Purification method and purification system for airborne molecular contaminants

Abstract

Provided are a purification method and a purification system for airborne molecular contaminants (AMC). The purification method comprises steps of: mixing AMC to be treated with a first water mist to obtain a gas-liquid mixture; allowing the gas-liquid mixture to contact photocatalysts on a porous substrate under radiation to react into a first treated mixture; washing the first treated mixture and the porous substrate with a second water mist to obtain a washing solution; and discharging a purified gas and the washing solution. The molecular weight of the first treated mixture is lower than that of the AMC to be treated, and the AMC content in the purified gas is lower than that of the AMC to be treated. The aforementioned technical means can improve the purification rate and extend the lifespan of the photocatalysts, thereby further improving overall purification performance.

Description

Technical Field

[0001] This work relates to a gas purification technology, and more particularly to a method for purifying gaseous molecular contaminants and a system for purifying gaseous molecular contaminants. Prior Technology

[0002] According to the F21-1102 standard published by Semiconductor Equipment and Materials International (SEMI), airborne molecular contaminants (AMCs) can be classified into four types: acidic (MA), basic (MB), condensable organic compounds (MCs), and dopants (MDs). Based on different gas characteristics, AMCs can be broadly classified into acidic gases, basic gases, and volatile organic compounds (VOCs). Their possible sources include exhaust gases from automobiles and motorcycles, ambient ozone, factory exhaust gases, chemical solvent volatilization, and acidic gases volatilized from etching processes.

[0003] In semiconductor manufacturing processes, the organic solvents volatilized from the photoetching adhesive generate gaseous molecular contaminants in the air. If these contaminants cannot be effectively removed or purified, they can easily settle on the wafer surface, causing defects and reducing the yield of semiconductor products. Furthermore, if they are accidentally leaked, they can endanger personnel safety and cause environmental pollution problems. Therefore, semiconductor manufacturers are actively building highly clean and isolated cleanrooms. This involves installing a Make-up Air Unit (MAU) at the air inlet to regulate the outside air to meet cleanroom specifications, and installing a Fan Filter Unit (FFU) on the ceiling. This allows airflow to pass through a High Efficiency Particulate Air Filter (HEPA) or Ultra Low Penetration Air Filter (ULPA) before entering the cleanroom, thereby purifying both the outside air and the air within the cleanroom.

[0004] While activated carbon filters can be used for adsorption in the past, once the activated carbon reaches saturation with gaseous molecular pollutants, it must be replaced to continue purifying the gas. This not only significantly increases the consumption of activated carbon filters but also reduces the purification efficiency of the cleanroom. Besides activated carbon adsorption, photocatalysts can also be used to directly decompose gaseous molecular pollutants under light. However, the time required for complete decomposition of gaseous molecular pollutants using photocatalysts is long, making it unsuitable for quickly and efficiently processing large quantities of gaseous molecular pollutants. Furthermore, the waste products generated from the decomposition of gaseous molecular pollutants continue to be adsorbed onto the photocatalyst surface, causing the decomposition rate to decrease after a period of time. Therefore, the purification process still needs to be periodically interrupted to regenerate the photocatalyst in order to continue purifying the gas using the regenerated photocatalyst.

[0005] In view of this, neither of the above two purification technologies can meet the current corporate emphasis on environmental protection, social responsibility, and corporate governance (ESG), and is even less likely to achieve the expectations of Sustainable Development Goals (SDGs). Therefore, there is currently an need to improve the treatment technology for gaseous molecular pollutants in order to overcome the shortcomings of traditional purification technologies. Summary of the Invention

[0006] One of the purposes of this work is to improve the purification rate of gaseous molecular pollutants, while also enhancing the overall purification efficiency.

[0007] Another objective of this invention is to extend the lifespan of photocatalysts used for purifying gaseous molecular pollutants, thereby addressing the previous problem of needing to frequently interrupt the purification process to regenerate the photocatalyst.

[0008] To achieve the aforementioned objective, this invention provides a method for purifying gaseous molecular pollutants, comprising: A gaseous molecular pollutant to be treated is mixed with a first water mist to obtain a gas-liquid mixture; Under the influence of a radiation source, the gas-liquid mixture is reacted with a photocatalyst on a porous substrate to react the gaseous molecular pollutant to be treated into a first treated product; The first treated material and the porous substrate are washed with a second water mist to obtain a washing solution in which the first treated material dissolves; and A purified gas and the washing solution are emitted, wherein the molecular weight of the first processed substance is lower than the molecular weight of the gaseous molecular pollutant to be treated, and the content of the gaseous molecular pollutant in the purified gas is lower than the content of the gaseous molecular pollutant to be treated.

[0009] By first mixing the gaseous molecular contaminants to be treated with a first water mist, and then reacting them with a photocatalyst on a porous substrate under a radiation source to decompose them into a first treated substance, the time required to treat gaseous molecular contaminants can be shortened and the purification rate of the gaseous molecular contaminants can be improved. Furthermore, using a second water mist to wash the porous substrate further facilitates the simultaneous dissolution of the first treated substance on the porous substrate into the washing solution during the purification process and removes it from the surface of the photocatalyst, achieving the purpose of regenerating the photocatalyst. Therefore, this invention can extend the lifespan of the photocatalyst and solve the problem of frequently interrupting the purification process to regenerate the photocatalyst. In particular, this invention's method for purifying gaseous molecular contaminants can also improve the overall purification efficiency, reducing the content of gaseous molecular contaminants in the purified gas to a much lower level. Overall, this invention's method for purifying gaseous molecular contaminants overcomes many shortcomings of past purification technologies and is more beneficial for enterprises to achieve their ESG and SDG goals.

