A laboratory exhaust gas purification device

Abstract

This application relates to a laboratory waste gas purification and treatment device, including a reaction chamber, a precursor supply module, a trigger judgment module, a photothermal enhancement module, a control module, and a collection module. The precursor supply module includes a first precursor channel and a second precursor channel. The first precursor solution contains photothermal nanoparticles with photothermal conversion and surface chelation functions. The trigger judgment module includes a gas sensor for detecting highly toxic gases. The photothermal enhancement module includes a near-infrared light source. The control module controls the opening of the second precursor channel and the near-infrared light source when the gas sensor detects that the concentration exceeds a preset threshold, switching the device to the trigger mode. Active species are generated through in-situ reaction of the two precursors, and the reaction is enhanced and the product is chelated and solidified in-situ under the photothermal effect of the photothermal nanoparticles. This application features a second-level response to sudden leaks, high removal rate, and low operating cost.

Description

Technical Field

[0001] This application relates to the field of waste gas purification, and in particular to a waste gas purification and treatment device for laboratory use. Background Technology

[0002] Laboratory exhaust gases are complex in composition and their emissions are intermittent and sudden. Especially concerning are experiments involving highly toxic gases (such as hydrogen cyanide, arsine, and hydrogen sulfide), posing a significant safety hazard due to operational errors or equipment malfunctions that could lead to the instantaneous leakage of high concentrations of these toxic gases. Existing laboratory exhaust gas treatment devices mostly employ single or combined processes such as adsorption, chemical scrubbing, or catalytic oxidation. Their common characteristic is that the treatment medium or energy field is in a constantly operational standby state—the adsorbent is pre-placed in the airflow channel, the scrubbing liquid is continuously circulated, and the catalytic module is continuously preheated or powered to respond to any potential exhaust pollutants.

[0003] However, the aforementioned "constantly operating capacity" mode makes it difficult to balance processing capacity, operating costs, and safety redundancy. Specifically, if a large-capacity adsorption bed or high-power processing module is configured to cope with occasional high-concentration toxic gas leaks, the device becomes bulky, and the daily energy consumption and consumable costs are exorbitant, exceeding the affordability of ordinary laboratories. If a small-capacity processing unit is configured to control size and cost, the processing medium capacity is limited in the face of sudden high-concentration shocks, posing a risk of penetration leakage and failing to provide a reliable safety backup. This fundamental contradiction stems from the lack of a response mechanism in existing devices that can dynamically allocate processing capacity based on actual hazard signals.

[0004] To address the aforementioned problems, this invention proposes a laboratory waste gas purification and treatment device. Summary of the Invention

[0005] To address the aforementioned problems, this application provides a laboratory waste gas purification and treatment device, employing the following technical solution: A laboratory waste gas purification and treatment device, comprising: An airflow channel is provided with an air inlet and an air outlet; A reaction chamber is disposed within the airflow channel; A precursor supply module includes a first precursor channel and a second precursor channel, which converge at an atomizing nozzle. Under triggered conditions, the two channels are used to collaboratively spray a cluster of composite microdroplets into the reaction chamber. Under normal conditions, only inert droplets are sprayed through the first precursor channel. The first precursor solution supplied by the first precursor channel contains photothermal nanoparticles, which have photothermal conversion and surface chelation functions. A trigger judgment module includes a gas sensor located upstream of the reaction chamber for real-time detection of the concentration of the target highly toxic gas; A photothermal enhancement module includes a near-infrared light source disposed within the reaction chamber, the near-infrared light source being configured to emit light toward the droplet group falling area; A control module, which is signal-connected to the trigger judgment module, the precursor supply module and the photothermal enhancement module, is used to simultaneously control the opening of the second precursor channel and the opening of the near-infrared light source when the gas sensor detects that the concentration of the target highly toxic gas exceeds a preset threshold. A collection module is located at the bottom of the reaction chamber to collect the droplets after the reaction.

[0006] Preferably, the photothermal nanoparticles are carbon dot@silica core-shell nanoparticles with a particle size of 50-80 nm; The carbon dot core has a near-infrared photothermal conversion efficiency of ≥85%; the silicon dioxide shell is 3-5nm thick and is used to isolate the carbon dot core from the chemical contact of the first precursor solution under normal operating conditions. The surface of the silica shell is modified with aminophosphonic acid groups, which are bridged to the surface of the silica shell by a silane coupling agent, thereby giving the photothermal nanoparticles a surface chelation function.

