channel 4 is preferably set in a horizontal direction.

[0048] In the photocatalytic reaction device of the present invention, in a preferred embodiment, the housing 5 wraps around the bottom and sides of the light guide frame 1. The thickness of the housing 5 can be 1-3 cm, preferably 1.5-2 cm. By adjusting the thickness of the housing 5, it can be adapted to geological conditions with different permeability. In practical applications, when the thickness of the housing 5 is 1-1.5 cm, it is suitable for weakly permeable layers with a permeability of 0.001-1 m / d, and when the thickness of the housing 5 is 1.5-3 cm, it is suitable for permeable layers with a permeability greater than 1 m / d.

[0049] In the photocatalytic reaction device of the present invention, in a preferred embodiment, the photocatalytic reaction material used to form the shell 5 is the same as the photocatalytic reaction material filling the chamber 2. In a specific example, the raw materials and preparation method for the photocatalytic reaction material of the shell 5 are the same as those for the photocatalytic reaction material filling the chamber 2.

[0050] In some specific embodiments, the photocatalytic reaction device of the present invention is a replaceable device structure, and the photocatalytic light source, photocatalytic reaction material, light guide frame and light guide plate can be adjusted and replaced according to changes in site pollution and device operation.

[0051] In some implementations, such as Figure 1 As shown, the photocatalytic reaction device of the present invention includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place a photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through 4-8 light guide plates 6, and the 4-8 light guide plates 6 divide the inner cavity of the cylindrical light guide frame 1 into 4-8 chambers 2, which are filled with photocatalytic reaction material. The outer wall of the cylindrical light guide frame 1 has a plurality of horizontally oriented guide channels 4, which are used to guide the flow of groundwater. The outer surface of the light guide frame 1 is coated with a TPU film layer with a light transmittance of 85-92%. The outer periphery of the cylindrical light guide frame 1 is provided with a shell 5 with a thickness of 1-3 cm, which is formed of photocatalytic reaction material. The light guide frame 1 and the light guide plate 6 are made of at least one of optical grade acrylic resin, optical grade polycarbonate and optical grade epoxy resin, respectively; the photocatalytic reaction material is prepared by etching the surface of the optical fiber fabric to form a number of light leakage points, then loading the photocatalyst and adsorbent in sequence, and then folding and shaping it; the photocatalytic reaction material used to form the shell 5 is the same as the photocatalytic reaction material filled in the chamber 2.

[0052] This invention also provides the application of the above-mentioned photocatalytic reaction device in the management and control of soil and groundwater. According to the application described in this invention, the photocatalytic reaction device improves light utilization efficiency and enhances the enrichment of pollutants in the reaction medium, thereby improving the timeliness and effectiveness of soil and groundwater management and control.

[0053] In the application described in this invention, the photocatalytic reaction device is mounted on a permeable reaction wall and / or a bioreactor core. The housing 5 can directly contact the outer shell of the permeable reaction wall and / or the bioreactor core. For example... Figure 2 As shown, the photocatalytic reaction device is mounted on the permeable reaction wall. Figure 3 As shown, the photocatalytic reaction device is installed on the bioreactor core.

[0054] In some implementations, the wavelength of the photocatalytic light source and the method of modifying the adsorbent material are determined through small-scale tests based on the composition of the target pollutant. Then, the specifications and structural design targets of the device of the present invention are determined based on the site geological conditions and in-situ treatment conditions. Finally, the reaction device is assembled and installed in the main body of the permeable reaction wall or bioreactor core project. The photocatalytic light source is started before the photocatalytic reaction material is fully impregnated, and the overall operation of the in-situ treatment technology begins.

[0055] In other embodiments, the device operation is continuously monitored by monitoring pollutant concentration and the internal light intensity of the photocatalytic reaction material. Once pollutant treatment is complete, the photocatalytic light source is turned off or the photocatalytic reaction device is removed. When the internal light intensity of the photocatalytic reaction material significantly decreases, the photocatalytic reaction device should be removed, and the operation of the photocatalytic light source and the state of the photocatalytic reaction material should be checked.

