Ultraviolet-excited catalyst-free dioxin degradation method

Abstract

The invention discloses an ultraviolet-excited catalyst-free dioxin degradation method which comprises the following steps: mixing a dioxin-containing solution with a hydroxyl-containing organic solution to obtain a to-be-degraded solution; introducing an oxygen source into the solution to be degraded, or keeping an argon atmosphere in the solution to be degraded; and irradiating the solution to be degraded by using a first light source, and stirring to react and degrade dioxin, the first light source includes ultraviolet light. The chemical structure of dioxin can be directly or indirectly destroyed by exciting free radicals generated by hydroxyl-containing organic liquid, and the toxic action mechanism of dioxin is destroyed, so that the toxicity of dioxin is remarkably reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of environmental treatment of dioxins, and specifically relates to a catalyst-free dioxin degradation method excited by ultraviolet light. Background Art

[0002] Dioxin pollutants come from a variety of sources, including solid waste incineration, chemical industry production, metal smelting and biochemical processes. Among these sources, solid waste incineration is the main pathway for dioxin emissions [see Li Yan, Guo Changsheng, Hou Song, et al. Research progress on dioxin emission and generation mechanism during solid waste incineration [J]. Environmental Chemistry, 2019, 38(04): 746-759].

[0003] Dioxins belong to the class of chlorinated oxygen-containing tricyclic aromatic hydrocarbons. The lone electron pair of their oxygen atoms can form a p-π conjugated system with the π electrons on the benzene ring. This conjugation effect delocalizes the electrons between molecular orbitals, thereby reducing the energy level of the entire molecule and enhancing the stability of the molecule. Due to this stable electronic structure, dioxins are difficult to degrade naturally in the environment.

[0004] In the human body, the toxic mechanism of dioxins involves their interaction with the aryl hydrocarbon receptor (AHR). After entering the human body, dioxin molecules bind to AHR, activate the signal transduction pathway in cells, and affect their protein expression. This interference may lead to immune system suppression, reproductive and developmental problems, and disorders of the hormone system, especially 2,3,7,8-chloro-substituted dioxin molecules, which are the most toxic. The "three-hazard" properties of dioxins - teratogenicity, carcinogenicity and mutagenicity - make them a significant threat to human health [see Huang Chao, Chen Ning, Yang Mingjia, et al. Toxic mechanism of dioxin compounds and their biological detection methods [J]. Journal of Ecotoxicology, 2015, 10(03): 50-62]. Therefore, it is particularly urgent to study and develop a dioxin degradation technology that is both economical and environmentally friendly to reduce its negative impact on the ecological environment and human health.

[0005] At present, although there are a variety of dioxin degradation technologies, such as high-temperature pyrolysis, chemical treatment, mechanochemical method, biodegradation, low-temperature pyrolysis and photocatalytic degradation, they still face some challenges in practical application [see Li X, et al. Study on the relationship between waste classification, combustion condition and dioxin emission from waste incineration [J]. Waste Disposal & Sustainable Energy, 2019 (1): 91–98].

[0006] Although high-temperature pyrolysis technology has a high degradation efficiency, it consumes a lot of energy and may cause secondary pollution; although selective catalytic oxidation has a high degradation efficiency, the cost and stability of the catalyst still need to be resolved; although low-temperature pyrolysis technology is environmentally friendly and energy-saving, there is a risk of secondary synthesis of dioxins; biodegradation technology is highly anticipated due to its environmental friendliness and low energy consumption, but its complex process and long cycle limit its large-scale application; photocatalytic degradation technology has low degradation efficiency due to the recombination of photogenerated electrons and holes in the photocatalytic process.

[0007] The fixed defects of the photocatalytic mechanism limit its further development. The recombination of photogenerated carrier pairs is much faster than the transfer and reaction process of photogenerated carrier pairs. The defects in the mechanism are difficult to optimize and improve. Therefore, a more efficient strategy is needed to promote the further development of photodegradation of dioxins. Summary of the invention

[0008] In order to overcome the deficiencies of the prior art, the present application provides a catalyst-free dioxin degradation method excited by ultraviolet light, so as to solve the problem of insufficient degradation efficiency caused by defects in the photocatalytic mechanism in the field of photodegradation of dioxins, and achieve effective degradation of dioxins.