[0007] Preferably, the first precursor solution and the second precursor solution constitute one of the following pairing systems: The first precursor is a ferrous sulfate solution, and the second precursor is a hydrogen peroxide solution, used to generate hydroxyl radicals in situ to oxidize hydrogen cyanide; or The first precursor is a zinc acetate solution, and the second precursor is a sodium hydroxide solution, used to generate zinc hydroxide nanoparticles in situ to precipitate hydrogen sulfide; or The first precursor is a potassium permanganate solution, and the second precursor is a dilute sulfuric acid solution, which are used to activate high-valence manganese in situ to oxidize arsine.

[0008] Preferably, the near-infrared light source is a ring array near-infrared LED module embedded in the inner wall of the reaction chamber, with a center wavelength of 808nm and the illumination direction pointing towards the droplet group falling area below the atomizing nozzle; The near-infrared light source is linked to the trigger judgment module and is turned on only when the gas sensor detects that the concentration of the target highly toxic gas exceeds a preset threshold; otherwise, it remains off under normal operating conditions.

[0009] Preferably, the collection module includes a liquid-sealed waste liquid collection tank and a detachable filter unit disposed in the collection tank, used to intercept the solid products after solidification by the chelating groups on the surface of the photothermal nanoparticles, thereby achieving the separation of reaction products and waste liquid.

[0010] Preferably, the atomizing nozzle is a coaxial composite atomizing nozzle, configured to spray composite microdroplets with a core-shell structure or a Janus asymmetric structure; In the Janus asymmetric structure, the surface of one hemisphere of the droplet is enriched with hydrophobic nanoparticles, while the surface of the other hemisphere is enriched with hydrophilic nanocellulose, so as to generate passive Marangoni convection during the droplet's fall and enhance the gas-liquid mass transfer efficiency.

[0011] Preferably, the control module is configured to perform the following operations synchronously: When the gas sensor detects that the concentration of the target highly toxic gas exceeds the preset threshold within ≤3 seconds, the second precursor channel is opened simultaneously, the near-infrared light source is turned on, and the first precursor channel is continuously supplied, so that the reaction chamber can seamlessly switch between normal operating conditions and triggering operating conditions.

[0012] Preferably, the first precursor solution also contains a low concentration of sodium carbonate or sodium sulfate for routine neutralization of acid and alkali mist under normal operating conditions. The photothermal nanoparticles are configured to be suspended in the reaction chamber with inert droplets under normal operating conditions, without producing a photothermal effect; When the near-infrared light source is turned on, the photothermal nanoparticles generate a local temperature rise, and at the same time, they have an inactivation effect on the microbial aerosols carried in the exhaust gas.

[0013] Preferably, the control module is further configured to: After the gas sensor detects that the concentration of the target highly toxic gas has fallen below the preset threshold, the second precursor channel is first closed, and the near-infrared light source is turned off after a preset time delay, so that the active species remaining in the reaction chamber can fully react and then return to the normal operating conditions.

[0014] Preferably, the carbon dot core of the carbon dot@silica core-shell nanoparticles is a nitrogen-doped carbon dot prepared by the citric acid / urea hydrothermal method, with a near-infrared absorption peak at 800-820 nm; the mass concentration of the carbon dot@silica core-shell nanoparticles in the first precursor solution is 0.5-2.0 mg / mL.

[0015] In summary, this application includes at least one of the following beneficial technical effects: This application achieves a proactive safety backup with a second-level response, overcoming the limitations of existing devices with fixed processing capacity. It employs a dual-mode operating mechanism: "normal operation in standby / dormant state, and trigger-activated response state." During normal operation, it maintains only inert droplet atomization without consuming active chemical reagents. When the gas sensor detects that the concentration of the target highly toxic gas exceeds a preset threshold within seconds, it simultaneously triggers in-situ reactions of the two precursors and near-infrared photothermal enhancement, completing the switch from an inert state to a highly active processing state within seconds. The device's safety redundancy is no longer limited by fixed parameters such as adsorption bed capacity or catalytic module power, but depends on the storage volume of the precursor solution, achieving an adjustable high-capacity safety backup. This fundamentally solves the problem of penetration risk inherent in existing devices facing sudden high-concentration leaks due to fixed processing capacity.

[0016] The photothermal enhancement effect significantly improves the yield of active species and mass transfer efficiency, ensuring the removal rate of highly toxic gases. This application disperses carbon-dot@silica core-shell nanoparticles with highly efficient photothermal conversion capabilities within droplets, generating a localized micro-thermal effect of 5-8°C upon simultaneous activation of a near-infrared light source. This temperature rise accelerates the chemical reaction rate between precursors, greatly increasing the yield of active species such as hydroxyl radicals; it also drives Marangoni convection within the droplets, effectively improving mass transfer efficiency and significantly increasing the probability of collisions between active species and gas molecules. The synergistic effect of these two factors significantly improves the removal rate of highly toxic gases compared to a single chemical triggering mode.

