Dual-chamber dynamic coupling secondary organic aerosol generation catalytic synergy simulation system

Abstract

The application belongs to the technical field of atmospheric pollution control and aerosol research, and particularly relates to a secondary organic aerosol generation catalytic synergistic simulation system with double-chamber dynamic coupling, which comprises an outer box, a main chamber and a secondary chamber arranged on the left and right sides in the outer box, and an industrial computer, wherein the main chamber and the secondary chamber are connected through a gas conveying pipeline, the main chamber is used for simulating the generation of fresh SOA and aged SOA, and the secondary chamber is used for catalytic reaction on the fresh SOA and the aged SOA. The secondary organic aerosol generation catalytic synergistic simulation system with double-chamber dynamic coupling is proposed, through the synergistic design of the main chamber and the secondary chamber, the combination of intelligent switching mode and real environment exposure function, the dynamic adjustment of SOA concentration, catalytic contact time and aging conditions, the high matching of laboratory data and actual atmospheric environment is realized, and a scientific basis is provided for SOA pollution control and catalytic material research and development.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of atmospheric pollution control and aerosol research, and particularly relates to a secondary organic aerosol generating catalytic synergistic simulation system with double-chamber dynamic coupling. BACKGROUND

[0002] Secondary organic aerosol (SOA) is an important pollutant in the atmospheric environment. It is mainly generated by volatile organic compounds (VOCs) through complex chemical reactions in the atmosphere, including gas-gas and gas-particle transformation processes. SOA has many adverse effects on the environment and human health. It can participate in photochemical reactions in the atmosphere, promote the formation of harmful pollutants such as ozone, and exacerbate air pollution. At the same time, SOA particles have strong adsorption properties and can adsorb various organic pollutants, including carcinogenic substances such as polycyclic aromatic hydrocarbons. These substances can enter the human body through respiration, causing damage to the respiratory and cardiovascular systems and increasing the risk of disease. In addition, SOA also has an impact on global climate change. It can scatter and absorb solar radiation, change the atmospheric radiation forcing, and have a complex regulating effect on regional and even global climate, affecting the balance of the climate system.

[0003] With the development of industrialization and the acceleration of urbanization, the emission of VOCs in the atmosphere is increasing, and the generation of SOA is also increasing. In order to effectively control air pollution and respond to climate change, it is of great practical significance to deeply study the generation mechanism, evolution law and catalytic conversion process of SOA. As an important atmospheric simulation experiment device, the smoke box has played a key role in the study of SOA. However, there are some core bottlenecks in the existing smoke box technology in studying the generation-catalysis coupling process of SOA and simulating the actual experimental environment.

[0004] In the prior art, traditional smoke box devices mainly study SOA generation or the catalytic degradation mechanism of SOA by catalytic materials, and cannot simulate the dynamic coupling process of SOA generation and catalytic degradation of SOA by catalytic materials in the actual atmosphere. For example, the device described in patent CN116510629A only studies the generation potential and method of SOA; Chen Yi et al. (Environmental Science and Technology, 52, 20, 11612-11620, 2018) only studies the influence of titanium dioxide on the formation of secondary organic aerosol. This fragmented research method limits the comprehensive understanding of the generation path and catalytic mechanism of SOA. Moreover, the catalysis of SOA is mostly carried out by using pure chemical reagents (such as toluene standard gas) or high-concentration SOA, which is significantly different from the actual atmosphere with complex components (such as PM 2.5 mixed particles) and low-concentration environment, making it difficult for laboratory data to guide pollution control strategies.

[0005] Secondly, the existing technology smog box catalytic degradation of SOA mostly uses TiO2 material, rarely uses composite material, and the cost is expensive. For example, Liqing Hao et al. studied the influence of titanium dioxide photocatalytic seed on the formation and mitigation of SOA particles generated by the oxidation of alpha-pinene or toluene in the chamber.

[0006] Furthermore, the prior art lacks segmented research on the life cycle of SOA, such as patent CN202110498396.7, which cannot quantify the difference in adsorption and catalytic conversion behavior of fresh SOA (generated <6 hours) and aged SOA (after photochemical / heterogeneous oxidation) on the surface of catalytic materials, restricting accurate prediction of the environmental lifetime of SOA. SUMMARY

[0007] In view of the problems existing in the prior art, the present application proposes a double-chamber dynamic coupling secondary organic aerosol generation catalytic synergistic simulation system. Through the synergistic design of the main chamber (SOA generation unit) and the auxiliary chamber (catalytic reaction unit), combined with intelligent switching mode and real environment exposure function, the defect that the existing technology cannot simulate the dynamic coupling of SOA generation and catalytic degradation is solved. The system realizes high matching of laboratory data and actual atmospheric environment by dynamically adjusting SOA concentration, catalytic contact time and aging conditions, providing a scientific basis for SOA pollution control and catalytic material research and development.

