An apparatus and method for photocatalytic degradation of polychlorinated naphthalenes in soil
By mixing S-doped graphitic carbon nitride/MIL-101(Fe) photocatalyst with soil and using visible light or natural light sources for photocatalytic degradation, the problem of efficient degradation of polychlorinated naphthalene, especially octachloronaphthalene, has been solved, achieving rapid and pollution-free treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2026-03-20
AI Technical Summary
Existing technologies are difficult to degrade polychlorinated naphthalenes efficiently and economically, especially octachloronaphthalene, and there are risks of secondary pollution and incomplete treatment.
S-doped graphitic carbon nitride/MIL-101(Fe) photocatalyst is mixed with soil and photocatalytically degraded using visible light or natural light sources. The efficient degradation of polychlorinated naphthalene is achieved through stirring and light regulation in the device.
It achieves efficient degradation of octachloronaphthalene within 20 days, avoids secondary pollution, is suitable for indoor and natural environments, is easy to operate, and has a wide range of applications.
Smart Images
Figure CN119216351B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of contaminated soil remediation, and particularly relates to a device and a degradation method for photocatalytic degradation of polychlorinated naphthalenes in soil. BACKGROUND
[0002] Polychlorinated naphthalenes (PCNs) are a class of persistent organic pollutants widely existing in the natural environment, which are formed by 1 to 8 chlorine atoms on naphthalene at different links, and there are 75 PCNs homologues. PCNs have high chemical and thermal stability, good insulation and low flammability, and are widely used in various industrial products, such as temperature regulating liquid, cable insulation, wood preservative, engine oil additive, etc. With the wide application of PCNs, PCNs enter the natural environment. Because PCNs have similar structure and properties to dioxins and polychlorinated biphenyls, they can cause "dioxin" toxicity, including embryonic toxicity, liver toxicity, immunotoxicity, skin lesions, teratogenicity and carcinogenicity, causing harm to biology and environment. Octachloronaphthalene (CN-75) is also called octachloronaphthalene. Because the chlorination degree of octachloronaphthalene is higher, the migration and transformation of octachloronaphthalene in the environment is more stable, and the degradation time is also longer. Therefore, octachloronaphthalene can migrate in the environment for a longer time, especially in the soil environment, which is more stable.
[0003] At present, the main degradation methods of PCNs are mechanical chemistry, biodegradation, high-temperature melting and ultrasonic degradation. For biodegradation of PCNs, although the treatment effect is good, there are disadvantages such as long cycle process, high requirement for environment, and difficult to control conditions. And for other physical and chemical methods, there are disadvantages such as high cost, incomplete treatment and easy to cause secondary pollution. Light degradation is one of the important ways of transformation and generation of organic matter in the environment. Because the sunlight reaching the earth's surface is mainly ultraviolet light and visible light, the light degradation or transformation of organic matter based on ultraviolet light and visible light has been concerned.
[0004] Graphitic carbon nitride (g-C3N4) is a common non-metallic photocatalyst, which has the advantages of wide band gap (about 2.7 eV), low cost, wide raw material sources, stable physical and chemical properties, etc. However, the disadvantages of g-C3N4 are also obvious, such as weak absorption efficiency of visible light, serious recombination of photo-generated electrons and holes, and weak photocatalytic performance. These shortcomings seriously limit its application in environmental remediation. Therefore, it is a feasible way to modify g-C3N4 with metals or elements to increase the photocatalytic ability of g-C3N4. Metal-organic framework (MOFs) is a new type of porous coordination polymer that has attracted much attention in recent years. MOFs can use various metal ions as connectors, and various organic ligands can also be selected as connectors. Fe-based MOFs have the advantages of low cost, environmental protection, high specific surface area, semiconductor and photosensitivity, and have been applied in the fields of adsorption, sensing, catalysis and battery, etc. SUMMARY
[0005] The purpose of the present application is to provide a device and method for photocatalytic degradation of polychlorinated naphthalene in soil, which is low in cost and simple to operate.
[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:
[0007] A device for photocatalytic degradation of polychlorinated naphthalene in soil, comprising a base, a metal support frame, a reaction glass tank body and a driving motor, characterized in that the base carries the metal support frame; the four corners of the metal support frame are respectively provided with adjusting nuts I, adjusting nuts II, adjusting nuts III and adjusting nuts IV; four gears, namely transmission gear I, transmission gear III, support gear I and support gear II, are installed on the metal support frame, and the four gears support the detachable reaction glass tank body; a driving motor is loaded on the tail side of the metal support frame, and the driving motor is connected with the transmission gear I; a tank body matching rotating knife is arranged in the reaction glass tank body.