[0017] This invention achieves in-situ chelation and solidification of reaction products, mitigating the risk of secondary pollution. The photothermal nanoparticles of this application are surface-modified with aminophosphonic acid chelating groups. Under triggered conditions, toxic products generated during the reaction, such as metal-cyanide complexes, arsenate ions, and metal sulfide nanoparticles, are locked in situ into solid particles through coordination bonds. The solid products are then retained by a filtration unit after entering a collection tank with the liquid droplets, achieving immediate separation of hazardous waste. The concentration of free hazardous substances in the waste liquid is below the detection limit, significantly reducing the difficulty of subsequent waste liquid treatment and effectively avoiding the secondary pollution problem caused by the migration of reaction products with the waste liquid in existing chemical spraying methods.

[0018] The operating cost is extremely low, and the maintenance cycle is long. Under normal operating conditions, this application only requires the atomization of inexpensive inorganic salt solutions (such as sodium sulfate and sodium carbonate solutions), without the need for a continuous supply of active chemical reagents such as hydrogen peroxide and potassium permanganate, nor the need for periodic replacement or regeneration of adsorbents and catalyst carriers. The precursor solution replenishment cycle can reach more than 3 months. The overall operating cost is significantly reduced compared to traditional chemical spraying methods, thus significantly reducing the total life cycle cost of the laboratory waste gas treatment device.

[0019] The modular design flexibly adapts to various scenarios and incorporates biosafety features. The precursor pairing system, preset thresholds, and atomization methods of this application can all be adjusted as needed. By simply changing the precursor solution, it can accommodate the treatment of various highly toxic gases such as hydrogen cyanide, hydrogen arsine, and hydrogen sulfide, making it suitable for various types of laboratories, including chemical, biological, and medical laboratories. The optional Janus asymmetric droplet structure further enhances gas-liquid mass transfer efficiency, and the compact vertical structure allows for direct installation next to a fume hood or in an exhaust duct. Furthermore, the localized temperature rise generated by the photothermal effect simultaneously inactivates microbial aerosols carried in the exhaust gas, making it particularly suitable for biosafety laboratory scenarios. Attached Figure Description

[0020] Figure 1 This is a system block diagram of a laboratory waste gas purification and treatment device according to an embodiment of this application; Figure 2 This is a system schematic diagram of a laboratory waste gas purification and treatment device according to an embodiment of this application; Figure 3 This is a flowchart illustrating the three-stage progressive working mechanism of a laboratory waste gas purification and treatment device according to an embodiment of this application.

[0021] Explanation of reference numerals in the attached drawings: 1. Airflow channel; 11. Air inlet; 12. Air outlet; 2. Reaction chamber; 3. Precursor supply module; 31. First precursor channel; 32. Second precursor channel; 33. First precursor storage tank; 34. Second precursor storage tank; 35. Atomizing nozzle; 4. Trigger judgment module; 41. Gas sensor; 5. Photothermal enhancement module; 51. Near-infrared light source; 6. Control module; 7. Collection module. Detailed Implementation

[0022] The following is in conjunction with the appendix Figures 1-3 This application will be described in further detail.

[0023] In the following description, for ease of understanding, key terms will first be uniformly defined: "Normal operating condition" refers to the operating state in which the laboratory fume hood is venting normally and the gas sensor located upstream of the reaction chamber does not detect the target highly toxic gas or its concentration is lower than the preset threshold. This state is also called standby dormant state. "Triggering condition" refers to the operating state in which the gas sensor detects that the concentration of the target highly toxic gas exceeds the preset threshold; "Preset threshold" is a concentration value that is artificially set in advance for a specific highly toxic gas, which serves as the basis for determining the start of the operating condition.

[0024] This application discloses a laboratory waste gas purification and treatment device. (Refer to...) Figure 1 A laboratory exhaust gas purification and treatment device that is fully integrated with the exhaust pipe of a laboratory fume hood.

[0025] The device includes an airflow channel 1 with an inlet 11 and an outlet 12 for connecting to the exhaust pipe of a laboratory fume hood. A vertical reaction chamber 2 is disposed within the airflow channel 1. The chamber material can be 316L stainless steel or carbon steel lined with polytetrafluoroethylene. In this embodiment, the inner diameter of the reaction chamber 2 is 100-300 mm, and its height is 500-1500 mm. A collection module 7 is connected to the lower part of the reaction chamber 2, and a demister is provided in front of the outlet 12 at the top to intercept escaping tiny droplets.