[0008] The application adopts the following technical scheme:

[0009] The double-chamber dynamic coupling secondary organic aerosol generation catalytic synergistic simulation system comprises an outer box body, a main chamber and an auxiliary chamber arranged on the left and right sides in the outer box body, and an industrial computer. The main chamber and the auxiliary chamber are connected through a gas pipeline. The main chamber is used to simulate the generation of fresh SOA and aged SOA, and the auxiliary chamber is used to perform catalytic reaction on fresh SOA and aged SOA. Environment control units, SOA particle and concentration detection units are arranged in the main chamber and the auxiliary chamber. A catalytic reaction unit and a catalytic reaction effect monitoring unit are arranged in the auxiliary chamber. Doppler light sources are arranged in the main chamber and the auxiliary chamber. The industrial computer is configured to control the generation of SOA, the operation of the environment control unit, the operation of the Doppler light source, the detection of SOA particle size and concentration, the action of the catalytic reaction unit and the catalytic reaction effect monitoring unit, and simultaneously collect information.

[0010] Preferably, the main chamber and the auxiliary chamber are both cubic structures and are transparent chambers made of high-transmittance quartz material. The side length of the main chamber is greater than that of the auxiliary chamber. The environment control units comprise built-in temperature and humidity control mechanisms and wind speed control mechanisms arranged on the main chamber and the auxiliary chamber respectively. The temperature and humidity control mechanisms and the wind speed control mechanisms are electrically connected to the industrial computer through wires.

[0011] Preferably, the temperature and humidity control mechanism includes refrigeration units, electric heating tubes and temperature and humidity sensors respectively arranged in the main chamber and the auxiliary chamber. Under the control of the industrial computer, the temperature and humidity control mechanism in the main chamber and the auxiliary chamber controls the temperature in each chamber within the range of -30℃ to 50℃ to simulate the atmospheric temperature conditions in different seasons and regions. The air speed simulator is an electric fan installed on the inner wall of one side of the main chamber or the auxiliary chamber.

[0012] Preferably, the SOA particle and concentration detection unit is a differential mobility particle sizer for real-time monitoring of the particle size distribution and concentration change of SOA.

[0013] Preferably, the multi-spectral light source is used to simulate different light conditions according to experimental requirements, including a lamp shell, a panel, an ultraviolet light emitting module, an infrared light emitting module and a visible light emitting module. The lamp shell is a sealed disc-shaped shell with a hole in the center of one side and a mode lens embedded in the hole. The mode lens is used to pass ultraviolet light, infrared light and visible light. The panel is fixed to the side of the inner wall of the lamp shell opposite to the mode lens. The ultraviolet light emitting module, the infrared light emitting module and the visible light emitting module are regularly arranged on the side of the panel close to the mode lens. Each light emitting module is electrically connected to a power supply, and the signal end of each light emitting module is connected to the industrial computer in communication.

[0014] Preferably, the catalytic reaction unit includes a catalytic carrier disc, which is a detachable and rotatable disc made of honeycomb-shaped ceramic and loaded with phenolic resin carbon / TiO2 catalytic material on the surface. The carrier is soaked in a solution containing catalytic material precursors by the dip-drawing method to ensure that the carrier fully absorbs the solution. Then the carrier is slowly drawn out of the solution, so that the excess solution drips back into the solution under the action of gravity. Finally, after drying and calcination, a uniform coating or particles of catalytic material are formed on the surface of the carrier. The preparation method of the catalytic material precursor solution is as follows: titanium alkoxide (such as butyl titanate) or inorganic titanium salt is dissolved in an organic solvent (such as ethanol) to form a stable TiO2 sol through hydrolysis and polycondensation reaction; resorcinol and hexamethylenetetramine are added to an aqueous solution, and after stirring for a period of time, a phenolic resin precursor solution is obtained; the TiO2 sol and the phenolic resin precursor solution are mixed to obtain the catalytic material precursor solution; the catalytic material precursor solution is dried and calcined in sequence to obtain the phenolic resin carbon / TiO2 catalytic material. The drying method is supercritical CO2 drying, and the calcination temperature is 400-600℃.

[0015] Preferably, the catalytic reaction effect monitoring unit includes a Fourier infrared spectrometer, which is used to scan the surface of the carrier in situ by combining the multi-spectral light source of the auxiliary chamber with the Fourier infrared spectrometer to obtain the functional group information of the adsorbed aerosol.

