Bleaching and photodegradation of textile dyes by H2O2 and solar or ultraviolet radiation

The photooxidation of textile dyes Yellow Procion H-4R, Bright Blue Remazol (blue reagent-19), Red Procion H-E7B, and the mixture of the two last dyes were investigated. The efficiency of photooxidation were compared using hydrogen peroxide (30%) as a bleaching reagent, solar and ultraviolet radiation, common glass borosilicate, quartz assay tubes, and no solid catalysts. The colour of blue dye and a mixture of blue and red dyes were almost completely removed after 3 h, either by solar or ultraviolet radiation. The best results of colour removal (93%) for the red and yellow dyestuffs were obtained only after 6 h, using quartz tubes, hydrogen peroxide and ultraviolet radiation. Using non-parametrical statistical tests (chi(2)), the treatment showed significant differences among the processes investigated (P < 0.01). (C) 2004 Published by Elsevier Ltd.