Photodegradation of Direct Blue 1 azo dye by polymeric carbon nitride irradiated with accelerated electrons
Abstract:
Water bodies throughout the world are severely affected by the discharge of industrial effluents contaminated with xenobiotic and recalcitrant substances. Due to the low biodegradability of these compounds, conventional treatments have proven to be insufficient for their removal. Although heterogeneous photocatalysis poses an alternative for the treatment of these substances, the overall solar activity of conventional photocatalysts (such as TiO2) is very limited because of their wide bandgap. Thus, new photocatalysts such as graphitic carbon nitride (g-C3N4), which exhibits catalytic activity using longer wavelengths, are receiving increasing attention. In this work, g-C3N4 irradiated with a high-energy electron beam was investigated for the degradation of Direct Blue 1 azo dye. g-C3N4 was synthesized by pyrolysis of urea and irradiated at doses between 2.2 and 25.0 kGy for different times. The irradiated material was characterized by X-ray diffraction (XRD), electron spin resonance (ESR), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy and transmission electron microscopy (TEM), together with BET surface area measurements. The results showed that the irradiation of the catalyst improved its dye adsorption ability, and 5 kGy was found to be the optimum irradiation dose, increasing the maximum dye adsorption capacity of irradiated g-C3N4 to 73.76 mg/g. No significant differences in the pseudo first order kinetic model constants of the photocatalytic degradation of the dye were observed as a result of the irradiation treatment, perhaps due to the blocking of the active sites of the catalyst after the adsorption step, but a 1.4 times higher activity was attained for the irradiated sample upon H2O2 addition. The presence of H2O2 promoted the photocatalytic degradation process, reaching 99% dye removal in 40 min, and improved the reusability of the catalyst. The proposed modification of g-C3N4 holds promise to enhance its activity.
Año de publicación:
2019
Keywords:
- Electron beam irradiation
- Carbon nitride
- Direct Blue 1
- Heterogeneous photocatalysis
Fuente:
Tipo de documento:
Article
Estado:
Acceso restringido
Áreas de conocimiento:
- Ingeniería química
- Polímero
- Química ambiental
Áreas temáticas:
- Física moderna
- Tecnología de otros productos orgánicos
- Química física