DEGRADATION OF TRIETHANOLAMINE AND CHEMICAL OXYGEN-DEMAND REDUCTION IN WASTE-WATER BY PHOTOACTIVATED PERIODATE

The rapid reduction of chemical oxygen demand (COD) of industrial wast ewater is achieved using a novel oxidant, periodate (IO4-), coupled wi th ultraviolet (UV) irradiation. The wastewater is characterized by a high COD, low total suspended solids, variable triethanolamine (TEA) c oncentrations, and low concentrations of iron and zinc. The use of per iodate and UV irradiation with either aqueous TEA solutions or real wa stewater is shown to be effective in reducing the COD to acceptable le vels. The optimal pH for COD degradation is determined to be 7.6 becau se of the combined effects of pH on the speciation of TEA and IO4-. In creasing the ratio of the initial concentrations of periodate to TEA, [IO4-](0)/[TEA](0), increased the degradation rare up to an apparent s aturation value. Irradiation with a 1 000-W mercury-xenon lamp increas ed the COD pseudo-first-order degradation rare constant by a factor of 5.5 for synthetic TEA solutions and 2.3 for industrial wastewater. co mpared to irradiation with a 1 000-W xenon lamp.