Detection method of ozone concentration in ozone generator

1. The amount of iodine: In the past, the classic measurement method was to free the iodine in the potassium iodide solution with ozonated gas, and then titrate it with sodium thiosulfate to reduce it to colorless, and calculate the ozone concentration according to the amount of sodium thiosulfate consumed. This method has intuitive color development and cheap equipment, but requires various chemical testing equipment such as medicines, washing bottles, graduated cylinders, balances, burettes, etc. , inconvenient to use and susceptible to interference from other oxidants (such as NO, CL, etc.). ). It is still the standard determination method in my country.

2. Ultraviolet absorption method: use ozone with absorption wavelength = 254nm to attenuate ultraviolet light in the ozone atmosphere, and then output data through photoelectric elements and electronic circuits (comparison circuits, data processing, digital-to-analog conversion). The method has high precision and can be continuously measured online. It has been selected as a standard method by developed countries such as the United States, but this instrument is expensive and is generally used as a testing unit, production and scientific research unit.

3. Electrochemical method: The disinfection equipment of Shandong ozone generator air source sewage treatment plant adopts the electrochemical reduction of ozone in water on the electroactive surface. The current change curve in the electrochemical circuit is proportional to the concentration of ozone in the solution, and has functions such as data output and online measurement. Thereby, the closed-loop feedback control of the ozone generator is realized. It is less expensive than the UV method and is smaller in size. It has been used in large-scale water treatment projects.

4. Colorimetric method: The concentration of ozone is determined by the color development or decolorization of the reaction between ozone and chemical reagents, which is the same chemical method as the iodometric method. Various chemicals such as potassium iodide, o-toluidine or indigo dye can be used. In contrast to standard color tubes or color wheels, it can also be detected with a spectrophotometer. This method is simple in operation and low in price, and is suitable for promotion in China at present, but the experimental drugs are disposable consumables.