An integrated device and method for precise simulation of a controllable coating and aging process of black carbon aerosols

Abstract

The application discloses an integrated device and method for accurately simulating controllable coating and aging process of black carbon aerosol, and belongs to the technical field of atmospheric environment monitoring and simulation, which comprises black carbon aerosol generating module, multi-substance controllable coating module, aging simulation module and whole-process online detection module which are sequentially connected. The multi-substance controllable coating module innovatively connects inorganic condensation coating unit and organic photochemical coating unit in parallel, and the controllable thickness coating of single or composite substance can be realized through valve timing control. The application controls the OH free radical exposure amount through pure mechanical light shielding mode under the premise of ensuring spectral stability. The whole-process online detection module realizes real-time in-situ monitoring of aerosol properties at three nodes of generation, coating and aging through a multi-way sampling valve. The application solves the technical problems of separation of functional modules, single coating substance and light adjustment easy to cause spectral drift in the prior art, and provides a high-precision experimental platform for black carbon aerosol climate effect research.

Description

Technical Field

[0001] This invention belongs to the field of atmospheric environment monitoring and simulation technology, specifically relating to a device and method for simulating the generation, coating and aging process of black carbon aerosols in the atmosphere, and realizing online control and detection. Background Technology

[0002] Black carbon aerosols, primarily produced by the incomplete combustion of fossil fuels and biomass, are the most important light-absorbing aerosols in the atmosphere, exerting a significant impact on global climate change, air quality, and human health. Newly formed black carbon aerosols typically exhibit a branched, chain-like aggregate structure with a relatively hydrophobic surface. However, after being released into the atmosphere, black carbon aerosols undergo a complex physicochemical process known as "aging." During aging, secondary aerosol components in the atmosphere (such as sulfates, nitrates, and secondary organic aerosols) form a coating on the black carbon surface through condensation and collision, altering the black carbon's mixing state (from an externally mixed state to an internally mixed state). This coating not only changes the morphology of the black carbon, causing it to collapse from a chain-like aggregate into a compact spherical structure, but also significantly enhances its light absorption capacity (lens effect) and alters its hygroscopicity, making it more susceptible to becoming cloud condensation nuclei (CCNs), thus affecting its atmospheric lifetime and radiative forcing effect.

[0003] To accurately assess the climate and environmental effects of black carbon aerosols, a deep understanding of their aging process and the evolution of their coating layers is essential. Currently, scholars both domestically and internationally primarily conduct research using a combination of laboratory simulations and field observations. However, existing laboratory simulation techniques suffer from the following main limitations: Existing research typically uses separate combustion generators to produce soot particles, which are then introduced into separate smoke chambers or oxidation flow reactors for aging. For example, Chinese patent database publication number CN109596475A discloses an aerosol smoke system for measuring atmospheric aerosol wall damage in simulated environments. This system is mainly used to simulate open-air biomass combustion emissions and does not specifically control the coating process of black carbon particles. Additionally, Chinese invention patent publication number CN112999989B discloses a black carbon aerosol generator, which only involves the generation of black carbon aerosols and does not address coating and aging simulation. Chinese utility model patent publication number CN205607806U discloses an environmental chamber system for simulating heterogeneous reactions of black carbon aerosols, but it mainly targets gas-solid heterogeneous chemical reactions. When these dispersed modules are used together, there is a lack of unified timing control logic, and aerosols are prone to state changes and sample loss during transfer between modules.

[0004] In the real atmosphere, the coating of black carbon is a complex mixture of various inorganic and organic substances. Existing simulation devices often only achieve coating of a single substance. For example, Ess et al. (2021, published in the Journal of Aerosol Science) coupled a micro smoke chamber with a miniCAST combustion generator, but could only achieve single coating of secondary organic matter (SOM), and could not achieve composite coating of inorganic and organic substances in the same device. Existing technologies struggle to quantitatively control the coating thickness and component ratio, and cannot reveal the synergistic enhancement effect of composite coatings on the optical properties of black carbon.