[0016] Preferably, the outer box body is provided with a zero gas generator, a VOCs gas cylinder and an ozone generator. The zero gas generator purifies impurity gas in the air, and provides high-purity zero gas for the main chamber and the auxiliary chamber through the air inlet pipeline one as dilution gas and basic gas for the reaction environment. The VOCs gas cylinder stores various standard VOCs gases such as benzene and toluene, which are released into the main chamber according to the experimental requirements through the air inlet pipeline two in a certain proportion to simulate the VOCs pollution source in the actual atmosphere. The ozone generator is used to generate ozone as an oxidizing agent and is input into the main chamber through the air inlet pipeline three to participate in the generation reaction of SOA. The air conveying pipeline between the main chamber and the auxiliary chamber is used to convey fresh SOA or aged SOA, and a Venturi ejector is arranged at the end of the air conveying pipeline and in the auxiliary chamber. The end of the auxiliary chamber away from the main chamber is connected with an exhaust pipeline. The air inlet pipeline one, the air inlet pipeline two, the air inlet pipeline three, the air conveying pipeline and the exhaust pipeline are respectively provided with electromagnetic valves, pressure valves and metering pumps. The air inlet pipeline one, the air inlet pipeline two and the air inlet pipeline three are respectively provided with vacuum pumps.

[0017] Preferably, the outer box body is a cuboid structure, a door body is mounted on one side wall of the outer box body, and a heat preservation layer is arranged on each of the six inner walls of the outer box body, and a reflective film is attached to the inner wall of each heat preservation layer. The main chamber and the auxiliary chamber are respectively fixed in the outer box body by supports, and the six side faces thereof are arranged in parallel with the six side faces of the outer box body.

[0018] The simulation method of the secondary organic aerosol generation catalytic synergistic simulation system with double-chamber dynamic coupling comprises the following steps:

[0019] Step one: start the industrial computer, open the air conveying pipeline and close the exhaust pipeline, use the vacuum pump to vacuum the main chamber and the auxiliary chamber to a vacuum state, and remove residual gas; start the zero gas generator to inject high-purity zero gas into the main chamber and the auxiliary chamber; repeat the vacuumization-zero gas injection operation for 3 times to ensure that there is no impurity gas interference in the chambers; set the temperature, humidity and light source of each chamber according to the target experimental environment through the industrial computer;

[0020] Step two: mix the VOCs standard gas and ozone into the main chamber according to the preset proportion, start the main chamber ultraviolet light source, photolyze the ozone to generate OH free radicals, and drive the VOCs to oxidize to generate SOA; monitor the SOA concentration in real time through the differential mobility particle sizer and feed back to the industrial computer dynamically;

[0021] When the differential mobility particle sizer detects that the SOA concentration reaches the preset threshold value, the industrial computer controls the metering pump of the air conveying pipeline to convey the SOA aerosol to the auxiliary chamber in proportion; if the SOA concentration fluctuates more than ±10%, the industrial computer automatically adjusts the VOCs inlet amount or the ultraviolet light intensity to maintain the stable generation rate;

[0022] Fresh SOA catalysis: fresh SOA generated in the main chamber is directly introduced into the auxiliary chamber through the gas supply pipeline and the Venturi ejector, and the multi-spectrum light source of the auxiliary chamber is started at the same time, i.e. visible light and ultraviolet light are combined, the rotation speed of the catalytic carrier disc is adjusted by the industrial computer, and the contact time of fresh SOA and phenolic resin carbon / TiO2 catalytic material is controlled;

[0023] The second mode of the step two is SOA circulation aging: the gas supply pipeline is closed, SOA circulates in the main chamber, the ozone generator is started and ultraviolet light irradiation is maintained, photochemical aging is carried out, after aging, the industrial computer is switched to the aging mode, the aged SOA is introduced into the auxiliary chamber, and the same catalytic condition is started;

[0024] Step three, according to the requirement, the multi-spectrum light source of the auxiliary chamber is used to combine the Fourier transform infrared spectrometer to perform in-situ scanning on the surface of the carrier, functional group information of the adsorbed aerosol is obtained, and aerosol samples are collected through the sampling pipeline every 1 hour for offline analysis;

[0025] Step four, after the experiment is completed, all gas supplies and light sources are turned off, a vacuum pump is started to pump the two chambers to vacuum, zero gas is injected for flushing three times, the catalytic carrier disc of the auxiliary chamber is disassembled, ultrapure water and ethanol are used for ultrasonic cleaning to remove surface deposits, and after drying, the catalytic activity is recovered by calcination.

