Application and Challenges of Nitrogen Dioxide Sensors in Industrial Waste Gas Monitoring
Nitrogen dioxide, with the chemical formula NO₂, is a reddish-brown gas. At room temperature (0~21.5℃), nitrogen dioxide and dinitrogen tetroxide coexist in a mixed state. It is toxic and irritating. When dissolved in concentrated nitric acid, it forms fuming nitric acid. It can polymerize into dinitrogen tetroxide. When reacting with water, it produces nitric acid and nitric oxide; when reacting with alkalis, it forms nitrates. It can undergo violent reactions with many organic compounds.
The social problems caused by environmental pollution have become increasingly prominent, and waste gas emissions from enterprises and factories are important factors affecting the atmospheric environment. Nitrogen dioxide plays a crucial role in the formation of ozone. It is mainly released from high-temperature combustion processes, such as emissions from motor vehicle exhaust and boiler waste gas. In recent years, factories have paid more and more attention to the monitoring of toxic gases during the production process of the chemical industry. Nitrogen dioxide (NO₂) is an important industrial gas, which can be used as an agent in industrial water treatment, as well as for bleaching pulp and fibers, refining flour, oils, and sugars, and removing hair from leather. A low concentration (4ppm) of nitrogen dioxide can cause nasal paralysis, which may lead to excessive inhalation. Long-term exposure to an environment with an NO₂ concentration of 40 to 100 mg/m³ will seriously affect health. Therefore, in order to prevent nitrogen dioxide from endangering the health of workers and affecting production, real-time monitoring of nitrogen dioxide gas in factories is essential.
Route of Exposure: Inhalation.
Health Hazards: Nitrogen oxides mainly damage the respiratory tract. In the early stage of inhalation, there are only mild irritation symptoms in the eyes and upper respiratory tract, such as sore throat and dry cough. Delayed pulmonary edema and acute respiratory distress syndrome usually occur after an incubation period of several hours to more than ten hours or even longer, accompanied by symptoms such as chest tightness, respiratory distress, cough, frothy sputum, and cyanosis. Complications such as pneumothorax and mediastinal emphysema may occur. Approximately two weeks after the pulmonary edema subsides, delayed obstructive bronchiolitis may develop.
Chronic Effects: The main manifestations include neurasthenic syndrome and chronic respiratory inflammation. In individual cases, pulmonary fibrosis may occur. It can also cause dental erosion.
Skin Contact: Remove contaminated clothing and rinse with running water.
Eye Contact: Immediately lift the eyelids and rinse with running water.
Inhalation: Quickly move the victim away from the contaminated area to a place with fresh air. Keep the respiratory tract unobstructed. If the victim has difficulty breathing, give oxygen. If breathing stops, immediately perform artificial respiration and seek medical attention.
Ingestion: Drink a sufficient amount of warm water to induce vomiting, then seek medical attention.
Quickly evacuate personnel in the contaminated area of the leak to the upwind direction, isolate the area, and strictly restrict access. It is recommended that emergency response personnel wear self-contained positive-pressure respirators and chemical protective clothing. Try to cut off the source of the leak as much as possible.
For gas leaks: Ensure proper ventilation to accelerate the diffusion of the gas. Spray water mist to dilute and dissolve the gas. Build dikes or dig pits to collect the large amount of waste water generated. Dispose of the leaking containers properly; they can be reused only after repair and inspection.
For liquid leaks: Rinse with a large amount of water, and discharge the rinsing water into the waste water system after dilution. In case of a large-scale leak, build dikes or dig pits for containment; spray water mist to cool and dilute the vapor. Use explosion-proof pumps to transfer the liquid to tank trucks or special collectors for recovery or transportation to waste disposal sites for treatment.
Industrialized society has promoted the vigorous development of technology enterprises, but it also has drawbacks, namely the serious environmental problems it brings, such as air pollution. Since we live on Earth and breathe air all the time, air quality has a profound impact on our health. Exhaust gases from motor vehicles and industrial emissions are directly released into the air, causing air pollution and leading to various health problems. For the detection of nitrogen dioxide in industrial waste gas, Shenzhen Sandate recommends the following electrochemical nitrogen dioxide sensor to detect the concentration of nitrogen dioxide gas, thereby protecting the personal safety of on-site workers and people in the surrounding areas.
The GS+4 NO₂ nitrogen dioxide sensor is an electrochemical sensor with the following advantages: high sensitivity, good selectivity, ability to filter dust and small water droplets, excellent linear output at low concentrations, good stability, and resistance to interference from CO, CO₂, and H₂. It is mainly used in NO₂ gas alarms for detecting the concentration of nitrogen dioxide gas in the atmosphere, as well as in industrial fields such as petroleum and chemical engineering.