[0005] Traditional smoke chambers are bulky, have long reaction times, and suffer significant wall damage. While existing commercial oxidation flow reactors (such as Aerodyne's PAM reactor or Dekati's DOFR) can rapidly simulate aging processes, they typically adjust ultraviolet light intensity by changing lamp voltage or switching the number of lamps on and off. This dimming method easily leads to changes in spectral distribution or uneven light field, resulting in inconsistent aging levels. Furthermore, Chinese invention patent CN109754692B discloses a device for simulating the photochemical reactions of atmospheric pollutants. Although it employs a double-layered tube structure, its ultraviolet lamps are positioned around the outer flow tube, lacking continuous, mechanical control over internal light intensity and OH radical exposure.

[0006] Existing systems often require offline sampling and analysis after aging, or only connect detection instruments at the end of the system. They cannot achieve real-time, in-situ monitoring of the changes in physicochemical properties (such as particle size, morphology, mass, optical properties, etc.) of the same batch of black carbon particles from generation, coating to aging. This results in large experimental errors and makes it difficult to obtain high-precision evolution law data.

[0007] There is an urgent need for an experimental device and method that can integrate the generation of black carbon aerosols, controllable coating of multiple substances, aging simulation, and online detection of the entire process, and can control the coating thickness, component ratio, and aging degree. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an integrated device and method for the controllable coating and accurate simulation of the aging process of black carbon aerosols. This invention, through the innovative design of a parallel multi-material coating architecture, an oxidation flow reactor with a sliding dimming sleeve, and a full-process online detection system, aims to systematically solve the technical problems of functional separation, single coating, uneven dimming, and monitoring lag in black carbon aerosol simulation, achieving efficient, in-situ simulation of the entire life cycle of black carbon aerosols.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: An integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol includes a black carbon aerosol generation module, a multi-material controllable coating module, an aging simulation module, and a full-process online detection module connected in sequence. The black carbon aerosol generation module is used to generate and purify black carbon aerosols. The multi-material controllable coating module is used to coat the black carbon aerosol with at least one coating material. The aging simulation module is used to simulate the photochemical aging of the coated aerosol. The full-process online detection module is used to perform online detection of the physicochemical properties of aerosols at at least two process nodes of the device; By sequentially connecting and functionally integrating the four modules, a continuous and controllable gas path is formed, from particle generation and surface modification to atmospheric aging simulation, thereby comprehensively reproducing and monitoring the complete evolution path of black carbon aerosols in the environment.

[0010] Preferably, the multi-substance controllable coating module includes an inorganic condensation coating unit and an organic photochemical coating unit arranged in parallel, as well as a switching unit for switching gas paths. The switching unit is configured to selectively direct the aerosol flow to the inorganic condensation coating unit, the organic photochemical coating unit, or sequentially to the two units. By designing parallel gas paths and controlling the flow path of the switching unit, the same stream of black carbon particles can be directed independently or in combination to different coating environments. Different types of coating layers can be added in a controlled manner through two physicochemical mechanisms: heterogeneous nucleation by vapor condensation and the generation of secondary aerosols by photochemical oxidation.

[0011] Preferably, the aging simulation module includes a photochemical reactor and an adjustable light intensity regulating component disposed outside the photochemical reactor. The light intensity regulating component is configured to continuously adjust the effective light intensity inside the photochemical reactor mechanically. By changing the physical blocking area of ​​the light intensity regulating component on the internal light source, the effective ultraviolet radiation flux entering the reactor is linearly adjusted, thereby achieving continuous and stable control of the photochemical aging reaction rate without changing the electrical parameters of the light source itself.

[0012] Preferably, the light intensity regulating component is a sliding sleeve fitted outside the photochemical reactor. By sliding along the axial direction of the photochemical reactor, it can block or expose the light source installed inside the photochemical reactor. The axial movement of the sliding sleeve can continuously and linearly change the relative position of its opening and the internal fixed ultraviolet lamp array. By changing the proportion of the exposed lamp length, stepless adjustment of the average light intensity of the reaction area can be achieved, thereby controlling the generation concentration and aging intensity of oxidants such as OH free radicals.

