关键词: 复合二氧化氯, 有效氯, 消毒副产物, 氯酸盐

Abstract: This paper studies the reaction between NaClO₃ and hydrochloric acid and investigates the effects of reaction temperature and reaction time on the compound chlorine dioxide and its chlorate disinfection byproducts. Findings:The compound chlorine dioxide produced through the reaction of NaClO₃ and hydrochloric acid does not produce chlorate in the process of disinfection of drinking water. The running water that is disinfected by the use of compound chlorine dioxide is detected to have chlorate disinfection by-products which are derived from the NaClO₃ that misses complete reaction in the reaction residual liquid. The residual amount of incompletely reacted NaClO₃ is the main factor affecting the chlorate content in disinfectant water, which decreases with the increase of reaction temperature or lengthening of the reaction time. The reaction residue enters the water body with ClO₂ and Cl₂. When the concentration of available chlorine was 2mg/L, the reaction temperature was 20℃ and the reaction time was 10min, the content of NaClO₃ in the disinfectant water was higher than 0.7mg/L of the national standard. When the reaction temperature was 20℃, and the reaction time was 30min and above, or the reaction temperature was 30℃ and above, the content of NaClO₃ in the disinfectant water was lower than 0.7mg/L of the national standard. When the reaction temperature was 90℃, and the reaction time was 70min, the content of NaClO₃ in the disinfectant water was the lowest, that was 0.019mg/L.

Key words: compound chlorine dioxide, available chlorine, disinfection by-product, chlorate