This is a repository copy of Converting an intensity-based sensor to a ratiometric sensor: luminescence colour switching of an Ir/Eu dyad upon binding of a V-series chemical warfare agent simulant.
In the present study, new heterocyclic organic ligands were synthesized using amoxil drug as a starting material through multi steps. The ligands were prepared through condensation reaction to form thiazole and imidazole derivatives containing azo or anil groups in their structures via azotization reaction and imination reaction. The new ligands of amoxil have been characterized by means of spectral (IR and 1H NMR) and thermal analyses.
The organic pollutant methyl violet dye photocatalytic degradation has been investigated using the UV irradiation and TiO2 as a catalyst. The degradation process included the study of the initial dye concentration, light intensity, catalyst weight, the effect of intensity of light, and effect of temperature to approach the best conditions for the optimum photo-degradation efficiency of dye. The optimum photocatalytic degradation of methyl violet dye was at 0.15 g/100cm3 of dosage mass of TiO2 and 10 ppm of the dye. Photocatalytic degradation of methyl violet dye was at 9 mW/cm2light intensity. The percentage efficiency of degradation methyl violet dye equals 97.46%.
The new azo dye [4-(4-hydroxy-2-methylnaphthyl)diazenyl]benzoic acid was synthesized by the reaction of 2-methyl-1-naphthol with p-amino benzoic acid. The photcatalytic degradation of azo dye has been investigated by using zinc oxide and cadmium sulfide. This degradation was carried out by the irradiation of aqueous suspended solutions containing different concentrations of this dye using 0.11 g/100 mL of metal oxide (semiconductors) ZnO and CdS. A mercury lamp 125 W in a Pyrex photoreaction cell of 100 mL at room temperature was used as an irradiation source. The effect of the catalyst on the photocatalytic degradation of the prepared dye was studied via several experiments at different conditions, where they involve the effect of the catalyst mass and the effect of the dye concentrations. The irradiated solutions were studied using UV-Vis spectrophotometer. It has been the performance of photocatalytic system that using ZnO was observed to be better than cadmium sulfide system for degrade the azo compound from its aqueous solution.
KEY WORDS: Photocatalytic, Degradation, Semiconductors, Zinc oxide; Cadmium sulphide, Azo dye
Bull. Chem. Soc. Ethiop. 2020, 34(3), 463-469.
DOI: https://dx.doi.org/10.4314/bcse.v34i3.3
The effects of azo dyes, a severe water pollution source, on the ecosystem and public health have been widely studied, and more studies were made to remove these dyes from water using chemical, biological, electrochemical and physicochemical methods. This study relies on the photocatalytic degradation process as a clean method to clean water from azo dyes. The 4-((2-methyl-1-hydroxy naphthalene-1-yl) diazenyl) benzoic acid azo dye was used as a model dye in this study and prepared from a coupling reaction of p-aminobenzoic acid with 2-methylnaphthol. The photocatalytic degradation of this dye has been carried out using ZnO and modified ZnO. The dye removal was tested at various weights of ZnO and modified ZnO, different concentrations of the dye under constant light irradiation by using a 250 watts UV lamp. The results showed the dye removal by the modified (ZnO) was 92.4%, which is higher than the removal efficiency by the unmodified ZnO (87.51%). In conclusion, the results of this study showed that modified ZnO removes a high percentage of the dyes; therefore, it is recommended to use it to remove other common pollutants in the Iraqi rivers, such as phosphate and turbidity.
The photocatalytic degradation of azo dye 2-(2-naphthyl azo)-4,5-diphenyl imidazole was studied. Solutions of different concentrations of this dye using zinc oxide under UV irradiation. Different parameters were measured such as the catalyst amount, dye concentrations, light intensity and effect of pH. The optimum concentration of catalyst was 0.15 g/100 mL while the optimum concentration of dye was 50 ppm. It has been shown that the best pH to degrade monoazo dye 8.1 with 8.44 mW/cm 2 light intensity. The photocatalytic degradation of azo dye follows the first order reaction. In addition, photocatalytic degradation of the dye has been studied using different concentrations of aluminium oxide suspended in an aqueous solution of this dye irradiated by ultraviolet lamp in a vessel reactor at room temperature, with 10 cm 3 /min air bubble has been passed through the solution. In addition, when the dye concentration increased, the photocatalytic degradation efficiency of dye decreased to 83.54 %.
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