[0010] On the other hand, the gaseous molecular pollutants to be treated in the gas-liquid mixture can come into contact with the photocatalyst and be decomposed by it, transforming into a first-processed substance with a lower molecular weight (e.g., acid, alkali, or organic pollutants), making the molecular weight of the first-processed substance lower than that of the gaseous molecular pollutants to be treated. After the gaseous molecular pollutants are decomposed into the first-processed substance by the photocatalyst, the solubility of the first-processed substance in the second water mist is also greater than that of the gaseous molecular pollutants to be treated in the second water mist. Therefore, the first-processed substance generated by the photocatalytic decomposition reaction can be more readily dissolved in the washing solution and discharged, making the content of gaseous molecular pollutants in the purified gas lower than that in the gaseous molecular pollutants to be treated.

[0011] Optionally, the gaseous molecular pollutant to be treated may include acetone, isopropanol, toluene, or combinations thereof, but is not limited to these. In one embodiment, the gaseous molecular pollutant to be treated may substantially not contain polyhalogenated compounds, benzene ring compounds, polycyclic aromatic hydrocarbons, long-chain alkane compounds, or combinations thereof. Taking acetone as an example, acetone in contact with the photocatalyst can be decomposed into formic acid (the first treated product). Therefore, the molecular weight of the first treated product can be lower than that of the gaseous molecular pollutant to be treated, and the solubility of the first treated product in the second water mist is also greater than that of acetone in the second water mist. This facilitates the decomposition of the gaseous molecular pollutant into the first treated product, which has higher solubility and lower molecular weight, and the first treated product is dissolved in the washing solution and discharged via a water washing method.

[0012] In the purification method of this invention, the gaseous molecular pollutant to be treated can be introduced into the cavity at a set inlet airflow rate, and the gaseous molecular pollutant to be treated is mixed with the first water mist in the cavity to obtain the gas-liquid mixture. Optionally, the inlet airflow rate of the gaseous molecular pollutant to be treated can be from 20 cubic meters / hour to 5000 cubic meters / hour, but is not limited to this. Optionally, the inlet airflow rate can be from 0.1 meters / minute to 2.5 meters / minute, but is not limited to this. In this specification, the inlet airflow rate (also known as face velocity) is the airflow velocity of the gaseous molecular pollutant to be treated through the cross-section of the cavity. When the inlet airflow rate is the same, the larger the cross-sectional area, the smaller the inlet airflow rate, and vice versa.

[0013] In the purification method of this invention, the second water mist may be composed of water, or water combined with organic solvents, inorganic solvents, or a combination thereof, wherein the water content in the second water mist is 80% or more by volume, or 80% to 100% by volume. Optionally, the flow rate of the first or second water mist may be 0.1 liters / minute to 1 liter / minute or 0.3 liters / minute to 1 liter / minute, but is not limited to these. For example, the second water mist may be composed of water, methanol, ethanol, acetic acid, or a combination thereof. Those skilled in the art can select a suitable second water mist to wash the first treated material and the porous substrate according to different needs. In one embodiment, the first water mist is equivalent to the second water mist, that is, both are from the same water mist source. The first water mist can be mixed with the gaseous molecular pollutants to be treated to obtain the gas-liquid mixture, and the first water mist can also be used to wash the first processed material and the porous substrate, thereby allowing the first water mist to simultaneously perform the functions of gas-liquid mixing and photocatalyst regeneration. When the first water mist is equivalent to the second water mist, the flow rate of the first water mist is 0.1 liters / minute to 1 liter / minute.

[0014] Preferably, the purification method of this creation may further include: Recycle the washing solution; The first processed product is separated from the washing solution to obtain a regenerated solution; The regeneration solution is sprayed to produce a regeneration water mist; and The regenerated water mist is first mixed with the gaseous molecular pollutant to be treated to obtain the gas-liquid mixture, and the regenerated water mist and the second water mist are used to wash the first treated material and the porous substrate.

[0015] Accordingly, this invention can separate the first treatment substance from the washing solution through, for example, filtration, thereby regenerating the washing solution into a reusable regenerated solution. Therefore, the purification method of this invention reduces water waste (i.e., reduces the amount of first and / or second water mist used) and reduces the amount of water discharged, further meeting the expectations of green purification treatment, water resource recycling, environmental protection, and other aspects, and moving towards the goals of ESG and SDGs.

[0016] Optionally, the regenerated water mist may be composed of water, or water and organic solvents, inorganic solvents, or combinations thereof, wherein the water content in the regenerated water mist is 80% or more by volume or 80% to 100% by volume.

[0017] In addition, to achieve the aforementioned objectives, this invention also provides a purification system for gaseous molecular pollutants, comprising: A cavity having a channel, wherein the channel has an air inlet and an air outlet that are interconnected; A first gas processing module is located between the air inlet and the exhaust outlet, and the first gas processing module includes at least one gas processing unit, each of the at least one gas processing unit comprising: A housing having a windward panel and a side panel, the side panel being arranged around the windward panel and forming a processing space, the windward panel having at least one air inlet and the side panel having at least one exhaust outlet; At least one porous substrate with photocatalysis is disposed in the processing space; At least one radiation source is disposed toward the at least one porous substrate having a photocatalyst; A water mist generating module includes a water inlet pipe and a water mist sprayer that are interconnected. The water mist sprayer is disposed on the windward plate, and one spray nozzle of the water mist sprayer faces the processing space.

[0018] With the aforementioned design, the gaseous molecular pollutants to be treated, introduced into the cavity through the air inlet, inevitably flow through the first gas treatment module. In the treatment space of the gas treatment unit, they undergo gas-liquid mixing with the first water mist from the water mist generation module. This mixture then contacts and decomposes into the first treated substance within the treatment space, thereby shortening the time required to treat the gaseous molecular pollutants and increasing the purification rate. Furthermore, the water mist generation module can spray the first and / or second water mists towards the treatment space, simultaneously dissolving the first treated substance on the porous substrate in the washing solution and removing it from the photocatalyst surface during the purification process. This achieves the purpose of regenerating the photocatalyst, thus extending its lifespan and solving the problem of frequently interrupting the purification process to regenerate it. In particular, this gaseous molecular pollutant purification system also improves overall purification efficiency, offering numerous advantages compared to previous treatment equipment.

