Device and method for realizing efficient debromination through direct ultraviolet photolysis of tetrabromobisphenol A

Abstract

The invention relates to a device and a method for realizing efficient debromination by direct ultraviolet photolysis of tetrabromobisphenol A. Compared with the prior art, the wastewater containing the TBBPA is directly irradiated by the ultraviolet light of 222nm emitted by the krypton chloride excimer lamp (KrCl *), efficient degradation and debromination of the TBBPA can be realized without adding a catalyst, and secondary pollution is avoided. According to the device, a parallel light irradiation mode is adopted, and the photolysis efficiency is remarkably improved by optimizing parameters such as light source wavelength, optical path depth and irradiation intensity. Experiments show that in a deionized water system, the degradation rate of TBBPA reaches 100%, and the debromination rate reaches 85% or above (in deionized water); good adaptability is also shown in complex water quality. The method has the advantages of simplicity and convenience in operation, low cost, no secondary pollution and the like, and is suitable for industrial wastewater and drinking water treatment.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a device and method for directly debrominating tetrabromobisphenol A by ultraviolet light. Background Art

[0002] Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant. Due to its excellent flame retardant properties, it is widely used in electronic devices, plastics, textiles and building materials. However, the environmental persistence, bioaccumulation and potential toxicity of TBBPA have attracted widespread attention. Studies have shown that TBBPA is difficult to degrade naturally in the environment and can accumulate in organisms through the food chain, posing a potential threat to ecosystems and human health.

[0003] Existing TBBPA treatment technologies mainly include biodegradation, chemical oxidation and physical adsorption. Biodegradation technology relies on the metabolism of microorganisms, but due to the stable chemical structure of TBBPA, the microbial degradation efficiency is low, and the degradation process is slow, which is difficult to meet the needs of practical applications. Although chemical oxidation technology (such as Fenton oxidation, ozone oxidation, etc.) can effectively degrade TBBPA, it has problems such as high cost, many by-products, and possible secondary pollution. Although physical adsorption technology (such as activated carbon adsorption) is simple to operate, it is difficult to regenerate the adsorbent and cannot completely degrade TBBPA, and can only achieve the transfer of pollutants.

[0004] In recent years, ultraviolet photolysis technology, as an emerging advanced oxidation technology, has shown potential for treating TBBPA. Ultraviolet photolysis technology degrades organic pollutants by generating strong oxidizing free radicals (such as hydroxyl radicals), and has the advantages of fast reaction speed and no secondary pollution. However, traditional ultraviolet light sources (such as mercury lamps) have disadvantages such as non-adjustable wavelength, low energy utilization, and the presence of heavy metal mercury. In addition, they have poor adaptability to complex water quality, which limits their promotion in practical applications.

[0005] Chinese patent CN113860557A discloses a photocatalytic treatment process for tetrabromobisphenol A comprehensive wastewater. First, the pH is adjusted to 3-4, and dibromophenol, tribromophenol and other organic compounds are separated by acid precipitation. Then, the organic compounds remaining in the aqueous solution are decomposed into bromoform by using hydrogen peroxide oxidant under the action of ultraviolet light, using bromine in the wastewater and the existing acidity. Finally, the bromoform in the water is removed by extraction. In this patent, it is necessary to combine ultraviolet light source with hydrogen peroxide to degrade pollutants such as tetrabromobisphenol A and achieve good degradation and removal effects, but the use of hydrogen peroxide will increase the processing cost and may also bring safety hazards to storage and transportation; under ultraviolet light catalysis, hydrogen peroxide reacts with organic compounds and may generate harmful byproducts such as bromoform. Although bromoform is removed by extraction in the process, this step increases the complexity and cost of the process; the scheme needs to be carried out under acidic conditions (pH 3-4) and requires ultraviolet light irradiation. These conditions have high requirements for equipment, increasing the difficulty and cost of operation. Summary of the invention

[0006] The purpose of the present invention is to provide a device and method for directly debrominating tetrabromobisphenol A by ultraviolet light. The present invention optimizes the ultraviolet light source (krypton chloride excimer lamp) and its processing parameters, so that when degrading tetrabromobisphenol A, etc., no oxidant needs to be added, and wastewater or pollutants containing tetrabromobisphenol A (TBBPA) can be efficiently degraded by direct photolysis of ultraviolet light, thereby achieving the target treatment effect.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A device for directly debrominating tetrabromobisphenol A by ultraviolet light to achieve efficient debromination comprises a container, a light source, a reaction vessel and a position adjustment component, wherein the light source is arranged at the top of the container, the position adjustment component is arranged at the bottom of the container, and the reaction vessel is arranged in the position adjustment component.

