Mutagenic activity removal of selected disperse dye by photoeletrocatalytic treatment

The degradation of black dye commercial product (BDCP) composed of C.I. Disperse Blue 373, C.I. Disperse Orange 37, C.I. Disperse Violet 93 dyes was investigated by photoelectrocatalysis process. The dyes have shown high mutagenic activity with Salmonella strain YG1041 and TA98 with and without S9. Samples of BCPD dye submitted to conventional chlorination and photoelectrocatalytic oxidation were compared monitoring its products by HPLC using a diode array detector, spectrophotometry UV–vis, TOC removal, and mutagenicity potency. The photoelectrocatalytic method operating with Ti/TiO₂ as anode at +1.0 V and UV illumination presented fast oxidation of test solutions containing 10 mg L⁻¹ of dye in 0.1 mol L⁻¹ NaCl pH 4.0 leading to 100% of discoloration, 67% of mineralization, and negative response to all tested Salmonella strains. The formation of Cl^•, CL₂ ^• on photoelectrocatalytic medium improved the efficiency of the method in relation to conventional chlorination method that promoted 100% of discoloration, but only 8% of TOC removal and more mutagenic product.