[0056] The following examples further illustrate the photocatalytic reaction device and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0057] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0058] Example 1

[0059] The photocatalytic reaction device of this embodiment includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place the photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through six light guide plates 6, and the six light guide plates 6 divide the inner cavity of the cylindrical light guide frame 1 into six chambers 2, which are filled with photocatalytic reaction material. Several horizontal flow channels 4 are formed on the outer wall of the cylindrical light guide frame 1, which are used to guide the flow of groundwater. The outer surface of the light guide frame 1 is covered with a TPU high-transmittance film (purchased from Zhongshan Boruis New Material Co., Ltd.) with a light transmittance of 92% and a thickness of 0.05 mm. A shell 5 with a thickness of 1.5 cm is provided on the outer periphery of the cylindrical light guide frame 1. The shell 5 is formed of photocatalytic reaction material. The light guide frame 1 and the light guide plate 6 are made of optical-grade acrylic resin. The preparation of the photocatalytic reaction material includes the following steps: surface marking of a polystyrene optical fiber fabric to form several light leakage points; preparation of 5nm diameter nano-TiO2 (purchased from Brofos Nanotechnology (Ningbo) Co., Ltd., brofos-TiO2) into a 0.1wt% ethanol solution; ultrasonic stirring to uniformly disperse the nano-TiO2 to form a seed solution; immersion of the optical fiber fabric in the seed solution for 6 hours; and then drying at 50℃. Carboxyl-containing activated carbon with a median pore size of 5.26 nm was immersed in 0.5 mol / L hydrochloric acid, then dried at 60 °C for 12 h, and then dispersed in 50% ethanol. Next, the optical fiber fabric was impregnated at 80 °C for 0.5 h and dried at 150 °C for 2 h. Finally, it was folded and shaped. The mass ratio of nano-TiO2, activated carbon and optical fiber fabric was 1:400:80. The photocatalytic reaction material used to form the shell 5 is the same as the photocatalytic reaction material filled in the chamber 2. The shell 5 is wrapped around the bottom and sides of the light guide frame 1.

[0060] The photocatalytic reaction device was tested in a sand box to evaluate its effectiveness by simulating the groundwater flow field and pollutant leakage and diffusion. The parameters of the photocatalytic reaction device are recorded in Table 1.

[0061] When the target pollutant is xylene, the wavelength of the photocatalytic light source is 365 nm, and the light intensity is 0.5 mW / cm². 2 50 μg of xylene was injected at the contaminant leakage point in the sand box to control the groundwater seepage rate at 0.04 m / h. The xylene concentration at different points in the sand box was measured 48 hours after the leakage and recorded in Table 2.

[0062] Example 2

[0063] The pollutants were treated according to the method of Example 1, except that the fiber optic fabric made of polystyrene was not surface-marked to form several light leakage points, but was directly loaded with nano-TiO2 and activated carbon in sequence, and then folded and shaped.

[0064] Comparative Example 1

[0065] The pollutants were treated according to the method in Example 1, except that the photocatalytic reactor was replaced with activated carbon adsorbent (4-12 mesh water treatment activated carbon, specific surface area 2059.36 m²). 2 / g). The results are shown in Table 2.

[0066] Table 1

[0067]

[0068] Table 2

[0069]

[0070] As can be seen from the data in Table 2, the comparison of xylene concentration data at different locations in Examples 1 and 2 with Comparative Example 1 shows that the photocatalytic reaction device described in this invention has a significant removal effect on groundwater pollutants, effectively inhibiting the diffusion of pollutants and achieving effective control and management of site pollution. The comparison of xylene concentration data at different locations in Examples 1 and 2 shows that light leakage points on the surface of the optical fiber fabric help remove groundwater pollutants.

[0071] Example 3

[0072] The photocatalytic reaction device of this embodiment includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place the photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through four light guide plates 6, and the inner cavity of the cylindrical light guide frame 1 is divided into four chambers 2 by the four light guide plates 6. The chambers 2 are filled with photocatalytic reaction material. The outer wall of the cylindrical light guide frame 1 has a plurality of horizontal flow channels 4, which are used to guide the flow of groundwater. The outer surface of the light guide frame 1 is covered with a TPU high-transmittance film (purchased from Dongguan Tepuyou Environmental Protection New Material Co., Ltd.) with a light transmittance of 85% and a thickness of 0.1 mm. The outer periphery of the cylindrical light guide frame 1 is provided with a shell 5 with a thickness of 2 cm, which is formed of photocatalytic reaction material. The light guide frame 1 and the light guide plate 6 are made of optical-grade polycarbonate. The preparation of the photocatalytic reaction material includes the following steps: the surface of the polycarbonate optical fiber fabric is etched to form several light leakage points; 2nm diameter nano-TiO2 (purchased from brofos-TiO2, Ningbo) is prepared into a 0.3wt% ethanol solution; ultrasonic stirring is used to uniformly disperse the nano-TiO2 to form a seed solution; the optical fiber fabric is then immersed in the seed solution for 12 hours, and then dried at 80℃. Molecular sieves with a median pore size of 2.35 nm were immersed in 0.5 mol / L hydrochloric acid, then dried at 40 °C for 10 h, and then dispersed in 30% ethanol. Next, optical fiber fabric was impregnated at 65 °C for 1 h and dried at 130 °C for 4 h. Finally, it was folded and shaped. The mass ratio of nano-TiO2, molecular sieve and optical fiber fabric was 1:600:100. The photocatalytic reaction material used to form the shell 5 was the same as the photocatalytic reaction material filled in the chamber 2. The shell 5 wrapped the bottom and sides of the light guide frame 1.

