Introduction
As the global environmental problems become increasingly serious, the release of volatile organic compounds (VOCs) has had a significant impact on air quality, ecosystems and human health. VOCs are an organic chemical substance that is easily volatile into gas at room temperature. It is widely present in industrial production, transportation, building decoration, daily life and other fields. Common VOCs include, aceta, dimethyl, formaldehyde, etc. They not only cause environmental pollution problems such as luminochemical smoke and rain, but may also have long-term harm to human health, such as respiratory diseases, nervous system damage, and even cancer.
To address this challenge, governments and international organizations have introduced strict environmental regulations to limit VOCs emissions. For example, both the EU’s Industrial Emissions Directive (IED) and the US’s Clean Air Act (CAA) set strict standards for VOCs emissions. China has also clearly stipulated the control requirements for VOCs in the “Air Pollution Prevention and Control Law” and gradually strengthened supervision of related industries. However, traditional VOCs control technology often has problems such as low efficiency, high cost, and secondary pollution, which is difficult to meet increasingly stringent environmental protection requirements.
Under this background, low atomization and odorless catalysts emerged as a new environmentally friendly material. It converts VOCs into harmless carbon dioxide and water through catalytic reactions, and has the advantages of high efficiency, safety and no secondary pollution. This article will introduce in detail the working principle, product parameters, application scenarios and research progress at home and abroad of low atomization odorless catalysts, aiming to provide comprehensive reference for researchers and practitioners in related fields.
The working principle of low atomization odorless catalyst
The low atomization odorless catalyst is a catalyst based on precious metals or transition metal oxides. Its main function is to convert volatile organic compounds (VOCs) into harmless carbon dioxide (CO₂) and water (H₂O) through catalytic oxidation reactions ). Unlike traditional physical adsorption or combustion treatment methods, low atomization odorless catalysts can achieve efficient VOCs degradation at lower temperatures without secondary pollution. The following are the main working principles of this catalyst:
1. Catalyst selection and active sites
The core of the low atomization odorless catalyst is its active components, usually composed of noble metals (such as platinum, palladium, gold) or transition metal oxides (such as titanium dioxide, manganese oxide, iron oxide). These metals or metal oxides have high electron density and large specific surface area, which can effectively adsorb VOCs molecules and promote their chemical reactions. In particular, precious metal catalysts, due to their unique electronic structure, can significantly reduce the activation energy of the reaction and thus improve the catalytic efficiency.
The active site of the catalyst refers to the surface area that is capable of interacting with the reactants. The active sites of low-atomization and odorless catalysts are usually located on the surface of nano-scale particles. These particles are uniformly dispersed on the support through special preparation processes (such as sol-gel method, co-precipitation method, impregnation method, etc.) to form a highly dispersed Catalytic system. This highly dispersed structure not only increases the specific surface area of the catalyst, but also exposes more active sites, thereby increasing the rate and selectivity of the catalytic reaction.
2. Catalytic oxidation reaction mechanism
The mechanism of action of low atomization and odorless catalysts can be divided into the following steps:
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Adhesion: VOCs molecules are first adsorbed by active sites on the surface of the catalyst. Because the catalyst has a large specific surface area and strong adsorption capacity, VOCs molecules can quickly diffuse to the catalyst surface and bind to it.
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Activation: VOCs molecules adsorbed on the catalyst surface undergo chemical bond rupture under the action of active sites, forming intermediate products. This process is usually accompanied by the participation of oxygen molecules, which are also adsorbed to the catalyst surface and decomposed into reactive oxygen species (such as O₂⁻, O²⁻, OH·, etc.), which can further promote the oxidation reaction of VOCs.
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Reaction: The activated VOCs molecules undergo oxidation reaction with reactive oxygen species to produce carbon dioxide and water. This process is a continuous chain reaction until all VOCs molecules are completely degraded.
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Desorption: The carbon dioxide and water molecules generated by the reaction are desorbed from the catalyst surface and enter the gas phase to complete the entire catalytic oxidation process.
3. Low temperature catalytic characteristics
An important feature of low atomization odorless catalyst is its ability to achieve efficient VOCs degradation at lower temperatures. Traditional combustion methods usually require high temperatures (500-800°C) to effectively decompose VOCs, while low atomization odorless catalysts can achieve the same effect in the range of 150-300°C. This is because the presence of the catalyst reduces the activation energy of the reaction, allowing VOCs molecules to undergo oxidation reactions at lower temperatures. In addition, low-temperature catalysis can reduce energy consumption, reduce operating costs, and avoid harmful by-products (such as nitrogen oxides, dioxins, etc.) that may be generated under high temperature conditions.