[0009] The reaction vessel is used for placing wastewater containing tetrabromobisphenol A at different depths, the light source is used for photolysis of tetrabromobisphenol A in the wastewater, and the position adjustment component is used for adjusting the distance between the reaction vessel and the light source.

[0010] Furthermore, the light source is a krypton chloride excimer lamp (KrCl*).

[0011] Furthermore, the cross section of the reaction vessel is circular, and the inner diameter is 50-60 mm, preferably 56 mm.

[0012] Furthermore, the reaction vessel is made of glass.

[0013] Furthermore, a sealing cover is provided on the top of the reaction vessel, and the sealing cover is made of quartz.

[0014] Furthermore, the position adjustment component includes a placement table and a bracket, the bottom end of the bracket is fixed to the bottom end of the container, the placement table is arranged in the bracket, the placement table is connected to the bracket for up and down sliding, and a reaction vessel is arranged on the placement table.

[0015] Furthermore, the container comprises a side shell, a top shell and a bottom shell, and a plurality of side shells, a top shell and a bottom shell constitute a closed reaction container.

[0016] Furthermore, in the above, a plurality of bases are provided under the bottom shell.

[0017] As a preferred technical solution, an ultraviolet intensity sensor probe is provided below the reaction vessel, and the ultraviolet intensity sensor probe is externally connected to a radiation intensity monitoring system.

[0018] The ultraviolet intensity sensor probe is used to monitor the light intensity, and the irradiation intensity monitoring system is used to provide real-time feedback of the light intensity parameters before and after the reaction.

[0019] As a preferred technical solution, the radiation intensity monitoring system is an American International lighttechnology 2400 optical meter.

[0020] In addition, the present invention also provides a method for directly debrominating tetrabromobisphenol A by ultraviolet light, and the specific steps are as follows:

[0021] S1. adjusting the pH of wastewater containing tetrabromobisphenol A;

[0022] S2, placing wastewater containing tetrabromobisphenol A at different depths in a reaction vessel, and adjusting the distance between the reaction vessel and the light source;

[0023] S3. Using a light source for irradiation, tetrabromobisphenol A is photolyzed at room temperature to achieve degradation and debromination of tetrabromobisphenol A.

[0024] As a preferred technical solution, step S0 is provided before step S1 to pretreat the wastewater containing tetrabromobisphenol A.

[0025] The present invention reduces the light shielding effect by combining pre-treatment (such as filtration) in complex water bodies.

[0026] Furthermore, in step S1, the pH is 6.0-8.0, preferably 7.5, to avoid extreme pH affecting the photolysis path.

[0027] Furthermore, in step S2, the depth of the wastewater in the reaction vessel ranges from 0.41 cm, 2.03 cm, and 4.06 cm, preferably 0.41 cm, and the optical path depth is controlled by the liquid level.

[0028] Furthermore, in step S2, the distance between the reaction vessel and the light source is 8-11 cm, preferably a standard distance of 9.29 cm.

[0029] Furthermore, in step S3, the emission wavelength of the light source is 222 nm.

[0030] The irradiance of the light source is 0.047 mW / cm 2 ;

[0031] Luminous flux: 0-1000mJ / cm 2 .

[0032] As a preferred technical solution, the room temperature is 20-25°C, and no additional heating or cooling is required.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The present invention uses a krypton chloride excimer lamp (KrCl*) to emit 222nm ultraviolet light to directly irradiate wastewater containing TBBPA, and can achieve efficient degradation and debromination of TBBPA without adding a catalyst, thereby avoiding secondary pollution. The device of the present invention adopts a parallel light irradiation mode, and significantly improves the photolysis efficiency by optimizing parameters such as the wavelength of the light source, the depth of the optical path, and the irradiation intensity. Experiments show that in a deionized water system, the degradation rate of TBBPA reaches 100%, and the debromination rate reaches more than 85% (in deionized water); it also shows good adaptability in complex water quality. The present invention has the advantages of simple operation, low cost, and no secondary pollution, and is suitable for industrial wastewater and drinking water treatment.

