Investigation On The Removal Of Disinfection By-products Precursor By TiO₂ Films Catalyzed Ozonation

In recent years, because of industrial, agricultural and urban pollution, the quality of drinking water sources is becoming worse and worse. Though conventional water treatment has played an important role in past years, it is now found ill-fited because of increasing malformagens, mutagens and carcinogens in chlorinated water, which are harmful to people. So how to reduce disinfection by-products (DBPs) has been greatly concerned. Various organic matter existing in the original water, including natural organic matter (NOM) (for example humic acid, HA) and contaminated organic matter, can produce the DBPs by chlorination. Therefore, it is an effective way to control DBPs in the drinking water by reducing DBPs precursor from source, which is removing the organic matter in the original water with most greatly possible.In this text, we discussed the effectiveness and mechanism of TiO₂/O₃ catalytic oxidation technique in removing DBPs precursor (on behalf of the HA). The resoults showed that the TiO₂ film has high catalytic activity on ozonation of DBPs precursor with removal rates increasing 28.8% at reaction time of 25min. And the TiO₂ films used for 8 times with no significant change of its activity, the catalyst has good stability. The catalysis follows a hydroxyl radical pathway that it was deduced from the effect of Na₂CO₃ on the reaction of catalytic activity .And the removal rates of DBPs precursor effected by films number, calcination temperature, ozone flow, reaction time, pH, initial concentration etc. Analyzed by the orthogonal test, the most important factor is reaction time and pH on the DBPs precursor removing, the follows are calcination temperature, initial concentration, films number and ozone flow. The optimal test program was A3B4C3D5E4F1, which the films number is six, the calcination temperature is 700℃, ozone flow is 9.3g/h, pH is 10, reaction time at 25min and the initial concentration is 10mg/L, and the removal rates of DBPs precursor up to 94.2%.The research work above is creative because there is no same work reported publicly until today. The conclusions of the work can give a new way for removing dissolved HAs and controlling DBPs, and also play a foundation in theory for the further research work.