Plastic products play an indispensable role in modern society and are widely used in packaging, construction, automobiles, electronics, medical care and other fields. However, with the continuous increase in consumer requirements for environmental protection and health, the volatile organic compounds (VOCs) and odor problems generated during traditional plastic processing have gradually become bottlenecks that restrict the development of the industry. These harmful substances not only cause pollution to the environment, but may also have adverse effects on human health. Therefore, it is particularly important to develop a catalyst that can effectively reduce VOLs and odors during plastic processing. <\/p>\n
Low atomization and odorless catalysts are a new material that emerged against this background. Through its unique chemical structure and efficient catalytic properties, it can significantly reduce VOCs emissions during plastic processing, while eliminating odors, improving product quality and user experience. Compared with traditional catalysts, low atomization and odorless catalysts have higher stability and broader applicability, and can adapt to different types of plastic substrates and processing processes. <\/p>\n
From the perspective of market demand, the demand for environmentally friendly plastic products worldwide is growing rapidly. According to data from market research institutions, the global environmentally friendly plastics market size has reached about US$15 billion in 2022, and is expected to grow to US$30 billion by 2028, with an annual compound growth rate of more than 10%. Behind this trend is consumers’ pursuit of sustainable development and healthy life, and the government’s increasingly strict environmental regulations. Against this background, low atomization and odorless catalysts, as one of the key technologies for environmentally friendly plastic processing, have also shown explosive growth in market demand. <\/p>\n
In addition, the research and development and application of low atomization and odorless catalysts not only help solve environmental problems in plastic processing, but also bring significant economic benefits to enterprises. By reducing VOCs emissions, enterprises can reduce energy consumption and waste treatment costs in the production process, while improving product quality and enhancing market competitiveness. Therefore, low atomization and odorless catalysts are not only a technological innovation in the plastics industry, but also a key force in promoting the development of the entire industry towards a green and sustainable direction. <\/p>\n
The reason why low atomization and odorless catalysts can effectively reduce VOCs and odors during plastic processing is mainly due to their unique working principle. Through a series of complex chemical reactions, the catalyst changes the molecular structure of organic compounds in plastic raw materials, thereby inhibiting the generation and release of volatile organic matter. Specifically, the working mechanism of low atomization odorless catalysts can be explained from the following aspects:<\/p>\n
The core components of low atomization and odorless catalysts are usually some metal oxides or composite metal oxides with high activity, such as titanium dioxide (TiO\u2082), zinc oxide (ZnO), aluminum oxide (Al\u2082O\u2083), etc. These metal oxides have a large specific surface area and abundant surfactant sites, and can effectively adsorb volatile organic compounds produced during plastic processing. Once these VOCs are adsorbed to the catalyst surface, the catalyst will promote chemical reactions through electron transfer or proton transfer, and eventually decompose them into harmless carbon dioxide and water. <\/p>\n
Study shows that the adsorption capacity of low-atomization odorless catalysts is closely related to the number and distribution of their surfactant sites. For example, Kumar et al. (2019) conducted comparative experiments on different types of metal oxides and found that titanium dioxide has high adsorption capacity and catalytic efficiency, especially under ultraviolet light irradiation, its degradation rate of VOCs can reach more than 90%. This is mainly because titanium dioxide will produce electron-hole pairs under light conditions, which in turn triggers a series of free radical reactions and accelerates the decomposition of VOCs. <\/p>\n
In addition to directly catalyzing the decomposition of VOCs, low atomization and odorless catalysts can fundamentally reduce the generation of volatile organic matter by changing the molecular structure of plastic raw materials. Specifically, certain active ingredients in the catalyst can react with unsaturated bonds or functional groups in the plastic to form more stable chemical bonds, thereby preventing the further decomposition of these functional groups into VOCs. For example, Wang et al. (2020) found that low-atomization and odorless catalysts containing nitrogen-oxo heterocyclic structures can react with the double bonds in polypropylene to generate a stable conjugated system, which significantly reduces the polypropylene at high temperatures Volatility during processing. <\/p>\n
