二氧化氯消毒后给水管网中氯酸根和亚氯酸根的转化规律研究

Study on the transformation law of chlorite and chlorate in water supply network after chlorine dioxide disinfection

目的研究给水管网中氯酸根和亚氯酸根的转化规律,为控制二氧化氯消毒副产物提供依据。方法采用离子色谱法检测水中氯酸根和亚氯酸根在pH值、温度、TOC浓度、二氧化氯残留浓度、管材和铁的存在条件下的含量变化。结果亚氯酸根在不同pH值、温度、TOC条件下均能稳定存在,而其浓度与二氧化氯残留浓度呈正相关,在铸铁材质中亚氯酸根转化后浓度为1.47mg/L,转化率为2.0%;在钢管中亚氯酸根转化后浓度为1.49mg/L,转化率为0.7%,其转化最先由二价铁离子和零价铁引起,而氯酸根在所研究条件下均能够稳定存在。结论给水管网中亚氯酸根能与铁及亚铁离子反应转化为氯离子,而氯酸根能在水中稳定存在。

Objective To provide a basis for controlling chlorine dioxide disinfection byproducts,the transformation of chlorite and chlorite in the water pipe network was studied.Method The concentration change of chlorate and chlorite in water under the condition of pH,temperature ,TOC concentration,chlorine dioxide residue concentration,pipe and iron was detected by ion chromatography.Results Under the condition of the variation of pH,temperature and TOC,the concentration of chlorite was stable.And the concentration of chlorite was positively correlated with the residual concentration of chlorine dioxide.The concentration of chlorite in cast iron was 1.47 mg/L and the conversion rate was 2.0%,the concentration of chlorate was 1.49 mg/L and the conversion rate was 0.7% in steel pipe.Thus,we induced that the conversion was first caused by ferric ions and zero -valent iron and chlorate could exist stably under the conditions studied.Conclusion In the water supply pipe network,chlorite can react with iron and ferrous ions and be converted into chloride ions,while chlorate can be stable in water.