[0035] 2. The 222nm ultraviolet light has a high match with the TBBPA absorption peak. The 222nm krypton chloride excimer lamp (KrCl*) can directly excite TBBPA molecules and achieve efficient breaking of the C-Br bond.

[0036] 3. The present invention improves the utilization rate of light energy by utilizing parallel light irradiation design combined with adjustable optical path depth;

[0037] 4. The present invention ensures that the UV transmittance is greater than 90% by providing a quartz cover, and has a small light shielding effect in low turbidity water bodies, and is suitable for a variety of scenarios.

[0038] 5. The operating cost of the device of the present invention is lower than that of the traditional method, and it is suitable for the remediation of drinking water, industrial wastewater and groundwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a device for directly debrominating tetrabromobisphenol A by ultraviolet light to achieve efficient debromination in Example 1 of the present invention;

[0040] Figure 2 is the TBBPA molar absorption coefficient diagram;

[0041] Figure 3 This is a comparison chart of the degradation efficiency of TBBPA in deionized water with different wavelengths of ultraviolet light in Example 3;

[0042] Figure 4 This is a graph showing the debromination rate of TBBPA in deionized water in Example 4;

[0043] Figure 5 This is a graph showing the debromination rate of TBBPA in the secondary effluent in Example 4;

[0044] Figure 6 The degradation effect of the optical path depth in the secondary sewage in Example 5;

[0045] Figure 7 is the apparent rate constant (k) of the optical path depth in the secondary sewage in Example 5 obs ).

[0046] Explanation of the accompanying figure numbers: 1. light source, 2. placement table, 3. bracket, 4. base, 5. side shell, 6. top shell. DETAILED DESCRIPTION

[0047] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0049] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0052] Example 1

[0053] See also Figure 1 This embodiment provides a device for directly debrominating tetrabromobisphenol A by ultraviolet light, comprising a container, a light source 1, a reaction vessel and a position adjustment component, wherein the light source 1 is arranged at the top of the container, the position adjustment component is arranged at the bottom of the container, and the reaction vessel is arranged in the position adjustment component.

[0054] The reaction vessel is used to place wastewater containing tetrabromobisphenol A at different depths, the light source 1 is used to photolyze tetrabromobisphenol A in the wastewater, and the position adjustment component is used to adjust the distance between the reaction vessel and the light source 1 .

[0055] In this embodiment, the light source 1 is a krypton chloride excimer lamp (KrCl*).

[0056] In this embodiment, the cross section of the reaction vessel is circular, and the inner diameter is 50-60 mm, preferably 56 mm.

[0057] In this embodiment, the reaction vessel is made of glass.

[0058] In this embodiment, a sealing cover is provided on the top of the reaction vessel, and the sealing cover is made of quartz.

[0059] In this embodiment, the position adjustment component includes a placement table 2 and a bracket 3, the bottom end of the bracket 3 is fixed to the bottom end of the container, the placement table 2 is arranged in the bracket 3, the placement table 2 is connected to the bracket 3 for up and down sliding, and a reaction vessel is arranged on the placement table 2.

[0060] In this embodiment, the container includes a side shell 5, a top shell 6 and a bottom shell. Several side shells 5, a top shell 6 and a bottom shell constitute a closed reaction container.

[0061] In this embodiment, a plurality of bases 4 are provided under the bottom shell.

[0062] In this embodiment, an ultraviolet intensity sensor probe is provided below the reaction vessel, and the ultraviolet intensity sensor probe is externally connected to a radiation intensity monitoring system.

[0063] The ultraviolet intensity sensor probe is used to monitor the light intensity, and the irradiation intensity monitoring system is used to provide real-time feedback of the light intensity parameters before and after the reaction.