[0026] To achieve dual-mode supply, the device includes a precursor supply module 3. This module includes independent first precursor channel 31 and second precursor channel 32. The first precursor channel 31 is connected to the first precursor storage tank 33 via a first metering pump, and the second precursor channel 32 is connected to the second precursor storage tank 34 via a second metering pump. The two channels converge at a coaxial composite atomizing nozzle 35 located at the top center of the reaction chamber 2. Under normal operating conditions, the control module 6 only activates the first metering pump, supplying the solution only through the first precursor channel 31, which is atomized by the nozzle to form an inert droplet cluster. Under triggered operating conditions, the control module 6 simultaneously activates the second metering pump, and the two channels supply the solution collaboratively, forming a composite microdroplet cluster. The first precursor solution contains uniformly dispersed photothermal nanoparticles, which have photothermal conversion and surface chelation functions.

[0027] The device includes a trigger judgment module 4, which has a gas sensor 41 installed in the gas flow channel 1 upstream of the reaction chamber 2 for real-time detection of the concentration of the target highly toxic gas (such as hydrogen cyanide, hydrogen arsine, hydrogen sulfide, etc.). The gas sensor 41 needs to be an electrochemical sensor for the corresponding gas, with a response time ≤3 seconds and a detection limit lower than a preset threshold.

[0028] The device includes a photothermal enhancement module 5, comprising a near-infrared light source 51 disposed within the reaction chamber. In this embodiment, the near-infrared light source 51 is a ring-array near-infrared LED module embedded in the inner wall surrounding the droplet falling area inside the reaction chamber 2. Preferably, the number of LEDs is 8-16, with a center wavelength of 808nm±10nm and a power density of 0.5-2W / cm². The illumination direction of the LED module is directed towards the droplet falling area below the atomizing nozzle 35. Furthermore, the LED module is linked with the trigger judgment module 4, turning on synchronously only when the gas sensor 41 detects that the concentration of the target highly toxic gas exceeds a preset threshold, and remaining off under normal operating conditions.

[0029] The device includes a control module 6, which can be a microcontroller, PLC, or embedded system. The control module 6 is connected to the gas sensor 41, the first metering pump, the second metering pump, and the near-infrared LED module. The control module 6 receives signals from the gas sensor 41. When it determines that the concentration exceeds a preset threshold, it synchronously outputs a control signal, opening the second precursor channel 32 and activating the near-infrared LED module. When the concentration falls back below the preset threshold, it closes the second precursor channel 32 and, after a preset time delay, turns off the near-infrared LED, restoring the device to normal operating conditions.

[0030] The device also includes a collection module 7 located at the lower part of the reaction chamber 2, which includes a liquid-sealed waste liquid collection tank. The bottom of the collection tank maintains a liquid seal height of not less than 50 mm. The collection tank is equipped with a removable filter unit, specifically a polypropylene or PTFE filter bag or filter screen with a pore size of 0.5-5 μm, for retaining the solid products after chelation and solidification.

[0031] Through the above modular design, the device only needs to maintain the atomization supply of inert droplets under normal operating conditions, without consuming active chemical reagents, and the operating cost is significantly lower than that of traditional continuous spraying or continuous catalysis devices.

[0032] In a preferred embodiment, the photothermal nanoparticles are carbon dot@silica core-shell nanoparticles (CDs@SiO2). The preparation method includes the following steps: (1) Preparation of carbon dot cores: Citric acid / urea hydrothermal method was used. Citric acid and urea were dissolved in deionized water at a mass ratio of 1:2 and transferred to a high-pressure reactor. The mixture was reacted at 180°C for 6 hours. After natural cooling, nitrogen-doped carbon dots were obtained by dialysis using a dialysis bag (molecular weight cutoff of 1000 Da). The obtained carbon dots had a particle size of 30-50 nm, a near-infrared absorption peak at 800-820 nm, and a photothermal conversion efficiency ≥85%.

[0033] (2) Silica shell coating: The carbon dots prepared above are dispersed in an ethanol / water mixed solvent, ammonia is added to adjust the pH value, tetraethyl orthosilicate (TEOS) is slowly added, and the mixture is stirred at room temperature for 12 hours. By controlling the amount of TEOS and the reaction time, the thickness of the silica (SiO2) shell is controlled to be 3-5 nm. After centrifugation and washing, CDs@SiO2 nanoparticles are obtained.

