Influence of the Mixed Disinfectant of ClO2 and Cl2 on Formation of Chloroform
ClO2和Cl2混合消毒剂对氯仿形成的影响

The study on influence of mixed solution of ClO2 and Cl2 on formation of chloroform from 9 THMs precursors, such as fulvic acid (FA), resorcinol, phloroglucinol and cresorcinol etc. under conditions of different ClO2/Cl2 ratio, content of precursors, reaction pH, reaction time and reaction temperature etc. was studied. Results showed that as the mass percentage of ClO2 in the mixed disinfectant was increased, the amount of chloroform formed was reduced; such as when mass percentages of ClO2 were 25%, 50% and 75%, CHCl3 formed reduced 55%-65%, 70%-86% and 80%-93% respectively; until ClO2 was 90%, reduction of CHCl3 reached 95%-99%. In order to control the formation of chloroform thoroughly, mass percentage of ClO2 must be higher than 90%. This provided important scientific base for the necessity of using highly pure ClO2 in disinfection and developing generator which produced high quality ClO2.