An ultraviolet fenton reactor

Abstract

The utility model relates to a kind of ultraviolet fenton reactor, belong to water treatment technical field.Ultraviolet fenton reactor is equipped with the flow guide cylinder that passes through up and down and ultraviolet light catalysis array.The region formed by flow guide cylinder is hydrogen peroxide activation area, the region covered by ultraviolet light catalysis array is ultraviolet light catalysis area, the region of the bottom of ultraviolet light catalysis array is reflux area.Ultraviolet light catalysis array includes grid array structure formed by the interlaced connection of several photocatalytic grid plates and several ultraviolet light sources.Ultraviolet fenton reactor further includes stirring device, hydrogen peroxide dosing pipe and water inlet pipe.Compared with prior art, ultraviolet fenton reactor using the utility model can overcome the limitation of traditional fenton method, strengthen the ultraviolet reduction of divalent iron and the oxidation degradation of organic matter, and has wide application prospect in wastewater treatment field.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to an ultraviolet Fenton reactor. Background Technology

[0002] The Fenton process is the most mature and longest-established advanced oxidation method, widely used in industries such as printing and dyeing, papermaking, chemicals, and pharmaceuticals. The core principle of the Fenton process is that under acidic conditions, ferrous ions react with hydrogen peroxide in a catalytic reaction to generate hydroxyl radicals, which possess extremely strong oxidizing power. These hydroxyl radicals can non-selectively attack and degrade most recalcitrant organic pollutants in water, such as dyes, pesticides, and pharmaceutical intermediates, mineralizing them into carbon dioxide, water, or small-molecule inorganic substances, thereby achieving deep treatment and purification of wastewater.

[0003] However, during the Fenton reaction, the ferrous ions acting as a catalyst are oxidized to ferric ions, forming a large amount of water-containing ferric hydroxide flocculent sludge in the subsequent alkali adjustment and precipitation process, thus creating "secondary pollutant" iron sludge. This iron sludge is not only massive in volume, requiring solid waste treatment and disposal, but also often contains incompletely degraded pollutants and intermediate products, necessitating treatment as "hazardous waste," significantly increasing production and operating costs.

[0004] To reduce or avoid the formation of iron sludge, existing technologies typically propose to convert the Fe produced by the Fenton reaction into Fe... 3+ Fe is reduced and regenerated 2+ For example, by using ultraviolet devices combined with photocatalysts to convert Fe 3+ Reduced to Fe 2+ For example, CN114634265A discloses a photo-Fenton process for treating recalcitrant organic wastewater, in which, after the oxidation reaction is completed, most of the ferrous ions (Fe2+) are removed. 2+ It has been converted into ferric ions Fe 3+ After passing through the reflux system, the fluid flows through the UV photocatalytic reactor; under the excitation of the UV photocatalytic reactor, ferric ions (Fe3+)... 3+ Reconstituted into ferrous ions Fe 2+ The solution is then reused. The UV photocatalytic reactor is positioned at the top or side of the oxidation reaction tank and dynamically connected to the oxidation reaction zone via inlet and return pipes. This method reduces the generation of iron sludge, primarily composed of ferric hydroxide, by reusing iron ions. However, the aeration and stirring employed in this technical solution oxidizes Fe... 2+ Severely damages Fe 2+ The reaction that activates H₂O₂ to generate •OH wastes reagents and also exacerbates the UV reduction of Fe. 3+The burden on the system is significant; moreover, in the high-efficiency mixing tank, it is impossible to achieve intense water turbulence during aeration and stirring, which in turn affects the effectiveness of •OH.

[0005] CN117819773A discloses a highly efficient and environmentally friendly photo-Fenton reaction treatment method and apparatus for pulping wastewater. This method reduces ferric iron (Fe3+) produced during the Fenton reaction to ferrous iron (Fe2+) under ultraviolet light, and then reacts it with hydrogen peroxide via reflux to improve COD removal from the wastewater. However, this scheme cannot form functional zones, i.e., it does not separate Fe2+ from Fe3+. 2+ Oxidized to Fe 3+ Region and UV reduction of Fe 3+ For Fe 2+ The division of the regions severely affected the reactions of both.