[0034] (3) Surface modification of aminophosphonic acid groups: CDs@SiO2 was dispersed in toluene, and 3-aminopropyltriethoxysilane (APTES) was added. The mixture was refluxed for 12 hours under nitrogen protection to obtain aminated particles. Subsequently, the particles were dispersed in a mixed solution of formaldehyde and phosphorous acid, and phosphonic acid groups were introduced onto the amino groups through the Mannich reaction to finally obtain CDs@SiO2 nanoparticles with aminophosphonic acid groups on the surface, which endowed them with chelating function.

[0035] The SiO2 shell isolates the carbon dot core from the first precursor solution under non-triggered conditions (i.e., normal operating conditions), avoiding side reactions; at the same time, the aminophosphonic acid groups on the shell surface provide active sites for subsequent chelation.

[0036] The preferred mass concentration of the CDs@SiO2 nanoparticles in the first precursor solution is 0.5-2.0 mg / mL, more preferably 0.8-1.2 mg / mL.

[0037] The CDs@SiO2 core-shell structure offers a triple synergistic advantage: the carbon dot core provides efficient photothermal conversion, the SiO2 shell isolates the carbon dots from the chemical environment under normal operating conditions to avoid side reactions, and the surface aminophosphonic acid groups enable product chelation and curing under triggered conditions. This structure integrates photothermal and chelation functions into the same nanoparticle, eliminating the need for separate heating or post-processing units in the device and significantly simplifying system complexity.

[0038] This invention provides three precursor pairing systems adapted to different highly toxic gases. The specific ratios and reaction principles of each system are as follows: System 1 (suitable for HCN): The first precursor is a 0.05-0.2 mol / L ferrous sulfate solution, dispersed with 1.0 mg / m³ LCDs@SiO2 nanoparticles; the second precursor is a 3% (w / w) hydrogen peroxide solution, with the pH adjusted to 3-4 by dilute sulfuric acid. Under the triggering condition, Fe²⁺ reacts with H₂O₂ in a Fenton-like reaction, generating hydroxyl radicals and Fe³⁺ in situ; the hydroxyl radicals oxidize and decompose HCN into CO₂ and N₂, and Fe... 3+ It forms a stable complex with residual CN⁻.

[0039] System 2 (suitable for hydrogen sulfide H2S): The first precursor is a 0.1-0.3 mol / L zinc acetate solution, with 0.8 mg / mLCDs@SiO2 nanoparticles dispersed therein; the second precursor is a 0.2-0.5 mol / L sodium hydroxide solution. The two phases are mixed in situ to generate highly active zinc hydroxide (Zn(OH)2) nanoparticles, which react rapidly with H2S to form irreversible ZnS precipitate. The precipitate is then chelated and immobilized by the photothermal nanoparticles.

[0040] System 3 (suitable for arsine AsH3): The first precursor is a 0.01-0.05 mol / L potassium permanganate solution, with 1.5 mg / m³ LCDs@SiO2 nanoparticles dispersed therein; the second precursor is a 0.05-0.1 mol / L dilute sulfuric acid solution. Acidification activates the strong oxidizing property of permanganate, oxidizing AsH3 to arsenate ions (AsO4). 3- Then, stable five-membered ring chelates are formed by chelation of aminophosphonic acid groups on the surface of nanoparticles.

[0041] In this embodiment, the atomizing nozzle is a coaxial composite atomizing nozzle with an inner channel diameter of 0.3-0.8 mm and an outer channel inner diameter of 1.0-2.0 mm. Compressed air-assisted atomization or ultrasonic atomization can be used to generate droplet clusters with a particle size of 5-20 μm.

[0042] In a preferred embodiment, by selecting the type of functional nanoparticles added to the precursor, the nozzle can selectively eject composite microdroplets with a core-shell structure or a Janus asymmetric structure.

[0043] (1) Core-shell structure: The second precursor solution flows through the inner channel, and the first precursor solution flows through the outer channel. The ejected droplet has the second precursor as the core and the first precursor as the shell, ensuring that the two precursors only come into contact and react after the droplet is formed.

[0044] (2) Janus asymmetric structure: Hydrophobic silane coupling agent-modified nano-SiO2 particles (mass fraction 0.1-0.5%) are added to the first precursor solution, and hydrophilic carboxylated nanocellulose (mass fraction 0.05-0.2%) is added to the second precursor solution. When the two phases meet at the nozzle outlet, the difference in wettability spontaneously forms a Janus droplet that is half hydrophilic and half hydrophobic. During the fall, the surface tension gradient drives passive Marangoni convection inside the droplet, which, combined with photothermal micro-convection, further enhances the gas-liquid mass transfer efficiency.

