使用环保合成的rGO@ZnO纳米复合材料增强亚甲基蓝染料的光催化降解

Enhanced photocatalytic degradation of methylene blue dye using eco-friendly synthesized rGO@ZnO nanocomposites.

作者信息

Negash Asfaw, Mohammed Said, Weldekirstos Hulugirgesh Degefu, Ambaye Abera D, Gashu Minbale

机构信息

Department of Chemistry, Debre Berhan University, P.O. Box 445, Debre Berhan, Ethiopia.

Institute for Nanotechnology and Water Sustainability, University of South Africa, Florida Science Campus, Johannesburg, 1710, South Africa.

出版信息

Sci Rep. 2023 Dec 14;13(1):22234. doi: 10.1038/s41598-023-48826-7.

Industrial chemical pollutants such as methylene blue (MB) dye are released into the water body and potentially cause harm to the human and aquatic biosphere. Therefore, this study aims to synthesize eco-friendly nanocatalysts, i.e., reduced graphene oxide (rGO), zinc oxide (ZnO), and reduced graphene oxide-zinc oxide (rGO@ZnO) nanocomposites, for efficient photocatalytic degradation of MB dye. A graphite rod was obtained from waste dry cell batteries for the electrochemical exfoliation synthesis of graphene oxide (GO) and rGO. For the eco-friendly synthesis of ZnO and rGO@ZnO nanocatalysts, Croton macrostachyus leaf extract was used as a reducing and capping agent. The synthesized nanocatalysts were characterized using a UV-Vis spectrophotometer, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy with energy-dispersive X-ray. The eco-friendly synthesized rGO, ZnO, and rGO@ZnO nanocatalysts were applied for the photocatalytic degradation of MB dye using direct sunlight irradiation. At optimum parameters, photocatalytic degradation of MB dye efficiency reached up to 66%, 96.5%, and 99.0%, respectively. Furthermore, kinetics of the photodegradation reaction based on rGO, ZnO, and rGO@ZnO nanocatalysts follow pseudo-first-order with a rate constant of 2.16 × 10 min, 4.97 × 10 min, and 5.03 × 10 min, respectively. Lastly, this study promotes a low catalyst load (20 mg) for the efficient photodegradation of MB dye.

亚甲基蓝（MB）染料等工业化学污染物被排放到水体中，可能会对人类和水生生物群落造成危害。因此，本研究旨在合成环保型纳米催化剂，即还原氧化石墨烯（rGO）、氧化锌（ZnO）和还原氧化石墨烯-氧化锌（rGO@ZnO）纳米复合材料，用于高效光催化降解MB染料。从废旧干电池中获取石墨棒，用于电化学剥离合成氧化石墨烯（GO）和rGO。为了环保合成ZnO和rGO@ZnO纳米催化剂，使用巴豆叶提取物作为还原剂和封端剂。使用紫外-可见分光光度计、傅里叶变换红外光谱、X射线衍射以及带有能量色散X射线的扫描电子显微镜对合成的纳米催化剂进行表征。将环保合成的rGO、ZnO和rGO@ZnO纳米催化剂应用于直接阳光照射下的MB染料光催化降解。在最佳参数下，MB染料的光催化降解效率分别达到66%、96.5%和99.0%。此外，基于rGO、ZnO和rGO@ZnO纳米催化剂的光降解反应动力学遵循准一级反应，速率常数分别为2.16×10⁻³ min⁻¹、4.97×10⁻³ min⁻¹和5.03×10⁻³ min⁻¹。最后，本研究促进了低催化剂负载量（20 mg）对MB染料的高效光降解。