[0013] Preferably, the full-process online detection module includes an automatic multi-channel sampling valve and at least one detection instrument. The multiple inlets of the automatic multi-channel sampling valve are respectively connected to different process nodes of the device, and its outlet is connected to the at least one detection instrument. The automatic multi-channel sampling valve is configured to automatically switch sampling between different process nodes according to a preset cycle. Through the timed cyclic switching of the automatic multi-channel sampling valve, the sample flow at different evolution stages in the device is alternately guided to the same set of high-precision detection instruments, ensuring the temporal correlation of measurement data at different stages and the consistency of instrument response, and realizing the synchronous and comparable measurement of key parameters of the same batch of particles after different processing stages.

[0014] Preferably, the black carbon aerosol generation module includes a burner, a primary diluent, a catalytic oxidation component, and a secondary diluent connected in sequence.

[0015] Preferably, the inorganic condensation coating unit includes an inorganic salt vapor generator, a mixing chamber, and a gradient cooling pipe. Saturated vapor is generated by heating the inorganic salt solution, which is then uniformly mixed with room-temperature black carbon aerosol in the mixing chamber. Subsequently, the vapor is made supersaturated by controlled cooling in the gradient cooling pipe, thereby driving it to undergo heterogeneous condensation with black carbon particles as condensation nuclei to form a coating layer. The cooling rate controls the thickness and morphology of the coating layer.

[0016] Preferably, the organic photochemical coating unit includes a VOCs volatilization tank, an ozone generator, and a micro photochemical reaction tube; VOCs vapor, ozone, and black carbon aerosol are introduced into the micro reaction tube under light conditions, and ultraviolet light initiates the photo-oxidation reaction of VOCs and ozone to rapidly generate low-volatility oxidation products. These products condense on the surface of black carbon particles or form an organic coating layer through heterogeneous reactions.

[0017] A method for accurately simulating the controllable coating and aging process of black carbon aerosols, employing an integrated device for accurately simulating the controllable coating and aging process of black carbon aerosols as described above, includes the following steps: Pure black carbon aerosol is generated using the black carbon aerosol generation module. The black carbon aerosol is coated using the multi-material controllable coating module. The aging simulation module was used to simulate the photochemical aging of the coated aerosol. The aerosol properties are detected online at at least two stages: after generation, after coating, and after aging, using the full-process online detection module. Preferably, the coating process includes inorganic coagulation coating and / or organic photochemical coating, and / or sequential inorganic coagulation coating and organic photochemical coating to form a composite coating layer.

[0018] The technical effects and advantages of the present invention in the above technical solution are as follows: This invention does not simply physically assemble individual modules, but rather integrates the generation of black carbon aerosols, multi-material coating, aging simulation, and online detection into a unified system with profound functional synergy through a unified gas path design and multi-valve timing control. This breaks through the limitations of traditional research methods that separate each step, avoids sample loss and state changes caused by inter-module transfers, and ensures the continuity and reliability of experimental data.

[0019] The multi-material controllable coating module of this invention, by connecting inorganic condensation coating units and organic photochemical coating units in parallel, can not only control the thickness of a single coating layer, but also simulate the composite coating of an inner layer of inorganic salts and an outer layer of secondary organic aerosols in the real atmosphere. Experimental data show that the enhancement factor of the composite coating structure on the optical absorption of black carbon is significantly greater than that of the simple superposition of single coatings, achieving an unexpected synergistic enhancement effect.

[0020] This invention adds a sliding metal dimming sleeve to the outside of the oxidation flow reactor. The purely mechanical shading scheme adjusts the effective light intensity without changing the lamp's operating voltage, effectively avoiding the spectral distribution drift caused by voltage changes and ensuring the uniformity of the light field distribution. This enables continuous and controlled control of the equivalent atmospheric aging time (from several hours to several weeks). At the same time, the air inlet flow equalization plate and laminar flow design effectively solve the problem of severe wall loss in traditional smoke chambers.

