Dechlorination and decolorization of chloro-organics, in pulp bleach plant E-1 effluents, by advanced oxidation processes

摘要

Studies were conducted on the composition of chloro-organics in kraft-pulp bleach plant E-1 effluents and their response toward advanced oxidation processes, such as UV-, O-2/UV-, O-3/UV- and O-3-H2O2/UV-photolysis processes with irradiation of 254 nm photons. The studies were extended to ozonation and O-3-H2O2 oxidation systems in alkaline aqueous solution. The effects of process variables included initial pH, addition of oxidant to the UV-photolysis system on the decolorization and dechlorination of the chloro-organics the E-1 bleaching effluents were also studied. The decolorization and dechlorination rate constants are increased in the presence of molecular oxygen in the UV-photolysis systems, but are decreased on addition of hydrogen peroxide. The dechlorination rate constants are increased appreciably on oxidation with ozone alone and a combination of ozone and hydrogen peroxide as compared to those of the corresponding UV-photolysis systems under aerial atmosphere. (C) 2004 Elsevier Ltd. All rights reserved.