[0019] In the purification system of this invention, the windward plate has a support hole, and the water mist sprayer is installed on the support hole. Preferably, there are multiple air inlets, which are located around the support hole, and multiple exhaust holes. Accordingly, the gaseous molecular pollutants to be treated, introduced through the air inlet, can be evenly dispersed by the multiple air inlets and enter the treatment space to mix with the first water mist, and then decomposed into the first treated substance upon contact with the photocatalyst. The purified gas is then evenly dispersed through the multiple exhaust holes and discharged from the treatment space.

[0020] In the purification system of this invention, the air inlets are opened along the airflow direction formed by the air inlet and the exhaust outlet, and the exhaust outlets are opened along a turbulence direction that is not parallel to the airflow direction. Optionally, the airflow direction may intersect with the turbulence direction, thereby allowing the gaseous molecular pollutants to be treated to flow through the air inlet into the treatment space, react with the photocatalyst, and then flow through the lateral exhaust outlets to be discharged from the treatment space. This helps to increase the time that the gaseous molecular pollutants to be treated remain in the treatment space and are in contact with the photocatalyst.

[0021] In the purification system of this invention, when the number of at least one porous substrate with photocatalyst is multiple, it may include a first porous substrate with photocatalyst and a second porous substrate with photocatalyst, wherein the first and second porous substrates with photocatalyst can be arranged facing each other in the processing space; and the number of at least one radiation source is multiple, with a portion of the radiation sources spaced apart from each other and arranged toward the first porous substrate with photocatalyst, and another portion of the radiation sources spaced apart from each other and arranged toward the second porous substrate with photocatalyst. For example, two to four radiation sources may be spaced apart from each other next to the first porous substrate with photocatalyst, and another two to four radiation sources may be spaced apart from each other next to the second porous substrate with photocatalyst, so as to uniformly irradiate the photocatalyst on the first and second porous substrates with photocatalyst, so that it can decompose gaseous molecular pollutants under the irradiation of the radiation sources, becoming a first processed product with lower molecular weight and better solubility in the second water mist.

[0022] Optionally, the first and second porous substrates with photocatalysts can be obliquely arranged in the processing space, and the distance between the sides of the first and second porous substrates with photocatalysts closest to the windward plate can be greater than the distance between the sides of the first and second porous substrates with photocatalysts furthest from the windward plate. That is, the first and second porous substrates with photocatalysts can be arranged in a V-shape. Compared to a parallel arrangement, the aforementioned oblique V-shaped arrangement allows the porous substrates to have a larger area in a given processing space, thus facilitating the adhesion of more photocatalysts to the porous substrates. Optionally, the radiation source includes a plurality of ultraviolet lamps, and the angle between the ultraviolet lamp facing the first porous substrate with photocatalyst and the ultraviolet lamp facing the second porous substrate with photocatalyst can be 30 degrees to 60 degrees. That is, the two ultraviolet lamps arranged opposite each other next to the first and second porous substrates with photocatalyst can also be arranged in a V-shape, corresponding to the aforementioned arrangement of the first and second porous substrates with photocatalyst.

[0023] Optionally, the number of ultraviolet lamps facing the first porous substrate with photocatalysis can be the same as the number of ultraviolet lamps facing the second porous substrate with photocatalysis, and they are arranged opposite each other in the processing space. Furthermore, the height at which the ultraviolet lamps facing the first porous substrate with photocatalysis are positioned in the processing space can be approximately equal to the height of the ultraviolet lamps facing the second porous substrate with photocatalysis in the processing space.

[0024] Optionally, a portion of the radiation sources may be disposed between the first porous substrate with photocatalyst and the side plate, and another portion of the radiation sources may be disposed between the second porous substrate with photocatalyst and the side plate.

[0025] In the purification system of this invention, the porous substrate can be selected from a group consisting of foamed ceramic substrates, activated carbon substrates, metal-organic frameworks, foamed metals, and combinations thereof. The porous structure design of the substrate increases its specific surface area, thereby increasing the amount of photocatalyst adhering to the substrate. Furthermore, this porous structure design also increases turbulence and prolongs the time that gaseous molecular pollutants remain in the treatment space and contact the photocatalyst, thus improving overall purification efficiency. Optionally, the specific surface area of ​​the porous substrate can be from 1000 m² / g to 3500 m² / g.

[0026] Optionally, the porous substrate has a pore size of 50 to 200 mesh. It is understood that the term "mesh number" as used in this specification represents the number of pores in a 1-inch × 1-inch area of ​​the porous substrate, with a higher mesh number indicating a greater number of pores.

[0027] Optionally, the thickness of the porous substrate can be from 10 mm to 100 mm, or from 10 mm to 60 mm, without any particular limitation, as long as the irradiation of the radiation source can cover the photocatalyst on the porous substrate so that it can decompose gaseous molecular pollutants.

[0028] Optionally, the radiation source can be selected from a group consisting of ultraviolet light sources, infrared light sources, microwave sources, plasma sources, X-ray sources, ion beam sources, and combinations thereof. When the radiation source is an ultraviolet light source, the power of the ultraviolet light source can be from 10 watts to 1000 watts, and the wavelength can be from 245 nanometers to 365 nanometers.

[0029] Preferably, to further improve the overall purification efficiency, the number of gas processing units in the first gas processing module can be multiple. Optionally, the gas processing units of the first gas processing module are arranged in a matrix.

[0030] Preferably, the air intake plates of these gas treatment units are adjacent to each other and extend to the inner wall of the channel, so that the gaseous molecular pollutants to be treated introduced from the air inlet can be converted into purified gas through the purification treatment of these gas treatment units.

[0031] Furthermore, to further enhance the overall purification efficiency, the purification system of this invention may also include a second gas processing module. The first gas processing module and the second gas processing module are spaced apart between the air inlet and the exhaust outlet, and the second gas processing module also includes at least one gas processing unit, wherein the at least one gas processing unit of the second gas processing module is substantially the same as the gas processing unit of the first gas processing module. For example, the number of the at least one gas processing unit of the second gas processing module is also multiple, and the air intake plates of the gas processing units of the second gas processing module are adjacent to each other and extend to the inner wall of the channel.