[0021] This invention designs a multi-channel sampling valve system, setting sampling channels at three key nodes: generation, coating, and aging, seamlessly integrating advanced detection instruments with various processing modules. This avoids sample degradation and errors associated with offline sampling, enabling high-precision capture of key microscopic physicochemical changes in black carbon particles during their aging lifecycle, such as morphological collapse, coating thickening, and enhanced light absorption. This invention is not only applicable to fundamental research on atmospheric environment and climate change, but can also be widely applied to areas such as improving climate model parameterization schemes, assessing the characteristics of black carbon emissions from vehicle exhaust, and studying aerosol effects in carbon capture, utilization, and storage (CCUS) processes. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0023] Figure 1 This is a structural principle block diagram of the integrated device for controllable coating and aging process simulation of black carbon aerosol according to the present invention.

[0024] Figure 2This is a detailed structural diagram of the multi-material controllable coating module of the present invention.

[0025] Figure 3 This is a schematic cross-sectional view of the oxidation flow reactor and dimming sleeve in the aging simulation module of the present invention.

[0026] Figure 4 This is a schematic diagram comparing the optical absorption enhancement factors of black carbon aerosol under different coating modes in the embodiments of the present invention.

[0027] Figure 5 This is a graph showing the relationship between the aging degree of black carbon aerosol dimming sleeve under different coating modes in embodiments of the present invention.

[0028] Explanation of reference numerals in the attached figures: 100-Black carbon aerosol generation module, 101-Inverted co-flow diffusion flame burner, 102-First-stage diluter, 103-Catalytic oxidation tube, 104-Second-stage diluter, 200-Multi-substance controllable coating module, 210-Inorganic condensation coating unit, 211-Inorganic salt vapor generator, 212-Mixing chamber, 213-Gradient cooling tube, 220-Organic photochemical coating unit, 221-VOCs volatilization tank, 222-Ozone generator, 223-Micro photochemical reaction tube, 230-Humidification control unit, 300-Aging simulation module, 301-Oxidation flow reactor, 302-Dimming sleeve, 400-Full-process online detection module, 401-Multi-channel sampling valve, 402-Detection instrument group. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] Example 1: like Figure 1 As shown, the integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol provided by the present invention mainly consists of four core modules: black carbon aerosol generation module 100, multi-material controllable coating module 200, aging simulation module 300, and full-process online detection module 400.

[0031] The structure of the black carbon aerosol generation module 100 includes: an inverted co-flow diffusion flame burner 101 using propane as fuel gas at a flow rate of 60 mL / min and an oxidizing gas (air) flow rate of 1.5 L / min. The generated high-temperature aerosol is rapidly diluted and cooled by a primary diluent 102 at a dilution ratio of approximately 10:1. It then enters a catalytic oxidation tube 103 heated to 300°C, containing a Pt / Al₂O₂ catalyst to thoroughly remove unburned volatile organic compounds adsorbed on the particle surface. Finally, it is adjusted to the target concentration (approximately 2000-5000 particles / cm³) by a secondary diluent 104. 3 The inverted co-current diffusion flame burner 101, the primary diluter 102, the catalytic oxidation tank 103, and the secondary diluter 104 are connected in sequence. The secondary diluter 104 is equipped with an external sampling point A, and the diluted aerosol is sent to the full-process online monitoring module 400 through the sampling point A.

[0032] like Figure 2 As shown, the multi-substance controllable coating module 200 consists of an inorganic condensation coating unit 210 and an organic photochemical coating unit 220 connected in parallel, as well as a downstream humidification control unit 230.

[0033] The inorganic condensation coating unit 210 includes an inorganic salt vapor generator 211 (heating temperature adjustable from 80 to 200°C), a mixing chamber (212) (volume approximately 50 mL, residence time approximately 2 s) and a gradient cooling tube 213 (cooling rate adjustable from 1 to 10°C / cm).

[0034] The organic photochemical coating unit 220 includes a VOCs volatilization tank 221 (constant temperature 25℃, with N2 as carrier gas), an ozone generator 222 (concentration adjustable from 0-10 ppm), and a micro photochemical reaction tube 223 (built-in 254nm ultraviolet lamp, residence time about 30s).