[0009] In order to achieve the above objectives, this application adopts the following technical solutions: A UV-excited catalyst-free dioxin degradation method comprising: Mixing a solution containing dioxins with an organic liquid containing hydroxyl groups to obtain a solution to be degraded; introducing an oxygen source into the solution to be degraded, or maintaining an argon atmosphere in the solution to be degraded; and The solution to be degraded is irradiated with a first light source and stirred to generate a reaction to degrade dioxins; the first light source includes ultraviolet light.

[0010] Furthermore, the hydroxyl-containing organic liquid includes methanol, ethanol or glycerol.

[0011] Furthermore, the step of irradiating the solution to be degraded with a first light source to generate a reaction to degrade dioxins comprises: The reaction temperature is controlled at 0-60°C and the reaction time is greater than 5 minutes.

[0012] Furthermore, the temperature is 20° C. and the time is 25 minutes.

[0013] Furthermore, the first light source includes at least one of an LED lamp, a xenon lamp, a mercury lamp and natural light.

[0014] Furthermore, the wavelength of the ultraviolet light is 200-280nm.

[0015] Further, the reaction comprises: The ultraviolet light irradiates the hydroxyl-containing organic liquid; and The CH bonds and CO bonds of the hydroxyl-containing organic liquid undergo homolytic cleavage to generate hydrogen free radicals H•, hydroxyl free radicals HO• and carbon free radical intermediates.

[0016] Furthermore, the reaction further comprises: The hydrogen radical H• replaces the chlorine atom on the benzene ring of dioxin through a substitution reaction mechanism, thereby reducing the toxicity of dioxin.

[0017] Furthermore, the reaction further comprises: The hydrogen radical H· reacts with oxygen to generate hydrogen peroxide, which oxidizes dioxins to further reduce the toxicity of dioxins. Furthermore, the reaction further comprises: The hydroxyl radical HO• oxidizes dioxins to promote the ring opening of dioxins, thereby reducing the toxicity of dioxins.

[0018] Compared with the prior art, this application has the following advantages: The present application provides a catalyst-free dioxin degradation method stimulated by ultraviolet light, and proposes a catalyst-free photodegradation strategy for dioxins. High-energy photon radiation is used to directly irradiate a hydroxyl-containing organic liquid, and its CH bonds and CO bonds are directly split to generate hydrogen radicals (H•), hydroxyl radicals (HO•) and carbon radical intermediates. The H• and HO• generated by the homolytic splitting can degrade dioxins because the hydrogen radicals will replace the chlorine atoms on the dioxin benzene ring through a reduction reaction, and the hydroxyl radicals will cause the dioxins to be oxidized and opened through an oxidation reaction; thereby achieving efficient degradation of dioxins. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application but do not constitute an improper limitation on the present application. In the drawings: Figure 1 The flowchart of the catalyst-free dioxin degradation method excited by ultraviolet light of the present application; Figure 2 The EPR test results of the free radical intermediates of this application; Figure 3 Schematic diagram for degrading dioxins Figure 1 ; Figure 4 Schematic diagram for degrading dioxins Figure 2 . DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0021] In the description of the present application, it should be understood that the relationship between the method steps can be in sequence or not, as long as it does not affect the overall technical effect, and therefore cannot be understood as a limitation on the present application. The following description of the present application is only to be understood as a description of individual embodiments of the technical solution of the present application. Other embodiments are not reflected in the following description, but it does not mean that the present application excludes these other embodiments, and the technical solution of the present application is not limited to the specific implementation methods described below, and the scope of protection of the present application is not limited to only the specific implementation methods described below. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present application.

[0022] It should be noted that if the terms "first", "second", etc. appear in the specification and claims of the present application and the above-mentioned drawings, the description is only used to distinguish similar objects, and is not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] In some embodiments, Figure 1 As shown, the present application provides a UV-excited catalyst-free dioxin degradation method, comprising: S1: mixing a solution containing dioxins with an organic liquid containing hydroxyl groups to obtain a solution to be degraded; Specifically, the hydroxyl-containing organic liquid may include methanol, ethanol or glycerol; methanol, ethanol, glycerol and other hydroxyl organic molecules containing CO bonds and CH bonds.

