Construction of RGO@N-ZnO nanocomposite photocatalyst for disinfection of microbes and dye degradation under visible light irradiation

• Published in: Journal of the Taiwan Institute of Chemical Engineers 2024-08, Vol.161, p.105510, Article 105510
• Main Authors: Suresh, M., Pravina, R., Shanmugavel, M., Sivasamy, A.
• Format: Article
• Language: English
• Subjects: Escherichia coli; Methylene blue dye; Photocatalytic disinfection; RGO@N-ZnO nanocomposite; Visible light irradiation
• ISSN: 1876-1070; 1876-1089
• DOI: 10.1016/j.jtice.2024.105510

•RGO@N-ZnO nanocomposite was synthesized by a Hummer's method followed by solvothermal method.•RGO@N-ZnO nanocomposite exhibits high specific surface area 141.2 m2 g−1.•Nanocomposite achieved over 99 % inactivation of E.coli, tannery waste water at 30 min of under visible light irradiation.•More the 95 % of Methylene Blue dye degradation at 45 min under visible light irradiation.•The RGO@N-ZnO nanocomposites manifest superior photocatalytic activity, cost effective and improved stability. Globally, water resources are becoming scarce, and there is an urgent need to develop sustainable and energy efficient methods of water and wastewater treatment, where photocatalysis is emerging as a promising method for water purification. Thus, the design of photocatalysts that is easy to recover, eco-friendly, cost-effective and reduce the environmental footprint. Present investigation, the RGO@N-ZnO nanocomposite photocatalyst was fabricated through the solvothermal method and it was characterized by various physio-chemical methods such as FE-SEM, RAMAN, HR-TEM, BET, EPR, EIS, PL and XPS etc., analyses. The photocatalytic activity of the photocatalyst was examined against Escherichia coli (E. coli), tannery wastewater and Methylene Blue (MB) dye degradation under visible light irradiation in a slurry photoreactor. The RGO@N-ZnO nanocomposite has a high specific surface area of 141.2 m2g−1. The results of electron spin resonance (ESR) spectra and free radicals trapping experimental studies confirmed that e−, •OH and •O2− radicals serve as the primary active species in photocatalytic disinfection. It has been observed that, after 30 min and 45 min of visible light irradiation, 100 mg/100 mL RGO@N-ZnO nanocomposite destroyed more than 99 % of E. coli present in the tannery wastewater and more than 95 % of Methylene Blue (MB) dye molecules were degraded. Reusability tests showed that, after four cycles of use RGO@N-ZnO retained more than 90 % of its photocatalytic activity with minimal loss. Thus, these findings manifest the RGO@N-ZnO nanocomposite is a potential photocatalyst due to its high photocatalytic efficiency, low-cost and is suitable for environmental remedial applications. [Display omitted]