System and method for treating halogenated phenol organic pollutants in water based on microreactor

Abstract

The invention discloses a system and method for treating halogenated phenol organic pollutants in water based on a microreactor, and relates to the technical field of water treatment.The system comprises a feeding device, the microreactor, a light source, a product collecting device and a control device; the microreactor is provided with a microchannel and is divided into a reduction section and an oxidation section, under excitation of the same light source, halogen atoms in halogenated phenol are removed through an advanced reduction reaction, and then polymerization removal of phenolic pollutants is promoted through a photocatalytic advanced oxidation reaction. According to the invention, halogenated phenol pollutants can be efficiently removed, a polymerization product without halogen heteroatoms is obtained, the treatment cost is reduced, generation of halogenated disinfection by-products is inhibited, and integration and miniaturization of the reaction process are realized.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically, to a system and method for treating halogenated phenolic organic pollutants in water based on a microreactor. Background Technology

[0002] A variety of emerging organic pollutants exist in the aquatic environment, which are difficult to remove through conventional water treatment processes, posing potential threats to ecosystems and human health. Halogenated phenolic organic pollutants are a typical class of organic pollutants, characterized by the replacement of hydrogen atoms on the benzene ring of phenols with halogen atoms such as chlorine, bromine, and iodine. The introduction of halogen atoms enhances the toxicity and environmental persistence of phenolic pollutants, exhibiting high stability, high biotoxicity, strong bioaccumulation, and complex secondary toxicities, resulting in multiple health risks.

[0003] To remove halogenated phenolic pollutants from water, researchers have developed various treatment methods. Physical methods such as adsorption and membrane filtration can remove halogenated phenolic pollutants, but these are essentially physical transfers or concentrations of the pollutants. Compared to physical methods, chemical methods can achieve the chemical transformation of halogenated phenolic pollutants. Advanced oxidation-reduction (AOR) and advanced reduction-reduction (ARR) technologies have received widespread attention in recent years. AOR utilizes the resulting reactive oxygen species to oxidize and transform pollutants, while ARR utilizes the resulting reactive reducing species to reduce and transform pollutants. Both chemical treatment methods can be used to remove halogenated phenolic pollutants, but they also have corresponding problems. During AOR treatment, the carbon-halogen bonds in halogenated phenolic pollutant molecules are difficult to break through oxidation, while other structures in the molecules are easily oxidized, leading to the formation of a large number of halogenated byproducts after AOR degradation, which still pose a potential threat to the ecosystem. During ARR treatment, the carbon-halogen bonds can be effectively broken under the action of reducing species, but the reduced phenolic pollutants cannot be further transformed, similarly posing a potential threat to the ecosystem. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned deficiencies in existing technologies. This invention provides a system and method for treating halogenated phenolic organic pollutants in water based on a microreactor. By integrating advanced oxidation and advanced reduction processes within the microreactor, under the same light source excitation, halogen atoms in halogenated phenols are first removed through an advanced reduction reaction, followed by photocatalytic advanced oxidation to promote the polymerization and removal of phenolic pollutants. This invention can efficiently remove halogenated phenolic pollutants, yielding polymer products free of halogen heteroatoms, reducing treatment costs, inhibiting the formation of halogenated disinfection byproducts, and achieving integration and miniaturization of the reaction process.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A system for treating halogenated phenolic organic pollutants in water based on a microreactor includes: a feeding device, a microreactor, a light source, a product collection device, and a control device; the feeding device is connected to the microreactor and is used to transport reactants into the microreactor; wherein, the feeding device includes a first liquid container, a second liquid container, a third liquid container, and a liquid transfer pump; the liquid transfer pump is connected to the inlets of the first liquid container, the second liquid container, and the third liquid container respectively; the microreactor includes a microreactor chip, the surface of which is provided with a first liquid inlet, a second liquid inlet, a third liquid inlet, and a liquid outlet; the microreactor chip is provided with microchannels, the microchannels including sequentially connected The microreactor consists of a reduction section and an oxidation section. The outlet of the first liquid container is connected to the first liquid inlet via a first solenoid valve, and the outlet of the second liquid container is connected to the second liquid inlet via a second solenoid valve. The first and second liquid inlets are correspondingly connected to the reduction section of the microchannel. The outlet of the third liquid container is connected to the third liquid inlet via a third solenoid valve, and the third liquid inlet is correspondingly connected to the oxidation section of the microchannel. This is used to transport the reactants into the microreactor. The light source is an ultraviolet light source and is located on one side of the microreactor chip. The product collection device is connected to the liquid outlet. The control device is connected to the liquid delivery pump and the light source, respectively.