[0073] The photocatalytic reaction device was tested in a sand box to evaluate its effectiveness by simulating the groundwater flow field and pollutant leakage and diffusion. The parameters of the photocatalytic reaction device are recorded in Table 3.

[0074] When the target pollutant is styrene, the wavelength of the photocatalytic light source is 275 nm, and the light intensity is 0.7 mW / cm². 2 5 μg of styrene was injected at the contaminant leakage point in the sand box to control the groundwater seepage rate at 0.04 m / h. The styrene concentration at different points in the sand box was measured 48 hours after the leak and recorded in Table 4.

[0075] Example 4

[0076] The pollutants were treated according to the method in Example 3, except that the fiber optic fabric made of polystyrene was not surface-marked to form several light leakage points, but was directly loaded with nano-TiO2 and activated carbon in sequence, and then folded and shaped.

[0077] Comparative Example 2

[0078] The pollutants were treated according to the method in Example 3, except that the photocatalytic reactor was replaced with activated carbon adsorbent (4-12 mesh water treatment activated carbon, specific surface area 2638.96 m²). 2 / g). The results are shown in Table 4.

[0079] Table 3

[0080]

[0081] Table 4

[0082]

[0083] As shown in Table 4, the comparison of styrene concentration data at different locations in Examples 3 and 4 with Comparative Example 2 indicates that the photocatalytic reaction device described in this invention has a significant removal effect on groundwater pollutants, effectively inhibiting the diffusion of pollutants and achieving effective control and remediation of site pollution. The comparison of styrene concentration data at different locations in Examples 3 and 4 also shows that light leakage points on the surface of the optical fiber fabric contribute to the removal of groundwater pollutants.

[0084] Example 5

[0085] The photocatalytic reaction device of this embodiment includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place the photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through eight light guide plates 6, and the inner cavity of the cylindrical light guide frame 1 is divided into eight chambers 2 by the eight light guide plates 6. The chambers 2 are filled with photocatalytic reaction material. The outer wall of the cylindrical light guide frame 1 has a plurality of horizontal flow channels 4, which are used to guide the flow of groundwater. The outer surface of the light guide frame 1 is covered with a TPU high-transmittance film (purchased from Zhongshan Boruis New Material Co., Ltd.) with a light transmittance of 92% and a thickness of 0.05mm. The outer periphery of the cylindrical light guide frame 1 is provided with a shell 5 with a thickness of 2cm, which is formed of photocatalytic reaction material. The light guide frame 1 and the light guide plate 6 are made of optical-grade epoxy resin. The preparation of the photocatalytic reaction material includes the following steps: the surface of the fiber optic fabric made of polystyrene is etched to form several light leakage points; 20nm diameter nano-TiO2 (purchased from brofos-TiO2 (Ningbo) Co., Ltd.) is prepared into a 0.3wt% ethanol solution; ultrasonic stirring is used to uniformly disperse the nano-TiO2 to form a seed solution; then the fiber optic fabric is immersed in the seed solution for 18 hours, and then removed and dried at 100℃. Hydroxyl-containing activated carbon with a median pore size of 3.98 nm was immersed in 0.5 mol / L hydrochloric acid, then dried at 60 °C for 12 h, and then dispersed in 60% ethanol. Next, the optical fiber fabric was impregnated at 80 °C for 0.5 h and dried at 200 °C for 2 h. Finally, it was folded and shaped. The mass ratio of nano-TiO2, activated carbon and optical fiber fabric was 1:300:50. The photocatalytic reaction material used to form the shell 5 is the same as the photocatalytic reaction material filled in the chamber 2. The shell 5 is wrapped around the bottom and sides of the light guide frame 1.