[0035] The inorganic condensation coating unit 210 and the organic photochemical coating unit 220 are switched via a three-way solenoid valve to achieve three coating modes: Mode I only activates the inorganic condensation coating unit (210); Mode II only activates the organic photochemical coating unit (220); and Mode III activates both units sequentially to achieve composite coating. The outlet of the three-way solenoid valve (sampling point B) is connected to the full-process online detection module 400.

[0036] The above-mentioned system utilizes a unique parallel multi-material controllable coating module, coupled with a three-way solenoid valve for switching, to conveniently achieve three coating modes, accurately simulating the real and complex scenario of black carbon particles mixing with different substances in the atmosphere. Furthermore, the temperature gradient of the inorganic condensation unit 210 and the ultraviolet light residence time of the organic photochemical unit are both adjustable, enabling flexible and controllable addition of the coating layer's composition and thickness.

[0037] like Figure 3 As shown, the core component of the aging simulation module 300 is an oxidation reactor 301 made of quartz glass, with an inner diameter of 15cm, a length of 100cm, and an effective volume of approximately 13L. A specially designed stainless steel flow equalization plate (0.5mm aperture, 40% opening rate) is installed at the reactor inlet to ensure that the aerosol flows through the reactor in a laminar flow state (Reynolds number Re < 100). Four 254nm low-pressure mercury lamps are evenly arranged axially inside the reactor 301. A sliding metal dimming sleeve 302, made of stainless steel and the same length as the reactor 301 (100cm), is fitted outside the reactor. By changing the axial sliding position of the sleeve, different areas of the ultraviolet lamps are blocked, achieving stepless adjustment of the average ultraviolet light intensity inside the reactor (5%-100% full power). The sulfur oxide reactor 301 is connected to the dimming sleeve 302. The aging simulation module 300 has an external sampling point C, through which the aerosol is sent to the full-process online monitoring module 400.

[0038] In the above, the aging simulation module 300 adopts an ultraviolet lamp array + external sliding metal dimming sleeve. Through mechanical sliding, the average ultraviolet light intensity (5%-100%) in the reactor is adjusted steplessly and linearly, thereby realizing continuous and stable control of the photochemical aging intensity. This overcomes the technical defects of traditional methods that control light intensity by adjusting voltage or switching the number of lamps, such as discontinuity, large fluctuations, and significant impact on lamp life.

[0039] The full-process online detection module 400 includes an automatic multi-channel sampling valve 401 and a detection instrument group 402. The multi-channel sampling valve 401 is connected to sampling point A (outlet of black carbon aerosol generation module 100), sampling point B (outlet of multi-material controllable coating module 200), and sampling point C (outlet of aging simulation module 300), with a switching cycle of 5 minutes per channel. This device is equipped with a central control system based on PLC or industrial computer to realize automatic acquisition and synchronization of data at each node. The detection instrument group 402 includes: a scanning electromobility particle size analyzer (SMPS, measuring particle size distribution 10-1000nm), a centrifugal particle mass analyzer (CPMA, measuring effective density), a single-particle carbon soot photometer (SP2, measuring single-particle rBC mass and coating thickness), and a photoacoustic spectrometer (PAS, measuring aerosol absorption coefficient).

[0040] In the above, by setting up an automatic multi-channel sampling valve 401 and connecting it with a unified high-end testing instrument group, sampling and measurement can be performed automatically and cyclically at three process points: after generation, after coating, and after aging, at a fixed time period.

[0041] By setting up a black carbon aerosol generation module 100, a multi-substance controllable coating module 200, an aging simulation module 300, and a full-process online detection module 400, the modules are sequentially connected through gas paths and key sampling points (A, B, C) are set up, enabling the research to start from a pure black carbon core, go through specific substance coating, and then to controllable intensity aging, and carry out full-process, segmented simulation and measurement.

[0042] This system simultaneously obtains key parameters across multiple dimensions, including particle size, mass, density, mixing state, and optical absorption, for the same particle group at different stages of evolution. This solves the problems of data fragmentation and difficulty in direct comparison caused by segmented testing, different instruments, and asynchronous testing in previous studies.