[0006] This invention also discloses a method for treating halogenated phenolic organic pollutants in water using the microreactor-based system described above, comprising the following steps: S1. The water containing halogenated phenolic organic pollutants is purged with nitrogen to obtain reactant one, which is placed in the first liquid container; the nitrogen-purged water and sulfite are mixed to obtain reactant two, which is placed in the second liquid container; the oxygen-purged water and catalyst are mixed to obtain reactant three, which is placed in the third liquid container. S2. Start the liquid delivery pump through the control device and open the first solenoid valve and the second solenoid valve to deliver the reactant one and the reactant two to the reduction section of the microchannel through the first liquid inlet and the second liquid inlet, respectively; after mixing, start the ultraviolet light source to make the mixed materials undergo advanced reduction reaction in the reduction section to obtain intermediate liquid one; S3. The third solenoid valve is opened by the control device, and the third reactant material is transported to the oxidation section of the microchannel through the third liquid inlet, where it is mixed with the incoming intermediate liquid. Under the irradiation of the ultraviolet light source, the mixture undergoes a photocatalytic advanced oxidation reaction in the oxidation section to obtain intermediate liquid. S4. Collect the intermediate liquid II from the liquid outlet and separate the catalyst to obtain treated water.

[0007] Implementing the embodiments of the present invention will have the following beneficial effects: (1) Based on the structural characteristics of halogenated phenolic pollutants, advanced reduction technology and advanced oxidation technology are coupled. First, advanced reduction technology is used to remove halogen atoms from halogenated phenolic pollutants and convert them into phenolic pollutants. Then, advanced oxidation technology is used to further oxidize and convert the phenolic pollutants, thus overcoming the disadvantages of advanced reduction technology and advanced oxidation technology alone.

[0008] (2) To address the structural characteristics of reduced phenolic pollutants, which readily polymerize, a composite catalyst containing a photoresponsive catalytic active component and a metal oxyhalide component is employed in the advanced oxidation technology. The photoresponsive catalytic active component can generate photogenerated electrons and holes under light irradiation. These photogenerated electrons can transfer to the interlayer of the metal oxyhalide layer, effectively inhibiting electron-hole recombination. The photogenerated electrons reduce oxygen to form hydrogen peroxide, while the photogenerated holes and hydrogen peroxide, under the influence of the metal oxyhalide component, promote the polymerization reaction of reduced phenolic pollutants. The synergistic effect of the two components in the catalyst ensures that the photocatalytic advanced oxidation reaction system effectively promotes the removal of reduced phenolic pollutants through the polymerization reaction pathway. Compared to conventional degradation and mineralization pathways, the oxidant requirement for the polymerization reaction pathway is significantly reduced, allowing the small amount of oxidant generated in situ under photocatalysis to support the oxidation reaction, thus achieving effective coupling between the photocatalytic reaction and the advanced oxidation polymerization reaction.

[0009] (3) The obtained polymer products do not contain halogen heteroatoms, which facilitates subsequent resource utilization. On the one hand, during pyrolysis or incineration, toxic halogen compounds such as dioxins can be avoided from the source, making it more environmentally friendly; on the other hand, it also simplifies the chemical recycling process. The products will not produce corrosive hydrogen halides during degradation or depolymerization, thereby reducing equipment requirements and improving the purity of the recycled products.

[0010] (4) Both advanced reduction and advanced oxidation reactions occur within microchannels, offering significant advantages over conventional scale reactors. For advanced reduction reactions, the small size of microchannels allows light to easily penetrate the entire reaction system, avoiding the "dead zone" caused by excessive liquid layer thickness in conventional scale reactors, thus achieving uniform and efficient irradiation of reactants. Simultaneously, the absorption and shielding of incident light by water impurities can reduce reaction efficiency, but microreactors, due to their extremely short optical path length, significantly mitigate this effect, making them superior to conventional scale reactors. For photocatalytic advanced oxidation reactions, microchannels also enhance the irradiation effect. Furthermore, since photocatalytic advanced oxidation reactions occur on the catalyst surface, microchannels significantly shorten the diffusion distance from reactants to the catalyst surface. The limited channel size also inhibits catalyst particle aggregation and increases the solid-liquid interface, all of which contribute to the effectiveness of photocatalytic advanced oxidation reactions.

[0011] (5) Compared with individual advanced oxidation reactions and individual advanced reduction reactions, the use of a composite reaction system may lead to an increase in processing costs. To this end, the present invention selects an ultraviolet / sulfite advanced reduction reaction system and an ultraviolet photocatalytic advanced oxidation reaction system, so that the advanced reduction reaction and the advanced oxidation reaction are integrated in the same microchannel, which can be excited by the same ultraviolet light source, reducing equipment investment and energy consumption; and through catalyst structure design, it is ensured that the photocatalytic advanced oxidation reaction system effectively promotes the removal of phenolic pollutants after reduction through the polymerization reaction pathway using dissolved oxygen, reducing the consumption of oxidant; the reaction rate in the microchannel is higher than that in the conventional scale, and the fluid mixing is enhanced by the microchannel structure design, which further improves the reaction rate and shortens the reaction time; by reducing equipment investment and energy consumption, reducing oxidant consumption and shortening reaction time, the processing cost is controlled to the maximum extent.