[0045] Janus droplets' passive Marangoni convection significantly enhances gas-liquid mass transfer without requiring external energy input. When superimposed with photothermal microconvection, it creates a dual-engine stirring effect, greatly increasing the probability of contact between active species within the droplets and gas molecules, enabling the device to achieve high processing efficiency within a compact volume.

[0046] Reference Figure 3 The working mechanism of the device disclosed in this application is divided into three progressive levels: standby dormancy under normal operating conditions, and trigger activation transition and photothermal enhancement product locking under trigger operating conditions.

[0047] S1, Standby Dormant State: Under normal operating conditions, the fume hood discharges exhaust gas containing low concentrations of volatile organic compounds, acid and alkali mists, and other conventional pollutants. The gas sensor does not detect the target highly toxic gas (concentration is below the preset threshold). The control module only activates the first metering pump, and the first precursor solution is atomized through nozzles to form inert droplet clusters. The droplet matrix contains a low concentration of sodium carbonate or sodium sulfate (0.05-0.1 mol / L), which can neutralize the acid and alkali mists. CDs@SiO2 nanoparticles are suspended in the droplets, but because the near-infrared LEDs are off, no photothermal effect is generated. In this state, the device operates with extremely low energy consumption, consuming only inexpensive salt solution, achieving economical daily operation.

[0048] S2. Triggered Activation Transition: When an experimental error causes the instantaneous release of highly toxic gases such as HCN, the gas sensor detects a concentration exceeding a preset threshold (e.g., 1 ppm for HCN, 0.5 ppm for AsH3) within ≤3 seconds. The control module immediately performs synchronous operations: activating the second metering pump, starting the second precursor channel, and simultaneously activating the near-infrared LED module, while maintaining continuous supply from the first precursor channel. The two precursor solutions converge at the nozzle, forming composite microdroplets. An in-situ chemical reaction occurs instantaneously upon droplet formation, generating highly reactive species (such as ·OH radicals, Zn(OH)2 nanoparticles, or activated MnO4). - It enables the switching of operating conditions and emergency start-up to be completed within 3 seconds.

[0049] S3. Photothermal Enhancement and Product Locking: After the near-infrared LEDs are simultaneously turned on, light with a wavelength of 808nm irradiates the area where the droplets fall. The CDs@SiO2 nanoparticles in the droplet shell efficiently absorb the near-infrared light and convert it into heat energy, causing the internal temperature of the droplets to rise instantaneously by 5-8℃. This temperature rise effect enhances the treatment effect in three ways: First, increased temperature accelerates the precursor reaction rate. Taking the Fenton-like system as an example, the ·OH yield increases by about 40% compared to room temperature, and the reaction rate constant increases by about 30%. Second, microthermal stimulation drives Marangoni convection or enhances existing convection within the droplets, significantly increasing the probability of collisions between active species and gas molecules, thus improving mass transfer efficiency by approximately 25%. Third, the chelating activity of the surface aminophosphonic acid groups is enhanced under elevated temperature conditions, which firmly locks the metal-cyanide complexes, arsenate ions, ZnS nanoparticles, and other products generated in the reaction through coordination bonds, forming solid particles. These solid products enter the collection tank with the droplets and are intercepted by the filtration unit, achieving in-situ solidification and separation of the products, which greatly reduces the difficulty of subsequent waste liquid treatment.

[0050] When the gas sensor detects that the concentration of highly toxic gas has fallen below a preset threshold, the control module immediately shuts down the second precursor channel, stopping the generation of active species. However, the near-infrared LED does not immediately turn off, but is delayed for 30-120 seconds (preferably 60 seconds) to ensure that any remaining active species and contaminants in the reaction chamber have fully reacted. Afterward, the device returns to its normal operating standby sleep state.

[0051] The photothermal enhancement locking effect is multifaceted: on the one hand, it increases the yield of active species and mass transfer efficiency, significantly improving the removal rate of highly toxic gases; on the other hand, it achieves in-situ solidification of reaction products, avoiding the risk of secondary pollution from the migration of ionic products in waste liquid, and reducing the difficulty of subsequent waste liquid treatment by more than 60%. In addition, the local temperature rise of 5-8℃ caused by near-infrared irradiation also simultaneously inactivates microbial aerosols (such as Escherichia coli, Staphylococcus aureus, etc.) that may be carried in the waste gas, with an inactivation rate of over 99%, making it particularly suitable for biological laboratory settings.