[0043] Example 2: This invention also discloses an experimental method for sulfuric acid coating and OH radical aging, the specific steps of which are as follows: A simulation experiment of sulfuric acid coating and OH radical aging of black carbon aerosol was conducted using the apparatus of Example 1: Step 1: Generating pure black carbon aerosol. Adjust the propane flow rate of burner 101 to 60 mL / min to generate pure black carbon particles with a geometric median diameter of approximately 120 nm. Switch the multi-channel sampling valve 401 to sampling point A. SP2 measured the median rBC mass of a single particle to be approximately 2.5 fg, and CPMA measured the effective density to be approximately 0.6 g / cm³. 3 The mass absorption cross section (MAC) measured by PAS is approximately 7.5 m. 2 / g (wavelength 550nm).

[0044] Step 2: Sulfuric acid coating treatment. Turn on the inorganic condensation coating unit 210 and turn off the organic photochemical coating unit 220. Adjust the temperature of the inorganic salt vapor generator 211 to 120℃ (using a 10% sulfuric acid solution), and set the cooling rate of the gradient cooling tube 213 to 5℃ / cm. Switch the multi-channel sampling valve 401 to sampling point B. SP2 measured the coating thickness to be approximately 30nm, and CPMA measured the effective density to be increased to 1.2 g / cm³. 3 The absorption enhancement factor (Eabs) measured by PAS was approximately 1.50.

[0045] Step 3: Aging Simulation. The coated black carbon aerosol is introduced into the oxidation reactor 301, and the dimming sleeve 302 is adjusted to block 50% of the lamp area. SO₂ is introduced. 12 molecules·cm -3 •s, equivalent to approximately 1 day of atmospheric aging. The tracer gas-calibrated OH free radical exposure is approximately 1.5 × 10⁻⁶. Step 4: Post-aging testing. The multi-channel sampling valve 401 was switched to sampling point C. SP2 measured the coating thickness to be approximately 45 nm, Eabs to be approximately 1.60, and the effective density to be further increased to 1.35 g / cm³. 3 This indicates that the aging process promotes further particle collapse and chemical transformation of the coating layer.

[0046] Example 3: This invention also discloses an experimental method for α-pinene SOA coating and OH radical aging, the specific steps of which are as follows: A simulation experiment of black carbon aerosol α-pinene SOA coating and aging was conducted using the apparatus of Example 1: Step 1: Generate pure black carbon aerosol, with parameters the same as in Example 2.

[0047] Step 2: SOA Coating Treatment. The inorganic condensation coating unit 210 is shut down, and the organic photochemical coating unit 220 is turned on. α-pinene liquid is added to the VOCs evaporation tank 221 and kept at a constant temperature of 25°C with N2 as the carrier gas at a flow rate of 50 mL / min. The ozone generator 222 produces approximately 5 ppm of ozone. A photochemical oxidation reaction occurs in the micro-photochemical reaction tube (223). The multi-channel sampling valve 401 is switched to sampling point B. SP2 measures the SOA coating layer thickness to be approximately 25 nm, and the Eabs is approximately 1.30.

[0048] Step 3: Aging simulation, parameters are the same as in Example 2.

[0049] Step 4: Post-aging testing. The multi-channel sampling valve 401 is switched to sampling point C. SP2 measures that the coating thickness has increased to approximately 35 nm and Eabs has increased to approximately 1.40.

[0050] Example 4: This invention also discloses an experimental method for sulfuric acid-α-pinene SOA composite coating and OH radical aging, the specific steps of which are as follows: Using the apparatus of Example 1, an OH radical aging simulation experiment was conducted on the sulfuric acid-α-pinene SOA composite coating of black carbon aerosol to verify the synergistic enhancement effect of the composite coating layer: Step 1: Generate pure black carbon aerosol, with parameters the same as in Example 2.

[0051] Step 2: Composite Coating Treatment. First, activate the inorganic condensation coating unit 210 and deactivate the organic photochemical coating unit 220 to form an inner sulfuric acid coating (parameters same as in Step 2 of Example 2). Then, introduce aerosol into the organic photochemical coating unit 220 to form an outer SOA coating (parameters same as in Step 2 of Example 3). Switch the multi-channel sampling valve 401 to sampling point B. SP2 measures the total coating thickness to be approximately 50 nm, and Eabs to be approximately 1.67.