[0026] The beneficial effects of the double-chamber dynamic coupling secondary organic aerosol generation catalytic synergistic simulation system are as follows:

[0027] The application successfully overcomes the bottleneck of traditional smoke boxes in synchronously simulating SOA generation and catalytic conversion through the innovative double-chamber dynamic coupling design, realizes the accurate reproduction of complex chemical processes in actual atmospheric environment, and provides a new technical means for atmospheric pollution control and environmental research. Specifically, the real atmospheric environment is accurately simulated, the main chamber and the auxiliary chamber work cooperatively, the SOA concentration and the catalytic contact time can be dynamically adjusted, the temperature and humidity, the wind speed simulation and the multi-spectrum light source are combined to comprehensively reproduce the spatial and temporal variation characteristics of urban atmosphere. Through the concentration self-adaptive feedback mechanism, the SOA flow is monitored and regulated in real time, so that the experimental data are highly consistent with the actual atmospheric fluctuations, and the problem that the traditional fixed concentration experiment is disconnected with the reality is avoided; the preparation process of the phenolic resin carbon / TiO2 composite catalytic material is innovatively proposed, the agglomeration is inhibited through supercritical fluid drying, and the photocatalytic activity and stability of the material are greatly improved through the calcination process. The material is uniformly loaded on the rotary support, the contact time is accurately controlled by regulating the rotating speed, the multi-phase reaction process of SOA on the surface of atmospheric particulate matter can be effectively simulated, and a reliable experimental platform is provided for the development of high-efficiency catalytic materials; the intelligent switching mechanism of "real-time mode" and "aging mode" is innovatively proposed, the immediate catalytic behavior of fresh SOA can be studied, and the conversion characteristics of SOA after photochemical aging can be analyzed, which breaks through the limitation of traditional smoke boxes in separating the generation and catalysis, and provides key technical support for revealing the evolution law of the whole life cycle of SOA. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of the application.

[0029] Figure 2 is the SEM, adsorption desorption isotherm and pore size diagram of the phenolic resin carbon / TiO2 composite catalytic material of the application.

[0030] Figure 3 is the comparison curve of fresh / aged SOA catalytic degradation efficiency.

[0031] In the figure: 1, outer box body; 2, main chamber; 3, auxiliary chamber; 4, temperature and humidity control mechanism; 5, temperature and humidity sensor; 6, wind speed simulator; 7, differential mobility particle sizer (SMPS); 8, multi-spectrum light source; 9, Fourier infrared spectrometer; 10, catalytic carrier support disc; 11, zero gas generator; 12, VOCs gas steel cylinder; 13, ozone generator; 14, electromagnetic valve; 15, pressure valve; 16, vacuum pump; 17, metering pump; 18, Venturi ejector; 19, exhaust pipeline; 20, industrial computer. DETAILED DESCRIPTION

[0032] The following description is merely exemplary of the present application and is not intended to limit the scope of the application being claimed. Any modification, equivalent substitution, and improvement made within the spirit and principle of the present application should be included in the scope of the present application.

[0033] The following examples can be understood as part of the separate expression of the partial structure or method of the present application, or as part of the mutual combination of the examples to explain the larger range of structure or method of the present application.

[0034] Example 1, in combination Figure 1 The secondary organic aerosol generating catalytic synergistic simulation system with double-chamber dynamic coupling includes a smoke box, an outer box body 1, a gas supply and adjustment unit, a pipeline system, a multi-spectrum light source 8, and an industrial computer 20. The smoke box has two chambers, a main chamber 2 and a secondary chamber 3, which are connected and are both square transparent boxes located inside the outer box body. The outer box body 1 has a heat preservation layer on each of the six inner walls, and the inner wall of each heat preservation layer is attached with a reflective film.

[0035] The main chamber 2 is an SOA generating unit, which is a closed transparent cavity made of high-transmittance quartz material to ensure uniform internal illumination and effectively simulate the photochemical reaction process in the actual atmosphere. The outer shape is a cube with a side length of 2 meters, the overall structure is stable, the sealing performance is good, and it can withstand certain pressure changes.

[0036] The main chamber 2 is internally provided with a temperature and humidity control mechanism 4, including a refrigeration unit and an electric heating pipe. The refrigeration unit is composed of a compressor, a condenser, and an evaporator. The compressor and the condenser are placed outside the chamber, and the evaporator is installed on the inner wall of the chamber. The electric heating pipe is in a uniform distribution net structure and is embedded in the inner wall of the chamber. The two work together to accurately control the temperature in the chamber within the range of -30℃ to 50℃ to simulate the atmospheric temperature conditions in different seasons and regions.

