A Study of Treatment of Reactive Red 45 Dye by Advanced Oxidation Processes and Toxicity Evaluation Using Bioassays

Advanced oxidation processes (AOPs) hold great promise to degrade and detoxify industrial-based effluents. The Reactive Red 45 dye aqueous solutions were treated with AOP using UV and gamma radiation alone and then in the presence of H 2 O 2 . The dye initial concentration, UV exposure time, and gamma-ray absorbed dose were optimized for maximum degradation. The degradation of dye was 88.85% and 77.7% using UV/H 2 O 2 (1 mL/L) at a UV exposure time of 180 min for 50 mg/L and 100 mg/L, respectively. The degradation was noted as 100% and 93.82% as the solutions were subjected to a gamma/H 2 O 2 (1 mL/L) absorbed dose of 2 kGy. The chemical oxygen demand was reduced to 77% and 85% by treating the dye samples with UV/H 2 O 2 and gamma/H 2 O 2 , respectively. The removal efficiency (G-value), dose constant (k), D 0.50 , D 0.90 , and D 0.99 for gamma-irradiated samples were also calculated. The reduction in toxicity for treated samples was monitored by using the Allium cepa , Hemolytic, and brine shrimp ( Artemia salina ) tests while the Ames test was performed for mutagenic assessment. The A. cepa test showed 39.13%, 36.36%, and 47.82% increases in root length (RL), root count (RC), and mitotic index (MI), respectively, in UV/H 2 O 2 -treated samples while 48.78%, 48.14%, and 57.14% increases were shown with gamma-ray in conjunction with H 2 O 2 . The hemolytic test showed 21.25% and 23.21% hemolysis after UV/H 2 O 2 and gamma/H 2 O 2 treatments, respectively. The brine shrimp ( Artemia salina ) test showed 84.09% and 90.90% decreases in the nauplii death after UV/H 2 O 2 and gamma/H 2 O 2 treatments, respectively. The mutagenicity of UV/H 2 O 2 -treated solutions was reduced up to 84.41% and 77.87%, while it was 87.83% and 80.88% using gamma/H 2 O 2 using TA98 and TA100 bacterial strains, respectively. The advanced oxidation processes based on UV and gamma radiation in conjunction with H 2 O 2 can be applied for the degradation and detoxification of textile waste effluents efficiently.