[0024] S2: introducing an oxygen source into the solution to be degraded, or maintaining an argon atmosphere in the solution to be degraded; and S3: irradiating the solution to be degraded with a first light source and stirring the solution to generate a reaction to degrade dioxins; the first light source includes ultraviolet light; Specifically, the reaction temperature can be controlled at 0-60° C. and the reaction time can be greater than 5 minutes.

[0025] In some embodiments, more preferably, the temperature can be controlled to be 20° C. and the time to be 25 minutes.

[0026] In some embodiments, the first light source includes at least one of an LED lamp, a xenon lamp, a mercury lamp, and natural light.

[0027] In some embodiments, the wavelength of the ultraviolet light is 200-280 nm.

[0028] In some embodiments, the reaction comprises: The ultraviolet light irradiates the hydroxyl-containing organic liquid; and The CH bonds and CO bonds of the hydroxyl-containing organic liquid undergo homolytic cleavage to generate hydrogen free radicals H•, hydroxyl free radicals HO• and carbon free radical intermediates.

[0029] In some embodiments, the reaction further comprises: The hydrogen radical H• replaces the chlorine atom on the benzene ring of dioxin through a substitution reaction mechanism, thereby reducing the toxicity of dioxin.

[0030] The hydrogen radical H· reacts with oxygen to generate hydrogen peroxide, which oxidizes dioxins to further reduce the toxicity of dioxins. The hydroxyl radical HO• oxidizes dioxins to promote the ring opening of dioxins, thereby reducing the toxicity of dioxins.

[0031] Specifically, the present invention uses ultraviolet radiation to directly act on hydroxy organic molecules to induce homolytic cleavage of CH bonds and CO bonds, generating hydrogen radicals (H•), hydroxyl radicals (HO•) and carbon radical intermediates. These highly reactive radical intermediates have the potential to degrade dioxins.

[0032] Specifically, hydrogen radicals (H•) replace the chlorine atoms on the benzene ring in the dioxin molecule through a reduction reaction, thereby reducing the toxicity of dioxins; hydroxyl radicals (HO•) promote the oxidative ring opening of dioxin molecules through an oxidation reaction, thereby achieving efficient degradation of dioxins; in addition, hydrogen radicals can also react with oxygen to generate hydrogen peroxide molecules (H2O2), indirectly degrading dioxins.

[0033] The dioxin degradation of the present invention is carried out only under the condition of the presence of a hydroxyl-containing organic liquid, through irradiation with artificial light or natural light.

[0034] This application tests the degradation performance of dioxins through the following experimental operation steps: A dioxin-containing solution (0.1 mL, water or organic solvent) was added to a reactor containing a hydroxyl-containing organic liquid (4.9 mL) to form a mixed system containing dioxins, and oxygen or air was introduced. The reaction system was irradiated with a light source containing ultraviolet light, and the reaction temperature was controlled at 0-60 °C. The reaction time was at least 10 min. After the reaction, the dioxin content, hydrogen peroxide content or free radical intermediates were detected; then the reaction was continued or terminated according to the degradation results. After the reaction, the degradation efficiency of dioxins was evaluated by gas chromatography-triple quadrupole mass spectrometry (GC-MS / MS, Shimazu, Japan), the organic intermediates were analyzed by gas chromatography-mass spectrometry (GC-MS, Agilent Technologies, Shanghai), and the electron paramagnetic resonance (EPR) technology (Minoscope MS-5000X, Magnettech, Germany) was used to detect the generation of free radical intermediates. Figure 2 As shown, the generation of free radical intermediates is detected by electron paramagnetic resonance (EPR) spectroscopy (Minoscope MS-5000X). The key free radical intermediates are detected. The figure shows the signals of carbon radicals, hydroxyl radicals and peroxyl radicals, and the surfaces show CH homolysis, CO homolysis and the generation of hydrogen peroxide, respectively.