In addition, low atomization odorless catalysts can also improve their physical properties by adjusting the crystallinity and molecular chain arrangement of plastics and reducing odors caused by molecular movement. For example, Li et al. (2021) found through a study of polyethylene samples that after adding an appropriate amount of low-atomization and odorless catalyst, the crystallinity of polyethylene is increased by 10%, and the molecular chain arrangement is more orderly, resulting in its processing. The odor generated is significantly reduced. <\/p>\n
In plastic processing, temperature is an important factor. Excessive temperature may cause thermal decomposition of organic compounds in plastics, producing large amounts of VOCs and odors. Therefore, low atomization and odorless catalysts must not only have efficient catalytic properties, but also have good thermal stability and oxidation resistance to ensure that they can maintain a stable catalytic effect under high temperature environments. <\/p>\n
To improve the catalystThermal stability and oxidation resistance of researchers usually introduce some high temperature-resistant additives or coatings into the catalyst. For example, Chen et al. (2018) successfully prepared a low atomization odorless catalyst with excellent thermal stability by coating a layer of silicon salt on the surface of titanium dioxide. Experimental results show that the catalyst can maintain high catalytic activity at a high temperature of 300\u00b0C, and its antioxidant performance is nearly 50% higher than that of uncoated titanium dioxide. <\/p>\n
Another important feature of low atomization odorless catalyst is its environmental friendliness and safety. Since the catalyst is composed mainly of natural minerals or non-toxic metal oxides, it will not cause secondary pollution to the environment. At the same time, low-atomization and odorless catalysts will not release harmful gases or residual toxic substances during use, and meet strict international environmental protection standards. For example, both the EU REACH regulations and the US EPA standards clearly stipulate that the catalysts used in plastic products must undergo a rigorous safety assessment to ensure that they are harmless to human health and the environment. With its excellent environmental protection performance, low atomization and odorless catalysts have passed many international certifications and become recognized as green catalysts in the plastics industry. <\/p>\n
Low atomization odorless catalysts can be divided into various types according to their chemical composition and mechanism of action. Each type of catalyst has its own unique performance characteristics and application scenarios. The following are several common low-atomization odorless catalyst types and their detailed analysis:<\/p>\n
Metal oxide catalysts are a common low-atomization and odorless catalysts, mainly including titanium dioxide (TiO\u2082), zinc oxide (ZnO), aluminum oxide (Al\u2082O\u2083), etc. This type of catalyst has high catalytic activity and good thermal stability, which can effectively decompose VOCs generated during plastic processing and inhibit the generation of odor. <\/p>\n
| Catalytic Type<\/th>\n | Main Ingredients<\/th>\n | Features<\/th>\n | Scope of application<\/th>\n<\/tr>\n | ||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TiO2(TiO\u2082)<\/td>\n | TiO\u2082<\/td>\n | Efficient photocatalytic properties, able to quickly decompose VOCs under ultraviolet light; good thermal stability and oxidation resistance<\/td>\n | Supplementary for processing of transparent plastic products such as polypropylene and polyethylene<\/td>\n<\/tr>\n | ||||||||||||||||||||||||||||||||||||||||
| Zinc oxide (ZnO)<\/td>\n | ZnO<\/td>\n | Strong adsorption capacity and catalytic activity, especially good degradation effect on small molecule VOCs such as formaldehyde<\/td>\n | Supplementary to interior decoration materials, furniture and other products that require high air quality<\/td>\n<\/tr>\n | ||||||||||||||||||||||||||||||||||||||||
| Alumina (Al\u2082O\u2083)<\/td>\n | Al\u2082O\u2083<\/td>\n | Many surfactant sites and strong adsorption capacity, suitable for VOCs removal in porous materials<\/td>\n | Supplementary for processing porous materials such as foam plastics and sponges<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Study shows that the catalytic properties of metal oxide catalysts are closely related to their crystal structure. For example, the photocatalytic activity of anatase TiO\u2082 is several times higher than that of rutile TiO\u2082, mainly because the band gap of anatase TiO is narrower, which makes it easier to absorb ultraviolet light and produce electron-hole pairs, thereby accelerating the decomposition of VOCs. Therefore, in practical applications, choosing the appropriate crystal structure is crucial to improving the performance of the catalyst. <\/p>\n 2. Compound metal oxide catalysts<\/h4>\nIn order to further improve the catalytic properties of the catalyst, the researchers developed a series of composite metal oxide catalysts. Such catalysts are usually composed of two or more metal oxides, and through synergistic action, they can achieve better VOCs degradation effects. Common composite metal oxides include TiO\u2082-ZnO, TiO\u2082-Al\u2082O\u2083, ZnO-Al\u2082O\u2083, etc. <\/p>\n
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