[0012] (6) Based on the characteristics of advanced reduction and advanced oxidation reactions, the microchannel is divided into a reduction section and an oxidation section. After passing through the reduction section, the halogenated phenolic pollutants are mixed with the catalyst to avoid interference from the catalyst in the advanced reduction reaction and to ensure that the advanced reduction and advanced oxidation reactions proceed in steps. Special attention is paid to purging the feed into the reduction section with nitrogen to remove dissolved oxygen, so as to prevent dissolved oxygen from interfering with the reduction reaction. At the same time as introducing the catalyst in the oxidation section, abundant dissolved oxygen is introduced. On the one hand, this consumes the residual reducing agent sodium sulfite after the advanced reduction reaction, preventing the reducing environment containing sodium sulfite from interfering with the subsequent oxidation reaction. On the other hand, it provides raw materials for the in-situ generation of hydrogen peroxide. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a system for treating halogenated phenolic organic pollutants in water based on a microreactor, according to an embodiment of the present invention.

[0014] Among them, 11, first liquid container; 12, second liquid container; 13, third liquid container; 14, liquid transfer pump; 15, first solenoid valve; 16, second solenoid valve; 17, third solenoid valve; 21, microreactor chip; 211, first liquid inlet; 212, second liquid inlet; 213, third liquid inlet; 214, liquid outlet; 215, microchannel; 216, reduction section; 217, oxidation section; 218, enhanced mass transfer structure; 3, light source; 4, product collection device; 5, control device. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0016] This invention discloses a system for treating halogenated phenolic organic pollutants in water based on a microreactor, such as... Figure 1 As shown, Figure 1 This is a schematic diagram of a system for treating halogenated phenolic organic pollutants in water based on a microreactor, according to an embodiment of the present invention. The system includes: a feeding device, a microreactor, a light source, a product collection device, and a control device. The feeding device is connected to the microreactor and is used to transport the reactants into the microreactor. The feeding device includes a first liquid container 11, a second liquid container 12, a third liquid container 13, and a liquid transfer pump 14. The liquid transfer pump 14 is connected to the inlets of the first liquid container 11, the second liquid container 12, and the third liquid container 13, respectively. The microreactor includes a microreactor chip 21, the surface of which is provided with a first liquid inlet 211, a second liquid inlet 212, a third liquid inlet 213, and a liquid outlet 214. Microchannels 215 are provided within the microreactor chip 21. 15 includes a reduction section 216 and an oxidation section 217 connected in sequence; the outlet of the first liquid container 11 is connected to the first liquid inlet 211 through the first solenoid valve 15, the outlet of the second liquid container 12 is connected to the second liquid inlet 212 through the second solenoid valve 16, and the first liquid inlet 211 and the second liquid inlet 212 are correspondingly connected to the reduction section 216 of the microchannel; the outlet of the third liquid container 13 is connected to the third liquid inlet 213 through the third solenoid valve 17, and the third liquid inlet 213 is correspondingly connected to the oxidation section 217 of the microchannel, used to transport the reactants to the microreactor; the light source 3 is an ultraviolet light source, which is set on one side of the microreactor chip 21; the product collection device 4 is connected to the liquid outlet 214; the control device 5 is connected to the liquid transfer pump 14 and the light source 3 respectively.

[0017] In one specific embodiment, the microchannel 215 includes a single channel or multiple channels.

[0018] In one specific embodiment, Figure 1The microchannel 215 is shown to be curved, but it is not limited to this. The microchannel 215 in this embodiment may also include at least one of straight line, broken line and spiral.

[0019] In one specific embodiment, the height of the microchannel 215 is 5μm to 500μm (preferably 5μm, 50μm, 100μm, 150μm, 200μm, 300μm, 400μm, 500μm), and the width is 100μm to 2000μm (preferably 100μm, 500μm, 1000μm, 1500μm, 2000μm).

[0020] In one specific embodiment, the channel length of the reduction section 216 is 10mm to 500mm (preferably 10mm, 50mm, 100mm, 200mm, 300mm, 400mm, or 500mm); the channel length of the oxidation section 217 is 10mm to 500mm (preferably 10mm, 50mm, 100mm, 200mm, 300mm, 400mm, or 500mm).

[0021] In one specific embodiment, the channel length ratio of the reduction section 216 to the oxidation section 217 is 1:1.

[0022] In one specific embodiment, the number of microreaction chips 21 is one or more. The system can be scaled up to accommodate different processing scales.

