Treatment and solution of volatile organic compounds in VOCs
In our country, VOCs (volatile organic compounds) volatile organic compounds are organic compounds with saturated vapor pressure more than 133.32 Pa at normal temperature and below 50~260 C under normal pressure, or any organic solid or liquid that can volatilize at normal temperature and atmospheric pressure. VOCs is the abbreviation of volatile organic compounds. There are several definitions, for example, the American ASTM D3960-98 standard defines VOC as any organic compound capable of participating in atmospheric photochemical reactions. The definition of the Federal Environmental Protection Agency (EPA): volatile organic compounds are any carbon compounds that take part in atmospheric photochemical reactions except CO, CO2, H2CO3, metal carbides, metal carbonate, and ammonium carbonate. The WHO (WHO, 1989) defines the total volatile organic compounds (TVOC) as the general name of the volatile organic compounds that have a melting point below room temperature and a boiling point at 50~260 degrees centigrade. The international standard ISO 4618/1-1998 and the German DIN 55649-2000 standard for the general terms of color lacquer and varnish are defined for VOC, in principle, any organic liquid and / or solid that can volatilize spontaneously at normal temperature and atmospheric pressure. At the same time, in determining the content of VOC, the German DIN 55649-2000 standard also made a limit, that is, under normal pressure, the boiling point or the initial distillate is lower than or equal to any organic compound at or equal to 250 C. The Basf Inc believes that the most convenient and most common method is to define which substances are VOC according to the boiling point, and the most common consensus is that VOC refers to those chemicals that have a boiling point equal to or below 250 C. Therefore, those substances with boiling point exceeding 250 C do not belong to the category of VOC and are often referred to as plasticizers. These definitions have similarities, but they also have different focuses. If the definition of the United States does not limit the boiling point, it emphasizes the participation in atmospheric photochemical reactions. Those who do not participate in atmospheric photochemical reactions are called exempting solvents, such as acetone, four chloroethane, etc. WHO and BASF limit boiling point or initial boiling point, whether or not they participate in atmospheric photochemical reactions. The international standard ISO 4618/1-1998 and the

German DIN 55649-2000 standard do not limit the initial boiling point of boiling point, and regardless of whether they participate in the photochemical reaction of the atmosphere, only emphasize that the definition of these VOC can be divided into two classes at normal temperature and atmospheric pressure. The other is the VOC definition in the general sense, which only explains what is volatile. Machinery, or under what conditions are volatile organic compounds; the other is a definition of environmental protection, that is, a lively class of volatile organic compounds, that is, the kind of volatile organic compounds that are harmful. Obviously, in terms of environmental protection, volatilization and participation in atmospheric photochemical reactions are very important. Nonvolatile or not participating in atmospheric photochemical reactions does not constitute harm. This is why Europe has categorized the solvents according to the potential of photochemical ozone. According to WHO definition, volatile organic compounds (VOC) refer to all kinds of organic compounds with boiling point of 50 ~260 ~C under normal pressure. According to their chemical structure, VOC can be further divided into alkanes, aromatics, esters, aldehydes and others. At present, more than 300 have been identified. The most common are benzene, toluene, xylene, styrene, trichloroethylene, trichloromethane, trichloroethane, diisocyanate (TDI), diisocyanatoluene ester and so on. Formaldehyde is also a volatile organic compound, but formaldehyde is easy to dissolve in water and is different from other volatile organic compounds. It has a wide range of indoor sources and high release concentration. Therefore, formaldehyde is often described with other volatile organic compounds. Except formaldehyde, most volatile organic compounds are insoluble in water and easily soluble in organic solvents. Their respective concentrations are often not very high indoor, but the combined effect of several VOCs in the indoor air can not be ignored. Because of their variety and low concentration of individual components, TVOC is commonly used to indicate the total amount of volatile organic compounds in the room. TVOC is a measure of indoor decoration such as decoration and furniture. An important indicator of the indoor air quality. The main sources of volatile organic compounds in indoor indoor air are the sources of volatile organic compounds in indoor air, which are similar to indoor formaldehyde, and are more extensive. The main sources are: 1, building materials, indoor decoration materials and living and office supplies. For example, organic solvents, paints, and watercut coatings; 2, incomplete combustion of domestic fuel and tobacco, human excrement, 3, outdoor industrial waste gas, automobile exhaust, photochemical smog, etc. the main factors affecting the concentration of volatile organic compounds in indoor air are affected by volatile organic compounds and indoor air in indoor air Temperature, relative humidity, loading degree of materials, ventilation times (indoor air circulation) and other factors are related. It is easy to cause acute poisoning when the concentration of volatile organic compounds in indoor air is too high. Headache, dizziness, coughing, nausea, vomiting, or drunken shape will appear in the light. The heavy people will be intoxicated and even soon coma, and some can also have life risk.
Long term inhabitation in volatile organic compounds can cause chronic poisoning, damage the liver and nervous system, cause systemic weakness, drowsiness, and skin itching. Some may also cause endocrine disorders and affect sexual functions. Benzene and xylene can damage the system and cause leukemia. Volatile organic compounds

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