[0032] Preferably, a plurality of gas treatment units can be detachably assembled to form the first gas treatment module. Similarly, a plurality of gas treatment units can also be detachably assembled to form the second gas treatment module. Optionally, those skilled in the art can assemble the first and second gas treatment modules using conventional welding, riveting, or locking methods, but are not limited to this. Those skilled in the art can also weld, rivet, or lock multiple gas treatment units onto a frame to form the first and second gas treatment modules respectively. With the aforementioned detachable design, this invention allows for the disassembly of specific individual gas treatment units as needed during the purification process without replacing the entire gas treatment module. This not only simplifies maintenance and reduces maintenance costs but also reduces the generation of waste gas treatment units. Therefore, the purification technology of this invention has multiple benefits, including green purification treatment, waste reduction, and environmental protection. It is more advantageous for implementing ESG and helps achieve the ultimate goal of net-zero emissions and sustainable development.

[0033] In the purification system of this invention, the purification system may further include at least one water collection tank, which may be disposed below the first gas treatment module and / or the second gas treatment module.

[0034] In the purification system of this invention, the system may further include a return pipe, which connects the aforementioned water collection tank and the inlet pipe. A filter unit is installed on the return pipe, connected to the inlet pipe, and branching off to a discharge pipe. Accordingly, this invention can send the washing solution collected in the water collection tank to the filter unit via the return pipe. The filter unit separates the first-processed material from the washing solution to obtain a reusable regenerated solution. The regenerated solution is then sent back to the treatment space for reuse through the return pipe and the inlet pipe. The first-processed material is discharged through the discharge pipe. Therefore, the purification system of this invention has the advantages of reducing water waste and lowering the volume of discharged water, further meeting the expectations of green purification treatment, water resource recycling, and environmental protection. It also contributes to the implementation of ESG and the ultimate goal of sustainable development. Simple Explanation of the Diagram

[0035] Figure 1 is a flowchart of the first purification method for gaseous molecular pollutants. Figure 2 is a flowchart of the second purification method for gaseous molecular pollutants. Figure 3 is a three-dimensional schematic diagram of the first embodiment of the purification system for gaseous molecular pollutants. Figures 4 and 5 are exploded schematic diagrams of the gas processing unit from different perspectives. Figure 6 is a top view of the gas processing unit. Figure 7 is a side view of the gas processing unit of the first gas processing module connected to the water mist generation module. Figure 8 is a frontal view of the second embodiment of the purification system for gaseous molecular pollutants. Figure 9 is a side view schematic diagram of the second embodiment of the purification system for gaseous molecular pollutants. Figure 10 is a three-dimensional schematic diagram of the third embodiment of the purification system for gaseous molecular pollutants. Figure 11 is a side view of the third embodiment of the purification system for gaseous molecular pollutants. Figure 12 is a schematic diagram showing the connection between the gas processing unit and the return pipe and the filter unit. Figure 13 is a graph showing the changes in the removal efficiency of isopropanol, acetone, and toluene over time during the continuous purification of gaseous molecular pollutants in Example 1. Figure 14 shows the acetone removal efficiency of Example 1, Comparative Examples 1 and 2, and Control Example after purifying the gaseous molecular pollutants to be treated for 1 hour. Figure 15 shows the acetone removal efficiency of Example 1 and Comparative Example 3 after purifying the gaseous molecular pollutants to be treated for 1 hour. Figure 16 shows the acetone removal efficiency curves measured at different time points after continuous long-term purification of gaseous molecular pollutants in Example 2. Implementation

[0036] The following examples illustrate the implementation of the purification method and system for gaseous molecular pollutants of this invention. Comparative examples and contrast examples are also provided to help those skilled in the art easily understand the advantages and effects of this invention through the following examples and contrast examples. It should be understood that the examples listed in this specification are merely illustrative of the implementation of this invention and are not intended to limit the scope of this invention. Those skilled in the art can make various modifications and changes based on their ordinary knowledge without departing from the spirit of this invention to implement or apply the content of this invention.

[0037] [Purification Methods for Gaseous Molecular Pollutants] []

[0038] Please refer to Figure 1, which illustrates a first purification method for gaseous molecular pollutants, comprising: The gaseous molecular contaminants (AMCs) to be treated are mixed with the first water mist to obtain a gas-liquid mixture; Under the influence of a radiation source, the gas-liquid mixture reacts with a photocatalyst on a porous substrate to decompose the gaseous molecular pollutant to be treated into a first-stage pollutant; The first treated material and the porous substrate are washed with a second water mist to obtain a washing solution in which the first treated material dissolves; and The purified gas and the washing solution are emitted, and the molecular weight of the first processed substance is lower than the molecular weight of the gaseous molecular pollutant to be treated, and the content of the gaseous molecular pollutant in the purified gas is lower than the content of the gaseous molecular pollutant to be treated.

[0039] Please refer to Figure 2, which illustrates a second purification method for gaseous molecular pollutants, comprising: The AMC to be treated is mixed with the first water mist to obtain a gas-liquid mixture; Under the influence of a radiation source, the gas-liquid mixture reacts with a photocatalyst on a porous substrate to decompose the gaseous molecular pollutant to be treated into a first-stage pollutant; The first treated material and the porous substrate are washed with a second water mist to obtain a washing solution in which the first treated material dissolves. The purified gas and the washing solution are emitted, and the molecular weight of the first treated substance is lower than the molecular weight of the gaseous molecular pollutant to be treated, and the content of the gaseous molecular pollutant in the purified gas is lower than the content of the gaseous molecular pollutant to be treated; Recycle the washing solution; The washing solution is filtered to separate the regeneration solution and the first treated product. The regeneration solution is sprayed to produce a regeneration water mist; and The regenerated water mist and the first water mist are first mixed with the gaseous molecular pollutants to be treated to obtain the gas-liquid mixture, and the regenerated water mist and the second water mist are used to wash the first treated material and the porous substrate.

[0040] [Purification System for Gaseous Molecular Pollutants] []

[0041] In the first embodiment of the purification system, the first gas processing module can complete the process of purifying gaseous molecular pollutants by setting only a single gas processing unit.