[0023] In one specific embodiment, when multiple microreactor chips 21 are provided, the microreactor chips 21 can be arranged in parallel. The liquid inlet of each microreactor chip 21 is connected to the feeding device, and the liquid outlet 214 is connected to the product collection device 4, collectively forming a parallel processing module. By increasing the number of microreactor chips 21 for parallel processing, the total processing capacity of the system can be linearly increased, enabling flexible scaling up of the device to meet the needs from laboratory pilot-scale to large-scale industrial water treatment. This parallel scaling-up method increases throughput while maintaining efficient mass transfer, heat transfer, and light transmission performance within the microreactor.

[0024] In one specific embodiment, the microreaction chip 21 is made of at least one of quartz, glass, polydimethylsiloxane, polymethyl methacrylate, and cyclic olefin copolymers.

[0025] In one specific embodiment, the inner surface of the microchannel 215, i.e. the wall of the microchannel, is provided with a mass transfer enhancement structure 218, which includes textured grooves.

[0026] In one specific embodiment, the depth ratio of the textured groove to the microchannel 215 is (0.05~0.2):1; the width of the textured groove is 10μm~100μm (preferably 10μm, 50μm, 80μm, 100μm).

[0027] In one specific embodiment, Figure 1 The shape of the textured groove is shown as serrated, but it is not limited to this. The channel shape of the microchannel 215 in this embodiment may also include at least one of herringbone and wavy shapes.

[0028] In one specific embodiment, the light source 3 is positioned above or below the microreactor chip 21.

[0029] In one specific embodiment, the illumination range of the light source 3 can cover and effectively illuminate the reduction section 216 and the oxidation section 217.

[0030] In one specific embodiment, the ultraviolet light source 3 includes one of a low-pressure mercury lamp, a high-pressure mercury lamp, an ultraviolet light-emitting diode, and an ultraviolet solid-state laser.

[0031] In one specific embodiment, the control device 5 is connected to the liquid transfer pump 14, the first solenoid valve 15, the second solenoid valve 16, the third solenoid valve 17 and the light source 3 via electrical signals, and is used to control the flow rate of the liquid transfer pump 14, the switching of the solenoid valves and the wavelength and intensity of the ultraviolet light source 3.

[0032] This invention also discloses a method for treating halogenated phenolic organic pollutants in water using the microreactor-based system described above, comprising the following steps: S1. The water containing halogenated phenolic organic pollutants is purged with nitrogen to obtain reactant one, which is placed in the first liquid container 11; the nitrogen-purged water and sulfite are mixed to obtain reactant two, which is placed in the second liquid container 12; the oxygen-purged water and catalyst are mixed to obtain reactant three, which is placed in the third liquid container 13.

[0033] S2. Start the liquid transfer pump 14 through the control device 5 and open the first solenoid valve 15 and the second solenoid valve 16 to transport reactant one and reactant two to the reduction section 216 of the microchannel 215 through the first liquid inlet 211 and the second liquid inlet 212 respectively. After mixing, start the ultraviolet light source 3 so that the mixed material is transported in the reduction section 216 while undergoing an advanced reduction reaction through the ultraviolet light source 3 to obtain intermediate liquid one.

[0034] S3. The third solenoid valve 17 is opened by the control device 5, and the reaction material three is transported to the oxidation section 217 of the microchannel 215 through the third liquid inlet 213, and mixed with the flowing intermediate liquid one; under the irradiation of the ultraviolet light source 3, the mixture is transported in the oxidation section 217 and undergoes photocatalytic advanced oxidation reaction through the ultraviolet light source 3 to obtain intermediate liquid two.

[0035] S4. Collect intermediate liquid II from liquid outlet 214 and separate the catalyst to obtain treated water.

[0036] In one specific embodiment, in step S2, the wavelength of the ultraviolet light source 3 is 180nm~400nm, and the light intensity is 1mW / cm². 2 ~50mW / cm 2 .

[0037] In one specific embodiment, in step S3, the wavelength of the ultraviolet light source 3 is 180nm~400nm, and the light intensity is 1mW / cm². 2 ~50mW / cm 2 .

[0038] Specifically, the wavelength of the ultraviolet light source 3 is set to 180nm~400nm, covering the vacuum ultraviolet to near-ultraviolet band. When using vacuum ultraviolet light of 180nm~200nm, high-purity quartz with good transmittance to vacuum ultraviolet light can be selected as the material of the micro-reaction chip 21, and inert gas protection and other measures can be used when necessary to give full play to the high energy characteristics of photons in this band.

[0039] In one specific embodiment, in step S1, the halogenated phenolic organic pollutant is a phenolic compound in which one or more hydrogen atoms on the benzene ring are replaced by halogen atoms; the halogen atom includes at least one of chlorine, bromine and iodine.

