Decoloration and mineralization of aqueous solution of cationic (basic) dye Astrazon Black FDL by using gamma rays

Abstract

Abstract Degree of decolorization due to the irradiation of aqueous solutions of commercial cationic (basic) Astrazon Black FDL textile dye was studied in this study. Factor effecting radiolysis of the dye such as dye concentration, absorbed dose, toxicity, COD, BOD5 and pH of solutions were studied at air, O2 saturated and H2O2 environments. Unirradiated Astrazon Black FDL was non-biodegradable, whereas it was biodegradable after irradiation. The biodegradability (BOD5/COD) increased at 2 kGy for Astrazon Black FDL in all solutions. The biorefractory organic compounds were converted into more easily biodegradable compounds having lower molecular weights. In optimum dose and pH determination experiments, 5 kGy pH 12 at air, 7 kGy pH 3 at O2 saturated, 9 kGy pH 3 at 2.6 mM H2O2 for Astrazon Black FDL were found as the optimum irradiation conditions. Toxicity level of unirradiated solutions was high, whereas toxicity level of irradiated solutions was lower.