[0008] Further, in the above-mentioned device for photocatalytic degradation of polychlorinated naphthalene in soil, the adjusting nuts III and the adjusting nuts IV are located at the tail end of the metal support frame, and the adjusting nuts I and the adjusting nuts II are located near the tank opening of the reaction glass tank body, and the adjusting nuts I and the adjusting nuts II can slide on the reserved track of the metal support frame.
[0009] Further, in the above-mentioned device for photocatalytic degradation of polychlorinated naphthalene in soil, the support gear I and the support gear II are located near the tank opening of the reaction glass tank body; a transmission gear II is installed at the tail of the reaction glass tank body, and the transmission gear II is connected with the transmission gear I and the transmission gear III in a meshing manner.
[0010] Further, the device for photocatalytic degradation of polychlorinated naphthalene in soil, the three rotating knives made of polytetrafluoroethylene are arranged on the inner wall of the reaction glass jar in a spaced manner.
[0011] Further, the device for photocatalytic degradation of polychlorinated naphthaline in soil, the transmission gear III is detachable.
[0012] The method for photocatalytic degradation of polychlorinated naphthaline in soil by using the device for photocatalytic degradation of polychlorinated naphthaline in soil is as follows: polychlorinated naphthaline contaminated soil and S-doped g-C3N4 / MIL-101(Fe) photocatalyst are placed in the reaction glass jar of the device for photocatalytic degradation of polychlorinated naphthaline in soil, and the driving motor is started to rotate the reaction glass jar, and the mixture is stirred in the dark until it is fully mixed; then, under the irradiation of the visible light source, the angle of the reaction glass jar is adjusted by adjusting the adjusting nut I and the adjusting nut II, so that the mixed soil sample in the reaction glass jar is fully irradiated by the light source, and the rotation speed of the reaction glass jar is controlled by the driving motor, and the rotating knives are constantly turned over the mixed soil sample in the jar when the reaction glass jar rotates, so as to catalytically degrade polychlorinated naphthaline in soil.
[0013] Further, the method for photocatalytic degradation of polychlorinated naphthaline in soil, the mass ratio of S-doped g-C3N4 / MIL-101(Fe) photocatalyst to polychlorinated naphthaline contaminated soil is 5:95, and the concentration of polychlorinated naphthaline contaminated soil is 5-10 mg / kg.
[0014] Further, the method for photocatalytic degradation of polychlorinated naphthaline in soil, the visible light source is an external LED light source or natural sunlight.
[0015] Preferably, the wavelength λ of the external LED light source is ≥420 nm, the distance between the light source and the soil is 50 cm, and the light intensity is 12.5 W / m 2 .
[0016] Further, the method for photocatalytic degradation of polychlorinated naphthaline in soil, the preparation method of the S-doped g-C3N4 / MIL-101(Fe) photocatalyst comprises the following steps:
[0017] 1) Melamine, urea and ethylthiouronium with a mass ratio of 3:2:1.5 are fully mixed by ball milling, and then the mixture is placed in a ceramic crucible with a cover, and is stabilized at 550°C for 2 hours, and then cooled to obtain S-doped g-C3N4.
[0018] 2) stirring FeCl3.6H2O in DMF, then adding S-doped g-C3N4 and H2BDC in sequence, the molar ratio of S-doped g-C3N4, FeCl3.6H2O and H2BDC is 2:1:2, stirring, transferring the mixture into a hydrothermal reactor, and reacting at 150 DEG C for 24h to obtain the S-doped g-C3N4 / MIL-101(Fe) photocatalyst.
[0019] The beneficial effects of the present application are:
[0020] 1. The device and method of the present application have high efficiency in removing octachloronaphthalene, which is a persistent organic pollutant and can migrate in the environment for hundreds of days or even years before being completely mineralized. The degradation period of octachloronaphthalene in the present method can be controlled within 20 days.
[0021] 2. The present application uses S-doped g-C3N4 / MIL-101(Fe) as a photocatalyst, which is stable in soil environment and has no soil toxicity and biological toxicity, and will not produce secondary pollution during the treatment process.
[0022] 3. The device of the present application can be applied to various environments, not only to small indoor simulation research, but also to photocatalytic degradation research under natural environmental conditions.
