Copper–ligand complex for the decolorization of synthetic dyes

The reaction system containing Cu(II), hydrogen peroxide and D-arabinono-1,4-lactone was found to be effective in the decolorization and reduction of toxicity of azo, thiazine-, triphenylmethane- and anthraquinone-based synthetic dyes. More than 85% decolorization was obtained with 100 ppm Acridine Orange, Azure B, Chicago Sky Blue 6B, Crystal Violet, Evans Blue, Poly B-411, Reactive Blue 2, Reactive Blue 5, and Remazol Brilliant Blue R incubated for 24 h in the presence of 10 mM CuSO4, 20 mM D-arabinono-1,4-lactone and 80 mM H2O2. The rate of decolorization was not affected by pH in the range of 3–9. The rapid decolorization was accompanied by a fast decomposition of H2O2 in the reaction mixture and by a fast production of hydroxyl radicals.