[0086] The main pollutant in the soil groundwater is xylene. The groundwater depth is 5.3m, the aquifer is relatively homogeneous, and the groundwater flow direction and velocity are relatively stable. Detailed pollution characterization revealed the distribution of the underground pollution plume, which showed a low diffusion rate. The treatment of benzene series pollution in soil groundwater can be achieved by combining this with a permeable reactive barrier.

[0087] (1) Based on the on-site hydrogeological conditions, the actual groundwater flow field was simulated through a small-scale test. The structural design of the reaction device was optimized by adjusting the width of the diversion channel and the permeability coefficient of the photocatalytic reaction material. The permeability coefficient and hydraulic residence time of the photocatalytic reaction device were then adjusted and recorded in Tables 5 and 6.

[0088] (2) For the main pollutant xylene, and considering the specifications of the photocatalytic reaction device, a photocatalytic wavelength of 365nm and a light intensity of 0.5mW / cm² were selected. 2The ultraviolet light source is designed with a circuit layout scheme to avoid voltage interference between individual light sources and ensure stable light intensity output.

[0089] (3) The photocatalytic reaction devices are arranged in layers within the permeable reactive wall. The top view of the arrangement is as follows: Figure 2 As shown, this ensures that the layout of the reaction device effectively captures the contamination plume;

[0090] (4) Groundwater monitoring wells were set up 10m upstream and 5m downstream of the permeable reactive wall to monitor the changes in groundwater level and pollutant concentration. The results were recorded in Table 7. The overall treatment effect of the engineering technology and the individual operation status of the photocatalytic reaction device were judged by combining the internal light intensity detection of the photocatalytic reaction material.

[0091] Table 5

[0092]

[0093] Table 6

[0094]

[0095] Table 7

[0096]

[0097] As can be seen from the data in Table 7, the xylene concentration data at different locations in Example 3 indicate that the photocatalytic reaction device described in this invention, which is layered and filled within a permeable reaction wall as a reaction medium, helps to remove groundwater pollutants, effectively inhibits the diffusion of pollutants, and achieves effective treatment and control of site pollution.

[0098] Example 6

[0099] The photocatalytic reaction device of this embodiment includes a cylindrical light guide frame 1 and a light source slot 3. The light source slot 3 is arranged along the central axis of the cylindrical light guide frame 1 and is used to place the photocatalytic light source. The light source slot 3 is connected to the cylindrical light guide frame 1 through six light guide plates 6, and the six light guide plates 6 divide the inner cavity of the cylindrical light guide frame 1 into six chambers 2, which are filled with photocatalytic reaction material. Several horizontal flow channels 4 are formed on the outer wall of the cylindrical light guide frame 1, which are used to guide the flow of groundwater. The outer surface of the light guide frame 1 is covered with a TPU high-transmittance film (purchased from Zhongshan Boruis New Material Co., Ltd.) with a light transmittance of 92% and a thickness of 0.05 mm. A shell 5 with a thickness of 1.5 cm is provided on the outer periphery of the cylindrical light guide frame 1. The shell 5 is formed of photocatalytic reaction material. The light guide frame 1 and the light guide plate 6 are made of optical-grade acrylic resin. The preparation of the photocatalytic reaction material includes the following steps: the surface of the fiber optic fabric made of polystyrene is etched to form several light leakage points; 5nm diameter nano-TiO2 (purchased from brofos-TiO2, Ningbo) is prepared into a 0.1wt% ethanol solution; ultrasonic stirring is used to uniformly disperse the nano-TiO2 to form a seed solution; then the fiber optic fabric is immersed in the seed solution for 6 hours, and then removed and dried at 50℃. Molecular sieves with a median pore size of 2.41 nm were immersed in 0.5 mol / L hydrochloric acid, followed by low-temperature drying at 60 °C for 12 h. Then, they were dispersed in 65% ethanol, followed by padding of optical fiber fabric at 80 °C for 0.5 h and drying at 150 °C for 2 h. Finally, they were folded and shaped. The mass ratio of nano-TiO2, molecular sieve and optical fiber fabric was 1:600:100. The photocatalytic reaction material used to form the shell 5 was the same as the photocatalytic reaction material filled in the chamber 2. The shell 5 wrapped the bottom and sides of the light guide frame 1.