[0037] The signal end of the temperature and humidity sensor 5 is in communication connection with the industrial computer 16. The wind speed simulator 6 in the main chamber 2 is an electric fan installed on the inner wall of one side of the smoke box, and the signal end of the electric fan is in communication connection with the industrial computer 20. The main chamber 2 is equipped with a detection instrument, a differential mobility particle sizer 7 (SMPS), which is used to monitor the particle size distribution and concentration change of SOA in real time, and the signal end thereof is in communication connection with the industrial computer 20.

[0038] The multi-spectrum light source 8 in the main chamber 2 includes a lamp shell, a panel, an ultraviolet light emitting module, an infrared light emitting module, and a visible light emitting module. The lamp shell is a disc-shaped sealed shell with a hole in the center of one side and a mode lens embedded in the hole. The panel is fixed to the side of the lamp shell opposite to the mode lens. The ultraviolet light emitting module, the infrared light emitting module, and the visible light emitting module are regularly arranged on the side of the panel close to the mode lens. Each light emitting module is connected to a power supply, and the signal end of each light emitting module is connected to the industrial computer 20.

[0039] The sub-chamber 3 is used as a catalytic reaction unit and has a structure similar to that of the main chamber 2. The sub-chamber 3 is also a transparent cavity made of quartz material and has a size slightly smaller than that of the main chamber, with a side length of 1.5 meters, to ensure good optical performance and sealing performance. The sub-chamber 3 also has a temperature and humidity control mechanism 4 and a wind speed simulator 6, which have the same structure as the corresponding devices in the main chamber and can independently control the temperature and humidity and the wind speed, and can monitor the SOA physical property parameters in real time during the catalytic reaction process. The sub-chamber detection instrument includes a differential mobility particle size spectrometer 7 (SMPS) for real-time monitoring of the particle size distribution and concentration change of the SOA. The Fourier infrared spectrometer 9 uses the multi-spectrum light source 8 (such as the infrared light module) in the sub-chamber to combine with the Fourier transform infrared spectrometer 9 (FTIR) to perform in-situ scanning on the carrier surface and obtain the functional group information of the adsorbed aerosol.

[0040] The catalytic carrier tray 10 in the sub-chamber is a detachable and rotatable disc (usually driven by a reduction motor) made of honeycomb ceramic and loaded with phenolic resin carbon / TiO2 catalytic material on the surface. The carrier is soaked in a solution containing a catalytic material precursor by the dip-coating method to ensure that the carrier fully absorbs the solution. Then the carrier is slowly pulled out of the solution, and the excess solution drops back into the solution under the action of gravity. Finally, after drying and calcination, a uniform coating or particles of the catalytic material are formed on the surface of the carrier.

[0041] The gas supply and adjustment unit includes a zero gas generator 11, a VOCs gas cylinder 12, and an ozone generator 13. The zero gas generator 11 provides high-purity zero gas by purifying impurity gases in the air, which is used as a dilution gas and a basic gas for the reaction environment. The VOCs gas cylinder 12 stores various standard VOCs gases such as benzene and toluene, which are released into the main chamber according to the experimental requirements to simulate the VOCs pollution source in the actual atmosphere. The ozone generator 13 is used to generate ozone as an oxidizing agent to participate in the generation reaction of SOA.

[0042] Each gas pipeline is equipped with solenoid valve 14, pressure valve 15, vacuum pump 16 and metering pump 17. Solenoid valve 13 is used to control the on-off of the gas, which has fast response speed and can complete switching operation within 0.1s, ensuring accurate control of gas flow; pressure valve 15 can adjust the gas pressure in the range of 0-1MPa, ensuring stable delivery of gas in the pipeline; vacuum pump 16 is used for vacuumizing operation of the chamber or pipeline, which can reduce the pressure in the system to below 10Pa, facilitating gas replacement before the experiment and simulation of low-pressure environment under some experimental conditions; metering pump 17 accurately controls the flow of each gas, with a flow adjustment range of 0-1000mL / min and an accuracy of ±0.2%, ensuring stable and accurate gas flow into the chamber, thereby realizing precise control of the SOA generation environment. The pipeline system between the main chamber 2 and the auxiliary chamber 3 can switch between two modes according to the differential mobility particle sizer 7 (SMPS). In real-time mode, SOA is immediately introduced into the auxiliary chamber through the Venturi injector 18 after generation. In aging mode, SOA is introduced into the auxiliary chamber after circulating and aging (4-72 hours) in the main chamber, and the switching is controlled by the industrial computer 20.

[0043] The industrial computer 20 includes a PLC controller, an operation interface, a data acquisition card and a computer. The PLC controller, as the core control unit of the system, integrates multiple control algorithms and can realize centralized control and automatic operation of devices such as solenoid valves, metering pumps, temperature and humidity control equipment, wind speed simulators, multi-spectral light sources, etc. The data acquisition card is connected to detection instruments and can collect data such as SOA particle size distribution and concentration change at high speed and high precision, and transmit the collected data to the computer for storage, analysis and processing.

