Degradation of iodinated disinfection by-products in water by UV, UV/H2O2 and UV/persulfate treatment
Date of Issue2017-03-06
School of Civil and Environmental Engineering
Iodinated trihalomethanes (I-THMs) and iodoacids could be formed as iodinated disinfection by-products (I-DBPs) during water treatment and water reclamation processes. To develop a cost-effective strategy for post-formation mitigation of I-DBPs, the degradation of I-THMs and iodoacids in water by UV254, UV/H2O2, and UV/PS (persulfate) processes was extensively investigated in this study. The effect of pH, and/or oxidant dose, matrix species, and different types of water on the degradation kinetics of I-DBPs in the UV254, UV/H2O2, and UV/PS processes was examined. A quantitative structure-reactivity relationship (QSAR) model for direct photolysis of I-DBPs was established to correlate the chemical activities with molecular structures. A steady-state kinetic model was developed to predict the degradation rate of I-THMs in the UV/H2O2 process. Using probe compounds, the respective contribution of UV, SO4∙‒ and HO∙ for iodoacid removal in the UV/PS process were quantitatively determined. Photodegradation end by-products for each process were also identified. Total cost of electrical energy and oxidant was calculated to evaluate the energy efficiencies of UV, UV/H2O2, and UV/PS processes for I-DBPs removal.