Instrument Calibration: A UV ozone detector was used to compare the ozone detector at 10 randomly selected test points. An error range of +1% was considered acceptable.
Chemical Titration: The internationally recognized chemical method, potassium iodide/sodium thiosulfate titration, was used to detect ozone concentration. Ten test points were also selected, and the results were compared between the ozone detector and the 10 points tested using the chemical titration method. The error range was controlled within +1%. The principle of the potassium iodide titration method is that the strong oxidant ozone reacts with potassium iodide, releasing iodine into the water, turning it tea-colored. (Reaction formula: O3 + 2KI + H2O → O2 + I2 + KOH) Titration with a sodium thiosulfate standard solution converts the free iodine into sodium iodide. The reaction endpoint is complete decolorization of the water. (Reaction formula: I₂ + 2Na₂S₂O₃ → 2NaI + Na₂S₄O₆)
Ozone concentration: C = (Ana × B × 2400) / V₀ Unit (mg/l)
(Note: Ana----volume of sodium thiosulfate standard solution (ml); B---concentration of sodium thiosulfate standard solution (mol/l); V₀-----volume of other samples taken for ozone oxidation (ml))