[0044] Example 2, in combination Figure 1 The secondary organic aerosol generation catalytic synergistic simulation system with double-chamber dynamic coupling comprises the following steps:

[0045] Step one, start the industrial computer 20, open the gas delivery pipeline between the main chamber 2 and the auxiliary chamber 3 through the PLC controller, close the exhaust pipeline, and use the vacuum pump 16 to vacuumize the two chambers to remove residual gas. Close the exhaust pipeline, start the zero gas generator 11 to inject high-purity zero gas into the main chamber 2 and the auxiliary chamber 3, and repeat the vacuumization-zero gas injection operation 3 times to ensure that there is no impurity gas interference in the chambers. According to the target experimental environment, set the temperature, humidity and light source of each chamber through the industrial computer.

[0046] Step two, mix VOCs standard gas and ozone into the main chamber 2 according to the preset ratio through the gas supply unit, start the ultraviolet light source of the main chamber 2, photolyze ozone to generate OH free radicals, and drive VOCs to oxidize to generate SOA. Monitor the SOA concentration in real time through the differential mobility particle sizer 7 (SMPS) and dynamically feedback to the industrial computer 20.

[0047] When the SMPS 7 detects that the SOA concentration reaches the preset threshold, the industrial computer 20 controls the metering pump 17 of the outlet pipeline of the main chamber 2 to proportionally deliver the SOA aerosol to the auxiliary chamber 3. If the SOA concentration fluctuates by more than ±10%, the industrial computer 20 automatically adjusts the VOCs gas inlet amount or the ultraviolet light intensity to maintain the stable generation rate.

[0048] Fresh SOA catalysis: the SOA generated in the main chamber 2 is directly introduced into the auxiliary chamber 3 through a Teflon pipeline and a Venturi ejector 18, and the multi-spectrum light source 8 (visible light + ultraviolet light combination) of the auxiliary chamber 3 is started at the same time. The contact time of SOA and phenolic resin carbon / TiO2 catalytic material is controlled by adjusting the rotating speed of the catalytic carrier disc 10 through the industrial computer 20.

[0049] Another mode of the second step is: SOA cyclic aging, the gas inlet pipeline is closed, and the SOA circulates in the main chamber 2. The ozone generator 18 is turned on and the ultraviolet light is maintained for photochemical aging. After aging is completed, the industrial computer 20 switches to the aging mode, the SOA is introduced into the auxiliary chamber 3, and the same catalytic conditions are started.

[0050] Step five, according to the requirements, the multi-spectrum light source 8 of the auxiliary chamber 3 is used to combine with the Fourier transform infrared spectrometer 9 to perform in-situ scanning on the surface of the carrier, and the functional group information of the adsorbed aerosol is obtained. Aerosol samples are collected through the sampling pipeline every 1 hour for offline analysis.

[0051] Step six, after the experiment is completed, all gas supplies and light sources are turned off, the vacuum pump 16 is started to pump the two chambers to vacuum, and zero gas is injected for flushing 3 times. The catalytic carrier disc 10 of the auxiliary chamber 3 is disassembled, ultrapure water and ethanol are used for ultrasonic cleaning to remove surface deposits, and the catalytic activity is recovered after drying and calcination.

[0052] Figure 2 The relevant characteristic diagram of the phenolic resin carbon / TiO2 composite catalytic material in the patent. Figure 2 (a) is a scanning electron microscope (SEM) diagram of the catalytic material, from which it can be seen that the catalytic material has a rough and porous surface structure, which can increase the specific surface area of the material and provide more active sites for the adsorption and catalytic reaction of SOA. And it can be seen that the titanium dioxide is attached to the surface of the carbon carrier. Figure 2 (b) is a nitrogen adsorption-desorption isotherm diagram of the catalytic material, from which it can be seen that it presents a typical IV curve, indicating that the material has a rich mesoporous structure. The material has a high adsorption capacity, indicating that it has a large specific surface area and rich pore structure, which is beneficial to the adsorption and transmission of SOA, thereby improving the catalytic efficiency. Figure 2(c) is the pore size distribution of the catalytic material, from which it can be seen that the material has a narrow pore size distribution range and is mainly mesoporous, such a pore structure helps the SOA particles to enter and fully contact the catalytic material, further enhancing the catalytic degradation performance of the catalytic material on SOA.

