What is nitrogen oxide (NOx）

Nitrogen oxides refer to compounds composed of only two elements, nitrogen and oxygen, such:Nitrous oxide, nitric oxide, nitrogen dioxide, dinitrogen trioxide, dinitrogen tetroxide, dinitrogen pentoxide, etc. Of these gases, nitrogen oxides other than nitrous oxide and nitrogen dioxide are unstable. As a pollutant in the air, what we call nitrogen oxides（NOx）Generally refers to nitric oxide（NO）with nitrogen dioxide（NO2）。

With the rapid development of modern industry, the environmental problems are becoming more and more serious. And because of nitrogen oxides (NOx) The increase in emissions has caused serious pollution to the human environment and ecology. Therefore, the control of nitrogen oxides is one of the urgent and necessary tasks in the field of air pollution control in China. Because of our countryNOxThe development of control technology is late and not comprehensive enough, so that the problem of air pollution is still the focus and unsolved problem. Therefore, in recent years, the state has increased the requirements of energy conservation and emission reduction."Denitrification" indicators, strict control of industrial flue gasNOxand forced denitrification. Therefore, the development and research of denitrification technology and its methods is urgent. Affected by China's national conditions, coal will still occupy the main position in China's energy structure in the future. However, the burning of coal is causedNOxThe main cause of pollution is zui. Coal-fired power plants areNOxOne of the main sources of pollution, accounting for the totalNOxEmissions of about80%。2008Year of our countryNOxThe emissions reached2000About 10,000 tons for the world.NOxemissions first,2012Year has grown2400If strong denitrification measures are not taken in time, then2020YearNOxEmissions are expected to exceed3000Tons. At the same time, most of our thermal power plantsNOxHigher emissions, approx.3.19g·kW-1。

Sources of nitrogen oxides

in the atmosphereNOxPrimary SourceThere areTwo aspects, natural and man-made. Natural causes are mainly caused by volcanic eruptions, lightning strikes or bacterial activity, produced in this wayNOxin the atmosphere only5%Left and right. The anthropogenic emissions can be divided into stationary source emissions (such as industrial boilers, coal-fired boilers, etc.) and mobile source emissions (such as vehicle emissions) according to the different emission methods of nitrogen oxides. Among them95%ofNOxemissions from vehicle traffic emissions and flue gas emissions from thermal power plants。

Hazards of nitrogen oxides

NOxIs a pungent odor and very toxic gas, as a pollutant,NOAsNOxThe main ingredients will endanger the health of the human body. AndNO2It is a brown gas with a foul smell, which is more toxic to the human body,NO2After inhalation, contact with the respiratory system,NO2It will react with the water in the human body to generate nitric acid and nitrous acid, which will cause certain corrosion and damage to the entire respiratory system and even the lungs. And when it is used as a secondary pollutant,NO2Can occur a series of photochemical chain reactions, the generationO3Photochemical smog will cause great harm to the central nervous system of the human body.NOxCan interact with other substances in the environment, can form acid rain. WhenNOxAfter contact with the water components in the atmosphere, the reaction can form nitric acid and nitrous acid, and contact with precipitation to form acid rain, which has serious harm to buildings, crops and soil. For example, acid rain can corrode marble and metal, and damage some buildings and cultural relics. At the same time, the metal dissolved by acid rain will be absorbed by crops, which will indirectly affect the health of humans and animals. When in the flue gasNOxExposure to hydrocarbons in the atmosphere produces ozone and photochemical smog in the presence of sunlight and ultraviolet light. SimultaneouslyNOxwould increase the greenhouse effect,N2Ocontribution to the greenhouse effect is second onlyCO2withCH4. andNOxIt will consume ozone, make ozone loss, and indirectly lead to the greenhouse effect, making it more serious.

Detection of nitrogen oxides

With the continuous improvement of people's living standards and the increasing attention to environmental protection, people pay more and more attention to the close relationship between human health and environmental pollution, and begin to detect various toxic and harmful gases. Monitoring air pollution, industrial waste gas and monitoring the quality of the living environment have put forward higher requirements for gas sensors. In order to meet the growing and demanding market demand,AlphasenseofB4Series of electrochemical sensors came into being.

Unlike regular three-electrode electrochemical sensors,B4The series has one more electrode, namely: auxiliary electrode, which is used to compensate the zero current, so that the sensor has a more stable zero current, and at the same time, it has fast response speed, anti-interference, high resolution, good linearity, and wide working range. And other advantages.

B4In addition to the monitoring of nitrogen oxides, the series also provides monitoring of several other common toxic gases in the atmosphere:

If rightAlphasenseofB4Sensors are interested, welcome to consult!