[0035] In the degradation process of the present application, when the hydroxy organic molecule is excited by ultraviolet light, it will undergo a femtosecond vibration relaxation process, transferring the absorbed energy to the CH bond and the CO bond. This process causes the CO bond and the CH bond to be directly split, generating hydrogen radicals, carbon radicals and hydroxyl radicals. These free radicals have high reactivity. Specifically, the generated hydrogen radicals can replace the chlorine atoms on the dioxin benzene ring through a substitution reaction mechanism, thereby reducing the toxicity of dioxins. At the same time, hydrogen radicals can also react with oxygen to generate hydrogen peroxide, which has strong oxidizing properties and can further oxidize dioxins, causing them to open the ring, and its chemical structure is destroyed, further reducing the toxicity of dioxins. In addition, hydroxyl radicals can also directly oxidize dioxins due to their high oxidizing properties, prompting them to open the ring, and also achieving the effect of reducing toxicity. In summary, the free radicals generated by exciting hydroxy organic molecules in the present application can directly or indirectly destroy the chemical structure of dioxins and destroy their toxic action mechanism, thereby significantly reducing their toxicity.

[0036] In some embodiments, specific operations are used below to demonstrate the performance of the method of the present application for dioxin degradation experiments.

[0037] In some embodiments, oxygen is used as an oxygen source, methanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source. The steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. During the whole reaction process, the oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested. The concentration was 46.41 ng / mL. Figure 3 ; (2) Degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 21.15 ng / mL. Figure 3 ; (3) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, the oxygen was kept in the air and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 4.84 ng / mL. Figure 3 ; (4) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, the oxygen was kept flowing in and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 0.9 ng / g. Figure 3 ; (5) Degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 0. Figure 3 ; from Figure 3 It can be seen that as the degradation time increases, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 25 minutes.

[0038] In some embodiments, oxygen is used as an oxygen source, ethanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source. The steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. During the entire reaction process, the oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 55.62 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 25.88 ng / mL. (3) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 7.65 ng / mL. (4) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 1.5 ng / g. (5) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was kept introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 0; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 25 minutes, but the degradation rate is slightly lower than that of the methanol system.

[0039] In some embodiments, oxygen is used as an oxygen source, propylene glycol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source, and the steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. During the entire reaction process, the oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 30.56 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 9.78 ng / mL. (3) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 0.55 ng / mL. (4) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was kept introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 0; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 15 minutes, but the degradation rate is better than that of the methanol system, probably because glycerol provides more hydroxyl groups.

[0040] In some embodiments, air is used as an oxygen source, methanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source. The steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and air was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. During the entire reaction process, the air was introduced and the air outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 48.52 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, air was kept in the air outlet provided on the side wall of the reactor and the air outlet was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 23.67 ng / mL. (3) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, air was kept in the air outlet and the air outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, and the concentration was 6.45 ng / mL. (4) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, air was allowed to flow in and the air outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 1.78 ng / mL. (5) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, air was kept in and the air outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 0; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 20 minutes, with no obvious difference from the oxygen atmosphere.

[0041] In some embodiments, methanol (4.9 mL) is used as a solvent, and a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed therewith to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source, and an argon atmosphere is maintained, and the steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor, and an LED light with UVC (200nm-280nm) and a light power density of 2.6 mW / cm2 was used to degrade the dioxin at 20°C for 5 min under the irradiation and stirring of the LED light. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 60.12 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 30.56 ng / mL; (3) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 15.23 ng / mL; (4) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 7.65 ng / mL; (5) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 0.19 ng / mL; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases, tends to zero at around 25 minutes, and is slightly lower than the air atmosphere.

[0042] In some embodiments, methanol (4.9 mL) is used as a solvent, and a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed therewith to form a system to be degraded (dioxin 100 ng / mL), and an LED light with UVC (200nm-280nm) is used as a light source, and an argon atmosphere is maintained, and the steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and argon was introduced into the reactor at a flow rate of 10 mL / min to remove impurities in the reaction system and maintain an argon atmosphere. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 58.74 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 31.47 ng / mL; (3) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 15.68 ng / mL; (4) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 4.45 ng / mL; (5) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the LED lamp. The argon atmosphere was maintained during the entire reaction process. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 0.23 ng / mL; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 25 minutes.

