To detect ozone concentration, we must first understand where ozone is used. Different concentrations of ozone gas have different applications.
Ozone is a strong oxidant and disinfectant, used in various aspects:
1. Food processing disinfection, deodorization, and preservation
2. In water treatment, it can kill bacteria, viruses, etc. in water
3. In medical treatment, it can disinfect equipment, purify air, and deodorize.
4. Disinfection and preservation of fruits and vegetables
5. Drinking water treatment, wastewater treatment, industrial wastewater treatment
6. Chemical, petroleum, paper making, textile, pharmaceutical and flavor and fragrance industries, water treatment, food and medicine sterilization workshops and other occasions
Ozone of different concentrations is used in different industries, such as:
China's safe working range: ozone concentration does not exceed 0.1mg/m3, about 0.05ppm
The US standard is 0.1ppm, and the international standard is 0.05ppm.
Water treatment disinfection: 1-4mg/l
Wastewater treatment: 4-10mg/l
Swimming pool: 0.8-1.2mg/l
Cold storage disinfection is 2-10ppm
Medical operating room is 5-20ppm for short-term disinfection
So how is ozone produced in industry?
There are several ways to produce ozone gas:
Ozone generator: O3 is produced by discharging air or O2;
High-energy ultraviolet light photolysis produces ozone;
Ozone gas itself is unstable and can be easily adsorbed or decomposed into O2 in a short time, so there is no standard ozone standard gas bottle, because it is difficult to store for a long time and can only be produced when it is used.
How to detect ozone concentration?
1 Ultraviolet absorption method: The principle is based on the absorption of ultraviolet light with a wavelength of 254nm by O3. According to Bill-Long's law, the concentration of O3 can be calculated. This method has a simple structure, high sensitivity, and fast response. It has good linearity in the high ozone concentration range (0-10000ppm), and the zero drift and range drift are very small. Ozone detectors based on this principle are expensive.
Electrochemical method: The measured ozone gas contacts the instrument in a diffusion or pumping manner, reacts, and outputs a stable electrical signal.
How to calibrate the ozone detector?
It is necessary to generate ozone gas of known concentration through a standard ozone generator, and then measure it with a detector, compare the measurement results with the standard value, and make adjustments based on the deviation.
At the same time, the ozone detector can also be cross-calibrated with a NO2 standard gas cylinder of a certain concentration.