挥发性有机物( VOCS) 是一类重要的空气污染物, 通常是指沸点50~260、室温下饱和蒸气压超过133. 132kPa的有机化合物, 包括烃类、卤代烃、芳香烃、多环芳香烃等。工业排放如化工厂排出的工艺尾气、废弃物焚烧的烟气中含有多种VOCS, 机动车排放的尾气中含有未完全燃烧的烃类物质。室内装饰、装修材料如油漆及其溶剂、木材防腐剂、涂料、胶合板等常温下可释放出甲苯、苯、二甲苯、甲醛等多种挥发性有机物质。日常生活中使用的化妆品, 除臭剂、杀虫剂、各种洗涤剂等导致VOCS 向大气中释放。此外, 燃料和烟草的不完全燃烧也会产生VOCS, 其中包括苯并芘。上述所有因素都将导致环境空气中VOCS 浓度升高和室内空气质量下降,据报道, 已在室内环境中检测出20多种VOC。
Volatile organic compounds (VOCS) are a kind of important air pollutants, usually refers to the boiling point of 50~260, saturated vapor pressure of more than 133. 132kPa at room temperature organic compounds, including hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, polycyclic aromatic hydrocarbons and so on. Industrial emissions such as chemical plant exhaust gas, waste incineration of flue gas contains a variety of VOCS, motor vehicle emissions of exhaust gas contains incomplete combustion of hydrocarbons. Toluene, benzene, xylene, formaldehyde and other volatile organic substances can be released from interior decoration and decoration materials such as paints and their solvents, wood preservatives, coatings and plywood at normal temperature. Cosmetics, deodorants, pesticides and detergents used in daily life lead to the release of VOCS into the atmosphere. In addition, incomplete combustion of fuels and tobacco also produces VOCS, including benzopyrene. All of the above factors will lead to higher VOCS concentrations in ambient air and lower indoor air quality, where more than 20 VOCS have been reported to have been detected.
The commonly used extraction method of volatile components is steam distillation, which has many problems such as time consuming, low utilization rate of medicinal materials and damage of active components by heat. Ultrasonic extraction technology in extracting volatile components, can use ultrasonic cavitation effect, mechanical effect and thermal effect of extracts from damage cellular structure and the solvent can quickly penetrate into cells, accelerate the dissolution of active ingredients, shorten extraction time, at the same time in the process of extracting temperature was not significant, can keep the extract characteristic flavor and odor and restrain in the process of extracting effective ingredients of volatile. In addition, ultrasonic technology can also be used to extract volatile oil or grease on other plants, such as oil of evodia rutaecarpa, fennel essential oil, bitter almond naphtha, lesser galangal rhizome volatile oil, ginger essential oil, fruit of Chinese magnoliavine volatile oil, clove essential oil, grape seed oil, sunflower oil, etc., mild reaction conditions, time and extract more volatile components, etc.