Degradation of reactive dyes - I. A comparative study of ozonation, enzymatic and photochemical processes

The environmental problems associated with textile activities are represent ed mainly by the extensive use of organic dyes. A great number of these com pounds are recalcitrant and shown carcinogenic or mutagenic character. In t his work three processes were studied for degradation of an anthraquinone d ye (C.I. reactive blue-19). The ozonation process leads to complete decolor ization with a very short reaction time; however, effective mineralization of the dye was not observed. The enzymatic process promotes quick decoloriz ation of the dye; nevertheless, maximum decolorization degrees of about 30% are insignificant in relation to the decolorization degree achieved by the other processes. The best results were found for the photocatalytical proc ess. The use of ZnO or TiO2 as photocatalysts, permits total decolorization and mineralization of the dye with reaction times of about 60 min. (C) 199 8 Elsevier Science Ltd. All rights reserved.