Synthesis and Characterization of Graphitic Carbon Nitride for the Removal of Methylene Blue Dye from Wastewater
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Date
2021-10-30
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Addis Ababa University
Abstract
Graphitic carbon nitride (g-C3N4) has received much attention for its potential application in pollutant degradation due to its unique optical and physicochemical properties. Various technologies have been developed to remove pollutants, but efficient and economical wastewater treatment remains a challenge in terms of energy and treatment costs. Herein, a visible-light active and robust semiconductor, g-C3N4 was synthesized from low-cost precursors like urea using pyrolysis at 500 ºC and 550 ºC. Herein, the as-synthesized material was characterized by UV-vis spectrophotometer to show the catalyst optical characteristics and can consider the best reaction temperature to obtain graphitic carbon nitride with maximum visible light response. Likewise, Fourier transform infrared spectroscopic (FT-IR) analysis was required to confirm the structure and the presence of C=N or functional groups. Sample morphology and structure were characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm analysis, X-ray diffraction (XRD). In this research important photocatalytic degradation procedure, the factors that affect the efficiency of photocatalytic degradation of organic pollutants, and the effects of different reaction parameters are highlighted. The photo-catalytic degradation of methylene blue (MB) was evaluated under visible light irradiation. As prepared sample having a specific surface area of 54.9 m2/g, the photo-catalytic activity under visible light irradiation performed and it takes 120 min for 96% degradation methylene blue. The Freundlich and Langmuir adsorption models were used to elucidate the adsorption efficiency of g-C3N4. The kinetic data depicts the pseudo first, second, and inter-particle diffusion model. Adsorption and kinetic isotherm showed that the adsorption process could be well described by pseudo-first -order kinetic model, with an adsorption capacity of 552 mg MB per gram adsorbent determined by Langmuir isotherm. These results provide some idea for the design and development of g-C3N4-based high activity photo catalysts, which is an effective strategy for organic pollutants degradation and solar energy conversion.
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Graphitic Carbon Nitride, Photocatalyst, Pollutant Degradation, Adsorption Isotherm, Kinetics