[0006] In summary, none of the aforementioned Fenton reactors can achieve efficient utilization of ultraviolet photocatalysis, making it difficult to realize the ultraviolet reduction of ferric iron in the Fenton reaction, and the oxidative degradation effect of organic pollutants still needs improvement. Therefore, a novel ultraviolet Fenton reactor needs to be developed. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology, such as low utilization rate of ultraviolet photocatalysis and Fe... 3+ / Fe 2+ To address at least one of the drawbacks of the difficulty in continuously converting between two valence states and the need to improve the oxidative degradation effect of organic pollutants, an ultraviolet Fenton reactor is provided.

[0008] The objective of this utility model can be achieved through the following technical solutions: This utility model first provides an ultraviolet Fenton reactor, including a reactor body, in which a flow guide tube and an ultraviolet photocatalytic array are arranged vertically through each other; wherein, the area formed by the flow guide tube is the hydrogen peroxide activation zone, the area covered by the ultraviolet photocatalytic array is the ultraviolet photocatalytic zone, and the area at the bottom of the ultraviolet photocatalytic array is the reflux zone. The ultraviolet photocatalytic array includes a grid-like array structure formed by interlacing several photocatalytic grid plates and several ultraviolet light sources; both sides of the photocatalytic grid plates are coated with a photocatalytic coating, and at least a portion of the photocatalytic coating is located within the irradiation range of the ultraviolet light sources; The ultraviolet Fenton reactor also includes a stirring device installed on the top of the reactor body and extending into the hydrogen peroxide activation zone, a hydrogen peroxide dosing pipe for introducing hydrogen peroxide solution into the hydrogen peroxide activation zone, and a water inlet pipe for introducing wastewater into the reactor body.

[0009] Furthermore, the bottom of the reactor body is provided with a drain pipe and an iron sludge discharge pipe.

[0010] Furthermore, the bottom of the reactor body is provided with a downwardly sloping, converging surface.

[0011] Furthermore, several angle steel brackets for fixing and installing the guide tubes are installed on the inner wall of the reactor body.

[0012] Furthermore, the guide tube is coaxially arranged with the reactor body.

[0013] Furthermore, the volume of the guide tube accounts for 3% to 5% of the total volume of the reactor body.

[0014] Furthermore, the top surface of the guide tube is higher than the top surface of the photocatalytic grid plate, and the bottom surface of the guide tube is higher than the bottom surface of the photocatalytic grid plate.

[0015] Furthermore, the grid-like array structure is divided into several regular or irregular polygonal units by photocatalytic grid plates, and the photocatalytic coating of the photocatalytic grid plate in each polygonal unit is within the irradiation range of the ultraviolet light source.

[0016] Furthermore, several ultraviolet light source support plates are horizontally installed between the inner walls of the reactor body.

[0017] Furthermore, the ultraviolet light source support plate is provided with an ultraviolet light source protective sleeve corresponding to the ultraviolet light source.

[0018] Furthermore, the stirring device is a propeller-type stirring paddle.

[0019] Compared with the prior art, the present invention has the following technical advantages: (1) In order to overcome the limitations of the traditional Fenton method and the existing ultraviolet Fenton method, this utility model innovatively designed a new type of ultraviolet Fenton reactor. Through the ingenious partition design and deep coupling of ultraviolet photocatalysis, the ultraviolet light efficiency is greatly improved, and the ultraviolet reduction of ferric iron and the oxidative degradation of organic pollutants in the Fenton reaction are strengthened.

[0020] (2) This invention cleverly incorporates a vertically connected guide tube within the reactor, which spatially constructs a relatively separate yet closely connected hydrogen peroxide activation zone and an ultraviolet photocatalytic zone, thereby enabling Fe... 2+ Activated H2O2 is oxidized with Fe 3+ The reducing active species generated by ultraviolet light are reduced back to Fe. 2+ The reactions are relatively separated, greatly improving the efficiency of the second type of reaction. Furthermore, the reactor of this invention is equipped with a stirring impeller with a lifting function and a reflux zone, allowing water to circulate between the hydrogen peroxide activation zone and the ultraviolet photocatalytic zone, inducing Fe... 3+ and Fe 2+ The repeated switching between two valence states.

[0021] (3) This invention innovatively assembles the photocatalytic grid plate and the ultraviolet light source into a grid-like ultraviolet photocatalytic array. Compared with the separate ultraviolet lamp and catalyst in the prior art, the ultraviolet photocatalytic array of this invention can significantly improve the utilization rate and photocatalytic efficiency of ultraviolet light, increase the amount of active reduced species generated in the aqueous solution, and greatly enhance the Fe 3+ The reduction efficiency is high. Furthermore, the catalytic layer on the surface of the photocatalytic grid plate can generate photogenerated holes with extremely strong oxidizing capabilities, further enhancing the oxidative decomposition of organic pollutants.