[0052] Unexpected technical effect verification: The composite coating of Eabs (1.67) is significantly greater than the simple linear superposition effect of sulfuric acid coating alone (1.50, Example 2) and SOA coating alone (1.30, Example 3), confirming the synergistic enhancement effect of inorganic / organic composite coating on the optical absorption of black carbon.

[0053] Aging simulation, with parameters the same as in Example 2.

[0054] Post-aging testing. The multi-channel sampling valve 401 was switched to sampling point C, further increasing Eabs to approximately 1.80 and effective density to 1.45 g / cm³. 3 .

[0055] Example 5: This invention also discloses an experimental method for continuously adjusting the equivalent aging time using a dimming sleeve, the specific steps of which are as follows: Using the apparatus of Example 1, while keeping the aerosol generation and coating parameters unchanged (using the composite coating conditions of Example 4), only the sliding position of the dimming sleeve 302 was changed to verify the continuous control capability of the dimming sleeve to the equivalent aging time: Experiment A (Mild Aging): The dimming sleeve 302 was adjusted to block 95% of the lamp tube area. The exposure of OH free radicals was approximately 1.5 × 10⁻⁶. 11 molecules·cm -3 •s, which is equivalent to approximately 2.4 hours of atmospheric aging. The Eabs value measured at sampling point C was 1.68.

[0056] Experiment B (Moderate Aging): The dimming sleeve 302 was adjusted to block 50% of the lamp area. The OH free radical exposure was approximately 1.5 × 10⁻⁶. 12 molecules·cm -3 •s, which is equivalent to about 1 day of atmospheric aging. Eabs was measured to be 1.80 at sampling point C.

[0057] Experiment C (Severe Aging): The dimming sleeve 302 was adjusted to block 0% of the lamp area (full exposure). The OH free radical exposure was approximately 3.0 × 10⁻⁶. 12 molecules·cm -3 •s, equivalent to approximately 3 weeks of atmospheric aging. Eabs was measured to be 1.65 at sampling point C.

[0058] Based on the data from Examples 2-5, such as Figure 4 As shown, Figure 4 The visual demonstration shows that the optical absorption enhancement factor under the composite coating mode is significantly greater than that under single coating. Figure 5The continuous quantitative relationship between the exposed area of ​​the dimming sleeve and the exposure amount of OH free radicals and the corresponding Eabs is demonstrated. Example 5 proves that the unique purely mechanical sliding dimming sleeve design of this invention can continuously simulate the equivalent atmospheric aging time of black carbon aerosols from several hours to several weeks without changing the operating voltage and spectral distribution of the UV lamp. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol, characterized in that, It includes a black carbon aerosol generation module (100), a multi-material controllable coating module (200), an aging simulation module (300), and a full-process online detection module (400) connected in sequence. The black carbon aerosol generation module (100) is used to generate and purify black carbon aerosols; The multi-material controllable coating module (200) is used to coat the black carbon aerosol with at least one coating material. The aging simulation module (300) is used to perform photochemical aging simulation on the coated aerosol; The online detection module (400) is used to perform online detection of the physicochemical properties of aerosols at at least two process nodes of the device; Through the sequential connection and functional integration of the four modules, a continuous and controllable gas path is formed from particle generation, surface modification to atmospheric aging simulation, thereby comprehensively reproducing and monitoring the complete evolution path of black carbon aerosols in the environment. The multi-substance controllable coating module (200) includes an inorganic condensation coating unit (210) and an organic photochemical coating unit (220) arranged in parallel, as well as a switching unit for switching gas paths. The switching unit is configured to selectively direct the aerosol flow to the inorganic condensation coating unit (210), the organic photochemical coating unit (220), or sequentially to the two units. By designing parallel gas paths and controlling the flow path of the switching unit, the same stream of black carbon particles can be directed independently or in combination to different coating environments. Different types of coating layers can be added in a controlled manner through two physicochemical mechanisms: heterogeneous nucleation by vapor condensation and the generation of secondary aerosols by photochemical oxidation.

2. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 1, characterized in that, The aging simulation module (300) includes a photochemical reactor (301) and an adjustable light intensity regulating component (302) disposed outside the photochemical reactor (301). The light intensity regulating component (302) is configured to continuously adjust the effective light intensity inside the photochemical reactor (301) mechanically. By changing the physical blocking area of ​​the light intensity regulating component (302) on the internal light source, the effective ultraviolet radiation flux entering the reactor (301) is linearly adjusted, thereby achieving continuous and stable control of the photochemical aging reaction rate without changing the electrical parameters of the light source itself.

3. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 2, characterized in that, The light intensity regulating component (302) is a sliding sleeve sleeved outside the photochemical reactor (301). It can block or expose the light source set inside the photochemical reactor (301) by sliding along the axial direction of the photochemical reactor (301). The axial movement of the sliding sleeve can continuously and linearly change the relative position of its opening and the internal fixed ultraviolet lamp array. By changing the length ratio of the exposed lamp tubes, the average light intensity of the reaction area can be steplessly adjusted, thereby controlling the generation concentration and aging intensity of oxidants such as OH free radicals.

4. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 1, characterized in that, The full-process online detection module (400) includes an automatic multi-channel sampling valve (401) and at least one detection instrument (402). The multiple inlets of the automatic multi-channel sampling valve (401) are respectively connected to different process nodes of the device, and its outlet is connected to the at least one detection instrument (402). The automatic multi-channel sampling valve (401) is configured to automatically switch sampling between different process nodes according to a preset cycle. By using the timed cyclic switching of the automatic multi-channel sampling valve (401), the sample streams at different evolution stages in the device are alternately guided to the same set of high-precision detection instruments (402), ensuring the temporal correlation of measurement data at different stages and the consistency of instrument response, and realizing the synchronous and comparable measurement of key parameters of the same batch of particles after different processing stages.

5. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 1, characterized in that, The black carbon aerosol generation module (100) includes a burner (101), a primary diluent (102), a catalytic oxidation component (103), and a secondary diluent (104) connected in sequence.

6. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 1, characterized in that, The inorganic condensation coating unit (210) includes an inorganic salt vapor generator (211), a mixing chamber (212), and a gradient cooling pipe (213). Saturated vapor is generated by heating the inorganic salt solution, and it is uniformly mixed with room temperature black carbon aerosol in the mixing chamber (212). Then, the vapor is made supersaturated by controlled cooling in the gradient cooling pipe (213), thereby driving it to undergo heterogeneous condensation with black carbon particles as condensation nuclei to form a coating layer. The cooling rate controls the thickness and morphology of the coating layer.

7. The integrated device for controllable coating and precise simulation of the aging process of black carbon aerosol according to claim 1, characterized in that, The organic photochemical coating unit (220) includes a VOCs volatilization tank (221), an ozone generator (222), and a micro photochemical reaction tube (223). VOCs vapor, ozone, and black carbon aerosol are introduced into the micro reaction tube (223) under light conditions. The photooxidation reaction between VOCs and ozone is initiated by ultraviolet light to quickly generate low-volatility oxidation products. These products condense on the surface of black carbon particles or form an organic coating layer through heterogeneous reaction.

8. A method for accurately simulating the controllable coating and aging process of black carbon aerosols, characterized in that, The integrated device for controlling the coating and aging process of black carbon aerosol as described in any one of claims 1 to 7 includes the following steps: Pure black carbon aerosol is generated using the black carbon aerosol generation module (100); The black carbon aerosol is coated using the multi-material controllable coating module (200); The photochemical aging of the coated aerosol was simulated using the aging simulation module (300); The aerosol properties are detected online at at least two nodes after generation, coating, and aging using the online detection module (400) throughout the entire process. The coating process includes inorganic coagulation coating and / or organic photochemical coating, and / or sequential inorganic coagulation coating and organic photochemical coating to form a composite coating layer.

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