[0042] Please refer to Figures 3 to 7. The purification system 1 for gaseous molecular pollutants may include a cavity 10, a first gas treatment module 20, a water mist generation module 30, and a water collection tank 40.

[0043] The cavity 10 has a channel 11 with an air inlet 111 and an exhaust outlet 112 that are interconnected, so that gaseous molecular pollutants to be treated are sent into the cavity 10, purified by the first gas treatment module 20, and then the purified gas is discharged out of the cavity 10 through the exhaust outlet 112.

[0044] The first gas treatment module 20 is disposed between the air inlet 111 and the exhaust port 112, and the single gas treatment unit 21 of the first gas treatment module 20 includes a housing 22, a first porous substrate 23 having a photocatalyst, a second porous substrate 24 having a photocatalyst, and a plurality of ultraviolet lamp tubes 25.

[0045] As shown in Figures 4 to 6, the housing 22 has a windward plate 221, two side plates 222, two cover plates 223, and a support shell 224. The side plates 222 and the cover plates 223 are connected to the support shell 224, and the side plates 222, the cover plates 223, and the support shell 224 are arranged around the windward plate 221 to form a processing space 225. The windward plate 221 has a plurality of air inlets 2211 and a bearing hole 2212. The air inlets 2211 are located around the bearing hole 2212, and the side plates 222 have a plurality of exhaust holes 2221. As shown in Figure 6, the air inlets 2211 are located along an airflow direction A formed by the air inlets 111 and the exhaust holes 112, and the exhaust holes 2221 are located along a turbulence direction B, which intersects with but is not parallel to the airflow direction A.

[0046] The first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst are respectively disposed facing each other in the processing space 225. Specifically, the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst are respectively disposed in the side plate 222 with exhaust holes 2221. In addition, the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst are each disposed obliquely, such that the distance D1 between the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst is greater than the distance D2 between the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst away from the windward plate 221. That is, the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst can be arranged in a roughly V-shaped structure, thereby increasing the area of ​​the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst.

[0047] The ultraviolet lamps 25 are arranged facing the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst. Specifically, four ultraviolet lamps 25 are installed on each of the two side plates 222, and the four ultraviolet lamps 25 are spaced apart from each other and arranged between the first porous substrate 23 with photocatalyst and the side plate 222. Another four ultraviolet lamps 25 are spaced apart from each other and arranged between the second porous substrate 24 with photocatalyst and the other side plate 222.

[0048] As shown in Figure 6, the angle between the ultraviolet lamp 25 facing the first porous substrate 23 with photocatalyst and the ultraviolet lamp 25 facing the second porous substrate 24 with photocatalyst can be 30 degrees to 60 degrees, that is, the two ultraviolet lamps 25 can be arranged in a roughly V-shaped structure.

[0049] The water mist generating module 30 is connected to the first gas treatment module 20. Specifically, the water mist generating module 30 includes a water inlet pipe 31 and a water mist sprayer 32 that are interconnected. The water mist sprayer 32 is installed on the bearing hole 2212 of the windward plate 221, and the spray nozzle of the water mist sprayer 32 faces the treatment space 225, thereby sending the first water mist into the treatment space 225 to mix with the gaseous molecular pollutants to be treated.

[0050] As shown in Figures 4 and 6, the length L, width W, and height H of each gas processing unit 21 can be adjusted as needed without any special limitations. In one embodiment, the specific surface area of ​​the porous substrate is from 1000 m² / g to 3500 m² / g, the pore size of the porous substrate is from 50 mesh to 200 mesh, and the thickness T of the porous substrate (as shown in Figure 6) can be from 50 mm to 60 mm.

[0051] The water collection tank 40 is disposed below the first gas treatment module 20 and is used to collect the washing solution overflowing from the first gas treatment module 20. In addition, the first gas treatment module 20 can be mounted on a metal frame 60, and the frame 60 is provided with a wind deflector 226. The wind deflector 221, the frame 60 and the wind deflector 226 can be disposed adjacent to each other and extend to the inner wall of the channel 11.

[0052] With the aforementioned structural design, the gaseous molecular pollutants to be treated, fed into the cavity 10 through the air inlet 111, will inevitably flow through the gas treatment unit 21 of the first gas treatment module 20. In the treatment space 225, they will first undergo gas-liquid mixing with the first water mist from the water mist sprayer 32 before contacting the photocatalyst. This allows the gaseous molecular pollutants in the gas to be treated to be decomposed into the first treated material more efficiently. Furthermore, the spraying range of the two water mist sprayers 32 can cover both the first porous substrate 23 with photocatalyst and the second porous substrate 24 with photocatalyst. Therefore, during the purification process, the first treated material on the porous substrate can be simultaneously dissolved in the washing solution and carried away from the surface of the photocatalyst, achieving the purpose of regenerating the photocatalyst. This helps to extend the lifespan of the photocatalyst and solves the problem of frequently interrupting the purification process to regenerate the photocatalyst. In particular, this gaseous molecular pollutant purification system can also improve the overall purification efficiency, reducing the content of gaseous molecular pollutants in the purified gas to a much lower level.

[0053] In the second embodiment of the purification system of this invention, the first gas processing module may include a plurality of gas processing units, each of which is generally as described in the first embodiment, and will not be described again.

[0054] Please refer to Figures 8 and 9. The second embodiment of the gaseous molecular pollutant purification system 1 includes a first gas processing module 20 as described in the first embodiment. The first gas processing module 20 includes a plurality of gas processing units 21, 21A. The frame 60A can be used to support the plurality of gas processing units 21, 21A. The plurality of gas processing units 21, 21A are detachably mounted on the frame 60A and arranged in a matrix. The frame 60A also has a plurality of... The wind deflectors 226, 226A, the wind-facing plates 221, 221A, the frame 60, and the wind deflectors 226, 226A can also be arranged adjacent to each other and extend to the inner wall of the channel 11, so that the gaseous molecular pollutants to be treated will necessarily flow through the multiple gas treatment units 21, 21A of the first gas treatment module 20 (as shown in the airflow direction A in Figure 9), and mix with water mist in the treatment space before contacting the photocatalyst. In this way, the overall purification capacity is improved by setting multiple gas treatment units 21, 21A.