[0043] In some embodiments, oxygen is used as an oxygen source, methanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and a mercury lamp is used as a light source. The steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The mercury lamp was 200 W and the light power density was 190 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the mercury lamp. During the entire reaction process, the oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 20.15 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation of the mercury lamp and stirring. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 6.28 ng / mL. (3) Degradation was continued at 20° C. for 5 min under the irradiation of the mercury lamp and stirring. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 0.19 ng / mL. (4) Degradation was continued at 20° C. for 5 min under the irradiation of the mercury lamp and stirring. During the entire reaction process, oxygen was kept flowing in and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, and the concentration was 0; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 25 minutes, which is better than the LED lamp system, which may be due to the enhanced light intensity.

[0044] In some embodiments, oxygen is used as an oxygen source, methanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and a xenon lamp is used as a light source, and the steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The xenon lamp was 300 W and the light power density was 200 mW / cm2. The degradation was carried out at 20°C for 5 min under the irradiation and stirring of the xenon lamp. During the whole reaction process, the oxygen was introduced and the gas outlet set on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, and the concentration was 70.00 ng / mL; (2) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the xenon lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 35.56 ng / mL. (3) Degradation was continued at 20° C. for 5 min under the irradiation and stirring of the xenon lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 19.71 ng / mL. (4) Degradation was continued at 20° C. for 5 min under the irradiation of the xenon lamp and stirring. During the entire reaction process, oxygen was kept introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 5.65; (5) Degradation was continued at 20° C. for 5 min under the irradiation of the xenon lamp and stirring. During the entire reaction process, oxygen was kept introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested, which was 1.08; From the degradation results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases, tends to zero at around 25 minutes, which is lower than that of the LED lamp system, which may be due to the decrease in effective photon concentration.

[0045] In some embodiments, oxygen is used as an oxygen source, methanol (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and natural light is used as a light source. The steps are as follows: (1) 5 mL of the dioxin degradation system (100 ng / mL) was placed in the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The reaction environment was switched to outdoor and degraded at 30°C to 60°C under natural light and stirring. The reaction liquid was collected every 5 minutes and its dioxin concentration was tested. The concentration of the first test (reaction time 5 minutes) was 83.15 ng / mL. (2) Degradation was continued at 20° C. for 5 min under the irradiation of natural light and stirring. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 54.84 ng / g; (3) Degradation was continued at 20° C. for 5 min under the irradiation of natural light and stirring. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 37.00 ng / g; (4) Degradation was continued at 20° C. for 5 min under the irradiation of natural light and stirring. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 25.10 ng / g; (5) Degradation was continued at 20° C. for 5 min under the irradiation of natural light and stirring. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested, which was 15.19 ng / g; From the results, it can be seen that with the increase of degradation time, the concentration of dioxins in the degradation system gradually decreases, and 84% is degraded in about 25 minutes, which shows its application potential under natural light.

[0046] In some embodiments, oxygen is used as an oxygen source, saturated d-glucose aqueous solution (4.9 mL) is used as a solvent, a dioxin aqueous solution (5000 ng / mL, 0.1 mL) is mixed with it to form a system to be degraded (dioxin 100 ng / mL), and an LED lamp is used as a light source. The steps are as follows: (1) 5 mL of the dioxin to be degraded system (100 ng / mL) was loaded into the reactor and oxygen was introduced into the reactor at a flow rate of 10 mL / min to form a reaction system. The LED light was equipped with UVC (200 nm-280 nm) and the light power density was 2.6 mW / cm2. The system was degraded at 20°C for 5 min under the irradiation and stirring of the LED light. During the whole reaction process, the oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction solution was collected and its dioxin concentration was tested. The concentration was 37.51 ng / mL. Figure 4 ; (2) Degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the entire reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 15.47 ng / mL. Figure 4 ; (3) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, the oxygen was kept flowing in and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 5.23 ng / mL. Figure 4 ; (4) The degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, the oxygen was kept flowing in and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 1.89 ng / g. Figure 4 ; (5) Degradation was continued at 20°C for 5 min under the irradiation and stirring of the LED lamp. During the whole reaction process, oxygen was introduced and the gas outlet provided on the side wall of the reactor was kept open. After the degradation time was up, the reaction liquid was collected and its dioxin concentration was tested. The concentration was 0. Figure 4 ; from Figure 4 It can be seen that as the degradation time increases, the concentration of dioxins in the degradation system gradually decreases and approaches zero at around 25 minutes.