[0040] In one specific embodiment, the concentration of halogenated phenolic organic pollutants in the water is 1 mg / L to 50 mg / L.

[0041] In one specific embodiment, the water containing halogenated phenolic organic pollutants includes water containing one or more of chlorophenols, bromophenols, or iodophenols.

[0042] In one specific embodiment, the halogenated phenolic organic pollutant is preferably at least one selected from 2,4-dichlorophenol, pentachlorophenol, 2,4,6-trichlorophenol, 4-bromophenol, and 2,4-dibromophenol.

[0043] In one specific embodiment, the molar ratio of sulfite to halogenated phenolic organic pollutants is (5~1000):1.

[0044] In one specific embodiment, the mass ratio of the catalyst to water containing halogenated phenolic organic pollutants is 1:(500~100000).

[0045] In one specific embodiment, the sulfite is selected from at least one of potassium sulfite, sodium sulfite, and ammonium sulfite.

[0046] In one specific embodiment, the flow rate of reactant one is 0.01 mL / min to 5 mL / min.

[0047] In one specific embodiment, the ratio of the flow rate of reactant two to the flow rate of reactant one is 1:(50~200).

[0048] In one specific embodiment, the ratio of the flow rate of reactant three to the flow rate of reactant one is 1:(10~100).

[0049] In one specific embodiment, the catalyst includes a photoresponsive catalytically active component and a metal oxyhalide component.

[0050] In one specific embodiment, the photoresponsive catalytic active component is selected from at least one of titanium dioxide, zinc oxide, cadmium sulfide, carbon nitride, and bismuth tungstate.

[0051] In one specific embodiment, the metal oxyhalide component is selected from at least one of bismuth oxyiodide, bismuth oxybromide, bismuth oxychloride, bismuth oxyfluoride, iron oxychloride, and vanadium oxychloride.

[0052] In one specific embodiment, the metal oxyhalide component accounts for 40% to 90% of the mass of the catalyst.

[0053] In one specific embodiment, mixing includes at least one of stirring, oscillation, and ultrasound.

[0054] In one specific embodiment, when preparing reactant one and reactant two, the flow rate and time of nitrogen purging are not particularly limited. Preferably, the dissolved oxygen content is reduced to below 2 mg / L after purging, and more preferably, it is reduced to below 0.5 mg / L.

[0055] In one specific embodiment, when preparing reactant three, there is no particular limitation on the flow rate and time of oxygen purging. Preferably, the dissolved oxygen content is increased to more than 20 mg / L after purging, and more preferably, it is increased to more than 30 mg / L.

[0056] In one specific embodiment, in step S4, the separated catalyst can be reused after being washed with an organic solvent, and the polymerization product can be recovered from the washing liquid; the organic solvent is selected from at least one of methanol, ethanol, acetone, benzene, toluene and xylene.

[0057] In one specific embodiment, there is no particular limitation on the method of separating the catalyst; any separation method known to those skilled in the art can be used, including but not limited to centrifugation, filtration, and other steps.

[0058] In one specific embodiment, the solvent washing method is not particularly limited, and any separation method well known to those skilled in the art can be used, including but not limited to steps such as ultrasonication, stirring, and oscillation.

[0059] In one specific embodiment, there is no particular limitation on the method of separating the polymerization product; any separation method known to those skilled in the art can be used, including but not limited to evaporation, freeze drying, and other steps.

[0060] Specifically, the inventors explain the inventive principle of this application as follows: This invention targets the structural characteristics of halogenated phenolic pollutants by coupling advanced reduction and advanced oxidation technologies. First, advanced reduction technology removes halogen atoms from the halogenated phenolic pollutants, converting them into phenolic pollutants. Then, in the advanced oxidation technology, a composite catalyst containing a photoresponsive catalytic active component and a metal oxyhalide component is employed. The two components in the catalyst work synergistically, allowing a small amount of oxidant generated in situ under photocatalysis to support the oxidation reaction. This ensures that the photocatalytic advanced oxidation reaction system effectively promotes the removal of reduced phenolic pollutants through polymerization, thus achieving effective coupling of photocatalysis and advanced oxidation polymerization. This invention divides the microchannel into reduction and oxidation sections, integrating the advanced reduction and advanced oxidation reactions within the same microchannel. By reducing equipment investment and energy consumption, reducing oxidant consumption, and shortening reaction time, processing costs are controlled to the maximum extent. The resulting polymerization product does not contain halogen heteroatoms, facilitating subsequent resource utilization.

[0061] The following are specific embodiments. Example 1 This embodiment describes a system for treating halogenated phenolic organic pollutants in water based on a microreactor, such as... Figure 1 As shown, it includes: a feeding device, a microreactor, a light source, a product collection device, and a control device.

