Treatment of Textile Industrial Dyes by Simple Ozonation with Water Recirculation

In this study, three textile dyes are destroyed by ozone in water solution. These dyes were selected because of their complex chemical structure and extended application in textile industry. Decomposition of dyes by simple ozonation was observed at the ini- tial pH of the aqueous colorants solutions UV-VIS analysis was used for preliminary control of the degree of decomposition. HPLC analy- sis was used to identify intermediates and final products formed dur- ing ozonation. It was shown that color disappears completely for all dyes after 1.5 - 2 min of ozonation. The pre-ozonated water was used for the preparation of colorant solutions until 8 times. The dyeing quality (using pretreated solutions) was determined by the standard AATCC method. In the water pre-ozonation byproducts accumulation was observed, but their presence in the solution did not affect the color quality. The ozonation of dyes solutions has not any influence on the coloration quality in 6 times water recirculation for DR28 and BG4, and in 8 times water recirculation for RB5. After several times of water recirculation ozonation procedure was conducted during 20 min to destroy intermediates. Dyes are completely destroyed in ozonation with the formation of final products (malonic and oxalic acids).