[0022] (4) The ultraviolet Fenton reactor of this invention can not only oxidize and degrade conventional organic pollutants, but also exhibits excellent dechlorination and oxidation effects on chlorinated organic compounds. In the ultraviolet Fenton reactor of this invention, the reducing active species generated in the ultraviolet photocatalytic zone can not only reduce Fe 3+ It can also dechlorinate chlorinated organic compounds. The dechlorination process of reducing active species and the oxidation degradation of organic compounds by oxidizing active species can be carried out simultaneously, realizing the efficient utilization of ultraviolet photocatalysis. It has shown unexpected and excellent results in reducing the AOX index of industrial wastewater. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the ultraviolet Fenton reactor of this utility model.

[0024] Figure 2 This is a simplified front view of the ultraviolet Fenton reactor of this utility model.

[0025] Figure 3 This is a simplified top view of the ultraviolet Fenton reactor of this utility model.

[0026] Figure 4 This is a detailed diagram of the ultraviolet photocatalytic array of the ultraviolet Fenton reactor of this invention.

[0027] Explanation of markings in the diagram: 1-Reactor body, 1.1-Drainage pipe, 1.2-Iron sludge discharge pipe; 2-Guide cylinder, 2.1-Guide cylinder angle steel bracket; 3-Ultraviolet photocatalytic array, 3.1-Photocatalytic grid plate, 3.2-Ultraviolet light source, 3.3-Ultraviolet light source support plate, 3.4-Ultraviolet light source protective sleeve; 4-Stirring device; 5-Hydrogen peroxide dosing pipe; 6-Inlet pipe; Region I - Hydrogen peroxide activation region; Region II - Ultraviolet photocatalytic region, Zone III - Recirculation Zone. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0029] In this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] To overcome the limitations of the traditional Fenton process, which produces iron sludge and consumes iron salt reagents, many researchers have attempted to solve this problem by addressing the Fenton reaction (Equation 1): Fe 2+ + H2O2→Fe 3+ + •OH + OH - (1).

[0032] The commonly proposed approach is to: [dispose of Fe] 3+ Fe is reduced and regenerated 2+ However, in the same reaction system, when ferrous salt and hydrogen peroxide are added, the reaction proceeds to the right according to Equation 1, which is determined by the chemical reaction potential. When Fe is generated... 3+ and Fe 2+ When the reactions are reversed, from an engineering perspective, the reaction in Equation 1 has already terminated. If no external energy or new products are added, the reaction direction of Equation 1 in the Fenton process will not change. The reaction in Equation 1 can only continue when H2O2 is in excess or added continuously.

[0033] Furthermore, numerous studies have shown that hydrated electrons (e) are generated in aqueous solutions when exposed to ultraviolet light. - a The photolysis produces q) and hydrogen free radicals (•H). If the water contains alcohols, organic acids, or other organic matter, it also produces organic free radicals (R•). These reducing reactive species generated by photolysis have a strong reducing ability, and can not only reduce Fe 3+ Fe is reduced and regenerated 2+ It can also dechlorinate chlorinated organic compounds, thereby significantly reducing the toxicity of organic compounds and improving their biodegradability.

[0034] Our research shows that in the traditional Fenton reaction, after the reaction (Equation 1) produces •OH, the organic matter must react rapidly with it to generate organic free radicals R• (Equation 2), otherwise •OH will be quenched. This is the first stage of the Fenton reaction, i.e., RH + •OH → R• + H2O (2). In the second stage of the Fenton reaction, the organic free radicals R• are further oxidized by oxidants such as molecular oxygen until they are completely degraded.

[0035] Experiments show that when Fe is added 2+ After reacting with H2O2 for 5 minutes, Fe 2+ With less than 5% remaining, •OH can no longer be generated. After 30 minutes of reaction, the degradation rate of organic matter decreases significantly, and the Fenton reaction is essentially complete. However, when ultraviolet irradiation is combined with the Fenton process, the situation is completely different: Fe 2+ When it drops to around 5%, with ultraviolet irradiation, Fe... 2+ The concentration actually started to rise, and after 30 minutes of reaction, Fe... 2+ The concentration can rise to over 50%. The degradation reaction of organic matter continues even after 30 minutes, and after 60 minutes of reaction, the removal rates of COD and TOC are significantly improved compared to the traditional Fenton process.