[0055] As described in the first embodiment, the gaseous molecular pollutant purification system 1 in the second embodiment also has a water collection tank 40, which is located below the first gas treatment module 20. Unlike the first embodiment, the gaseous molecular pollutant purification system 1 further includes a return pipe 51A connecting the water collection tank 40 and the water inlet pipe 31, and a filter unit 52A is provided on the return pipe 51A, with a branch outlet pipe 53A. Accordingly, the washing solution collected from the water collection tank 40 can be separated into a regeneration solution and a first treated product by the filter unit 52A. The first treated product can be discharged through the outlet pipe 53A, while the regeneration solution can be recycled within the purification system. Driven by a drive device (not shown, such as a motor) on the return pipe 51A, it is returned to the water inlet pipe 31 and continuously sprayed to form a regeneration water mist for the gas-liquid mixing and washing steps described above.

[0056] In the third embodiment of the purification system of this invention, the purification system may include a plurality of gas processing modules, each gas processing module including a plurality of gas processing units, and each gas processing unit is generally as described in the first embodiment, and will not be described again.

[0057] Please refer to Figures 10 to 12. The third embodiment of the gaseous molecular pollutant purification system 1 includes a first gas processing module 20 as described in the first embodiment and similar second gas processing modules 20A and third gas processing modules 20B. The frame 60B can be used to support the first gas processing module 20 and similar second gas processing modules 20A and third gas processing modules 20B, thereby allowing the first gas processing module 20, the second gas processing module 20A, and the third gas processing module 20B to be spaced apart between the air inlet 111 and the exhaust port 112. Each of the first gas processing module 20, the second gas processing module 20A, and the third gas processing module 20B has a water collection tank 40, 40A, and 40B below it. In addition, as shown in Figure 10, a maintenance door 70 may also be provided between the first gas treatment module 20 and the second gas treatment module 20A, and a maintenance door 70A may also be provided between the second gas treatment module 20A and the third gas treatment module 20B, or a maintenance door 70B may also be provided between the third gas treatment module 20B and the exhaust port 112, so as to replace specific gas treatment units as needed.

[0058] As shown in Figures 10 and 11, each gas processing module contains multiple gas processing units arranged in a matrix. These gas processing units may be substantially the same or different. Accordingly, by setting up multiple gas processing modules, the gaseous molecular pollutants to be treated can flow sequentially through the first gas processing module 20, the second gas processing module 20A, and the third gas processing module 20B (as shown by airflow direction A in Figure 11), so that the gaseous molecular pollutants in the gas to be treated undergo multiple purification processes in sequence, thereby improving the overall purification efficiency.

[0059] As shown in Figure 12, the washing solution collected in the water collection tank 40 can be sent to the filter unit 52A through the return pipe 51A for filtration treatment, thereby separating the washing solution into a regenerated solution and a first treated material. The first treated material can be discharged through the discharge pipe 53A, while the regenerated solution can be recycled and reused in the purification system. It is sent back to the water inlet pipe 31 by the drive device (not shown) on the return pipe 51A and continuously sprayed to form a regenerated water mist, so that the gaseous molecular pollutants to be treated flowing through the air inlet 2211 on the wind vane 221 can be mixed with the regenerated water mist or the first water mist again for the gas-liquid mixing and washing steps as described above.

[0060] [Example] [1]

[0061] To verify the beneficial effects of the purification method and equipment for gaseous molecular pollutants of this invention, the purification equipment shown in Figures 3 to 8 was used to complete the purification method shown in Figure 1 as Example 1. The specific parameters are set as follows: Inlet gas flow rate: 2.0 m / s; Inlet flow rate of the gas to be treated: 162 cubic meters per hour; The length, width, and height of a single gas processing unit are 693 mm, 664 mm, and 631 mm, respectively. The air intake vents on the windward panel are 427 mm long and 555 mm wide. Water mist continuously fed into a single gas treatment unit: 0.1 liters / minute; Specific surface area of ​​various porous substrates: 2800 square meters / gram; Pore ​​size of various porous substrates: 60 mesh; The length, width, and thickness of each porous substrate are: 600 mm, 600 mm, and 50 mm, respectively. Types of porous substrates: foamed ceramic substrates; The angle between the two UV lamps is 30 degrees. The spacing between the ultraviolet lamps is 152.7 mm. The wavelength of the ultraviolet lamp tube is approximately 365 nanometers. The power of the ultraviolet lamp tube is approximately 10 watts.

[0062] In the purification process, VOCs in the gaseous molecular pollutants to be treated can undergo a decomposition reaction through photocatalysis, forming a first-stage product with a smaller molecular weight. The reaction formula for the decomposition of acetone under light via photocatalysis is as follows: ; The reaction formula for the decomposition of isopropanol under light irradiation via photocatalysis is as follows: ; The reaction formula for the decomposition of toluene under light via photocatalysis is as follows:

[0063] The contents of isopropanol, acetone, and toluene in the gaseous molecular pollutants to be treated and in the purified gas were measured using ion chromatography (IC). The removal efficiency of each VOC was calculated by subtracting the percentage of each VOC content in the purified gas relative to the VOC content in the gaseous molecular pollutants to be treated from 100%. The results are shown in Figures 13 and 14. Figure 14 compares the acetone removal efficiency measured after 1 hour of purification treatment for Examples 1, Comparative Examples 1 and 2, and the control example to evaluate their removal efficiency under the same purification time.

[0064] As shown in Figure 13, the purification technology for gaseous molecular pollutants of this invention can be applied to effectively remove isopropanol, acetone and toluene from the gaseous molecular pollutants to be treated. As can be seen from the analysis results of Example 1, it has good removal efficiency for treating these three volatile organic compounds, and after a long reaction, there is no need to interrupt the purification process to regenerate the photocatalyst, and it still maintains good removal efficiency.