[0052] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects: (1) Enhanced safety: Breaking away from the existing technology's "constant processing capacity" model, a three-level progressive response mechanism of "standby hibernation - trigger activation - photothermal enhancement" is adopted. Under normal operating conditions, the device is in a low-energy inert state. Once a highly toxic gas leak is detected, a trigger response can be completed in a very short time. Safety redundancy is no longer limited by the fixed capacity of the processing unit, but depends on the amount of precursor solution stored, achieving adjustable high safety margin.

[0053] (2) High treatment efficiency and controllable secondary pollution: The microthermal effect of photothermal nanoparticles enhances the precursor reaction rate, increasing the yield of active species by about 40%, mass transfer efficiency by about 25%, and the removal rate of highly toxic gases can reach over 99%. At the same time, the chelating groups on the surface of photothermal nanoparticles solidify the reaction products in situ, significantly reducing the migration risk of ionic products in the waste liquid, and reducing the difficulty of waste liquid treatment by more than 60%.

[0054] (3) Operating costs are significantly reduced: Under normal operating conditions, only inexpensive inorganic salt solutions (such as sodium sulfate and sodium carbonate) are consumed. There is no need to continuously supply active chemical reagents, nor is it necessary to replace adsorbents or catalyst carriers regularly. The overall operating cost is reduced to less than 1 / 5 of that of the traditional spraying method, and the maintenance cycle is extended to more than 3 months.

[0055] (4) Compact and adaptable device: The modular design allows the device to be adapted to different laboratory scenarios. By changing the precursor pairing system and adjusting the preset threshold, it can flexibly address the leakage risks of various highly toxic gases such as hydrogen cyanide, hydrogen arsine, and hydrogen sulfide. The optional Janus droplet structure and microbial inactivation function further expand the application range.

[0056] To make the technical solution of the present invention clearer, two specific embodiments are given below, but the present invention is not limited thereto.

[0057] Example 1 (HCN system): Device parameters: reaction chamber inner diameter 150mm, height 800mm; first precursor solution is 0.1mol / L FeSO4 solution containing 1.0mg / mL CDs@SiO2 nanoparticles; second precursor solution is 3% H2O2 (pH=3.5); atomization method is compressed air-assisted atomization, droplet average particle size is 12μm; gas sensor is HCN electrochemical sensor, preset threshold 1ppm; 12 near-infrared LEDs, total power 10W.

[0058] Normal operating condition: The laboratory fume hood discharges waste gas containing low concentrations of VOCs such as acetic acid and ethanol at a flow rate of 50L / min. The device remains in standby dormant state, only spraying inert droplets of the first precursor. The pollutant concentration at the outlet is far below the emission standard, and the operation is stable.

[0059] Simulated Leakage: HCN standard gas was instantaneously injected into the gas stream using a syringe pump, causing the inlet concentration to surge to 10 ppm. The sensor detected the exceedance within 2 seconds, triggering the control module to activate, opening the second channel, and illuminating the LED. The outlet gas showed an HCN removal rate of 99.2%. In contrast, the control group, where only activation was triggered and the LED was off, had a removal rate of 84.5%, demonstrating the significant photothermal enhancement effect. The solids retained by the collection tank filtration unit were identified as Fe-CN complexes, and the free cyanide concentration in the waste liquid was below 0.1 mg / L.

[0060] Example 2 (H2S system): Apparatus parameters: reaction chamber inner diameter 200 mm, height 1000 mm; first precursor solution is 0.2 mol / L Zn(CH3COO)2 containing 0.8 mg / mL CDs@SiO2 nanoparticles; second precursor solution is 0.3 mol / L NaOH; gas sensor is H2S electrochemical sensor with a preset threshold of 1 ppm; the rest is similar to Example 1.

[0061] Simulated H2S leakage was performed with an inlet concentration of 15 ppm. After activation, the outlet H2S concentration dropped to below 0.1 ppm, achieving a removal rate of over 99.3%. White ZnS precipitate was visible in the collection tank, retained by the filter bag, and the waste liquid became clear. The experiment ran continuously for 30 days, and no degradation in the photothermal performance of the CDs@SiO2 nanoparticles was observed.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A laboratory waste gas purification and treatment device, characterized in that, include: An airflow channel is provided with an air inlet and an air outlet; A reaction chamber is disposed within the airflow channel; A precursor supply module includes a first precursor channel and a second precursor channel, which converge at an atomizing nozzle. Under triggered conditions, the two channels are used to collaboratively spray a cluster of composite microdroplets into the reaction chamber. Under normal conditions, only inert droplets are sprayed through the first precursor channel. The first precursor solution supplied by the first precursor channel contains photothermal nanoparticles, which have photothermal conversion and surface chelation functions. A trigger judgment module includes a gas sensor located upstream of the reaction chamber for real-time detection of the concentration of the target highly toxic gas; A photothermal enhancement module includes a near-infrared light source disposed within the reaction chamber, the near-infrared light source being configured to emit light toward the droplet group falling area; A control module, which is signal-connected to the trigger judgment module, the precursor supply module and the photothermal enhancement module, is used to simultaneously control the opening of the second precursor channel and the opening of the near-infrared light source when the gas sensor detects that the concentration of the target highly toxic gas exceeds a preset threshold. A collection module is located at the bottom of the reaction chamber to collect the droplets after the reaction.

2. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The photothermal nanoparticles are carbon dot@silica core-shell nanoparticles with a particle size of 50-80 nm. The carbon dot core has a near-infrared photothermal conversion efficiency of ≥85%; the silicon dioxide shell is 3-5nm thick and is used to isolate the carbon dot core from the chemical contact of the first precursor solution under normal operating conditions. The surface of the silica shell is modified with aminophosphonic acid groups, which are bridged to the surface of the silica shell by a silane coupling agent, thereby giving the photothermal nanoparticles a surface chelation function.

3. A laboratory waste gas purification and treatment device according to claim 1, characterized in that, The first precursor solution and the second precursor solution constitute one of the following pairing systems: The first precursor is a ferrous sulfate solution, and the second precursor is a hydrogen peroxide solution, used to generate hydroxyl radicals in situ to oxidize hydrogen cyanide; or The first precursor is a zinc acetate solution, and the second precursor is a sodium hydroxide solution, which are used to generate zinc hydroxide nanoparticles in situ to precipitate hydrogen sulfide. or The first precursor is a potassium permanganate solution, and the second precursor is a dilute sulfuric acid solution, which are used to activate high-valence manganese in situ to oxidize arsine.

4. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The near-infrared light source is a ring array near-infrared LED module, embedded in the inner wall of the reaction chamber, with a center wavelength of 808nm and the illumination direction pointing towards the droplet group falling area below the atomizing nozzle; The near-infrared light source is linked to the trigger judgment module and is turned on only when the gas sensor detects that the concentration of the target highly toxic gas exceeds a preset threshold; otherwise, it remains off under normal operating conditions.

5. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The collection module includes a liquid-sealed waste liquid collection tank and a detachable filter unit installed inside the collection tank, which is used to intercept the solid products after solidification by the chelating groups on the surface of the photothermal nanoparticles, thereby achieving the separation of reaction products from waste liquid.

6. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The atomizing nozzle is a coaxial composite atomizing nozzle, configured to spray composite microdroplets with a core-shell structure or a Janus asymmetric structure; In the Janus asymmetric structure, the surface of one hemisphere of the droplet is enriched with hydrophobic nanoparticles, while the surface of the other hemisphere is enriched with hydrophilic nanocellulose, so as to generate passive Marangoni convection during the droplet's fall and enhance the gas-liquid mass transfer efficiency.

7. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The control module is configured to perform the following operations synchronously: When the gas sensor detects that the concentration of the target highly toxic gas exceeds the preset threshold within ≤3 seconds, the second precursor channel is opened simultaneously, the near-infrared light source is turned on, and the first precursor channel is continuously supplied, so that the reaction chamber can seamlessly switch between normal operating conditions and triggering operating conditions.

8. The laboratory waste gas purification and treatment device according to claim 1, characterized in that, The first precursor solution also contains a low concentration of sodium carbonate or sodium sulfate for routine neutralization of acid and alkali mist under normal operating conditions. The photothermal nanoparticles are configured to be suspended in the reaction chamber with inert droplets under normal operating conditions, without producing a photothermal effect; When the near-infrared light source is turned on, the photothermal nanoparticles generate a local temperature rise, and at the same time, they have an inactivation effect on the microbial aerosols carried in the exhaust gas.

9. A laboratory waste gas purification and treatment device according to claim 1, characterized in that, The control module is also configured to: After the gas sensor detects that the concentration of the target highly toxic gas has fallen below the preset threshold, the second precursor channel is first closed, and the near-infrared light source is turned off after a preset time delay, so that the active species remaining in the reaction chamber can fully react and then return to the normal operating conditions.

10. A laboratory waste gas purification and treatment device according to claim 2, characterized in that, The carbon dot@silica core-shell nanoparticles have a carbon dot core that is a nitrogen-doped carbon dot prepared by hydrothermal method of citric acid and urea, with a near-infrared absorption peak at 800-820 nm; the mass concentration of carbon dot@silica core-shell nanoparticles in the first precursor solution is 0.5-2.0 mg / mL.

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