Absorbance Of Dye Solution Research Articles

Green synthesized silver nanoparticles: Characterization, phytostimulatory impacts, and degradation potential for organic pollutants

Green synthesis of nanoparticles using plants is one of the most convenient, economical, and eco-friendly methods nowadays. Moreover, green synthesized silver nanoparticles (AgNPs) have gained interest due to their possible uses in agriculture and the environmental field. The present study focused on the biological synthesis of AgNPs using Triticum aestivum and Zea mays, their characterization, and their phytostimulatory impact and remediation potential for organic pollutants. Three different types of AgNPs treatments were prepared, T1 was synthesized by using Triticum aestivum, T2, by using Zea mays, and T3 was a mixture of both types of nanoparticles. T1 analyzed via EDX showed the presence of 44% of Ag0 and T2 showed 66% of Ag0 present in dried pellets extracted after synthesis. At 40 μg mL−1 of T1, T2, and T3 applied on methylene blue, 43.3, 47.4, and 49.7% decrease in absorbance of dye solution was recorded, respectively. Paper samples treated with Brevundimonas diminuta showed 40% more degradation than Bacillus tropicus. At 40 μg mL−1 of T1 and T2 and 30 μg mL−1 of T3 142.8, 71.4 and 33.2% higher degradation was recorded against paper, compared to Brevundimonas diminuta. At 20 μg mL−1 of T1, T2, and T3 wheat plants showed ≈17.7, 24.6, and 23.9% increase in plant growth, respectively. Similarly, 79.2, 142 and 34.4% increase in chlorophyll content, 26.5, 65.3 and 38.7% increase in protein content was also found by T1, T2, and T3 respectively. Corn plants showed 16.9, 26.1, and 12.3% increases in plant growth, 79, 151.6, and 196.7% increases in chlorophyll content, 118, 185, and 114.7% increase in protein content by T1 and T2. In conclusion, AgNPs showed a significant increase in plant growth and biochemical parameters of corn and wheat and appeared to act as potential remediating agents for organic pollutants.

Additive SnO<sub>2</sub>-ZnO Composite Films for Photocatalytic Degradation Efficiency of Organic Dye

SnO2-ZnO composite films were employed as photocatalytic degradation of organic dye. SnO2 and ZnO were mixed in polyethylene glycol solution with various weight ratios of SnO2. The composite paste was screened onto glass substrate with active area of 1 cm2 and annealed at 400 °C. The photocatalytic activity of composite films for the degradation of Eosin-Y dye was investigated under UV light irradiation. It was found that the normalized absorbance of dye solution decreased after treatment indicated that dye molecules were reduced. The composite films showed better degradation efficiency than conventional ZnO films due to reduced recombination encourage longer reaction time of electron and hole with surrounded environment. The optimized weight ratio of 30% showed the highest degradation rate constant and the lowest half lift.

Storage Stability and Color Reproducibility of Yellow and Red Dyes Extracted from Carthamus tinctorius L.

The stability of yellow and red dyes prepared from safflower (Carthamus tinctorius L.) in aqueous solution and in solid state was investigated. External factors such as light irradiation and temperature on the stability were examined during storage. Changes in absorbance of dye solutions and the color changes of fabrics dyed after long time storage were measured. Also, color reproducibility during storage was investigated by dyeing test on various fabrics. Red colorant in aqueous solution was very unstable to light, resulting that about 40% of absorbance were lost in 12hrs. The absorbance of yellow dye solutions was not decreased within 84hrs. In aqueous medium, yellow dye was much more stable than carthamin. Both dyes are relatively stable for long storage when they are stored in solid state compared to when in aqueous solution. Color changes are marginal in both dyes.

The Fenton Chemistry and Its Combination with Coagulation for Treatment of Dye Solutions

Aqueous solutions of Acid Blue 74, Acid Orange 10, and Acid Violet 19 were subjected to Fenton/Fenton‐like oxidation and its combination with lime coagulation. The analysis indicated no dependence of chemical oxidation efficacy on dye concentration in the range of 0.1–1 g L−1. Complete or nearly complete (higher than 95%) color removal of all treated samples was observed. Dye:H2O2 weight ratio of 1∶2 proved optimal for treatment of all dye solutions by means of Fenton/Fenton‐like oxidation. Moderate doses of hydrogen peroxide led to the improvement of biodegradability of dye solutions. No formation of any toxic intermediates during the oxidation of Acid Orange 10 and Acid Violet 19 was detected. Only a slight toxicity increase was observed after Acid Blue 74 degradation by Fenton chemistry. H2O2/Fe3+ system with pH adjusted to 3 proved the most effective oxidation process. The combination of Fenton chemistry and subsequent lime coagulation was the most feasible treatment method of removing COD and UV254 and UVmax absorbance of dye solutions. Combined oxidation and coagulation was more effective for Acid Blue 74 and Acid Orange 10 elimination than for Acid Violet 19.