[0023] 4. The device of the present application is easy to operate, and the stirring speed can be adjusted by controlling the rotation speed of the tank body, and the angle of the tank body can also be controlled to control the incidence and irradiation of light. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 It is a front view structural schematic diagram of the device of the present application.
[0025] Figure 2 It is a left view structural schematic diagram of the device of the present application.
[0026] Figure 3 It is a right view structural schematic diagram of the device of the present application.
[0027] In the figure: 1, base, 2, metal support frame, 3, reaction glass tank body, 4, tank body matching rotating knife, 5, driving motor, 6, transmission gear I, 7, transmission gear II, 8, transmission gear III, 9, support gear I, 10, support gear II, 11, adjusting nut I, 12, adjusting nut II, 13, adjusting nut III, 14, adjusting nut IV. DETAILED DESCRIPTION
[0028] The following will be further described in combination with specific implementation measures.
[0029] Example 1: Device for photocatalytic degradation of polychlorinated naphthalene in soil
[0030] The utility model provides a kind of photocatalytic degradation polychlorinated naphthalene in soil, including base 1, metal support frame 2, reaction glass jar body 3, jar body matching rotating knife 4, driving motor 5, transmission gear I 6, transmission gear II 7, transmission gear III 8, support gear I 9, support gear II 10, adjusting nut I 11, adjusting nut II 12, adjusting nut III 13, adjusting nut IV 14.
[0031] The base 1 of the device carries the metal support frame 2, which has adjusting nut I 11, adjusting nut II 12, adjusting nut III 13 and adjusting nut IV 14 at its four corners. Adjusting nut III 13 and adjusting nut IV 14 are located at the tail end of the metal support frame 2, while adjusting nut I 11 and adjusting nut II 12 are located near the mouth of the reaction glass jar body 3. By sliding adjusting nut I 11 and adjusting nut II 12 on the reserved track of the metal support frame 2, the angle of the metal support frame 2 with the base 1 can be adjusted, thereby adjusting the angle of the reaction glass jar body 3. The mouth of the reaction glass jar body 3 can be tilted and raised by 0-35°.
[0032] The metal support frame 2 is installed with transmission gear I 6, transmission gear III 8, support gear I 9 and support gear II 10. Transmission gear III 8 is a detachable component. The above four gears support the detachable reaction glass jar body 3. After transmission gear III 8 is detached from the metal support frame 2, the reaction glass jar body 3 can be detached. Support gear I 9 and support gear II 10 are located near the mouth of the reaction glass jar body 3 and support the mouth of the reaction glass jar body 3. The tail of the reaction glass jar body 3 is installed with transmission gear II 7, which is connected with transmission gear I 6 and transmission gear III 8 in a meshing manner. The driving motor 5 is loaded on the side of the tail of the metal support frame 2 and is connected with transmission gear I 6. The driving motor 5 provides power for the entire device. When the driving motor 5 is turned on, it drives transmission gear I 6, which drives transmission gear II 7, which drives the rotation of the reaction glass jar body 3 and transmission gear III 8. At the same time, support gear I 9 and support gear II 10 support the jar body to ensure smooth rotation of the reaction glass jar body 3. The speed of the reaction glass jar body 3 is also controlled by the driving motor 5.
[0033] The inside of the reaction glass jar body 3 is provided with jar body matching rotating knife 4, which includes three rotating knives made of polytetrafluoroethylene material. The three rotating knives are adhered to the inner wall of the jar body and are distributed at intervals. When the reaction glass jar body 3 rotates, the jar body matching rotating knife 4 will continuously turn over the soil sample in the jar to achieve uniform illumination.
[0034] Example 2 Preparation method of S-doped g-C3N4 / MIL-101(Fe) photocatalyst
[0035] 1) Melamine, urea and ethylthiurea with mass ratio of 3:2:1.5 were mixed by ball milling, then the mixture was put into a covered ceramic crucible, and was stabilized at 550℃ for 2 hours. After cooling, S-doped g-C3N4 was obtained.
[0036] 2) FeCl3.6H2O was weighed and stirred in DMF, then S-doped g-C3N4 was added, followed by the addition of H2BDC. The molar ratio of S-doped g-C3N4: FeCl3.6H2O: H2BDC was 2:1:2. After stirring, the mixture was transferred into a hydrothermal reactor, and reacted at 150℃ for 24 hours to obtain S-doped g-C3N4 / MIL-101(Fe).
