Factors on the formation of disinfection by-products MX, DCA and TCA by chlorination of fulvic acid from lake sediments.

[3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone] (MX) and chlorinated acetic acids such as dichlorinated acetic acid (DCA) and trichlorinated acetic acid (TCA) have always been the focus of disinfection by-products (DBPs) studies. In order to find out the influences of reaction time, TOC, chlorine dose, pH and temperature on the formation of MX, DCA and TCA, we extracted fulvic acid (FA) from the sediment of Tai Lake, and conducted simulated chlorination of samples rich in FA. Results showed positive relationship between TOC and the yields of MX, DCA and TCA. But the influences of pH, chlorine dose, reaction time, and temperature are quite complex. The optimal chlorination condition for the formation of MX is pH = 2, T = 45 degrees C, C/Cl2 = 1/4, t = 12 h. Lower pH, longer time, greater chlorine dose can result in greater yield of both DCA and TCA, and there is a strong linear relationship between the formation of DCA and TCA.