[0065] [Comparison Example] []

[0066] Unlike Example 1, the comparative example refers to a system without any photocatalyst or porous substrate, where only the same amount of water is fed into the system, and the gas to be treated is fed into the system at the same inlet air velocity and flow rate as set in Example 1. The results are shown in Figure 14.

[0067] [Comparative Example] [1]

[0068] Unlike Example 1, the purification system in Comparative Example 1 did not have any photocatalyst, but it did have a porous substrate. The gas to be treated was introduced into the system at the same airflow rate and flow rate as in Example 1, and the same amount of water was introduced into the system for testing. The results are shown in Figure 14.

[0069] [Comparative Example] [2]

[0070] Unlike Example 1, Comparative Example 2 differs from Example 1 in that the water mist was not mixed with the gaseous molecular contaminants to be treated beforehand. Instead, the gaseous molecular contaminants were reacted with the photocatalyst first before the water mist was sprayed onto the porous substrate. The inlet air velocity, inlet flow rate, and water mist volume for the other gaseous molecular contaminants to be treated were set to conditions roughly the same as those set in Example 1. The results are shown in Figure 14.

[0071] As shown in Figure 14, compared with the control example, comparative example 1 and comparative example 2, the acetone removal efficiency of example 1 is significantly better, showing that the purification method using the gaseous molecular pollutant purification system of this invention can specifically improve the VOC removal efficiency. [, , ] []

[0072] [Comparative Example] [3]

[0073] Unlike the aforementioned embodiments, Comparative Example 3 uses existing equipment to purify gaseous molecular contaminants, rather than the purification equipment of this invention. Specifically, although the equipment used in Comparative Example 3 includes a photocatalyst, it does not include a porous substrate. During the purification process, although the gaseous molecular contaminants to be treated are fed into the system with the same inlet air velocity and flow rate, they are not pre-mixed with liquid or water mist before interacting with the photocatalyst. Instead, they are introduced into the system with the same amount of water after the photocatalyst has acted upon them for testing. The results are shown in Figure 15.

[0074] As shown in Figure 15, the acetone removal efficiency of Example 1 is also significantly better than that of Comparative Example 3, demonstrating that the purification method using the gaseous molecular pollutant purification system of this invention can specifically improve the VOC removal efficiency.

[0075] [Example] [2]

[0076] Unlike Embodiment 1, multiple gas processing units can be combined as needed, i.e., the purification system shown in Figures 8 and 9 can be used for purification. Specifically, the specific parameter settings for Embodiment 2 are adjusted as follows: Inlet flow rate of the gas to be treated: 2592 cubic meters per hour; The length, width, and height of a single gas processing unit are 693 mm, 664 mm, and 631 mm, respectively. The number of gas processing units in the first gas processing module is 56. The continuous flow rate of water mist fed into a single gas treatment unit is 0.7 liters per minute.

[0077] Figure 16 shows the results of purifying the gaseous molecular pollutants using the purification system shown in Figures 8 and 9. As can be seen from Figure 16, even when a large number of gaseous molecular pollutants are processed at the same time, the acetone removal efficiency can still be maintained between 28% and 40%, which shows that the purification system for gaseous molecular pollutants created in this paper can exhibit excellent purification performance regardless of whether small or large amounts of gaseous molecular pollutants are processed at the same time.

[0078] In summary, the proposed purification method and system for gaseous molecular pollutants can shorten the time required to treat them, increase the purification rate, extend the lifespan of photocatalysts, and solve the problem of frequent interruptions in the purification process for photocatalyst regeneration. In particular, this invention can significantly improve overall purification efficiency, reducing the concentration of gaseous molecular pollutants in the purified gas to an even lower level. Therefore, the proposed purification method and system overcome many previous shortcomings and are beneficial for companies to achieve their ESG and SDG goals.

[0079] 1: Purification system for gaseous molecular pollutants 10: Cavity 11: Channel 111: Air Inlet 112: Exhaust port 20: First Gas Processing Module 20A: Second Gas Processing Module 20B: Third Gas Processing Module 21, 21A: Gas handling unit 22: Shell 221, 221A: Windward plate 2211: Air intake 2212: Bearing Hole 222: Side panel 2221: Exhaust port 223: Cover plate 224: Support shell 225: Processing Space 226, 226A: Windshield 23: The first porous substrate with photocatalytic properties 24: Second porous substrate with photocatalytic properties 25: Ultraviolet lamp tube 30: Water Mist Generation Module 31:Inlet pipe 32: Water mist sprayer 40, 40A, 40B: Water collection tank 51A: Return pipe 52A: Filter Unit 53A: Discharge pipe 60, 60A, 60B: Frame 70, 70A, 70B: Maintenance Door A: Airflow direction B: Direction of turbulence D1, D2: Spacing L: Length W: Width H: Height T: Thickness

[0080] none.

Claims

1. A method for purifying gaseous molecular pollutants, comprising: mixing a gaseous molecular pollutant to be treated with a first water mist to obtain a gas-liquid mixture; reacting the gas-liquid mixture with a photocatalyst on a porous substrate under a radiation source to react the gaseous molecular pollutant to be treated into a first treated material; washing the first treated material and the porous substrate with a second water mist to obtain a washing solution, wherein the first treated material is dissolved in the washing solution; and discharging a purified gas and the washing solution, wherein the molecular weight of the first treated material is lower than the molecular weight of the gaseous molecular pollutant to be treated, and the content of the gaseous molecular pollutant in the purified gas is lower than the content of the gaseous molecular pollutant to be treated.

2. The purification method as described in claim 1, wherein, The gaseous molecular pollutant to be treated is introduced into a cavity at an inlet flow rate, and the gaseous molecular pollutant to be treated is mixed with the first water mist in the cavity to obtain the gas-liquid mixture. The inlet flow rate is 0.1 m / min to 2.5 m / min.

3. The purification method as described in claim 1, wherein, The inlet flow rate of the gaseous molecular pollutant to be treated is from 20 cubic meters per hour to 5000 cubic meters per hour.