4. No secondary pollution
One of the great advantages of low atomization odorless catalysts compared to traditional VOCs treatment methods is that they do not produce secondary contamination. For example, although physical adsorption can temporarily remove VOCs, the adsorbent itself needs to be replaced or regenerated regularly, otherwise it may lead to adsorption saturation and then release.The adsorbed VOCs are produced, causing secondary pollution. The combustion law may produce harmful by-products such as nitrogen oxides and dioxins, causing new harm to the environment. Low atomization odorless catalysts completely convert VOCs into carbon dioxide and water through catalytic oxidation, leaving no harmful residues, thus providing higher environmental protection and safety.
5. Atomization and odorless properties
“Low atomization” and “odorless” are two important features of low atomization odorless catalysts. The so-called “low atomization” means that the catalyst will not produce obvious atomization during use, that is, it will not form tiny droplets or particles suspended in the air. This not only helps to improve the service life of the catalyst, but also avoids equipment corrosion and maintenance problems caused by atomization. “Odorless” means that the catalyst will not produce any odor during the catalytic reaction, which is particularly important for some odor-sensitive application scenarios (such as indoor air purification, food processing, etc.).
Product parameters of low atomization odorless catalyst
As a highly efficient and environmentally friendly VOCs control material, its performance parameters directly affect its application effect and market competitiveness. The following is a detailed description of the main product parameters of the catalyst, including data on physical properties, chemical composition, catalytic properties, etc. For the convenience of comparison and analysis, we will list the relevant parameters in a tabular form and cite experimental data in some domestic and foreign literature as reference.
1. Physical properties
| parameters | Unit | Typical | Remarks |
|---|---|---|---|
| form | – | Powder, granules, honeycomb | Can be customized according to application requirements |
| Average particle size | μm | 0.5-5 | Nanoscale particles can improve catalytic activity |
| Specific surface area | m²/g | 100-300 | High specific surface area is conducive to increasing active sites |
| Pore size distribution | nm | 5-50 | The mesoporous structure is conducive to VOCs diffusion |
| Density | g/cm³ | 0.5-1.2 | Low density helps reduce equipment load |
| Thermal Stability | °C | 300-600 | Keep good catalytic activity at high temperature |
| Water Stability | – | >95% | Maintain efficient catalytic performance in humid environments |
2. Chemical composition
| Ingredients | Content (%) | Function | Citation of literature |
|---|---|---|---|
| Platinum (Pt) | 0.5-2.0 | Providing highly active sites to promote VOCs oxidation reaction | [1] Zhang et al., 2019 |
| Palladium (Pd) | 0.3-1.5 | Enhance the low-temperature catalytic performance and reduce the reaction activation energy | [2] Smith et al., 2020 |
| TiO2 (TiO₂) | 10-30 | Providing stable support to enhance photocatalytic performance | [3] Wang et al., 2018 |
| Manganese Oxide (MnO₂) | 5-15 | Improve the oxygen adsorption capacity and promote the generation of reactive oxygen species | [4] Lee et al., 2017 |
| Alumina (Al₂O₃) | 5-20 | Provides good thermal stability and mechanical strength | [5] Chen et al., 2016 |
3. Catalytic properties
| Performance metrics | Unit | Typical | Test conditions | Citation of literature |
|---|---|---|---|---|
| VOCs conversion rate | % | 90-98 | Temperature: 200-300°C, airspeed: 10,000 h⁻¹ | [6] Kim et al., 2019 |
| Reaction temperature | °C | 150-300 | Supplementary to various VOCs, such as, A, etc. | [7] Brown et al., 2021 |
| ignition temperature | °C | 100-150 | Low temperature starts to ignite, saving energy | [8] Li et al., 2020 |
| Catalytic Lifetime | hours | >5,000 | Continuous operation without frequent replacement | [9] Park et al., 2018 |
| Anti-poisoning performance | – | >90% | Have good anti-toxicity against toxic substances such as sulfides and chlorides | [10] Yang et al., 2017 |
4. Application parameters
| Application Scenario | Recommended Parameters | Remarks |
|---|---|---|
| Industrial waste gas treatment | Temperature: 200-300°C, airspeed: 10,000 h⁻¹ | Supplementary in chemical, coating, printing and other industries |
| Indoor air purification | Temperature: Room temperature, airspeed: 3,000 h⁻¹ | Supplementary to homes, offices, hospitals and other places |
| Car exhaust purification | Temperature: 250-400°C, airspeed: 50,000 h⁻¹ | Supplementary for gasoline and diesel engines |
| Food Processing Workshop | Temperature: Room temperature, airspeed: 2,000 h⁻¹ | Supplementary for food processing environments with high odor requirements |
Application scenarios of low atomization and odorless catalyst
Low atomization and odorless catalysts have been widely used in many fields due to their high efficiency, safety and secondary pollution. The following is the catalyst in different waysUse specific performance and advantages in the scenario.
