Measurement of ozone concentration in water and stability of ozone in three liquids

To study the attenuation behavior of ozone in water, two methods were used to measure ozone concentration in water, indigo disulphonate spectrophotometry (IDS)and iodine titration method(ITM). The results of IDS were: when pH 2.0, the absorbency of black dropped by 3%, the absorbency of sample dropped by 40%; at pH 6.8, dropped by 1% and by 2%, respectively; at pH 11.9, dropped by 83% and by 52%, respectively; this implied that condition of this method used to measure the ozone concentration in water needed to be studied further. The results of ITM were: the trend of the ozone concentration in distilled water was declining, and its speed before and after 15～42 min after ozonation was different; the trend of the ozone concentration in tap water and nutrition solution was steady, which was different with distilled water; The ozone concentration was: about 3 mg/L(in nutrition solution)