[0036] In the traditional Fenton process, H2O2 is added in a single step (or at a single flow point in a continuous flow reactor), which leads to a violent initial Fenton reaction (Equation 1), resulting in a high concentration of Fe. 3+ It will inevitably undergo hydrolysis, easily reaching the solubility product of Fe(III) hydroxylate precipitation, thus producing a large amount of iron sludge precipitate. Furthermore, when the H2O2 concentration is greater than that of Fe... 2+ At the equivalent concentration of the reaction, H2O2 in Fe 3+ Under the catalytic action, the ineffective decomposition shown in Equation 3 will occur: 2 H2O2→2 H2O +O2↑ (3).

[0037] Based on the above research results and findings, the purpose of this invention is to overcome the limitations of the traditional Fenton method and significantly improve the ultraviolet light efficiency through the design of a novel ultraviolet Fenton reactor, thereby greatly enhancing the Fe... 2+ Ultraviolet reduction and oxidative degradation of organic pollutants.

[0038] Based on this, the present invention provides an ultraviolet Fenton reactor, which includes a reactor body 1, a vertically penetrating guide tube 2, and an ultraviolet photocatalytic array 3. The area enclosed by the guide tube 2 is the hydrogen peroxide activation zone I, the area covered by the ultraviolet photocatalytic array 3 is the ultraviolet photocatalytic zone II, and the area at the bottom of the ultraviolet photocatalytic array 3 is the reflux zone III. The ultraviolet photocatalytic array 3 includes a grid-like array structure formed by several photocatalytic grid plates 3.1 connected in an alternating pattern, and several ultraviolet light sources 3.2. Both sides of the photocatalytic grid plates 3.1 are coated with a photocatalytic coating, and at least a portion of the photocatalytic coating is within the irradiation range of the ultraviolet light sources 3.2. The ultraviolet Fenton reactor also includes a stirring device 4 installed at the top of the reactor body 1 and extending into the hydrogen peroxide activation zone I, a hydrogen peroxide dosing pipe 5 for introducing hydrogen peroxide solution into the hydrogen peroxide activation zone I, and a water inlet pipe 6 for introducing wastewater into the reactor body 1.

[0039] Ferrous salts in the wastewater can be added separately to a container outside the reactor body 1 and fed into the reactor body 1 together with the wastewater; or they can be added separately after the wastewater is fed into the reactor body 1. Those skilled in the art can choose according to actual needs, and no specific limitation is made here.

[0040] In some specific embodiments, the bottom of the reactor body 1 is provided with a drain pipe 1.1 and an iron sludge discharge pipe 1.2 for discharging the treated and settled wastewater and iron sludge, respectively. The iron sludge discharge pipe 1.2 can discharge the iron sludge by suction from a negative pressure pump.

[0041] In some specific embodiments, the bottom of the reactor body 1 is provided with a downwardly sloping and converging slope to induce the precipitation of iron sludge.

[0042] In some specific embodiments, a plurality of guide tube angle steel brackets 21 are installed on the inner wall of the reactor body 1 to fix the guide tube 2 inside the reactor body 1.

[0043] In some specific embodiments, the guide tube 2 is coaxially arranged with the reactor body 1.

[0044] In some specific embodiments, the volume of the guide tube 2 accounts for 3% to 5% of the total volume of the reactor body 1. The volume of the hydrogen peroxide activation zone I enclosed by the guide tube 2 is very small, therefore the water residence time in this area is extremely short (10 s to 30 s), because vigorous stirring can cause Fe... 2+ The reaction with H2O2 rapidly generates •OH. The lifetime of •OH is only on the order of nanoseconds. It needs to react with organic matter extremely quickly to generate organic free radicals, otherwise quenching will occur. Therefore, the volume ratio of the guide tube 2 should be within a reasonable range and the reaction time should be controlled.

[0045] In some specific embodiments, the top surface of the guide tube 2 is higher than the top surface of the photocatalytic grid plate 3.1, and the bottom surface of the guide tube 2 is higher than the bottom surface of the photocatalytic grid plate 3.1. Based on this setting, the wastewater overflowing from the hydrogen peroxide activation zone I can directly enter the ultraviolet photocatalytic zone II, where the Fe generated by reduction is located. 2+ It can then enter the bottom reflux zone III and re-enter the hydrogen peroxide activation zone I.