[0064] Example 2

[0065] This embodiment provides a method for directly debrominating tetrabromobisphenol A by ultraviolet light, and the specific steps are as follows:

[0066] S1. adjusting the pH of the wastewater containing tetrabromobisphenol A to 7.5;

[0067] S2, placing wastewater containing tetrabromobisphenol A with a solution depth of 0.41 cm in a reaction vessel, and adjusting the distance between the reaction vessel and the light source 1 to 9.29 cm;

[0068] S3, irradiation is performed using light source 1 with an emission wavelength of 222 nm and an irradiation intensity of 0.047 mW / cm 2 , luminous flux is 0-1000mJ / cm 2 , tetrabromobisphenol A was photolyzed under room temperature conditions to achieve the degradation and debromination of tetrabromobisphenol A.

[0069] Example 3

[0070] This embodiment provides a comparative experiment of multi-wavelength degradation of TBBPA in deionized water, except that in step S1, the initial concentration of TBBPA in the wastewater is 1 μM; in step S3, 222 nm (KrCl*), 255 nm, and 280 nm UV-LED light sources are used for irradiation respectively; the remaining steps are the same as those in Example 2.

[0071] The experimental results are as follows Figure 3 As shown: TBBPA exhibits excellent photolysis efficiency under 222nm KrCl* excimer lamp irradiation. When the UV absorption flux reaches 15mJ / cm 2 When the initial concentration was 1 μM, the removal rate of TBBPA exceeded 90%. The apparent rate constant (k obs )TBBPA is 0.3119 cm 2 / mJ. Among them, the photolysis efficiency of TBBPA under 222nm KrCl* lamp is more significant, and its kobs value is 35 and 111 times higher than that under 255nm and 280nm UV-LED lamp irradiation; therefore, with the increase of emission wavelength, the degradation effect becomes worse.

[0072] Example 4

[0073] This example provides a comparative experiment of debromination of TBBPA in deionized water and secondary sewage, and the specific steps are as follows:

[0074] S1. Adjust the pH of the secondary sewage and deionized water containing tetrabromobisphenol A to 7.5, and the initial concentration of TBBPA in the debromination experiment to 10 μM;

[0075] S2, placing the wastewater containing tetrabromobisphenol A with a solution depth of 0.41 cm in a reaction vessel, and adjusting the distance between the reaction vessel and the light source 1 to 9.29 cm;

[0076] S3, 222nm (KrCl*), 255nm, 280nm UV-LED light source 1 were used for irradiation, and the irradiation intensity was 0.047mW / cm 2 , luminous flux is 0-1000mJ / cm 2 , photolysis of tetrabromobisphenol A at room temperature.

[0077] The experimental results are as follows Figure 4 and 5 As shown: TBBPA pollutants showed the best debromination efficiency under the 222nm KrCl* excimer lamp system, and the effect was better in deionized water. The bromide ion release rate of TBBPA was faster than that in secondary sewage at the same absorption flux. 2 The debromination effect differs by 10% under the light flux of . The impurities such as dissolved organic matter (DOM), inorganic ions and suspended particles contained in the secondary sewage will still significantly weaken the UV 222 penetration ability, thereby inhibiting the debromination reaction.

[0078] Example 5

[0079] This embodiment provides an experiment on the degradation effect of optical path depth in secondary sewage, and the specific steps are as follows:

[0080] S1. Filtering secondary sewage containing tetrabromobisphenol A;

[0081] S2, adjusting the pH of the secondary wastewater containing tetrabromobisphenol A to 7.5, and the initial concentration of TBBPA to 1 μM;

[0082] S3, placing wastewater containing tetrabromobisphenol A with solution depths of 0.41 cm, 2.03 cm and 4.06 cm in a reaction vessel, and adjusting the distance between the reaction vessel and the light source 1 to 9.29 cm;

[0083] S4, irradiate with light source 1 having an emission wavelength of 222 nm, with an irradiation intensity of 0.047 mW / cm 2, luminous flux is 0-1000mJ / cm 2 , tetrabromobisphenol A was photolyzed under room temperature conditions to achieve the degradation and debromination of tetrabromobisphenol A.