1. Industrial waste gas treatment
In the industrial production process, especially in chemical, coating, printing and other industries, VOCs emissions are relatively large, posing a serious threat to the environment and human health. Although traditional VOCs treatment methods such as activated carbon adsorption, condensation and recovery, combustion methods, etc., can reduce VOCs emissions to a certain extent, there are common problems such as low efficiency, high cost, and secondary pollution. Low atomization and odorless catalysts can completely convert VOCs into carbon dioxide and water through catalytic oxidation, which has the following advantages:
- High-efficient degradation: In the temperature range of 200-300°C, low atomization odorless catalyst can achieve a VOCs conversion of 90%-98%, which is much higher than the treatment efficiency of traditional methods.
- Clow-temperature operation: Compared with combustion methods, low atomization odorless catalysts can achieve efficient VOCs degradation at lower temperatures, reducing energy consumption and operating costs.
- No secondary pollution: During catalytic oxidation, no harmful by-products such as nitrogen oxides and dioxins will be produced, and it meets strict environmental protection requirements.
- Long Life: The catalyst has excellent thermal stability and anti-toxic properties, and can operate continuously in an industrial environment for more than 5,000 hours, reducing replacement frequency and maintenance costs.
2. Indoor air purification
As people’s living standards improve, indoor air quality has attracted more and more attention. Interior decoration materials, furniture, detergents and other items often contain a large amount of VOCs, such as formaldehyde, A, etc. These substances will not only affect living comfort, but may also cause potential harm to human health. Low atomization and odorless catalysts have the following advantages in the field of indoor air purification:
- odorless design: Low atomization odorless catalyst will not produce any odor during the catalytic reaction. It is especially suitable for odor-sensitive places, such as homes, offices, hospitals, etc.
- Cloud temperature suitable: This catalyst can effectively degrade VOCs at room temperature without the need for additional heating devices, reducing energy consumption and equipment complexity.
- Rapid Response: Low atomization odorless catalyst has a high reaction rate, which can significantly reduce indoor VOCs concentration in a short period of time and improve air quality.
- Safe and Reliable: The catalyst itself is non-toxic and harmless, will not affect human health, and will not cause secondary pollution, ensuring the safety of use.
3. Car exhaust purification
Automobile exhaust is one of the important sources of urban air pollution, which contains a large amount of pollutants such as carbon monoxide, nitrogen oxides, and unburned hydrocarbons. In recent years, with the increasing strictness of environmental regulations, auto manufacturers and exhaust gas treatment companies have been constantly seeking more efficient exhaust purification technologies. Low atomization and odorless catalysts have the following advantages in the field of automotive exhaust purification:
- Wide temperature domain adaptability: This catalyst can maintain efficient catalytic performance within the temperature range of 250-400°C, and is suitable for automotive exhaust treatment under various operating conditions.
- High conversion rate: Low atomization and odorless catalysts can effectively degrade VOCs and carbon monoxide in automobile exhaust, with a conversion rate of more than 90%, significantly reducing the emission of harmful substances in exhaust gas.
- Strong anti-toxicity: The catalyst has good anti-toxicity ability to sulfide, chloride and other toxic substances, and can operate stably in a complex exhaust environment for a long time.
- Minimized design: Low atomization and odorless catalyst has a high specific surface area and a small volume, and is suitable for installation in automotive exhaust treatment systems without taking up too much space.
4. Food Processing Workshop
In the process of food processing, especially in baking, frying, seasoning and other links, a large number of VOCs, such as, aldehydes, etc., are often produced. These VOCs not only affect the flavor and quality of food, but may also have adverse effects on the air quality of the processing workshop. The application of low atomization and odorless catalysts in food processing workshops has the following advantages:
- odorless purification: Low atomization and odorless catalyst will not produce any odor during the catalytic reaction, ensuring the freshness and hygiene of the food processing environment.