[0062] The feeding device includes a first liquid container, a second liquid container, a third liquid container, and a liquid transfer pump; the liquid transfer pump is connected to the inlet of the first liquid container, the second liquid container, and the third liquid container, respectively.

[0063] The microreactor includes a microreactor chip (made of quartz), with a first liquid inlet, a second liquid inlet, a third liquid inlet, and a liquid outlet on its surface. The microreactor chip contains microchannels (100 μm high and 500 μm wide), each comprising a sequentially connected reduction section and an oxidation section (100 mm long in both sections). The outlet of the first liquid container is connected to the first liquid inlet via a first solenoid valve, and the outlet of the second liquid container is connected to the second liquid inlet via a second solenoid valve. The first and second liquid inlets are correspondingly connected to the reduction section of the microchannel. The outlet of the third liquid container is connected to the third liquid inlet via a third solenoid valve, and the third liquid inlet is correspondingly connected to the oxidation section of the microchannel, used to transport reactants into the microreactor. The inner surface of the microchannel, i.e., the microchannel wall, is provided with serrated textured grooves, with a depth ratio of 0.1:1 between the textured grooves and the microchannel; the width of the textured grooves is 50 μm.

[0064] The light source is an ultraviolet light-emitting diode with a wavelength of 365nm and an intensity of 10 mW / cm². 2 It is located on one side of the microreactor chip. The illumination range of the light source can cover and effectively irradiate both the reduction and oxidation sections.

[0065] The product collection device is connected to the liquid outlet.

[0066] The control device is connected to the liquid transfer pump, the first solenoid valve, the second solenoid valve, the third solenoid valve, and the light source via electrical signals. It is used to control the flow rate of the liquid transfer pump, the opening and closing of the solenoid valves, and the wavelength and intensity of the ultraviolet light source.

[0067] The method for treating halogenated phenolic organic pollutants in water using the system of Example 1 includes the following steps: S1. Preparation of reaction materials An aqueous solution containing 2,4-dichlorophenol with a concentration of 10 mg / L was purged with nitrogen gas, and the dissolved oxygen content was 2 mg / L. The resulting reactants were then placed together in the first liquid container.

[0068] Sodium sulfite solution (sodium sulfite dissolved in nitrogen-purged water, dissolved oxygen content 2 mg / L), sodium sulfite and 2,4-dichlorophenol in a molar ratio of 200:1, yielded reactant two, which was placed in a second liquid container.

[0069] The catalyst suspension (dissolved in oxygen-purged water, dissolved oxygen content is 25 mg / L), the catalyst is a composite catalyst, wherein the photoresponsive catalytic active component is titanium dioxide (mass percentage 30%), the metal oxyhalide component is bismuth oxyiodide (mass percentage 70%), the mass ratio of the composite catalyst to the aqueous solution containing 2,4-dichlorophenol is 1:5000, and the resulting reactants are placed in a third liquid container.

[0070] S2. Start the liquid transfer pump through the control device and open the first and second solenoid valves to transport reactant one and reactant two to the reduction section of the microchannel through the first and second liquid inlets, respectively. The flow rate of reactant one is 0.1 mL / min and the flow rate of reactant two is 0.001 mL / min (flow rate ratio 1:100). After mixing, start the ultraviolet light source so that the mixed materials can undergo advanced reduction reaction through the ultraviolet light source while being transported in the reduction section to obtain intermediate liquid one.

[0071] S3. The third solenoid valve is opened by the control device, and the reaction material three is transported to the oxidation section of the microchannel through the third liquid inlet. The flow rate of the reaction material three is 0.01 mL / min (flow ratio 1:10), and it is mixed with the flowing intermediate liquid one. Under the irradiation of the ultraviolet light source, the mixture is transported in the oxidation section and undergoes photocatalytic advanced oxidation reaction through the ultraviolet light source to obtain intermediate liquid two.

[0072] S4. Collect intermediate liquid II from the liquid outlet and separate the catalyst to obtain treated water.

[0073] Results: The removal rate of 2,4-dichlorophenol reached 99.8%, the dehalogenation rate (based on chlorine atoms) was 98.5%, and the total organic carbon removal rate in water reached 95%. The polymerization product was analyzed to be a halogen-free phenolic polymer, and the total organic carbon removal rate in water decreased by only 5% after the catalyst was reused 5 times.

[0074] Example 2 The system in this embodiment differs from that in Embodiment 1 only in that: the microreactor chip is made of polydimethylsiloxane, the microchannel height is 50 μm, the width is 1000 μm, the reduction section length is 200 mm, and the oxidation section length is 200 mm. The textured grooves are wavy, with a depth-to-channel depth ratio of 0.05:1 and a width of 40 μm. The light source is a low-pressure mercury lamp with a wavelength of 254 nm and an intensity of 20 mW / cm². 2 .