[0053] Figure 3 is the catalytic degradation efficiency comparison curve of fresh SOA and aged SOA. It can be seen from the figure that the catalytic degradation efficiency of fresh SOA (dashed line) and aged SOA (solid line) gradually increases with the increase of contact time, but the degradation efficiency of fresh SOA is obviously higher than that of aged SOA under the same contact time. This is because in the system of the present application, fresh SOA is just generated, its chemical reaction activity is high, and it can react quickly after contacting with the catalytic material; while the aged SOA has undergone photochemical aging process, its chemical structure and physical properties have changed, the reaction activity is relatively reduced, so the degradation efficiency is also reduced. This result fully embodies the intelligent switching mechanism of the system of the present application through "real-time mode" and "aging mode", which can respectively study the catalytic degradation characteristics of fresh SOA and aged SOA on the surface of the catalytic material, and provides strong technical support for in-depth understanding of the evolution law of SOA full life cycle and its catalytic conversion mechanism.

[0054] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples, and the changes, modifications, additions or replacements made by the person skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.

Claims

1. A dual-chamber dynamically coupled catalytic synergistic simulation system for secondary organic aerosol generation. Its features include: an outer casing, a main chamber and a secondary chamber located on the left and right sides of the outer casing, and an industrial control computer. The main chamber and the secondary chamber are connected by a gas supply pipeline. The main chamber is used to simulate the generation of fresh SOA and aged SOA, and the secondary chamber is used to catalyze the reaction of fresh SOA and aged SOA. Both the main chamber and the secondary chamber are equipped with an environmental control unit and an SOA particle and concentration detection unit. The secondary chamber is also equipped with a catalytic reaction unit and a catalytic reaction effect monitoring unit. Both the main chamber and the secondary chamber are equipped with a multi-spectral light source. The industrial control computer is configured to control the generation of SOA, the operation of the environmental control unit, the operation of the multi-spectral light source, the detection of SOA particle size and concentration, and the operation of the catalytic reaction unit and the catalytic reaction effect monitoring unit, and simultaneously collect information. The catalytic reaction unit includes a catalytic carrier disk, which is a detachable, rotating disk made of honeycomb ceramic with a surface loaded with... The phenolic resin carbon / TiO2 catalyst material is prepared by immersing the support in a solution containing the catalyst precursor using an impregnation-pulling method, ensuring full adsorption of the solution by the support. The support is then slowly pulled out of the solution, allowing excess solution to drip back into the solution under gravity. Finally, drying and calcination steps are performed to form a uniform coating or particles of the catalyst material on the support surface. The catalyst precursor solution is prepared as follows: titanium alkoxide or inorganic titanium salt is used as a precursor, dissolved in an organic solvent, and a stable TiO2 sol is formed through hydrolysis and condensation reactions. Resorcinol and hexamethylenetetramine are added to an aqueous solution and stirred for a period of time to obtain a phenolic resin precursor solution. The TiO2 sol and the phenolic resin precursor solution are mixed to obtain the catalyst precursor solution. The catalyst precursor solution is then subjected to drying and calcination to obtain the phenolic resin carbon / TiO2 catalyst material. Supercritical CO2 drying is used, and the calcination temperature is 400–600℃.

2. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 1, characterized in that: Both the main chamber and the secondary chamber are cubic structures and are transparent chambers made of high-transmittance quartz material. The side length of the main chamber is longer than that of the secondary chamber. The environmental control unit includes built-in temperature and humidity control mechanisms and wind speed control mechanisms respectively installed in the main chamber and the secondary chamber. The temperature and humidity control mechanisms and wind speed control mechanisms are respectively connected to the industrial control computer via wires.

3. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 2, characterized in that: The temperature and humidity control mechanism includes a refrigeration unit, an electric heating element, and a temperature and humidity sensor respectively located in the main chamber and the auxiliary chamber. Under the control of the industrial control computer, the temperature and humidity control mechanism in the main chamber and the auxiliary chamber regulates the temperature in their respective chambers within the range of -30℃ to 50℃ to simulate atmospheric temperature conditions in different seasons and regions. The wind speed control mechanism is an electric fan, which is installed on the inner wall of one side of the main chamber or the auxiliary chamber.

4. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 3, characterized in that: The SOA particle and concentration detection unit is a differential migration particle size spectrometer, used to monitor the particle size distribution and concentration changes of SOA in real time.

5. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 4, characterized in that: The multi-spectral light source is used to simulate different lighting conditions according to experimental requirements. It includes a lamp housing, a panel, an ultraviolet light emission module, an infrared light emission module, and a visible light emission module. The lamp housing is a disc-shaped sealed shell with a central opening on one side and a mode lens embedded in the opening. The mode lens is used to pass through ultraviolet light, infrared light, and visible light. The panel is fixed to the inner wall of the lamp housing on the side opposite to the mode lens. The ultraviolet light emission module, infrared light emission module, and visible light emission module are regularly arranged on the side of the panel close to the mode lens. Each emission module is electrically connected to a power supply, and the signal terminal of each emission module is connected to an industrial control computer for communication.

6. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 5, characterized in that: The catalytic reaction effect monitoring unit includes a Fourier transform infrared spectrometer, which uses a multi-band light source in the sub-chamber combined with the Fourier transform infrared spectrometer to perform in-situ scanning of the carrier surface and obtain functional group information of the adsorbed aerosols.

7. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 6, characterized in that: The outer casing is equipped with a zero-gas generator, a VOCs gas cylinder, and an ozone generator. The zero-gas generator purifies impurities in the air and provides high-purity zero gas to the main and secondary chambers through inlet pipe one, serving as a dilution gas and the base gas for the reaction environment. The VOCs gas cylinder stores various standard VOCs gases, which are released into the main chamber in a certain proportion according to experimental needs through inlet pipe two, simulating VOCs pollution sources in the actual atmosphere. The ozone generator produces ozone, which is used as an oxidant through inlet pipe two. The three gas lines enter the main chamber to participate in the SOA generation reaction; the gas supply line between the main chamber and the auxiliary chamber is used to transport fresh SOA or aged SOA. A Venturi injector is installed at the end of the gas supply line and located in the auxiliary chamber. The end of the auxiliary chamber away from the main chamber is connected to an exhaust line. The first, second, and third gas supply lines, the gas supply line, and the exhaust line are respectively equipped with a solenoid valve, a pressure valve, and a metering pump. The first, second, and third gas supply lines are respectively equipped with a vacuum pump.

8. The dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 7, characterized in that: The outer casing is a cubic structure with a door installed on one side wall. Each of the six inner walls of the outer casing is provided with an insulation layer, and the inner wall of each insulation layer is covered with a reflective film. The main chamber and the secondary chamber are fixed to the outer casing by brackets, and their six sides are arranged parallel to the six sides of the outer casing.

9. The simulation method for the dual-chamber dynamically coupled secondary organic aerosol generation catalytic synergistic simulation system as described in claim 8, characterized in that, Includes the following steps: Step 1: Start the industrial control computer, open the gas supply line and close the exhaust line, use the vacuum pump to evacuate the main chamber and the auxiliary chamber to a vacuum state, and remove residual gas; start the zero gas generator to inject high-purity zero gas into the main chamber and the auxiliary chamber; repeat the evacuation-zero gas filling operation 3 times to ensure that there is no impurity gas interference in the chamber; according to the target experimental environment, set the temperature, humidity and light source of each chamber through the industrial control computer; Step 2: VOCs standard gas and ozone are mixed in the main chamber according to a preset ratio. The ultraviolet light source in the main chamber is activated to photolyze ozone to generate OH radicals, which drive the oxidation of VOCs to generate SOA. The SOA concentration is monitored in real time by a differential migration particle size analyzer and dynamically fed back to the industrial control computer. When the differential migration particle size analyzer detects that the SOA concentration has reached the preset threshold, the industrial control computer controls the metering pump in the gas delivery pipeline to deliver SOA aerosol to the sub-chamber in proportion; if the SOA concentration fluctuates by more than ±10%, the industrial control computer automatically adjusts the VOCs intake or ultraviolet light intensity to maintain a stable generation rate. Fresh SOA catalysis: Fresh SOA generated in the main chamber is directly introduced into the secondary chamber through the gas pipeline and Venturi injector. At the same time, the multi-spectral light source in the secondary chamber is activated, which combines visible light and ultraviolet light. The contact time between fresh SOA and phenolic resin carbon / TiO2 catalytic material is controlled by adjusting the rotation speed of the catalytic carrier disk through the industrial control computer. Another mode of step two is: SOA cyclic aging: the gas pipeline is closed, the SOA circulates in the main chamber, the ozone generator is turned on and ultraviolet light is maintained to carry out photochemical aging. After aging is completed, the industrial control computer switches to aging mode, introduces the aged SOA into the auxiliary chamber, and starts the same catalytic conditions. Step 3: As needed, use the multi-band light source in the secondary chamber and Fourier transform infrared spectrometer to perform in-situ scanning of the carrier surface to obtain information on the functional groups of the adsorbed aerosols. Collect aerosol samples every hour through the sampling pipeline for offline analysis. Step 4: After the experiment, turn off all gas supply and light source, start the vacuum pump to evacuate both chambers to a vacuum, and inject zero gas to rinse 3 times. The catalytic carrier disk in the secondary chamber was disassembled, and ultrasonically cleaned with ultrapure water and ethanol to remove surface deposits. After drying, it was calcined to restore catalytic activity.

Images