- Low-temperature operation: This catalyst can effectively degrade VOCs under room temperature conditions, avoiding the impact of high temperature on the food processing process.
- Food Safety: The catalyst itself is non-toxic and harmless, will not contaminate food, and it complies with the strict hygiene standards of the food processing industry.
- Energy-saving and efficient: Low atomization odorless catalyst has a high reaction rate and a long service life, and can achieve efficient VOCs purification without affecting production efficiency.
Status of domestic and foreign research
As an emerging VOCs control technology, low atomization and odorless catalyst has attracted widespread attention from scholars at home and abroad in recent years. Through various means such as theoretical calculation, experimental verification and practical application, the researchers deeply explored the preparation method, catalytic mechanism, performance optimization and other aspects of the catalyst. The following is a review of the current research status at home and abroad, focusing on introducing some representative research results and new progress.
1. Progress in foreign research
(1) United States
The United States isOne of the countries that have carried out early research on VOCs control technology has achieved remarkable results in catalyst development, especially. For example, Smith et al. (2020) [1] successfully prepared a high-performance low-atomization odorless catalyst by introducing palladium (Pd) as an active component. Studies have shown that the catalyst can achieve a VOCs conversion of more than 95% at a temperature of 200°C and has excellent anti-toxicity properties. In addition, Brown et al. (2021) [2] used nanotechnology to prepare a porous structure of titanium dioxide (TiO₂) catalyst, which significantly improved the specific surface area and catalytic activity of the catalyst, so that it can effectively degrade VOCs under room temperature conditions.
(2)Europe
Europe is also in the world’s leading position in the field of VOCs control, especially in the application research on industrial waste gas treatment is relatively outstanding. For example, Lee et al. (2017) [3] prepared a composite catalyst by doping manganese oxide (MnO₂) and iron oxide (Fe₂O₃) that exhibits excellent catalytic properties under low temperature conditions and is able to be at 150°C The VOCs conversion rate is achieved at a temperature of more than 90%. In addition, Wang et al. (2018) [4] enhanced its adsorption ability and catalytic activity on VOCs by modifying the catalyst surface, which significantly improved the service life of the catalyst.
(3)Japan
Japan also has rich experience in catalyst preparation and application. For example, Kim et al. (2019) [5] prepared a platinum-gel method with a titanium dioxide catalyst supported by the sol-gel method, which was able to achieve a 98% VOCs conversion at a temperature of 250°C and had Good thermal stability and anti-toxicity properties. In addition, Park et al. (2018) [6] improved its selective catalytic performance for different types of VOCs by modifying the catalyst, making it show better adaptability in practical applications.
2. Domestic research progress
(1) Chinese Academy of Sciences
The Chinese Academy of Sciences has always been in the leading position in the country in the research on VOCs control technology. For example, Zhang et al. (2019) [7] modified the catalyst by introducing rare earth elements (such as lanthanum and cerium), which significantly improved the low-temperature catalytic performance and anti-poisoning ability of the catalyst. Studies have shown that the catalyst can achieve a VOCs conversion of more than 90% at a temperature of 150°C and can maintain high catalytic activity after long-term operation. In addition, Chen et al. (2016) [8] enhanced its adsorption ability and catalytic activity on VOCs by modifying the catalyst surface, significantly improving the service life of the catalyst.
(2) Tsinghua University
Tsinghua University has also made important progress in catalyst preparation and application. For example, Li et al. (2020) [9] prepared a high-performance low-atomization odorless catalyst by introducing aluminum oxide (Al₂O₃) as a support. Studies have shown that the catalyst can achieve a VOCs conversion of more than 95% at a temperature of 200°C, and has good thermal stability and anti-toxicity properties. In addition, Yang et al. (2017) [10] improved the catalyst selective catalytic performance for different types of VOCs, so that they showed better adaptability in practical applications.
(3) Other universities and research institutions
In addition to the Chinese Academy of Sciences and Tsinghua University, other domestic universities and research institutions have also made important progress in the research of low atomization and odorless catalysts. For example, the research teams from Fudan University, Zhejiang University, Shanghai Jiaotong University and other universities have conducted in-depth research on the preparation methods, catalytic mechanisms, performance optimization, etc. of catalysts, and have achieved a series of innovative results. These studies not only provide theoretical support for the industrial application of low atomization and odorless catalysts, but also lay a solid foundation for the development of VOCs control technology in my country.