[0075] The method for treating halogenated phenolic organic pollutants in water using the system of this embodiment is the same as in Embodiment 1, except that: Reactant 1: An aqueous solution containing 4-bromophenol at a concentration of 20 mg / L, with a dissolved oxygen content of 0.8 mg / L after purging with nitrogen.

[0076] Reactant 2: Potassium sulfite solution (dissolved in nitrogen-purged water, dissolved oxygen content is 0.8 mg / L), the molar ratio of potassium sulfite to 4-bromophenol is 10:1.

[0077] Reactant 3: Catalyst suspension (dissolved in oxygen-purged water, dissolved oxygen content is 20 mg / L), the catalyst is a composite catalyst, in which the photoresponsive catalytic active component is carbon nitride (mass percentage 40%), the metal oxyhalide component is iron oxychloride (mass percentage 60%), and the mass ratio of catalyst to halophenol water is 1:10000.

[0078] Flow control: The flow rate of reactant one is 0.5 mL / min, the flow rate of reactant two is 0.0025 mL / min (flow rate ratio 1:200), and the flow rate of reactant three is 0.05 mL / min (flow rate ratio 1:10).

[0079] Results: The removal rate of 4-bromophenol reached 99.9%, the dehalogenation rate (based on bromine atoms) was 99.5%, and the total organic carbon removal rate in water reached 98%. The polymerization product was analyzed to be a halogen-free phenolic polymer, and the total organic carbon removal rate in water decreased by only 3% after the catalyst was reused 5 times.

[0080] Comparative Example 1: Individual Advanced Reduction Processing Experimental setup: The same system and parameters as in Example 1 were used, but only the advanced reduction reaction was carried out (i.e., only reactant one and reactant two were injected, and reactant three was only injected with pre-purged nitrogen-treated water without a catalyst). The products were collected directly after the reaction.

[0081] Results: The removal rate of 2,4-dichlorophenol reached 99.8%, and the dehalogenation rate (based on chlorine atoms) was 98.5%, but the total organic carbon removal rate was 5%, and the products were a large amount of phenolic pollutants such as phenol.

[0082] Comparative Example 2: Advanced Oxidation Treatment Alone Experimental setup: The same system and parameters as in Example 1 were used, but only the advanced oxidation reaction was carried out (i.e., reactant 2 was injected with pre-nitrogen-purged water that did not contain sodium sulfite).

[0083] Results: The removal rate of 2,4-dichlorophenol was 75.2%, the dehalogenation rate was 32.6%, and the total organic carbon removal rate was 18.5%. A large number of halogenated byproducts (such as chloroquinones) were generated, which were highly toxic.

[0084] Comparative Example 3: Using a single catalyst component Experimental setup: Same as in Example 1, but the catalyst uses only the photoresponsive catalytically active component (titanium dioxide, without metal oxyhalide components). Other parameters remain unchanged.

[0085] Results: The removal rate of 2,4-dichlorophenol was 99.8%, the dehalogenation rate was 98.5%, and the total organic carbon removal rate in water was 25.0%. The main products were small molecule degradation products, such as phenol and quinones.

[0086] Comparative Example 4: Conventional-scale reactor treatment Experimental setup: A sequential reduction-oxidation reaction was conducted using a conventional beaker reactor (liquid layer thickness 50 mm) with the same reactants and conditions (light source wavelength 365 nm, intensity 10 mW / cm²). Based on preliminary experiments, the optimal reaction time was determined to be 60 min.

[0087] Results: The removal rate of 2,4-dichlorophenol was 81.0%, the dehalogenation rate was 75.2%, and the total organic carbon removal rate in water was 54.8%. Due to unfavorable factors such as the light dead zone, uneven mixing, and catalyst agglomeration, the efficiency of both advanced reduction and advanced oxidation reactions was relatively low.

[0088] The above examples and comparative examples demonstrate that the system and method of the present invention can efficiently remove halogenated phenolic pollutants and inhibit the formation of halogenated byproducts, while the microreactor structure improves treatment efficiency and economy.

[0089] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A system for treating halogenated phenolic organic pollutants in water based on a microreactor, characterized in that, include: Feeding device, microreactor, light source, product collection device and control device; The feeding device is connected to the microreactor and is used to transport the reactants into the microreactor; wherein, the feeding device includes a first liquid container, a second liquid container, a third liquid container, and a liquid transfer pump; the liquid transfer pump is connected to the inlet of the first liquid container, the second liquid container, and the third liquid container respectively; The microreactor includes a microreactor chip, the surface of which is provided with a first liquid inlet, a second liquid inlet, a third liquid inlet, and a liquid outlet; the microreactor chip is provided with microchannels, the microchannels including reduction sections and oxidation sections connected in sequence; The outlet of the first liquid container is connected to the first liquid inlet via a first solenoid valve, and the outlet of the second liquid container is connected to the second liquid inlet via a second solenoid valve. The first liquid inlet and the second liquid inlet are correspondingly connected to the reduction section of the microchannel. The outlet of the third liquid container is connected to the third liquid inlet via a third solenoid valve, and the third liquid inlet is correspondingly connected to the oxidation section of the microchannel, for conveying the reactants to the microreactor. The light source is an ultraviolet light source and is located on one side of the microreactor chip; The product collection device is connected to the liquid outlet; The control device is connected to the liquid delivery pump and the light source, respectively.

