Methods for Detecting Concentration Using Ozone Aging Tester

Since ozone is a highly chemically unstable gas, measuring its concentration in air and water within a short timeframe has long been challenging. However, using a plastic ozone aging test chamber simplifies this process significantly. Below, we explore several detection methods:

Iodometric Titration:

A classical method where ozone oxidizes potassium iodide (KI) solution, releasing iodine (I₂) which imparts a color. The liberated iodine is then titrated with sodium thiosulfate (Na₂S₂O₃) until the solution becomes colorless. The ozone concentration is calculated based on the volume of thiosulfate consumed.

Advantages: Cost-effective equipment, visually intuitive results.

Disadvantages: Requires chemical reagents (e.g., KI, Na₂S₂O₃), volumetric flasks, balances, and burettes. Susceptible to interference from other oxidizing agents. Still designated as China’s standard method.

Ultraviolet (UV) Absorption Spectrometry:

Measures ozone concentration by exploiting its strong UV absorption at specific wavelengths (e.g., 254 nm). UV light attenuation in an ozone-containing atmosphere is detected via photodetectors, followed by electronic signal processing (e.g., comparison circuits, data conversion) for quantitative output.

Advantages: Enables continuous online monitoring. Adopted as a standard method in industrialized nations like the U.S.

Disadvantages: High equipment cost, typically used by regulatory bodies, research institutions, or industrial facilities.

Electrochemical Sensing:

Relies on the electrochemical reduction of ozone at an activated electrode surface. The current generated in the electrochemical circuit correlates linearly with ozone concentration. Sensors with data output capabilities allow real-time measurements and closed-loop feedback control of ozone generators.

Advantages: More affordable than UV systems, compact design, suitable for large-scale water treatment applications.

Disadvantages: Limited to aqueous ozone detection.

Colorimetric Analysis:

A chemical method where ozone reacts with indicators (e.g., potassium iodide, o-tolidine, or indigo dye) to induce color changes or bleaching. Results are compared visually with standard color tubes/disks or measured via spectrophotometry.

Advantages: Simple, low-cost, and adaptable for field use in China.

Disadvantages: Consumable reagents generate waste.

Conclusion:

Each method offers distinct trade-offs between accuracy, cost, and complexity. Iodometric titration remains a low-cost benchmark, while UV spectrometry and electrochemical sensors cater to advanced industrial needs. Colorimetric methods provide a practical middle ground for routine applications.