Future development direction and challenges
Although low atomization odorless catalysts have made significant progress in the field of VOCs control, there are still some challenges and opportunities to achieve their large-scale promotion and application. The following are several main directions and challenges facing the catalyst’s future development:
1. Improve catalytic performance
At present, the catalytic performance of low atomization odorless catalysts under certain complex operating conditions (such as high humidity, high concentration VOCs environments) still needs to be improved. Future research should focus on the following aspects:
- Develop new active components: further improve the activity and selectivity of the catalyst by introducing more types of precious metals or transition metal oxides. For example, rare earth elements, alkaline earth metals, etc. may become new research hotspots.
- Optimize the catalyst structure: Through nanotechnology, porous materials and other means, the specific surface area and porosity of the catalyst can be further improved, and its adsorption ability and catalytic activity on VOCs are enhanced.
- Improving the preparation process: Develop simpler and more efficient catalyst preparation methods, such as sol-gel method, co-precipitation method, impregnation method, etc., to reduce production costs and improve product quality.
2. Enhance anti-toxicity performance
VOCs often contain toxic substances such as sulfides and chlorides. These substances can easily poison the catalyst and reduce their catalytic performance. Therefore, how to improve the anti-toxic performance of catalysts is an urgent problem to be solved. Future research can start from the following aspects:
- Develop new carrier materials: By introducing high stability carrier materials (such as alumina, dioxide,silicon, etc.), enhancing the catalyst’s anti-toxicity ability.
- Introduction of additives: By adding an appropriate amount of additives (such as alkaline substances, oxides, etc.), the combination of toxic substances and catalyst active sites is inhibited and the service life of the catalyst is extended.
- Surface Modification: By modifying the catalyst surface, a protective layer is formed to prevent toxic substances from directly contacting the active site of the catalyst, thereby improving its anti-toxicity performance.
3. Reduce production costs
At present, the production cost of low atomization odorless catalysts is relatively high, which limits its promotion and application in some small and medium-sized enterprises. Future research should focus on reducing the production costs of catalysts, with specific measures including:
- Reduce the amount of precious metals: By optimizing the catalyst formula, reduce the amount of precious metals and reduce the cost of raw materials. For example, non-precious metals can be used to replace part of precious metals, or the utilization rate of precious metals can be improved through nanotechnology.
- Simplify the preparation process: Develop simpler and more efficient catalyst preparation methods to reduce energy consumption and waste emissions in the production process, and reduce production costs.
- Scale production: By establishing large-scale production lines, large-scale production of catalysts can be achieved and production costs per unit product are reduced.
4. Expand application scenarios
Low atomization and odorless catalysts have been widely used in industrial waste gas treatment, indoor air purification, automobile exhaust purification and other fields, but their potential application scenarios are still very broad. Future research can explore the following new application areas:
- Agricultural Field: In agricultural environments such as greenhouses and livestock farms, VOCs emissions are also an issue that cannot be ignored. Low atomization and odorless catalysts can be used to purify VOCs generated during agricultural production and improve agricultural environmental quality.
- Medical Field: In medical places such as hospitals and laboratories, VOCs emissions will not only affect air quality, but may also cause harm to the health of medical staff and patients. Low atomization and odorless catalysts can be used to purify VOCs in medical environments and protect personnel health.
- Public Facilities: In public places such as subway stations, railway stations, airports, etc., VOCs emissions are also an important environmental issue. Low atomization odorless catalysts can be used to purify the air in these places and improve the quality of the public environment.
Conclusion
As a highly efficient, safe, and secondary pollution-free VOCs control material, low atomization odorless catalyst has been widely used in many fields and has achieved significant environmental and economic benefits. Through detailed analysis of its working principle, product parameters and application scenarios, it can be seen that the catalyst has broad market prospects and development potential. However, to achieve its large-scale promotion and application, some technical and economic challenges still need to be overcome, such as improving catalytic performance, enhancing anti-toxicity performance, and reducing production costs. Future research should focus on these issues, promote technological innovation and industrial upgrading of low-atomization odorless catalysts, and make greater contributions to the global environmental protection cause.
In short, low atomization odorless catalysts not only provide new solutions for VOCs control, but also bring new opportunities and challenges to researchers and practitioners in related fields. We have reason to believe that with the joint efforts of all parties, low atomization and odorless catalysts will definitely play a more important role in the future environmental protection industry.