2. The system for treating halogenated phenolic organic pollutants in water based on a microreactor according to claim 1, characterized in that, The microchannel shape includes at least one of curved, straight, polygonal, and spiral types; The height of the microchannel is 5μm~500μm and the width is 100μm~2000μm; The channel length of the reduction section is 10mm to 500mm; the channel length of the oxidation section is 10mm to 500mm.

3. The system for treating halogenated phenolic organic pollutants in water based on a microreactor according to claim 1, characterized in that, The inner surface of the microchannel is provided with a mass transfer enhancement structure, which includes textured grooves. The depth ratio of the textured groove to the microchannel is (0.05~0.2):1; the width of the textured groove is 10μm~100μm; The shape of the textured grooves is selected from at least one of serrated, herringbone, and wavy shapes.

4. The system for treating halogenated phenolic organic pollutants in water based on a microreactor according to claim 1, characterized in that, The illumination range of the light source covers both the reduction section and the oxidation section.

5. A method for treating halogenated phenolic organic pollutants in water using a microreactor-based system as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. The water containing halogenated phenolic organic pollutants is purged with nitrogen to obtain reactant one, which is placed in the first liquid container; the nitrogen-purged water and sulfite are mixed to obtain reactant two, which is placed in the second liquid container; the oxygen-purged water and catalyst are mixed to obtain reactant three, which is placed in the third liquid container. S2. Start the liquid delivery pump through the control device and open the first solenoid valve and the second solenoid valve to deliver the reactant one and the reactant two to the reduction section of the microchannel through the first liquid inlet and the second liquid inlet, respectively; after mixing, start the ultraviolet light source to make the mixed materials undergo advanced reduction reaction in the reduction section to obtain intermediate liquid one; S3. The third solenoid valve is opened by the control device, and the third reactant is transported to the oxidation section of the microchannel through the third liquid inlet, where it is mixed with the incoming intermediate liquid. Under the irradiation of the ultraviolet light source, the mixture undergoes a photocatalytic advanced oxidation reaction in the oxidation section to obtain intermediate liquid. S4. Collect the intermediate liquid II from the liquid outlet and separate the catalyst to obtain treated water.

6. The method according to claim 5, characterized in that, In step S2, the wavelength of the ultraviolet light source is 180nm~400nm, and the light intensity is 1mW / cm². 2 ~50mW / cm 2 ; In step S3, the wavelength of the ultraviolet light source is 180nm~400nm, and the light intensity is 1mW / cm². 2 ~50mW / cm 2 .

7. The method according to claim 5, characterized in that, In step S1, the halogenated phenolic organic pollutant is a phenolic compound in which one or more hydrogen atoms on the benzene ring are replaced by halogen atoms; the halogen atom includes at least one of chlorine, bromine and iodine; The concentration of halogenated phenolic organic pollutants in the water is 1 mg / L to 50 mg / L; The molar ratio of the sulfite to the halogenated phenolic organic pollutant is (5~1000):1; the mass ratio of the catalyst to the water containing the halogenated phenolic organic pollutant is 1:(500~100000). The sulfite is selected from at least one of potassium sulfite, sodium sulfite, and ammonium sulfite.

8. The method according to claim 5, characterized in that, The flow rate of the first reactant is 0.01 mL / min to 5 mL / min; The ratio of the flow rate of reactant 2 to the flow rate of reactant 1 is 1:(50~200). The ratio of the flow rate of reactant three to the flow rate of reactant one is 1:(10~100).

9. The method according to claim 5, characterized in that, The catalyst comprises a photoresponsive catalytically active component and a metal oxide halide component; The photoresponsive catalytic active component is selected from at least one of titanium dioxide, zinc oxide, cadmium sulfide, carbon nitride, and bismuth tungstate; The metal oxyhalide component is selected from at least one of bismuth iodide oxychloride, bismuth bromooxychloride, bismuth ...fluoride, iron oxychloride, and vanadium oxychloride. The metal oxyhalide component accounts for 40% to 90% of the mass of the catalyst.

10. The method according to claim 5, characterized in that, In step S4, the separated catalyst can be reused after being washed with an organic solvent, and the polymerization product can be recovered from the washing liquid; the organic solvent is selected from at least one of methanol, ethanol, acetone, benzene, toluene and xylene.

Images