[0046] In some specific embodiments, the grid-like array structure is divided into several regular or irregular polygonal units by a photocatalytic grid plate 3.1, and the photocatalytic coating of the photocatalytic grid plate 3.1 within each polygonal unit is within the irradiation range of the ultraviolet light source 3.2. This invention innovatively assembles the photocatalytic grid plate 3.1 and the ultraviolet light source into a grid-like ultraviolet photocatalytic array 3. Compared to the separate ultraviolet lamp and catalyst in the prior art, the ultraviolet photocatalytic array 3 of this invention can significantly improve the utilization rate and photocatalytic efficiency of ultraviolet light, increase the generation of active reduced species in aqueous solution, and greatly enhance Fe… 3+ The reduction efficiency is high. Furthermore, the catalytic layer on the surface of the photocatalytic grid plate 3.1 can generate photogenerated holes with extremely strong oxidizing capabilities, further enhancing the oxidative decomposition of organic pollutants.

[0047] In some more specific embodiments, the polygonal unit can be any of the following shapes: triangle, quadrilateral, pentagon, hexagon, and other polygons. The shape of the polygonal unit can be regular or irregular. Those skilled in the art can flexibly set and arrange it according to actual needs and the installation method of the ultraviolet light source, and no specific limitation is made here.

[0048] In some specific embodiments, several ultraviolet light source support plates 3.3 are horizontally installed between the inner walls of the reactor body 1. The ultraviolet light source support plates 3.3 are provided with ultraviolet light source protective sleeves 3.4 corresponding to the ultraviolet light sources 3.2. The ultraviolet light sources 3.2 are vertically installed in the corresponding ultraviolet light source protective sleeves 3.4.

[0049] In some specific embodiments, the stirring device 4 is preferably a propeller-type stirring paddle. The propeller-type stirring paddle with lifting function can effectively promote the reaction, enhance mass transfer, ensure that the turbulence intensity G value and water residence time in the hydrogen peroxide activation zone I are maintained within a reasonable range, and drive the water flow to circulate between the hydrogen peroxide activation zone I and the ultraviolet photocatalytic zone II, inducing Fe... 2+ and Fe 3+ The two valence states repeatedly switch. The use of a propeller-type agitator prevents the oxidation of Fe. 2+ Furthermore, stirring is only performed in the very small hydrogen peroxide activation zone I, resulting in a significant reduction in energy consumption.

[0050] In some specific embodiments, one end of the hydrogen peroxide dosing pipe 5 extends from below into the hydrogen peroxide activation zone I of the guide tube 2, and the other end of the hydrogen peroxide dosing pipe 5 extends out of the reactor body 1 and is connected to the hydrogen peroxide supply container, so that hydrogen peroxide can be continuously added into the reactor body 1.

[0051] Each of the above embodiments can be implemented individually, or in any combination of two or more. The following detailed description of specific examples will further illustrate these embodiments.

[0052] Example 1: This embodiment provides a UV Fenton reactor, such as Figure 1-2 As shown, it includes a reactor body 1, within which is a vertically connected guide tube 2 and an ultraviolet photocatalytic array 3. The area enclosed by the guide tube 2 is the hydrogen peroxide activation zone I, the area covered by the ultraviolet photocatalytic array 3 is the ultraviolet photocatalytic zone II, and the area at the bottom of the ultraviolet photocatalytic array 3 is the reflux zone III.

[0053] In this embodiment, the reactor body 1 is equipped with a drain pipe 1.1 and an iron sludge discharge pipe 1.2 at the bottom for discharging the treated and settled wastewater and iron sludge, respectively. The bottom of the reactor body 1 is provided with a downwardly sloping, converging surface to induce iron sludge sedimentation and achieve solid-liquid separation between iron sludge and supernatant during the settling process.

[0054] In this embodiment, the flow guide tube 2 is coaxially arranged with the reactor body 1, that is, located in the exact center of the reactor body 1, and the volume of the flow guide tube 2 accounts for 3.3% of the total volume of the reactor body 1. Figure 3 As shown, the guide tube 2 is fixedly installed on the reactor body 1 by means of the horizontally set guide tube angle steel bracket 21.

