Removal of Dimethylamine by Ozone Combined with Hydrogen Peroxide (O3/H2O2)

Ozonation of dimethylamine (DMA), the most direct and common precursor of high carcinogenic disinfection by-product N-nitrosodimethylamine (NDMA), in aqueous solutions and in the presence of H2O2 was studied at ozone doses of 1.8mg/L. The removal ratio of DMA increases from 46.7% to 77.1% with the dosage of H2O2 increasing from 0 to 1mM, and the removal rate can be improved by increasing pH. According to the results of H2O2 addition time experiments, hydroxyl radicals might play important roles in the destruction of DMA during combined oxidation process. With the treatment of O-3/H2O2 for 24h (containing 0.5mM DMA), the yield of NDMA formation was below our detection limit (0.1 mu g/L) and the yield of NDMA formation after chloramination (24h) of DMA containing water could be reduced by 90%.