Application of natural dyes has increased interest in the past few years due to the eco-friendly behavior of these dyes. The present research is concerned with the effect of UV on dyeing behavior of cotton using marigold as source of natural Lutein dye. This is colorant lutein which imparts greenish yellow color to cotton fabric. The dye powder and cotton fabric were exposed to UV-radiation for different time intervals prior to dyeing and dyeing was performed at different dyeing variables. International Standard Organization (ISO) methods were employed to evaluate the color fastness properties, such as color fastness to light, washing and rubbing. It is found that 90 min exposure of UV radiations was the optimum condition for surface modification and dyeing of 70 min at 40°C give excellent results using 4 g/L salt to achieve maximum exhaustion. For improvement of color fastness, tannic acid (8%) as pre- and 6% as post-mordant is the best condition. It is found that UV ray treatment can be used to other fabrics followed by dyeing using extracts of dye yielding plants without any physical characteristics damage.

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 H₂O₂. 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/H₂O₂ (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/H₂O₂ (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/H₂O₂ and gamma/H₂O₂, 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/H₂O₂-treated samples while 48.78%, 48.14%, and 57.14% increases were shown with gamma-ray in conjunction with H₂O₂. The hemolytic test showed 21.25% and 23.21% hemolysis after UV/H₂O₂ and gamma/H₂O₂ treatments, respectively. The brine shrimp (Artemia salina) test showed 84.09% and 90.90% decreases in the nauplii death after UV/H₂O₂ and gamma/H₂O₂ treatments, respectively. The mutagenicity of UV/H₂O₂-treated solutions was reduced up to 84.41% and 77.87%, while it was 87.83% and 80.88% using gamma/H₂O₂ using TA98 and TA100 bacterial strains, respectively. The advanced oxidation processes based on UV and gamma radiation in conjunction with H₂O₂ can be applied for the degradation and detoxification of textile waste effluents efficiently.

Advanced oxidation processes (AOPs) have emerged as a promising approach for the removal of organic dyes from effluents. Different AOPs were employed for the degradation of Reactive Yellow 160A (RY-160A) dye, i.e., SnO₂/UV/H₂O₂ and TiO₂/UV/H₂O₂. In the case of UV treatment, maximum degradation of 28% was observed, while UV/H₂O₂ furnished 77.78% degradation, and UV/H₂O₂/TiO₂ degraded the RY-160A dye up to 90.40% (RY-160A 30 mg/L, 0.8 mL of H₂O₂). The dye degradation was 82.66% in the case of UV/H₂O₂/SnO₂ at pH 3. FTIR and LC-MS analyses were performed in order to monitor the degradation by-products. The cytotoxicity and mutagenicity of RY-160A dye were evaluated by hemolytic and Ames (TA98 and TA100 strains) assays. It was observed that the RY-160A dye solution was toxic before treatment, and toxicity was reduced significantly after treatment. Results indicated that UV/H₂O₂/TiO₂ is more efficient at degrading RY-160A versus other AOPs, which have potential application for the remediation of dyes in textile effluents.

The dye-contaminated industrial effluent causes serious health issues when it gets mixed with underground water without primary treatment. The current project was designed to treat reactive blue-19 dye aqueous solutions in the presence of hydrogen peroxide (H ₂ O ₂ ) and titanium dioxide (TiO ₂ ) under UV-LED light. The characterization of the photocatalyst was carried out via X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) for structure, purity, and surface study. The effect of various factors such as pH, TiO ₂ dose, UV-LED light exposure time, H ₂ O ₂ , and dye concentration, on the degradation rate and cytotoxicity reduction was evaluated and optimized through the Response Surface Methodology (RSM). The maximum degradation of dye solution and chemical oxygen demand (COD) reduction was achieved at 98.81 and 86.22 %, respectively for 50 ppm solution, using UV-LED/H ₂ O ₂ (3 %)/TiO ₂ (6 g/L) hybrid process. The toxicity evaluation through the Allium cepa test demonstrated a 62.40, 65.2, and 56.97 % increase in root length (RL), root count (RC), and mitotic index (MI), respectively, following treatment with the UV-LED/H₂O₂/TiO₂ combined process for 150 min. The hemolytic and brine shrimp tests revealed a reduction in toxicity up to 92.18 and 84.08 %, respectively, after applying the same treatment. Additionally, the Ames test indicated up to 80.94 % reduction in mutagenicity for TA98 and an 84.04 % reduction for TA100 strain when dye samples were treated with UV-LED light in the presence of H₂O₂ and TiO₂ for 150 min. The findings suggested that UV-LED light in conjunction with H ₂ O ₂ and TiO ₂ can be a useful tool for the degradation and detoxification of toxic pollutants found in textile wastewater.