[0055] like Figure 4As shown, the ultraviolet photocatalytic array 3 of this embodiment includes a grid-like array structure formed by interlaced photocatalytic grid plates 3.1 and a number of ultraviolet light sources 3.2. The grid-like array structure is divided into several quadrilateral units by the photocatalytic grid plates 3.1, and the photocatalytic grid plates 3.1 near the inner wall of the reactor body 1 are firmly connected to the inner wall of the reactor body 1. The top surface of the guide tube 2 is higher than the top surface of the photocatalytic grid plates 3.1, and the bottom surface of the guide tube 2 is higher than the bottom surface of the photocatalytic grid plates 3.1. The ultraviolet photocatalytic array 3 can significantly improve the utilization rate of ultraviolet light and the photocatalytic efficiency, increase the amount of active reduced species generated in the aqueous solution, and greatly enhance the Fe... 3+ Efficiency of restoration.

[0056] In this embodiment, both sides of the photocatalytic grid plate 3.1 are coated with a TiO2 photocatalytic coating, and each quadrilateral unit is equipped with a 254 nm ultraviolet light source 3.2, ensuring that the photocatalytic coating of the photocatalytic grid plate 3.1 in each polygonal unit is within the irradiation range of the ultraviolet light source 3.2. To achieve the ultraviolet light source 3.2, several ultraviolet light source support plates 3.3 are horizontally installed between the inner walls of the reactor body 1. The ultraviolet light source support plates 3.3 are equipped with ultraviolet light source protective sleeves 3.4 corresponding to the ultraviolet light sources 3.2, and the ultraviolet light sources 3.2 are vertically installed in the corresponding ultraviolet light source protective sleeves 3.4.

[0057] The UV Fenton reactor in this embodiment also includes a stirring device 4 installed on the top of the reactor body 1 and extending into the hydrogen peroxide activation zone I. The stirring device 4 includes a vertically arranged stirring paddle connected to a drive component for rotating and vertically raising / lowering it. The stirring paddle with a lifting function effectively promotes the reaction, enhances mass transfer, ensures that the turbulence intensity G and water residence time in the hydrogen peroxide activation zone I are maintained within a reasonable range, and can drive water to circulate between the hydrogen peroxide activation zone I and the UV photocatalytic zone II, inducing Fe... 2+ and Fe 3+ The two valence states switch repeatedly.

[0058] The ultraviolet Fenton reactor of this embodiment also includes a hydrogen peroxide dosing pipe 5 for introducing hydrogen peroxide solution into the hydrogen peroxide activation zone I. One end of the hydrogen peroxide dosing pipe 5 extends into the hydrogen peroxide activation zone I of the guide tube 2 from below, and the other end of the hydrogen peroxide dosing pipe 5 extends out of the reactor body 1 and is connected to the hydrogen peroxide supply container, so that hydrogen peroxide can be continuously introduced into the reactor body 1.

[0059] The ultraviolet Fenton reactor in this embodiment also includes an inlet pipe 6 for introducing the wastewater to be treated into the reactor body 1. The inlet pipe 6 can extend directly into the hydrogen peroxide activation zone I, and the specific inlet position can be adjusted according to requirements.

[0060] The ultraviolet Fenton reactor in this embodiment can be used to treat wastewater containing organic pollutants. The specific working principle is as follows: (1) The reaction is a sequential batch reaction. First, wastewater containing ferrous salt (ferrous sulfate) is added to the reactor body 1 through the inlet pipe 6, and the pH value is adjusted to about 5.

[0061] (2) A guide tube 2 is installed at the center of the reactor body 1, which encloses a hydrogen peroxide activation zone (Zone I) where hydrogen peroxide solution is continuously added. To promote the reaction and enhance mass transfer, a stirring paddle with lifting function is installed in this zone to ensure that the turbulence intensity G value in the zone is controlled at approximately 750 s⁻¹. -1 The lifting action of the agitator can drive the water flow upward, controlling the water residence time in this zone to be approximately 20 seconds.

[0062] (3) Most of the area within reactor body 1 is the ultraviolet photocatalytic zone (zone II), where wastewater overflowing from zone I enters from top to bottom. Zone II not only undergoes the Fenton second-stage organic matter oxidation and degradation reaction but also the ultraviolet photocatalytic reaction. Ultraviolet irradiation of the aqueous phase generates e - a The UV lamp tube contains active reducing species such as q and •H, and a photocatalytic grid plate 3.1 coated with TiO2 catalyst is installed around it, which greatly improves the photocatalytic efficiency, generates more active reducing species, and makes the Fe in this area more efficient. 3+ Reduced to Fe 2+ The reactions, as well as the dechlorination reactions of chlorinated organic compounds, are more thorough. Simultaneously, the TiO2 catalyst coating on the surface of the photocatalytic grid plate 3.1 can generate photogenerated holes, further enhancing the oxidation of organic compounds through its powerful oxidizing ability.

