In this study, the effect of molecular weights (MWs) on mineralization, energy consumption, kinetic reaction, and trihalomethane formation potential (THMFP) of humic acid was evaluated by the process of H2O2/UV oxidation. Three ranges of MWs of 100 k-10 kDa (sample A), 10 k-1 kDa (sample B), and less than 1 kDa (sample C) were investigated. The results showed that the reaction constant k increased with either increased UV intensity or increased H2O2 dose; the order of k was kA > kB > kC, for all UV intensities from 16 to 64 W and H2O2 dose from 25 to 100 mg L(-1). In terms of EEO and EEM, the energy consumption decreased as the H2O2 dose increased with the descending order of sample C > sample B > sample A. The three samples had an initial dissolved organic carbon (DOC) of 20 mg L(-1) with the related values of THMFP of 325, 359, and 468 μg L(-1) for samples A, B, and C, respectively. After H2O2/UV oxidation, the combination of a higher UV power with a shorter time was a better treatment condition for samples A and B as residual DOC and THMFP were smaller.
Keywords: Energy consumption; H2O2/UV; THMFP; humic acid; molecular weight.