[0037] Example 3 Degradation method of photocatalytic degradation of octachloronaphthalene in soil
[0038] Octachloronaphthalene was selected as a representative of PCNs homologues.
[0039] 1) 1.0 kg of soil was taken, naturally air-dried, ground, and autoclaved for 3 times. After air-drying, it was ready for use.
[0040] 2) Preparation of octachloronaphthalene contaminated soil: The sterilized soil sample prepared in step 1) was added to n-hexane solution containing octachloronaphthalene at a mass: volume ratio of 1 g: 1 mL (5 mg of octachloronaphthalene per 1000 mL of n-hexane). Then the soil sample was placed in a ventilated place for ventilation for 12 hours to obtain octachloronaphthalene contaminated soil with a concentration of 5 mg / kg.
[0041] 3) 190 g of octachloronaphthalene contaminated soil was weighed and mixed with S-doped g-C3N4 / MIL-101(Fe) at a mass ratio of 5:95, i.e. 10 g of S-doped g-C3N4 / MIL-101(Fe) was mixed with 190 g of soil, i.e. 200 g of mixed soil sample.
[0042] 4) The 200 g of mixed soil sample was placed in the reaction glass jar body of the device in Example 1, and the driving motor was started to rotate the reaction glass jar body. The mixed soil sample was stirred in the dark until it was fully mixed. Then, under the irradiation of LED group culture lamp light source (wavelength λ≥420 nm, the distance between the mixed soil sample and the light source was 50 cm, the light intensity was 12.5 W / m 2 , the temperature was 25±0.1℃, and the humidity was 70±0.1%), the angle of the reaction glass jar body was adjusted by adjusting the adjusting nut I and the adjusting nut II to ensure that the mixed soil sample in the reaction glass jar body was fully irradiated by the light source. At the same time, the rotation speed of the reaction glass jar body was controlled by the driving motor, and the matching rotating knife in the jar body constantly turned the mixed soil sample in the jar body when the reaction glass jar body rotated. The light irradiation lasted for 20 days.
[0043] 5) every two days, 5 g of mixed soil sample was taken in a 15 mL centrifuge tube, and 5 mL of n-hexane mixed solution containing 5% acetone was used for single 5 mL water bath ultrasonic extraction for 15 min, 3000 r / min centrifugation for 10 min, extraction for three times, and the total solution volume was 15 mL. The content of octachloronaphthalene in the combined mixed solution was determined.
[0044] Treatment effect: After 2 days and 20 days of irradiation, the degradation rate of octachloronaphthalene in the soil reached 15.57% and 92.54%, respectively.
[0045] Example 4 Degradation method of photocatalytic degradation of octachloronaphthalene in soil
[0046] 1) 1.0 kg of soil was taken, naturally air-dried, ground, and intermittently autoclaved for 3 times, and then air-dried for standby use.
[0047] 2) Preparation of octachloronaphthalene contaminated soil: The sterilized soil sample prepared in step 1) was added to the n-hexane solution containing octachloronaphthalene (10 mg of octachloronaphthalene per 1000 mL of n-hexane) according to the mass: volume ratio of 1 g: 1 mL. Then the soil sample was placed in a ventilated place for ventilation for 12 h, and octachloronaphthalene contaminated soil with a concentration of 10 mg / kg was obtained.
[0048] 3) 190 g of octachloronaphthalene contaminated soil was weighed, and S doped g-C3N4 / MIL-101(Fe) was mixed with octachloronaphthalene contaminated soil according to the mass ratio of 5:95, that is, 10 g of S doped g-C3N4 / MIL-101(Fe) was mixed with 190 g of soil, and 200 g of mixed soil sample was obtained.
[0049] 4) 200 g of mixed soil sample was placed in the reaction glass jar body of the device in example 1, and the driving motor was started to make the reaction glass jar body rotate. The mixed soil sample was stirred in the dark until it was fully mixed. Subsequently, under natural sunlight irradiation (the intensity of natural sunlight irradiation was 150-175 W / m 2 , the average temperature was 27±0.1℃, and the average humidity was 65±0.1%), the angle of the reaction glass jar body was adjusted by adjusting the adjusting nut I and the adjusting nut II, so that the mixed soil sample in the reaction glass jar body could be fully irradiated by the light source. At the same time, the speed of the reaction glass jar body was controlled by the driving motor, and the matching rotating knife of the jar body constantly turned the mixed soil sample in the jar when the reaction glass jar body rotated. The light irradiation lasted for 20 days.