[0084] The experimental results are as follows Figure 6 and 7 As shown: In the secondary sewage system, KrCl* excimer lamp (UV 222 ) showed a significant downward trend in the photolysis efficiency of TBBPA with the increase of light path length. Specifically, in the filtered sewage plant secondary wastewater, when the solution depth increased from 0.41 cm to 4.03 cm, the apparent rate constant (k obs ) from 3.0506cm 2 / mJ significantly decreased to 1.1874cm 2 / mJ, a decrease of 61.1%. This significant efficiency decay indicates that although the turbidity of secondary sewage is low, impurities such as dissolved organic matter (DOM), inorganic ions and suspended particles contained in it can still significantly weaken UV 222 The penetration ability of the light source 1 is reduced, thereby inhibiting the progress of the photolysis reaction. Therefore, it is necessary to appropriately reduce the distance between the reaction vessel and the light source 1.

[0085] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A device for directly debrominating tetrabromobisphenol A by ultraviolet light to achieve efficient debromination, characterized in that: The invention comprises a container, a light source (1), a reaction vessel and a position adjustment component, wherein the light source (1) is arranged at the top end of the container, the position adjustment component is arranged at the bottom end of the container, and the reaction vessel is arranged inside the position adjustment component. The reaction vessel is used to place wastewater containing tetrabromobisphenol A at different depths, the light source (1) is used to photolyze tetrabromobisphenol A in the wastewater, and the position adjustment component is used to adjust the distance between the reaction vessel and the light source (1).

2. The device for directly debrominating tetrabromobisphenol A by ultraviolet light according to claim 1 is characterized in that: The light source (1) is a krypton chloride excimer lamp.

3. The device for directly debrominating tetrabromobisphenol A by ultraviolet light according to claim 1 is characterized in that: The cross section of the reaction vessel is circular, and the inner diameter is 50-60 mm; The reaction vessel is made of glass; A sealing cover is provided on the top of the reaction vessel, and the material of the sealing cover is quartz.

4. The device for directly debrominating tetrabromobisphenol A by ultraviolet light according to claim 1, characterized in that: The position adjustment component comprises a placement table (2) and a bracket (3), wherein the bottom end of the bracket (3) is fixed to the bottom end of the container, the placement table (2) is arranged in the bracket (3), the placement table (2) and the bracket (3) are connected to each other in an upward and downward sliding manner, and a reaction vessel is arranged on the placement table (2).

5. The device for directly debrominating tetrabromobisphenol A by ultraviolet light according to claim 1, characterized in that: The container comprises a side shell (5), a top shell (6) and a bottom shell. A plurality of side shells (5), a top shell (6) and a bottom shell form a closed reaction container.

6. The device for directly debrominating tetrabromobisphenol A by ultraviolet light according to claim 5, characterized in that: A plurality of bases (4) are arranged under the bottom shell.

7. A method for directly debrominating tetrabromobisphenol A by ultraviolet light, characterized in that: The method is carried out using the device as described in any one of claims 1 to 6, and the specific steps are as follows: S1. adjusting the pH of wastewater containing tetrabromobisphenol A; S2, placing wastewater containing tetrabromobisphenol A at different depths in a reaction vessel, and adjusting the distance between the reaction vessel and the light source (1); S3. Using the light source (1) for irradiation, tetrabromobisphenol A is photolyzed at room temperature to achieve degradation and debromination of tetrabromobisphenol A.

8. The method for achieving efficient debromination of tetrabromobisphenol A by direct ultraviolet light decomposition according to claim 7, characterized in that: In step S1, the pH is 6.0-8.

0.

9. The method for achieving efficient debromination of tetrabromobisphenol A by direct ultraviolet light decomposition according to claim 7, characterized in that: In step S2, the depth range of the wastewater in the reaction vessel includes 0.41 cm, 2.03 cm and 4.06 cm; The distance between the reaction vessel and the light source (1) is 8 to 11 cm.

10. The method for achieving efficient debromination of tetrabromobisphenol A by direct ultraviolet light decomposition according to claim 7, characterized in that: In step S3, the emission wavelength of the light source (1) is 222 nm. The irradiation intensity of the light source (1) is 0.047 mW / cm 2 ; Luminous flux: 0-1000mJ / cm 2 .

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