[0063] (4) A reflux zone (Zone III) is set at the bottom of the reactor body 1. Organic pollutants have been oxidized and degraded in Zone II, and Fe is reduced to form Fe. 2+ The mixture is then re-entered into Zone I through the reflux zone.

[0064] (5) At the start of the Fenton reaction, turn on the ultraviolet light source 3.2, start the agitator, and continuously add hydrogen peroxide solution. The total amount of hydrogen peroxide added during operation is related to the Fe... 2+ The molar ratio is controlled at around 3:1, and the addition time is controlled between 85-90% of the reaction time.

[0065] (6) After the Fenton reaction is completed, liquid alkali is added to the reaction tank to adjust the pH value of the wastewater to 6.8-7.2, and then settling is started. The supernatant after sedimentation is discharged from the drain pipe 1.1 as treated wastewater; the settled Fe(III) sludge is retained and enters the next batch of wastewater treatment.

[0066] (7) When treating the second batch of wastewater, first adjust the pH value of the wastewater to the level required for the Fenton reaction. Then turn on the ultraviolet lamp and the agitator to circulate the wastewater in the reactor for 5-10 minutes, quickly measure the total dissolved iron ion concentration, calculate the proportion of iron salts lost after the previous batch of wastewater treatment, and add ferrous salts as needed.

[0067] (8) Start a new round of sequencing batch reaction and repeat step 5. After multiple batches of wastewater are treated, when the Fenton reaction is over and the pH of the wastewater has not been adjusted, let it stand for 30 minutes to settle. At this time, the iron sludge precipitated under acidic conditions is aged and relatively stable Fe(III) sludge, which can be discharged from the system through iron sludge discharge pipe 1.2 first, and then add liquid alkali to adjust the pH of the effluent.

[0068] (9) During operation, adjust the initial pH value according to different water quality, while minimizing the amount of Fe(III) sludge produced, increase the initial pH value of the Fenton reaction, and reduce the amount of acid and alkali solution required to neutralize the wastewater.

[0069] Application example: This application example uses wastewater from a dyeing and printing industrial park as an example, employing the UV Fenton reactor described in Example 1 for oxidative degradation. The COD of the wastewater to be treated is 158 mg / L, requiring post-treatment to meet the discharge standards of the dyeing and finishing industry, i.e., an effluent COD value below 80 mg / L. The COD in the following wastewater samples was determined using the dichromate method (Standard HJ 828-2017).

[0070] In this application example, the ratio of added hydrogen peroxide to influent COD mass concentration is 0.8:1, and the ratio of hydrogen peroxide to Fe... 2+ The molar ratio is 1:0.2, therefore the dosage of hydrogen peroxide is 126 mg / L (3.72 mol / L), Fe 2+ The dosage was 42 mg / L. The generated FeOOH iron sludge was 67 mg / L (the above dosage and generation amounts are average amounts per unit volume of wastewater, not instantaneous concentrations). After treatment, the effluent COD was 57 mg / L, achieving a removal rate of 64%.

[0071] If the traditional Fenton process is used to treat wastewater from the dyeing and printing industrial park, the specific solution is as follows: A reactor of the same size as in Example 1 was used, except that the reactor lacked the ultraviolet lamp, photocatalytic grid, and their corresponding fixing devices. The ratio of added hydrogen peroxide to influent COD mass concentration was 1:1, and the ratio of hydrogen peroxide to Fe... 2+ The molar ratio is 1:1, therefore the dosage of hydrogen peroxide is 158 mg / L (4.65 mol / L), Fe 2+The dosage was 260 mg / L; the FeOOH production from iron sludge was 413 mg / L (the above dosage and production amounts are average amounts per unit volume of wastewater, not instantaneous concentrations). Testing showed that the COD of the treated effluent was 77 mg / L, with a removal rate of 51%.

[0072] The results above show that the ultraviolet Fenton reactor of this invention can reduce the amount of iron sludge by 84%. Based on a wet sludge disposal cost of 500 yuan / ton (80% water content), this translates to a saving of 0.87 yuan / m³ in wastewater treatment operating costs. 3 Furthermore, in Example 1, a total of 44 ultraviolet lamps were used, each lamp being 28 W, with an illumination time of 20 minutes, and a water treatment volume of 0.39 M³. 3 The power consumption is 1.05 kWh / m³. 3 Based on an electricity price of 0.8 yuan / kWh, the wastewater treatment operating cost is 0.84 yuan / m³. 3 .