4. The purification method as described in claim 1, wherein, The flow rate of the first water mist is 0.1 liters / minute to 1 liter / minute.

5. The purification method as described in claim 1, wherein, The first water mist is equivalent to the second water mist, and the first water mist is first mixed with the gaseous molecular pollutant to be treated to obtain the gas-liquid mixture. The first water mist then washes the first treated material and the porous substrate, and the flow rate of the first water mist is 0.1 liters / minute to 1 liter / minute.

6. The purification method as described in claim 1, wherein the specific surface area of ​​the porous substrate is from 1,000 m² / g to 3,500 m² / g.

7. The purification method as described in claim 1, wherein the porous substrate has a pore size of 50 mesh to 200 mesh.

8. The purification method as described in claim 1, wherein, The radiation source is selected from a group consisting of ultraviolet light sources, infrared light sources, microwave sources, plasma sources, X-ray sources, ion beam sources, and combinations thereof.

9. The purification method as described in claim 1, wherein, The solubility of the first processed substance in the second water mist is greater than the solubility of the gaseous molecular pollutant to be treated in the second water mist.

10. The purification method as described in any one of claims 1 to 9, wherein, The purification method includes: recovering the washing solution; separating the first processed material from the washing solution to obtain a regenerated solution; spraying the regenerated solution to produce a regenerated water mist; and mixing the regenerated water mist with the gaseous molecular pollutants to be treated to obtain the gas-liquid mixture, and using the regenerated water mist and the second water mist to wash the first processed material and the porous substrate again.

11. A purification system for gaseous molecular pollutants, comprising: a cavity having a channel having an air inlet and an exhaust outlet communicating with each other; a first gas treatment module located between the air inlet and the exhaust outlet, the first gas treatment module comprising at least one gas treatment unit, each of the at least one gas treatment unit comprising: a housing having a windward plate and a side plate, the side plate being disposed around the windward plate and forming a treatment space, the windward plate having at least one air inlet hole and the side plate having at least one exhaust hole; at least one porous substrate having a photocatalyst disposed in the treatment space; at least one radiation source disposed toward the at least one porous substrate having a photocatalyst; a water mist generation module comprising a water inlet pipe communicating with each other and a water mist sprayer, the water mist sprayer being disposed on the windward plate, and a spray nozzle of the water mist sprayer facing the treatment space.

12. The purification system as described in claim 11, wherein, The windward plate has a bearing hole, the water mist sprayer is installed on the bearing hole, the number of the at least one air inlet is multiple, the air inlets are opened around the bearing hole, and the number of the at least one exhaust hole is multiple.

13. The purification system as described in claim 12, wherein, The air intake holes are opened along an airflow direction formed by the air intake and the exhaust port, and the exhaust holes are opened along a turbulence direction that is not parallel to the airflow direction.

14. The purification system as described in claim 11, wherein, The at least one porous substrate with photocatalysis includes a first porous substrate with photocatalysis and a second porous substrate with photocatalysis. The first porous substrate with photocatalysis and the second porous substrate with photocatalysis are disposed facing each other in the processing space. The number of the at least one radiation source is multiple. A portion of the radiation sources are spaced apart from each other and disposed toward the first porous substrate with photocatalysis, and another portion of the radiation sources are spaced apart from each other and disposed toward the second porous substrate with photocatalysis.

15. The purification system as described in claim 14, wherein, The radiation sources include a plurality of ultraviolet lamps, with the angle between the ultraviolet lamp facing the first porous substrate with photocatalysis and the ultraviolet lamp facing the second porous substrate with photocatalysis being 30 to 60 degrees.

16. The purification system as described in claim 14, wherein, One portion of the radiation sources is disposed between the first porous substrate with photocatalyst and the side plate, and the other portion of the radiation sources is disposed between the second porous substrate with photocatalyst and the side plate.

17. The purification system as described in claim 14, wherein, The first porous substrate with photocatalyst and the second porous substrate with photocatalyst are each arranged obliquely, and the distance between the first porous substrate with photocatalyst and the second porous substrate with photocatalyst on the side closer to the windward plate is greater than the distance between the first porous substrate with photocatalyst and the second porous substrate with photocatalyst on the side farther away from the windward plate.

18. The purification system as claimed in claim 11, wherein the specific surface area of ​​the porous substrate is from 1,000 m² / g to 3,500 m² / g.

19. The purification system as described in claim 11, wherein, The porous substrate has a pore size of 50 to 200 mesh.

20. The purification system as described in claim 11, wherein, The thickness of the porous substrate ranges from 10 mm to 100 mm.

21. The purification system as claimed in claim 11, wherein the porous substrate is selected from the group consisting of foamed ceramic substrates, activated carbon substrates, metal-organic frameworks, foamed metals, and combinations thereof.

22. The purification system as described in claim 11, wherein, The purification system includes a water collection tank, which is located below the first gas treatment module.

23. The purification system as described in claim 22, wherein, The purification system includes a return pipe that connects the water collection tank and the water inlet pipe, and a filter unit is provided on the return pipe. The filter unit is connected to the water inlet pipe and has a branch outlet pipe.

24. The purification system as described in any one of claims 11 to 23, wherein, The number of the at least one gas processing unit is multiple, and the gas processing units are detachably assembled with each other to form the first gas processing module.

25. The purification system as described in claim 24, wherein, The gas processing units of the first gas processing module are arranged in a matrix, and the air-facing plates of the gas processing units are adjacent to each other and extend into the inner wall of the channel.

26. The purification system as described in any one of claims 11 to 23, wherein, The purification system includes a second gas processing module, the first gas processing module and the second gas processing module are spaced apart between the air inlet and the exhaust port, and the second gas processing module includes at least one gas processing unit, which is equivalent to the at least one gas processing unit of the first gas processing module.

27. The purification system as described in claim 26, wherein, The number of the at least one gas processing unit of the second gas processing module is multiple, and the gas processing units of the second gas processing module are detachably assembled with each other, and the air-facing plates of the gas processing units of the second gas processing module are adjacent to each other and extend to the inner wall of the channel.

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