[0100] The main pollutant in the soil and groundwater is styrene. The groundwater is buried at a depth of 6.5m, the aquifer is relatively homogeneous, the groundwater flow direction is relatively stable and the flow velocity is low. Detailed pollution characterization revealed the distribution of the underground pollution plume, which showed a low diffusion rate. The treatment of benzene series pollution in the soil and groundwater was achieved by combining bioreactor core technology with the following methods:

[0101] (1) Design a photocatalytic reaction device adapted to the specifications of the bioreactor core. Based on the permeability of the water layer shell of the bioreactor core, adjust the width of the flow channel of the reaction device of the present invention, the permeability coefficient of the photocatalytic reaction material, and the overall permeability coefficient of the bioreactor core to achieve an effective hydraulic residence time and record it in Tables 8 and 9.

[0102] (2) For the main pollutant styrene, and considering the specifications of the photocatalytic reaction device, a photocatalytic wavelength of 275 nm and a light intensity of 0.7 mW / cm² were selected. 2The ultraviolet light source is designed with a circuit layout scheme to avoid voltage interference between individual light sources and ensure stable light intensity output.

[0103] (3) Figure 3 As shown, the photocatalytic reaction device of the present invention is fixed inside the bioreactor core by a snap fastener, and then the entire bioreactor core is deployed in the aquifer at the treatment site.

[0104] (4) A groundwater monitoring well was set up 1.5m downstream of the bioreactor core to monitor the changes in pollutant concentrations and record them in Table 10. The overall treatment effect of the engineering technology and the individual operation status of the photocatalytic reaction device were judged by combining the internal light intensity detection of the photocatalytic reaction material.

[0105] Table 8

[0106]

[0107] Table 9

[0108]

[0109] Table 10

[0110]

[0111] As can be seen from the data in Table 10, the styrene concentration data at different locations in Example 6 indicate that the photocatalytic reaction device of the present invention, combined with the bioreactor core technology, can effectively treat areas with high concentrations of pollutants by rationally deploying the bioreactor core, which helps to remove groundwater pollutants, effectively inhibits the spread of pollutants, and achieves effective treatment and control of site pollution.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A photocatalytic reaction device, characterized in that, The photocatalytic reaction device includes a columnar light guide frame (1) and a light source slot (3). The light source slot (3) is arranged along the central axis of the columnar light guide frame (1). The light source slot (3) is used to place the photocatalytic light source. The light source slot (3) is connected to the columnar light guide frame (1) through several light guide plates (6). The several light guide plates (6) divide the inner cavity of the columnar light guide frame (1) into several chambers (2). The chambers (2) are filled with photocatalytic reaction materials. The outer wall of the column-shaped light guide frame (1) is formed with a plurality of flow guide grooves (4), which are used to guide the flow of groundwater; The outer periphery of the column-shaped light guide frame (1) is provided with a shell (5), which is formed of a photocatalytic reaction material.

2. The photocatalytic reaction device according to claim 1, characterized in that, The light guide frame (1) and the light guide plate (6) are made of at least one of acrylic resin, polycarbonate and epoxy resin, respectively.

3. The photocatalytic reaction device according to claim 1 or 2, characterized in that, The number of light guide plates (6) is 4-8.

4. The photocatalytic reaction device according to any one of claims 1-3, characterized in that, The outer surfaces of the light guide frame (1) and the light guide plate (6) are respectively covered with TPU film layers.

5. The photocatalytic reaction device according to claim 1, characterized in that, The photocatalytic reaction material includes optical fiber fabric and photocatalyst and adsorbent loaded on the optical fiber fabric.

6. The photocatalytic reaction device according to claim 5, characterized in that, The photocatalyst is TiO2.

7. The photocatalytic reaction device according to claim 5, characterized in that, The adsorbent is activated carbon and / or molecular sieve.

8. The photocatalytic reaction device according to claim 5, characterized in that, The optical fiber fabric is made of polystyrene and / or polycarbonate.

9. The photocatalytic reaction device according to any one of claims 5-8, characterized in that, The photocatalytic reaction material is prepared through the following process: The surface of the optical fiber fabric is etched to form several light leakage points, then photocatalysts and adsorbents are loaded sequentially, and then folded and shaped.

10. The photocatalytic reaction device according to any one of claims 1-9, characterized in that, The housing (5) is wrapped around the bottom and sides of the light guide frame (1).

11. The photocatalytic reaction device according to any one of claims 1-10, characterized in that, The photocatalytic reaction material used to form the shell (5) is the same as the photocatalytic reaction material filled in the chamber (2).

12. The application of the photocatalytic reaction device according to any one of claims 1-11 in the management and control of soil and groundwater; Preferably, the photocatalytic reaction device is installed on a permeable reaction wall and / or a bioreactor core.

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