[0047] This application avoids cumbersome steps and does not rely on catalysts. Instead, it directly uses ultraviolet light to excite hydroxyl organic molecules and promote their bond breaking. The hydroxyl radicals (·OH) generated in this process are highly active and can directly react with dioxins, thereby effectively degrading these harmful substances. In this way, not only the degradation steps are simplified, but also the degradation efficiency is improved, making the entire process more efficient and environmentally friendly.

[0048] Compared with the prior art, the method described in this application has the following beneficial technical effects: (1) Catalyst-free photodegradation method: This application does not rely on traditional photocatalysts, thus avoiding the problems of low degradation efficiency, high cost and insufficient stability that may be introduced by catalysts.

[0049] (2) Direct bond homolysis mechanism: This application directly triggers the homolysis of CH bonds and CO bonds in hydroxyl organic molecules through high-energy photon radiation, which is a novel degradation mechanism that is different from the traditional photocatalytic process.

[0050] (3) Generation of free radical intermediates: The method of the present application can generate free radical intermediates with high reactivity. These free radicals can effectively react with dioxin molecules to promote their degradation.

[0051] (4) Potential environmental friendliness: Since the present invention does not rely on externally added catalysts, the method reduces the risk of secondary pollution and improves environmental compatibility.

[0052] (5) Improvement of degradation efficiency: This application simplifies the degradation mechanism and optimizes the degradation route. The simplified degradation route avoids the problems of lengthy routes and low efficiency in traditional photocatalytic technology, and significantly improves the degradation efficiency of dioxins.

[0053] (6) Simple operation: The present application is easy to control. It only requires mixing the dioxin-containing solution with the hydroxyl-containing organic liquid, introducing oxygen or air, and irradiating with a light source.

[0054] (7) Wide applicability: The selection range of hydroxyl organic molecules is wide, including but not limited to methanol, ethanol, propylene glycol and other hydroxyl organic molecules containing CO bonds and CH bonds.

[0055] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the selection and description of the implementation scheme is to best illustrate the principles of the present application and its practical application, so as to enable other technicians in the field to best use the present application and the various described implementation schemes with various modifications suitable for the specific purpose conceived.

Claims

1. A method for degrading dioxins without catalysts by ultraviolet light, characterized in that: include: Mixing a solution containing dioxins with an organic liquid containing hydroxyl groups to obtain a solution to be degraded; introducing an oxygen source into the solution to be degraded, or maintaining an argon atmosphere in the solution to be degraded; as well as The solution to be degraded is irradiated with a first light source and stirred to generate a reaction to degrade dioxins; the first light source includes ultraviolet light.

2. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 1, characterized in that: The hydroxyl-containing organic liquid includes methanol, ethanol or glycerol.

3. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 1, characterized in that: The step of irradiating the solution to be degraded with a first light source to generate a reaction to degrade dioxins comprises: The reaction temperature is controlled at 0-60°C and the reaction time is greater than 5 minutes.

4. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 3, characterized in that: The temperature is 20° C. and the time is 25 minutes.

5. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 1, characterized in that: The first light source includes at least one of an LED lamp, a xenon lamp, a mercury lamp and natural light.

6. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 5, characterized in that: The wavelength of the ultraviolet light is 200-280nm.

7. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 1, characterized in that: The reaction includes: The ultraviolet light irradiates the hydroxyl-containing organic liquid; and The CH bonds and CO bonds of the hydroxyl-containing organic liquid undergo homolytic cleavage to generate hydrogen free radicals H•, hydroxyl free radicals HO• and carbon free radical intermediates.

8. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 7, characterized in that: The reaction also includes: The hydrogen radical H• replaces the chlorine atom on the benzene ring of dioxin through a substitution reaction mechanism, thereby reducing the toxicity of dioxin.

9. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 8, characterized in that: The reaction also includes: The hydrogen radical H· reacts with oxygen to generate hydrogen peroxide, and the hydrogen peroxide oxidizes dioxins to further reduce the toxicity of dioxins.

10. The method for degrading dioxins without catalyst by ultraviolet light excitation according to claim 7, characterized in that: The reaction also includes: The hydroxyl radical HO• oxidizes dioxins to promote the ring opening of dioxins, thereby reducing the toxicity of dioxins.

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