水中臭氧浓度的检测及三种液体中臭氧的稳定性

为了研究臭氧在水中的衰减行为,采用靛蓝二磺酸钠法和碘化钾法测定水中的臭氧浓度.其中靛蓝二磺酸钠法,在pH值2.0条件下,48 h内空白的吸光度降低了3%,含样品溶液的吸光度降低了40%;在pH值6.8条件下分别降低了1%和2%;在pH值11.9条件下分别降低了83%和52%.该法测定水中臭氧含量的应用条件仍需研究.用碘化钾法测定时发现,蒸馏水中臭氧浓度变化的总体趋势是衰减的,臭氧浓度在曝气停止后大约42 min前后衰减速度不同,在42 min以前衰减较快,之后一直到3h内基本稳定;自来水和营养液中60 min内臭氧浓度变化的总趋势是稳定的,与蒸馏水中表现不同;3种液体中的臭氧浓度的高低顺序是蒸馏水中(约15 mg/L)>自来水中(约10 mg/L)>营养液中(约3 mg/L).

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)