[0073] Therefore, it can be seen that the wastewater treatment cost does not increase significantly while the COD removal rate is significantly improved by using the UV Fenton reactor and UV Fenton treatment method of this invention.

[0074] Therefore, the novel ultraviolet Fenton method of this invention overcomes the limitations of the traditional Fenton method, and greatly enhances the Fe... 2+ The three major processes of ultraviolet reduction and oxidative degradation significantly improve the light efficiency of ultraviolet light, demonstrating unexpectedly excellent results in reducing the AOX index of industrial wastewater. Furthermore, in the ultraviolet Fenton reactor of this invention, the reducing active species generated in the ultraviolet photocatalytic zone can not only reduce Fe... 3+ It can also dechlorinate chlorinated organic compounds without negatively impacting the oxidation of organic compounds by oxidizing active species.

[0075] In summary, in order to overcome the limitations of the traditional Fenton process, this utility model innovatively designs a new type of ultraviolet Fenton reactor, which can efficiently oxidize and degrade organic pollutants in industrial wastewater. It also exhibits unexpected dechlorination and oxidation effects on chlorinated organic compounds, and is expected to be widely used in many industries such as printing and dyeing, prevention and control, papermaking, electroplating, and biomedicine.

[0076] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. A UV Fenton reactor, comprising a reactor body (1), characterized in that, The reactor body (1) is equipped with a vertically connected guide tube (2) and an ultraviolet photocatalytic array (3). The area formed by the flow guide tube (2) is the hydrogen peroxide activation zone (I), the area covered by the ultraviolet photocatalytic array (3) is the ultraviolet photocatalytic zone (II), and the area at the bottom of the ultraviolet photocatalytic array (3) is the reflux zone (III). The ultraviolet photocatalytic array (3) includes a grid-like array structure formed by interlacing a number of photocatalytic grid plates (3.1) and a number of ultraviolet light sources (3.2); both sides of the photocatalytic grid plates (3.1) are coated with a photocatalytic coating, and at least a portion of the photocatalytic coating is located within the irradiation range of the ultraviolet light sources (3.2); The ultraviolet Fenton reactor also includes a stirring device (4) installed on the top of the reactor body (1) and extending into the hydrogen peroxide activation zone (I), a hydrogen peroxide dosing pipe (5) for introducing hydrogen peroxide solution into the hydrogen peroxide activation zone (I), and a water inlet pipe (6) for introducing wastewater into the reactor body (1).

2. The ultraviolet Fenton reactor according to claim 1, characterized in that, The bottom of the reactor body (1) is provided with a drain pipe (1.1) and an iron sludge discharge pipe (1.2).

3. The ultraviolet Fenton reactor according to claim 1, characterized in that, The bottom of the reactor body (1) is provided with a downward-sloping, converging slope.

4. The ultraviolet Fenton reactor according to claim 1, characterized in that, The reactor body (1) has several guide tube angle steel brackets (21) installed on the inner wall for fixing the guide tube (2).

5. The ultraviolet Fenton reactor according to claim 1, characterized in that, The guide tube (2) is coaxially arranged with the reactor body (1).

6. The ultraviolet Fenton reactor according to claim 1, characterized in that, The volume of the guide tube (2) accounts for 3% to 5% of the total volume of the reactor body (1).

7. The ultraviolet Fenton reactor according to claim 1, characterized in that, The top surface of the guide tube (2) is higher than the top surface of the photocatalytic grid plate (3.1), and the bottom surface of the guide tube (2) is higher than the bottom surface of the photocatalytic grid plate (3.1).

8. The ultraviolet Fenton reactor according to claim 1, characterized in that, The grid-like array structure is divided into several regular or irregular polygonal units by a photocatalytic grid plate (3.1), and the photocatalytic coating of the photocatalytic grid plate (3.1) in each polygonal unit is within the irradiation range of the ultraviolet light source (3.2).

9. The ultraviolet Fenton reactor according to claim 1, characterized in that, Several ultraviolet light source support plates (3.3) are horizontally installed between the inner walls of the reactor body (1). The ultraviolet light source support plates (3.3) are provided with ultraviolet light source protective sleeves (3.4) that correspond one-to-one with the ultraviolet light sources (3.2).

10. A UV Fenton reactor according to claim 1, characterized in that, The stirring device (4) is a propulsion-type stirring paddle.

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