[0050] 5) every two days, 5 g of mixed soil sample was taken in a 15 mL centrifuge tube, and 5 mL of n-hexane mixed solution containing 5% acetone was used for single 5 mL water bath ultrasonic extraction for 15 min, 3000 r / min centrifugation for 10 min, extraction for three times, and the total solution volume was 15 mL. The content of octachloronaphthalene in the combined mixed solution was determined.
[0051] Treatment effect: After 2 days and 20 days of irradiation, the degradation rate of octachloronaphthalene in soil reached 16.21% and 96.22%, respectively.
Claims
1. A method for photocatalytic degradation of polychlorinated naphthalene in soil, characterized in that, The method is as follows: The polychlorinated naphthalene contaminated soil and S-doped g-C3N4 / MIL-101(Fe) photocatalyst are placed in the reaction glass tank (3) of the device for photocatalytic degradation of polychlorinated naphthalene in soil. The drive motor (5) is started to make the reaction glass tank (3) rotate. The mixture is stirred until fully mixed under dark conditions. Then, under the illumination of a visible light source, the angle of the reaction glass tank (3) is adjusted by adjusting the adjusting nut I (11) and adjusting nut II (12) so that the mixed soil sample in the reaction glass tank (3) is fully irradiated by the light source. At the same time, the rotation speed of the reaction glass tank (3) is controlled by the drive motor (5). The rotating blade (4) of the tank continuously flips the mixed soil sample in the tank when the reaction glass tank (3) rotates, thus catalytically degrading the polychlorinated naphthalene in the soil. The device for photocatalytic degradation of polychlorinated naphthalene in soil includes a base (1), a metal support frame (2), a reaction glass tank (3), and a drive motor (5). The base (1) supports the metal support frame (2). The four corners of the metal support frame (2) are respectively provided with adjusting nuts I (11), II (12), III (13), and IV (14). Four gears, namely transmission gear I (6), transmission gear III (8), support gear I (9), and support gear II (10), are installed on the metal support frame (2). The four gears support the detachable reaction glass tank (3). The drive motor (5) is installed on the side of the tail of the metal support frame (2). The drive motor (5) is connected to the transmission gear I (6). The reaction glass tank (3) is provided with a tank-matching rotary cutter (4).
2. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The adjusting nut III (13) and adjusting nut IV (14) are located at the tail end of the metal support frame (2), and the adjusting nut I (11) and adjusting nut II (12) are located near the mouth of the reaction glass tank (3). The adjusting nut I (11) and adjusting nut II (12) can slide on the reserved track of the metal support frame (2).
3. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The support gear I (9) and support gear II (10) are located near the mouth of the reaction glass tank (3); the tail of the reaction glass tank (3) is equipped with transmission gear II (7), which is connected to transmission gear I (6) and transmission gear III (8) in a meshing manner.
4. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The rotating blades (4) that come with the tank include three rotating blades made of polytetrafluoroethylene material. The three rotating blades are attached to the inner wall of the reaction glass tank (3) and are distributed at intervals.
5. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The transmission gear Ⅲ (8) is detachable.
6. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The mass ratio of S-doped g-C3N4 / MIL-101(Fe) photocatalyst to polychlorinated naphthalene contaminated soil is 5:95; the concentration of polychlorinated naphthalene contaminated soil is 5-10 mg / kg.
7. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The visible light source is an external LED light source or natural sunlight.
8. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 7, characterized in that, The external LED light source has a wavelength λ ≥ 420nm, is 50cm away from the soil, and has a light intensity of 12.5W / m². 2 .
9. The method for photocatalytic degradation of polychlorinated naphthalene in soil according to claim 1, characterized in that, The preparation method of the S-doped g-C3N4 / MIL-101(Fe) photocatalyst includes the following steps: 1) Melamine, urea and ethylamine thiourea in a mass ratio of 3:2:1.5 were thoroughly mixed by ball milling. The mixture was then placed in a covered ceramic crucible and stabilized at 550°C for 2 hours. After cooling, S-doped g-C3N4 was obtained. 2) FeCl3·6H2O was stirred in DMF, and then S-doped g-C3N4 and H2BDC were added sequentially. The molar ratio of S-doped g-C3N4, FeCl3·6H2O and H2BDC was 2:1:
2. The mixture was stirred and then transferred to a hydrothermal reactor. The reaction was carried out at 150℃ for 24 h to obtain the S-doped g-C3N4 / MIL-101(Fe) photocatalyst.